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Sample records for silicone rubber sheet

  1. Research and Application Progress of Silicone Rubber Materials in Aviation

    Directory of Open Access Journals (Sweden)

    HUANG Yanhua

    2016-06-01

    Full Text Available The research progress of heat resistance, cold resistance, electrical conductivity and damping properties of aviation silicone rubber were reviewed in this article. The heat resistance properties of silicone rubber can be enhanced by changing the molecular structure (main chain, end-group, side chain and molecular weight of the gum and adding special heat-resistance filler. The cold resistance of aviation silicone rubber can be enhanced by adjusting the side chain molecular structure of the gum and the content of different gum chain. The electrical conductivity of silicone rubber can be improved by optimizing, blending and dispersing of conductive particles. The damping property of silicone rubber can be improved by designing and synthesizing of high-molecular polysiloxane damping agent. Furthermore, the application of aviation silicone rubber used in high-low temperature seal, electrical conduction and vibration damping technology are also summarized, and the high performance (for example long-term high temperature resistance, ultralow temperature resistance, high electromagnetic shelding, long-term fatigue resistance vibration damping, quasi constant modulus and so on of special silicone rubber is the future direction of aviation silicone rubber.

  2. Hardness measurements of silicon rubber and polyurethane rubber cured by ionizing radiation

    International Nuclear Information System (INIS)

    Basfar, A.A.

    1995-01-01

    This work investigates the hardness of both silicon rubber and polyurethane rubber cured by ionizing radiation. Shore A Hardness is used to characterize the subject elastomers in relation to the crosslinking process. Various formulations of both materials have been investigated in order to achieve the optimum cure conditions desired. A small amount of the curing agent has been incorporated in some formulations in order to reduce the required dose to achieve full cure conditions. Silicon rubber has shown improvements in hardness as absorbed dose is increased, whereas hardness remained constant over a range of absorbed doses for polyurethane rubber

  3. RTV Silicone Rubber Degradation Induced by Temperature Cycling

    Directory of Open Access Journals (Sweden)

    Xishan Wen

    2017-07-01

    Full Text Available Room temperature vulcanized (RTV silicone rubber is extensively used in power system due to its hydrophobicity and hydrophobicity transfer ability. Temperature has been proven to markedly affect the performance of silicone rubbers. This research investigated the degradation of RTV silicone rubber under temperature cycling treatment. Hydrophobicity and its transfer ability, hardness, functional groups, microscopic appearance, and thermal stability were analyzed using the static contact angle method, a Shore A durometer, Fourier transform infrared spectroscopy (FTIR, scanning electron microscopy (SEM, and thermogravimetry (TG, respectively. Some significant conclusions were drawn. After the temperature was cycled between −25 °C and 70 °C, the hydrophobicity changed modestly, but its transfer ability changed remarkably, which may result from the competition between the formation of more channels for the transfer of low molecular weight (LMW silicone fluid and the reduction of LMW silicone fluid in the bulk. A hardness analysis and FTIR analysis demonstrated that further cross-linking reactions occurred during the treatment. SEM images showed the changes in roughness of the RTV silicone rubber surfaces. TG analysis also demonstrated the degradation of RTV silicone rubber by presenting evidence that the content of organic materials decreased during the temperature cycling treatment.

  4. 3D silicone rubber interfaces for individually tailored implants.

    Science.gov (United States)

    Stieghorst, Jan; Bondarenkova, Alexandra; Burblies, Niklas; Behrens, Peter; Doll, Theodor

    2015-01-01

    For the fabrication of customized silicone rubber based implants, e.g. cochlear implants or electrocortical grid arrays, it is required to develop high speed curing systems, which vulcanize the silicone rubber before it runs due to a heating related viscosity drop. Therefore, we present an infrared radiation based cross-linking approach for the 3D-printing of silicone rubber bulk and carbon nanotube based silicone rubber electrode materials. Composite materials were cured in less than 120 s and material interfaces were evaluated with scanning electron microscopy. Furthermore, curing related changes in the mechanical and cell-biological behaviour were investigated with tensile and WST-1 cell biocompatibility tests. The infrared absorption properties of the silicone rubber materials were analysed with fourier transform infrared spectroscopy in transmission and attenuated total reflection mode. The heat flux was calculated by using the FTIR data, emissivity data from the infrared source manufacturer and the geometrical view factor of the system.

  5. Durable crystalline Si photovoltaic modules based on silicone-sheet encapsulants

    Science.gov (United States)

    Hara, Kohjiro; Ohwada, Hiroto; Furihata, Tomoyoshi; Masuda, Atsushi

    2018-02-01

    Crystalline Si photovoltaic (PV) modules were fabricated with sheets of poly(dimethylsiloxane) (silicone) as an encapsulant. The long-term durability of the silicone-encapsulated PV modules was experimentally investigated. The silicone-based modules enhanced the long-term durability against potential-induced degradation (PID) and a damp-heat (DH) condition at 85 °C with 85% relative humidity (RH). In addition, we designed and fabricated substrate-type Si PV modules based on the silicone encapsulant and an Al-alloy plate as the substratum, which demonstrated high impact resistance and high incombustible performance. The high chemical stability, high volume resistivity, rubber-like elasticity, and incombustibility of the silicone encapsulant resulted in the high durability of the modules. Our results indicate that silicone is an attractive encapsulation material, as it improves the long-term durability of crystalline Si PV modules.

  6. Moisture content in raw rubber sheet analyzed by transflectance near infrared spectroscopy

    Directory of Open Access Journals (Sweden)

    Ronnarit Rittiron

    2014-07-01

    Full Text Available Moisture content is an important trait for rubber sheet trading system. Therefore, a calibration equation for predicting moisture content was created by near infrared (NIR technique in order to develop a more fair trading system in Thailand. Spectra were recorded in two systems. One was measurement on each rubber sheet and the other was on a pile of sheets. Both were measured by a handheld NIR spectrometer in the short wavelength region (700–1100 nm in the transflectance mode using Teflon as a diffuse reflector. The spectra showed the peak at about 900 nm which belongs to isoprene, the major component of rubber sheet. Pretreatment with second derivative was applied to remove baseline shift effect occurring due to thickness differences on each rubber sheet. From validation results, moisture contents predicted by single sheet system were more accurate than a pile of sheet system with standard error of prediction (SEP = 0.39% and bias of -0.07%, and they were not significantly different from the actual values at 95% confidence. As a result, determining moisture content in each rubber sheet by a handheld NIR spectrometer provided accurate values, easy and rapid operation.

  7. Radiation modification of silicone rubber with glycidylmethacrylate

    International Nuclear Information System (INIS)

    Segura, Tania; Burillo, Guillermina

    2013-01-01

    The grafting of glycidilmethacrylate(GMA) was grafted onto silicone rubber (SR) by using the γ-ray pre-irradiation grafting method under different conditions. The effect of reaction time, total dose, reaction temperature and monomer concentration on the graft yield was studied. It was found that the degree of grafting can be controlled by adjusting these parameters. The chemical structure of SR before and after grafting was characterized using FTIR-ATR and SEM–EDS. The analysis revealed that the surface of the SR was uniformly covered by GMA and the cross-section analysis indicated that the grafting occurred in the bulk. Thermogravimetric analysis (TGA) showed that the graft copolymer was more thermally stable than polyglycidylmethacrylate but less stable than SR, and the DSC confirmed that the GMA was grafting onto silicone rubber. - Highlights: • A graft copolymer with silicone rubber was synthesized by gamma pre-irradiation method. • SEM–EDS analysis showed that the surface and the bulk of the new copolymer were grafted. • The thermal properties of the silicone rubber used were modified with grafting. • The new copolymer could be used to immobilize nucleophilic biomolecules

  8. Effect of vulcanization temperature and humidity on the properties of RTV silicone rubber

    Science.gov (United States)

    Wu, Xutao; Li, Xiuguang; Hao, Lu; Wen, Xishan; Lan, Lei; Yuan, Xiaoqing; Zhang, Qingping

    2017-06-01

    In order to study the difference in performance of room temperature vulcanized (RTV) silicone rubber in vulcanization environment with different temperature and humidity, static contact angle method, FTIR and TG is utilized to depict the properties of hydrophobicity, transfer of hydrophobicity, functional groups and thermal stability of RTV silicone rubber. It is found that different vulcanization conditions have effects on the characteristics of RTV silicone rubber, which shows that the hydrophobicity of RTV silicone rubber changes little with the vulcanization temperature but a slight increase with the vulcanization humidity. Temperature and humidity have obvious effects on the hydrophobicity transfer ability of RTV silicone rubber, which is better when vulcanization temperature is 5°C or vulcanization humidity is 95%. From the Fourier transform infrared spectroscopy, it can be concluded that humidity and temperature of vulcanization conditions have great effect on the functional groups of silicone rubber, and vulcanization conditions also have effect on thermal stability of RTV silicone rubber. When vulcanization temperature is 5°C or vulcanization humidity is 15% or 95%, the thermal stability of silicone rubber becomes worse.

  9. Radiation cured silicone rubber articles

    International Nuclear Information System (INIS)

    DuPont, J.G.; Goodwin, P.A.

    1984-01-01

    A process for making radiation cured silicone rubber articles is disclosed wherein a hydroxyl-terminated polysilaxane having a molecular weight from about 50,000 to about 2,000,000, optionally modified by mixing with up to 85% of an end-stopped silicone rubber, is mixed with from about 10 to about 70 parts per hundred of rubber of a finely divided silica filler with a particle size in the reinforcing range and other inert fillers as determined by desired final properties; the composition so prepared is formed into the desired shape at room temperature; the article so formed is precured to improve the mechanical properties of the material with which it is made by exposure to ammonia gas, ammonium hydroxide, or to the vapors or solutions of a volatile amine at room temperature; and the precured article is irradiated with high energy electrons or gamma radiation to effect a permanent cure of the material from which the article is formed

  10. Boron-Loaded Silicone Rubber Scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Bell, Z.W.; Maya, L.; Brown, G.M.; Sloop, F.V.Jr

    2003-05-12

    Silicone rubber received attention as an alternative to polyvinyltoluene in applications in which the scintillator is exposed to high doses because of the increased resistance of the rubber to the formation of blue-absorbing color centers. Work by Bowen, et al., and Harmon, et al., demonstrated their properties under gamma/x-ray irradiation, and Bell, et al. have shown their response to thermal neutrons. This last work, however, provided an example of a silicone in which both the boron and the scintillator were contained in the rubber as solutes, a formulation which led to the precipitation of solids and sublimation of the boron component. In the present work we describe a scintillator in which the boron is chemically bonded to the siloxane and so avoids the problem of precipitation and loss of boron to sublimation. Material containing up to 18% boron, by weight, was prepared, mounted on photomultipliers, and exposed to both neutron and gamma fluxes. Pulse height spectra showing the neutron and photon response were obtained, and although the light output was found to be much poorer than from samples in which boron was dissolved, the higher boron concentrations enabled essentially 100% neutron absorption in only a few millimeters' thickness of rubber.

  11. Thermal endurance tests on silicone rubber specimens

    International Nuclear Information System (INIS)

    Warburton, C.

    1977-07-01

    Thermal endurance tests have been performed on a range of silicone rubber specimens at temperature above 300 0 C. It is suggested that the rubber mix A2426, the compound from which Wylfa sealing rings are manufactured, will fail at temperatures above 300 0 C within weeks. Hardness measurements show that this particular rubber performs in a similar manner to Walker's S.I.L./60. (author)

  12. Thermal modeling of the forced convection Sandwich Greenhouse drying system for rubber sheets

    International Nuclear Information System (INIS)

    Tanwanichkul, B.; Thepa, S.; Rordprapat, W.

    2013-01-01

    Highlights: • Sandwich Greenhouse is designed for better quality and efficiency of rubber sheet drying. • Thermal models are developed to predict the convection heat transfer coefficient. • The models are validated and show good agreement with the actual experimental data. • The proposed greenhouse can maintain 40–60 °C, suitable for rubber sheet drying. • This greenhouse can bring down the moisture content to 2.8% in fewer than 2 days. - Abstract: In this paper, a novel “Sandwich Greenhouse” for rubber sheet drying is proposed. Using solar energy as the only heat source instead of traditional smoke house that requires firewood, it eliminates shortcomings such as skilled labor monitoring requirement, possible fire hazard, and darken-color rubber sheets due to soot particle contamination. Our greenhouse is specially designed to retain solar energy within, while minimizing the heat loss to the outside environment. The mathematical models are developed to predict the convection mass transfer coefficient and to study the thermal behavior during the drying of rubber sheets under our proposed greenhouse design. Validated with experimental observations, the models show good agreement with the actual experimental data. The experiment demonstrates an effectiveness of our proposed Sandwich Greenhouse, as the temperature of the rubber sheet is 15 °C and 5 °C higher than the ambient temperature during the daytime and nighttime, respectively. As a result, the moisture content of the rubber sheets can decrease from 36.4% to 2.8% in fewer than 2 days

  13. Neutron absorbing room temperature vulcanizable silicone rubber compositions

    International Nuclear Information System (INIS)

    Zoch, H.L.

    1979-01-01

    A neutron absorbing composition is described and consists of a one-component room temperature vulcanizable silicone rubber composition or a two-component room temperature vulcanizable silicone rubber composition in which the composition contains from 25 to 300 parts by weight based on the base silanol or vinyl containing diorganopolysiloxane polymer of a boron compound or boron powder as the neutron absorbing ingredient. An especially useful boron compound in this application is boron carbide. 20 claims

  14. High breakdown-strength composites from liquid silicone rubbers

    DEFF Research Database (Denmark)

    Vudayagiri, Sindhu; Zakaria, Shamsul Bin; Yu, Liyun

    2014-01-01

    In this paper we investigate the performance of liquid silicone rubbers (LSRs) as dielectric elastomer transducers. Commonly used silicones in this application include room-temperature vulcanisable (RTV) silicone elastomers and composites thereof. Pure LSRs and their composites with commercially...

  15. Silicone rubber band for laparoscopic tubal sterilization.

    Science.gov (United States)

    Ansari, A H; Sealey, R M; Gay, J W; Kang, I

    1977-12-01

    In 1974, Yoon and associates (Am J Obstet Gynecol 120:132, 1974) described a new approach in which laparoscopic tubal occlusion was accomplished by utilizing the silicone rubber band technique. Recognizing the great advantages of the new technique in eliminating potential thermal injury associated with electrocoagulation, the authors have utilized the Yoon silicone rubber band technique in these institutions over the past 20 months. Thus far the procedure has been performed in 304 patients without any major complications. In the hope of eliminating and/or reducing possible pregnancy-failure rates, in 110 cases. In addition to application of the silicone band, the tube within the band was transected with non-electrical Seigler biopsy forceps. This, we believe, should provide an interesting long-term comparative study.

  16. Geometrical metrology on vacuum cast silicone rubber form using computed tomography

    DEFF Research Database (Denmark)

    Pacurar, Ramona; Müller, Pavel; De Chiffre, Leonardo

    An investigation on geometrical measurements of silicone rubber cake form and polyamide molds using three measuring techniques - CMM, optical scanner and CT scanner - was carried out. The only measurand was diameter of a cone measured at specified levels. An uncertainty budget for all three...... techniques. It was found that when the silicon rubber form was measured on the supported bottom mold or the bottom mold was measured itself, the diameter measurements performed on optical scanner and CT scanner were bigger compared to CMM measurements. On the other hand, the diameter resulted in smaller...... values when the silicon rubber form was measured on the supported top mold or the top mold was measured itself. A procedure for measurement of highly deformable part, such as silicone rubber form, was developed. Uncertainties from measurement on the optical scanner were big. This was mainly connected...

  17. Damage effects and mechanisms of proton irradiation on methyl silicone rubber

    International Nuclear Information System (INIS)

    Zhang, L.X.; He, Sh.Y.; Xu, Zh.; Wei, Q.

    2004-01-01

    A study was performed on the damage effects and mechanisms of proton irradiation with 150 keV energy to space-grade methyl silicone rubber. The changes in surface morphology, mechanical properties, infrared attenuated total reflection (ATR) spectrum, mass spectrum and pyrolysis gas chromatography-mass spectrum (PYGC-MS) indicated that, under lower fluence, the proton radiation would induce cross-linking effect, resulting in an increase in tensile strengths and hardness of the methyl silicon rubber. However, under higher proton fluence, the radiation-induced degradation, which decreased the tensile strengths and hardness, became a dominant effect. A macromolecular-network destruction model for the silicone rubber radiated with the protons was proposed

  18. Effect of organo-clay on the dielectric relaxation response of silicone rubber

    International Nuclear Information System (INIS)

    Gharavi, N; Razzaghi-Kashani, M; Golshan-Ebrahimi, N

    2010-01-01

    Dielectric elastomers are light weight, low-cost, highly deformable and fast response smart materials capable of converting electrical energy into mechanical work or vice versa. Silicone rubber is a well-known dielectric elastomer which is used as actuator, and in order to enhance the efficiency of this smart material, compounding of silicone rubber with various fillers can be carried out. The effect of organically modified montmorillonite (OMMT) nano-clay on improvement of dielectric properties, actuation stress and its relaxation response was considered in this study. OMMT was dispersed in room temperature vulcanized (RTV) silicone rubber, and a composite film was cast. Using an in-house actuation set-up, it was shown that the actuation stress for a given electric field intensity is higher for composites than that for pristine silicone rubber. Also, the time-dependent actuation response of the samples was evaluated, and it was shown that the characteristic relaxation time of the actuation stress for composites is less than for the pristine rubber as a result of OMMT addition

  19. In vitro formation of oropharyngeal biofilms on silicone rubber treated with a palladium/tin salt mixture

    NARCIS (Netherlands)

    Dijk, F; Westerhof, M; Busscher, HJ; van Luyn, MJA; van der Mei, HC

    2000-01-01

    Adhesion of yeasts and bacteria to silicone rubber is one of the first steps in the biodeterioration of indwelling, silicone rubber voice prostheses. In this paper, silicone rubber, so-called "Groningen button," voice prostheses were treated with a colloidal palladium/tin solution to form a thin

  20. DEB-silicone rubber hydrogen absorbing Raman detection technology research

    International Nuclear Information System (INIS)

    Yang Suolong; Zhong Jingrong; Wang Huang; Yang Kaixu; Xiao Jiqun; Liu Jiaxi; Liao Junsheng

    2012-01-01

    The DEB-Pd/C hydrogen getter powder and DEB-Pd/C-silicone rubber getter film were prepared and used for hydrogen detection in close systems by laser Raman method. The DEB alkanes Raman peak intensity changes with the getter time were monitored by Raman spectrometer. As a result, silicone rubber has good compatibility with DEB getter, slow access to hydrogen and good flexible. The alkanes peak intensity-getter time followed a exponential rule. DEB getter films are suitable for Raman on-line monitor of cumulative hydrogen of a closed system at long time. (authors)

  1. Experimental testing on free vibration behaviour for silicone rubbers proposed within lumbar disc prosthesis

    Energy Technology Data Exchange (ETDEWEB)

    Rotaru, Iuliana, E-mail: rotaruiuliana2000@gmail.com [“Gheorghe Asachi” Technical University of Iasi, Faculty of Mechanical Engineering, Department of Mechanical Engineering, Mechatronics and Robotics, 61-63 Bd. Dimitrie Mangeron, 700050 Iasi (Romania); “Gr. T. Popa” University of Medicine and Pharmacy of Iasi, Faculty of Medical Bioengineering, Department of Biomedical Sciences, 9-13 M. Kogalniceanu Street, 700454 Iasi (Romania); Bujoreanu, Carmen [“Gheorghe Asachi” Technical University of Iasi, Faculty of Mechanical Engineering, Department of Mechanical Engineering, Mechatronics and Robotics, 61-63 Bd. Dimitrie Mangeron, 700050 Iasi (Romania); Bele, Adrian; Cazacu, Maria [“Petru Poni” Institute of Macromolecular Chemistry, Aleea Gr. Ghica Voda 41 A, 700487 Iasi (Romania); Olaru, Dumitru [“Gheorghe Asachi” Technical University of Iasi, Faculty of Mechanical Engineering, Department of Mechanical Engineering, Mechatronics and Robotics, 61-63 Bd. Dimitrie Mangeron, 700050 Iasi (Romania)

    2014-09-01

    This research was focused on the damping capacity study of two types of silicone rubbers proposed as layers within total lumbar disc prostheses of ball-and-socket model. In order to investigate the damping capacity, the two silicone rubber types mainly differing by the molecular mass of polymeric matrix and the filler content, as was emphasized by scanning electron microscopy and differential scanning calorimetry, were subjected to free vibration testing. Using an adapted experimental installation, three kinds of damping testing were realised: tests without samples and tests with three samples of each type of silicone rubber (69 ShA and 99 ShA). The free vibration tests were performed at a frequency of about 6 Hz using a weight of 11.8 kg. The relative damping coefficient was determined by measuring of two successive amplitudes on the vibrogram and calculating of the logarithmic decrement. The test results with silicone rubber samples showed a relative damping coefficient of 0.058 and respectively 0.077, whilst test results without samples showed a relative damping coefficient of 0.042. These silicone rubbers were found to have acceptable damping properties to be used as layers placed inside the prosthetic components. - Highlights: • Two types of silicone rubber were proposed within the total lumbar disc prostheses. • The filler content of elastomers was highlighted by microscopy investigation. • Damping capacity of the two elastomers was evaluated using free vibration analysis. • The logarithmic decrement and the relative damping coefficient were determined. • The silicone rubbers prepared in our work showed acceptable damping properties.

  2. Experimental testing on free vibration behaviour for silicone rubbers proposed within lumbar disc prosthesis

    International Nuclear Information System (INIS)

    Rotaru, Iuliana; Bujoreanu, Carmen; Bele, Adrian; Cazacu, Maria; Olaru, Dumitru

    2014-01-01

    This research was focused on the damping capacity study of two types of silicone rubbers proposed as layers within total lumbar disc prostheses of ball-and-socket model. In order to investigate the damping capacity, the two silicone rubber types mainly differing by the molecular mass of polymeric matrix and the filler content, as was emphasized by scanning electron microscopy and differential scanning calorimetry, were subjected to free vibration testing. Using an adapted experimental installation, three kinds of damping testing were realised: tests without samples and tests with three samples of each type of silicone rubber (69 ShA and 99 ShA). The free vibration tests were performed at a frequency of about 6 Hz using a weight of 11.8 kg. The relative damping coefficient was determined by measuring of two successive amplitudes on the vibrogram and calculating of the logarithmic decrement. The test results with silicone rubber samples showed a relative damping coefficient of 0.058 and respectively 0.077, whilst test results without samples showed a relative damping coefficient of 0.042. These silicone rubbers were found to have acceptable damping properties to be used as layers placed inside the prosthetic components. - Highlights: • Two types of silicone rubber were proposed within the total lumbar disc prostheses. • The filler content of elastomers was highlighted by microscopy investigation. • Damping capacity of the two elastomers was evaluated using free vibration analysis. • The logarithmic decrement and the relative damping coefficient were determined. • The silicone rubbers prepared in our work showed acceptable damping properties

  3. Synthesis of Novel Reactive Disperse Silicon-Containing Dyes and Their Coloring Properties on Silicone Rubbers

    Directory of Open Access Journals (Sweden)

    Ning Yu

    2018-01-01

    Full Text Available Novel red and purple reactive disperse silicon-containing dyes were designed and synthesized using p-nitroaniline and 6-bromo-2,4-dinitro-aniline as diazonium components, the first condensation product of cyanuric chloride and 3-(N,N-diethylamino-aniline as coupling component, and 3-aminopropylmethoxydimethylsilane, 3-aminopropylmethyldimethoxysilane, and 3-aminopropyltrimethoxysilane as silicone reactive agents. These dyes were characterized by UV-Vis, 1H-NMR, FT-IR, and MS. The obtained reactive disperse silicon-containing dyes were used to color silicone rubbers and the color fastness of the dyes were evaluated. The dry/wet rubbing and washing fastnesses of these dyes all reached 4–5 grade and the sublimation fastness was also above 4 grade, indicating outstanding performance in terms of color fastness. Such colored silicone rubbers showed bright and rich colors without affecting its static mechanical properties.

  4. Adhesion of yeasts and bacteria to fluoro-alkylsiloxane layers chemisorbed on silicone rubber

    NARCIS (Netherlands)

    Everaert, EPJM; van der Mei, HC; Busscher, HJ

    1998-01-01

    Indwelling voice prostheses are most often made of silicone rubber. However, the silicone rubber surface attracts huge quantities of adhering yeasts and bacteria and their colonization on the valve side of voice prostheses leads to frequent malfunctioning. On average, indwelling voice prostheses

  5. Low frequency acoustic properties of a honeycomb-silicone rubber acoustic metamaterial

    Science.gov (United States)

    Gao, Nansha; Hou, Hong

    2017-04-01

    In order to overcome the influence of mass law on traditional acoustic materials and obtain a lightweight thin-layer structure which can effectively isolate the low frequency noises, a honeycomb-silicone rubber acoustic metamaterial was proposed. Experimental results show that the sound transmission loss (STL) of acoustic metamaterial in this paper is greatly higher than that of monolayer silicone rubber metamaterial. Based on the band structure, modal shapes, as well as the sound transmission simulation, the sound insulation mechanism of the designed honeycomb-silicone rubber structure was analyzed from a new perspective, which had been validated experimentally. Side length of honeycomb structure and thickness of the unit structure would affect STL in damping control zone. Relevant conclusions and design method provide a new concept for engineering noise control.

  6. Effect of chain extender on properties of silicone rubber sealant

    Science.gov (United States)

    Liu, Jiesheng; Wu, Shaopeng; Mi, Yixuan; Zhu, Guojun; Zheng, Shaoping

    2010-03-01

    The room-temperature vulcanizing silicone rubber sealant was prepared with chain extender. The effect of chain extender on the properties of silicone rubber sealant was discussed. The composite samples with chain extender were investigated from the aspects of tack-free time, cross-linkage density, hardness (penetration number) and adhesive strength with the concrete slab. It was found that the adding of the chain extender effectively makes the molecular chain length increase and causes the mechanical properties improvement. In addition, the increase in the amount of the chain extender reduces the cross-linkage density and hardness of silicone rubber sealant, which is accompanied with a decrease in the tack-free time. Adhesive strength is one of the most important requirements for sealant. The effect of chain extender on the adhesive strength was also investigated in this study. It was found that the increase in the amount of the chain extender makes the adhesive strength between the sealant and the concrete slab decrease.

  7. Effect of 200 keV proton irradiation on the properties of methyl silicone rubber

    International Nuclear Information System (INIS)

    Zhang Lixin; Xu Zhou; Wei Qiang; He Shiyu

    2006-01-01

    The effects of 200 keV proton irradiation on methyl silicone rubber were studied. The changes in surface morphology, mechanical properties, cross-linking density, glass transition temperature, infrared attenuated total reflection spectrum and mass spectrum indicated that, at lower fluence, the proton irradiation induced cross-linking, resulting in an increase in tensile strength and hardness of the methyl silicone rubber. However, at higher proton fluence, radiation-induced degradation, which decreased the tensile strength and hardness, became dominant. A macromolecular-network destruction model for silicone rubber irradiated with protons was proposed

  8. Adhesion enhancement for liquid silicone rubber and different ...

    Indian Academy of Sciences (India)

    Keywords. Adhesion property; platinum catalyst; liquid silicone rubber; vinyltrimethoxysilane. ... 2003), elastomeric housing materials of composite insula- .... formula given below: ... surface was cured to generate Al–O–Si covalent bond on the.

  9. Temperature and humidity effect on aging of silicone rubbers as sealing materials for proton exchange membrane fuel cell applications

    International Nuclear Information System (INIS)

    Chang, Huawei; Wan, Zhongmin; Chen, Xi; Wan, Junhua; Luo, Liang; Zhang, Haining; Shu, Shuiming; Tu, Zhengkai

    2016-01-01

    Highlights: • Aging of silicone rubbers with different hardness was investigated. • Existed water molecules from humidified gases can accelerate the aging process. • Silicone rubber with hardness of 40 is more suitable as sealing materials. • Silicone rubbers can be used as sealing materials below 80 °C but not above 100 °C. - Abstract: Durability and reliability of seals around perimeter of each unit are critical to the lifetime of proton exchange membrane fuel cells. In this study, we investigate the aging of silicone rubbers with different hardness, often used as sealing materials for fuel cells, subjected to dry and humidified air at different temperatures. The aging properties are characterized by variation of permanent compression set value under compression, mechanical properties, and surface morphology as well. The results show that aging of silicone rubbers becomes more severe with the increase in subjected temperature. At temperature above 100 °C, silicone rubbers are not suitable for fuel cell applications. The existed water molecules from humidified gases can accelerate the aging of silicone rubbers. Among the tested samples, silicone rubber with hardness of 40 is more durable than that with hardness of 30 and 50 for fuel cells. The change of chemical structure after aging suggests that the aging of silicone rubbers mainly results from the chemical decomposition of cross-linker units for connection of polysiloxane backbones and of methyl groups attached to silicon atoms.

  10. Factors affecting alcohol-water pervaporation performance of hydrophobic zeolite-silicone rubber mixed matrix membranes

    Science.gov (United States)

    Mixed matrix membranes (MMMs) consisting of ZSM-5 zeolite particles dispersed in silicone rubber exhibited ethanol-water pervaporation permselectivities up to 5 times that of silicone rubber alone and 3 times higher than simple vapor-liquid equilibrium (VLE). A number of conditi...

  11. Experimental testing on free vibration behaviour for silicone rubbers proposed within lumbar disc prosthesis.

    Science.gov (United States)

    Rotaru, Iuliana; Bujoreanu, Carmen; Bele, Adrian; Cazacu, Maria; Olaru, Dumitru

    2014-09-01

    This research was focused on the damping capacity study of two types of silicone rubbers proposed as layers within total lumbar disc prostheses of ball-and-socket model. In order to investigate the damping capacity, the two silicone rubber types mainly differing by the molecular mass of polymeric matrix and the filler content, as was emphasized by scanning electron microscopy and differential scanning calorimetry, were subjected to free vibration testing. Using an adapted experimental installation, three kinds of damping testing were realised: tests without samples and tests with three samples of each type of silicone rubber (69 ShA and 99 ShA). The free vibration tests were performed at a frequency of about 6 Hz using a weight of 11.8 kg. The relative damping coefficient was determined by measuring of two successive amplitudes on the vibrogram and calculating of the logarithmic decrement. The test results with silicone rubber samples showed a relative damping coefficient of 0.058 and respectively 0.077, whilst test results without samples showed a relative damping coefficient of 0.042. These silicone rubbers were found to have acceptable damping properties to be used as layers placed inside the prosthetic components. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. Plasma jet array treatment to improve the hydrophobicity of contaminated HTV silicone rubber

    Science.gov (United States)

    Zhang, Ruobing; Han, Qianting; Xia, Yan; Li, Shuang

    2017-10-01

    An atmospheric-pressure plasma jet array specially designed for HTV silicone rubber treatment is reported in this paper. Stable plasma containing highly energetic active particles was uniformly generated in the plasma jet array. The discharge pattern was affected by the applied voltage. The divergence phenomenon was observed at low gas flow rate and abated when the flow rate increased. Temperature of the plasma plume is close to room temperature which makes it feasible for temperature-sensitive material treatment. Hydrophobicity of contaminated HTV silicone rubber was significantly improved after quick exposure of the plasma jet array, and the effective treatment area reached 120 mm × 50 mm (length × width). Reactive particles in the plasma accelerate accumulation of the hydrophobic molecules, namely low molecular weight silicone chains, on the contaminated surface, which result in a hydrophobicity improvement of the HTV silicone rubber.

  13. The effect of organo-clay on the dielectric properties of silicone rubber

    International Nuclear Information System (INIS)

    Razzaghi-Kashani, M; Gharavi, N; Javadi, S

    2008-01-01

    Dielectric elastomers are highly deformable and fast response smart materials capable of actuation under electric fields. Among commercially available dielectric elastomers, silicone rubber can be compounded with different fillers in order to modify its electrical and mechanical properties. To study the effect of organically modified montmorillonite (OMMT) on the dielectric properties of silicone rubber, OMMT was added to this rubber at two levels, 2% and 5%, using two methods, low-shear and high-shear mixing. Composites were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), and atomic force microscopy (AFM). The XRD patterns showed different crystallite structures for silicate platelets in the rubber matrix as a result of the two different mixing methods. In low-shear mixing, the ordered crystallite structure of the clay remains almost unchanged, whereas in high-shear mixing it loses its ordered structure, leading to the disappearance of the diffraction peaks. SEM and AFM micrographs depicted better dispersion and more uniform distribution of the organo-clay under high-shear mixing compared to those obtained by low-shear mixing. The tensile properties also confirmed the different degree of dispersion of the nano-clay resulting from the two different methods of mixing. The dielectric properties of the composites were measured under AC electric fields, and the results were compared with reference silicone rubbers with no OMMT. It was shown that the order of organo-clay layers in the less dispersed structure of the clay imparts an additional ionic polarization and higher dielectric permittivity compared to the case where the clay layers are more dispersed and lost their order. The storage and loss dielectric constants of base silicone rubber increase when it is compounded with OMMT

  14. Silicon Sheet Quality is Improved By Meniscus Control

    Science.gov (United States)

    Yates, D. A.; Hatch, A. E.; Goldsmith, J. M.

    1983-01-01

    Better quality silicon crystals for solar cells are possible with instrument that monitors position of meniscus as sheet of solid silicon is drawn from melt. Using information on meniscus height, instrument generates feedback signal to control melt temperature. Automatic control ensures more uniform silicon sheets.

  15. Natural Contamination and Surface Flashover on Silicone Rubber Surface under Haze–Fog Environment

    Directory of Open Access Journals (Sweden)

    Ang Ren

    2017-10-01

    Full Text Available Anti-pollution flashover of insulator is important for power systems. In recent years, haze-fog weather occurs frequently, which makes discharge occurs easily on the insulator surface and accelerates insulation aging of insulator. In order to study the influence of haze-fog on the surface discharge of room temperature vulcanized silicone rubber, an artificial haze-fog lab was established. Based on four consecutive years of insulator contamination accumulation and atmospheric sampling in haze-fog environment, the contamination configuration appropriate for RTV-coated surface discharge test under simulation environment of haze-fog was put forward. ANSYS Maxwell was used to analyze the influence of room temperature vulcanized silicone rubber surface attachments on electric field distribution. The changes of droplet on the polluted room temperature vulcanized silicone rubber surface and the corresponding surface flashover voltage under alternating current (AC, direct current (DC positive polar (+, and DC negative polar (− power source were recorded by a high speed camera. The results are as follows: The main ion components from haze-fog atmospheric particles are NO3−, SO42−, NH4+, and Ca2+. In haze-fog environment, both the equivalent salt deposit density (ESDD and non-soluble deposit density (NSDD of insulators are higher than that under general environment. The amount of large particles on the AC transmission line is greater than that of the DC transmission line. The influence of DC polarity power source on the distribution of contamination particle size is not significant. After the deposition of haze-fog, the local conductivity of the room temperature vulcanized silicone rubber surface increased, which caused the flashover voltage reduce. Discharge is liable to occur at the triple junction point of droplet, air, and room temperature vulcanized silicone rubber surface. After the deformation or movement of droplets, a new triple junction

  16. Lifetime Analysis of Rubber Gasket Composed of Methyl Vinyl Silicone Rubber with Low-Temperature Resistance

    Directory of Open Access Journals (Sweden)

    Young-Doo Kwon

    2015-01-01

    Full Text Available Most machines and instruments constantly require elastomeric materials like rubber for the purposes of shock absorption, noise attenuation, and sealing. The material properties and accurate lifetime prediction of rubber are closely related to the quality of machines, especially their durability and reliability. The properties of rubber-like elastomers are influenced by ambient conditions, such as temperature, environment, and mechanical load. Moreover, the initial properties of rubber gaskets must be sustained under working conditions to satisfy their required function. Because of its technical merits, as well as its low cost, the highly accelerated life test (HALT is used by many researchers to predict the long-term lifetime of rubber materials. Methyl vinyl silicone rubber (VMQ has recently been adopted to improve the lifetime of automobile radiator gaskets. A four-parameter method of determining the recovery ability of the gaskets was recently published, and two revised methods of obtaining the recovery were proposed for polyacrylate (ACM rubber. The recovery rate curves for VMQ were acquired using the successive zooming genetic algorithm (SZGA. The gasket lifetime for the target recovery (60% of a compressed gasket was computed somewhat differently depending on the selected regression model.

  17. Toward 3D Printing of Medical Implants: Reduced Lateral Droplet Spreading of Silicone Rubber under Intense IR Curing.

    Science.gov (United States)

    Stieghorst, Jan; Majaura, Daniel; Wevering, Hendrik; Doll, Theodor

    2016-03-01

    The direct fabrication of silicone-rubber-based individually shaped active neural implants requires high-speed-curing systems in order to prevent extensive spreading of the viscous silicone rubber materials during vulcanization. Therefore, an infrared-laser-based test setup was developed to cure the silicone rubber materials rapidly and to evaluate the resulting spreading in relation to its initial viscosity, the absorbed infrared radiation, and the surface tensions of the fabrication bed's material. Different low-adhesion materials (polyimide, Parylene-C, polytetrafluoroethylene, and fluorinated ethylenepropylene) were used as bed materials to reduce the spreading of the silicone rubber materials by means of their well-known weak surface tensions. Further, O2-plasma treatment was performed on the bed materials to reduce the surface tensions. To calculate the absorbed radiation, the emittance of the laser was measured, and the absorptances of the materials were investigated with Fourier transform infrared spectroscopy in attenuated total reflection mode. A minimum silicone rubber spreading of 3.24% was achieved after 2 s curing time, indicating the potential usability of the presented high-speed-curing process for the direct fabrication of thermal-curing silicone rubbers.

  18. A silicone rubber based composites using n-octadecane/poly (styrene-methyl methacrylate microcapsules as energy storage particle

    Directory of Open Access Journals (Sweden)

    W.L. Wu

    Full Text Available A phase-change energy-storage material, silicone rubber (SR coated n-octadecane/poly (styrene-methyl methacrylate (SR/OD/P(St-MMA microcapsule composites, was prepared by mixing SR and OD/P(St-MMA microcapsules. The microcapsule content and silicone rubber coated method were investigated. The morphology and thermal properties of the composites were characterized by scanning electron microscopy (SEM, thermogravimetric analysis (TG, differential scanning calorimetry (DSC and heat storage properties. The results showed that the thermal and mechanical properties of SR/OD/P(St-MMA composites were excellent when the microcapsules were coated with room temperature vulcanized silicone rubber (RTVSR, of which content was 2 phr (per hundred rubber. The enthalpy value of the composites was 67.6 J g−1 and the composites were found to have good energy storage function. Keywords: n-Octadecane, Silicone rubber, Microcapsule, Energy-storage, Composites

  19. Modeling the high-frequency complex modulus of silicone rubber using standing Lamb waves and an inverse finite element method.

    Science.gov (United States)

    Jonsson, Ulf; Lindahl, Olof; Andersson, Britt

    2014-12-01

    To gain an understanding of the high-frequency elastic properties of silicone rubber, a finite element model of a cylindrical piezoelectric element, in contact with a silicone rubber disk, was constructed. The frequency-dependent elastic modulus of the silicone rubber was modeled by a fourparameter fractional derivative viscoelastic model in the 100 to 250 kHz frequency range. The calculations were carried out in the range of the first radial resonance frequency of the sensor. At the resonance, the hyperelastic effect of the silicone rubber was modeled by a hyperelastic compensating function. The calculated response was matched to the measured response by using the transitional peaks in the impedance spectrum that originates from the switching of standing Lamb wave modes in the silicone rubber. To validate the results, the impedance responses of three 5-mm-thick silicone rubber disks, with different radial lengths, were measured. The calculated and measured transitional frequencies have been compared in detail. The comparison showed very good agreement, with average relative differences of 0.7%, 0.6%, and 0.7% for the silicone rubber samples with radial lengths of 38.0, 21.4, and 11.0 mm, respectively. The average complex elastic moduli of the samples were (0.97 + 0.009i) GPa at 100 kHz and (0.97 + 0.005i) GPa at 250 kHz.

  20. AC/TiO2/Rubber Composite Sheet Catalysts; Fabrication, Characterization and Photocatalytic Activities

    Directory of Open Access Journals (Sweden)

    Sriwong Chaval

    2015-01-01

    Full Text Available The AC/TiO2/Rubber (ACTR composite sheets weresuccessfully fabricated by a simply mixing of fixed TiO2 suspension and natural rubber latex (60% HA contents withthe varyingamounts of activated carbon (AC suspension, followed by stirring, pouring into apetri dish mold, drying at room temperature (RT, after that taking out from a mold, reversing and drying again at RT. Then, the as-fabricated ACTR composite sheets were characterized by X-ray diffractometer (XRD, attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR, energy dispersive X-ray spectroscopy (EDS and scanning electron microscopy (SEMtechniques. The photocatalytic efficiencies of all ACTR composite sheet samples were evaluated by photo degrading of methylene blue (MB dye solution under UV light irradiation. The results showed that the photocatalytic activity of ACTR sheet with10.0wt%AC loading has the highest efficiency for the photo degradation of MB dye than the other sheets. This is due to the fact that it is relatively with the synergistic effect of well-combined titanium dioxide catalyst and activated carbon adsorbent.

  1. Novel thermoplastic vulcanizates (TPVs based on silicone rubber and polyamide exploring peroxide cross-linking

    Directory of Open Access Journals (Sweden)

    K. Naskar

    2014-04-01

    Full Text Available Novel thermoplastic vulcanizates (TPVs based on silicone rubber (PDMS and polyamide (PA12 have been prepared by dynamic vulcanization process. The effect of dynamic vulcanization and influence of various types of peroxides as cross-linking agents were studied in detail. All the TPVs were prepared at a ratio of 50/50 wt% of silicone rubber and polyamide. Three structurally different peroxides, namely dicumyl peroxide (DCP, 3,3,5,7,7-pentamethyl 1,2,4-trioxepane (PMTO and cumyl hydroperoxide (CHP were taken for investigation. Though DCP was the best option for curing the silicone rubber, at high temperature it suffers from scorch safety. An inhibitor 2,2,6,6-tetramethylpiperidinyloxyl (TEMPO was added with DCP to stabilize the radicals in order to increase the scorch time. Though CHP (hydroperoxide had higher half life time than DCP at higher temperature, it has no significant effect on cross-linking of silicone rubber. PMTO showed prolonged scorch safety and better cross-linking efficiency rather than the other two. TPVs of DCP and PMTO were made up to 11 minutes of mixing. Increased values of tensile strength and elongation at break of PMTO cross-linked TPV indicate the superiority of PMTO. Scanning electron micrographs correlate with mechanical properties of the TPVs. High storage modulus (E' and lower loss tangent value of the PMTO cross-linked TPV indicate the higher degree of cross-linking which is also well supported by the overall cross-link density value. Thus PMTO was found to be the superior peroxide for cross-linking of silicone rubber at high temperature.

  2. Economic assessment of possible electron accelerator applications in curing silicon rubber based electric installation material

    International Nuclear Information System (INIS)

    Rmot, L.

    1976-01-01

    A description is given of the conventional technology of production of conductors with silicon rubber insulation and of the radiation vulcanization method, i.e., the radiation cross-linking of silicon rubber. An economic comparison is shown for both technologies. The analysis shows that the indices for the radiation cross-linking technology are favourable and that the introduction thereof would be advantageous. (J.P.)

  3. Adhesion to silicone rubber of yeasts and bacteria isolated from voice prostheses : Influence of salivary conditioning films

    NARCIS (Netherlands)

    Busscher, HJ; GeertsemaDoornbusch, GI; vanderMei, HC

    Adhesion of yeasts and bacteria to silicone rubber is one of the first steps in the biodeterioration of silicone rubber voice prostheses. In this paper, adhesion of two streptococcal, staphylococcal, Candida albicans and Candida tropicalis strains, isolated from explanted voice prostheses was

  4. Investigations of surface characterization of silicone rubber due to ...

    Indian Academy of Sciences (India)

    Unknown

    †Department of Polymer Technology, Crescent Engineering College, Chennai 600 048, India. Abstract. In the present work, tracking ... Silicone rubber; surface degradation; tracking; WAXD; TG–DTA. 1. Introduction. Power transmission at ... mena in polymer insulators under d.c. voltages. Hence the tracking phenomena ...

  5. Zeolite-filled silicone rubber membranes. Experimental determination of concentration profiles

    NARCIS (Netherlands)

    te Hennepe, H.J.C.; Boswerger, W.B.F.; Bargeman, D.; Bargeman, D.; Mulder, M.H.V.; Smolders, C.A.; Smolders, C.A.

    1994-01-01

    Permeant concentrations in silicalite-filled silicone rubber membranes during pervaporation of propanol/water mixtures were measured using multi-layered membranes. Experimentally determined concentration profiles show that the propanol concentration in the silicalite-filled membrane increases with

  6. A silicone rubber based composites using n-octadecane/poly (styrene-methyl methacrylate) microcapsules as energy storage particle

    Science.gov (United States)

    Wu, W. L.; Chen, Z.

    A phase-change energy-storage material, silicone rubber (SR) coated n-octadecane/poly (styrene-methyl methacrylate) (SR/OD/P(St-MMA)) microcapsule composites, was prepared by mixing SR and OD/P(St-MMA) microcapsules. The microcapsule content and silicone rubber coated method were investigated. The morphology and thermal properties of the composites were characterized by scanning electron microscopy (SEM), thermogravimetric analysis (TG), differential scanning calorimetry (DSC) and heat storage properties. The results showed that the thermal and mechanical properties of SR/OD/P(St-MMA) composites were excellent when the microcapsules were coated with room temperature vulcanized silicone rubber (RTVSR), of which content was 2 phr (per hundred rubber). The enthalpy value of the composites was 67.6 J g-1 and the composites were found to have good energy storage function.

  7. Effects of 400 keV electrons flux on two space grade silicone rubbers

    Energy Technology Data Exchange (ETDEWEB)

    Jochem, H. [ONERA – The French Aerospace Lab, F-31055 Toulouse (France); Université de Toulouse, UPS, and CNRS, LHFA, UMR 5069, 118 route de Narbonne, F-31062 Toulouse Cedex 9 (France); CNES – French Aerospace Agency, 18 Avenue Edouard Belin, F-31401 Toulouse Cedex 9 (France); Rejsek-Riba, V. [ONERA – The French Aerospace Lab, F-31055 Toulouse (France); Maerten, E., E-mail: maerten@chimie.ups-tlse.fr [Université de Toulouse, UPS, and CNRS, LHFA, UMR 5069, 118 route de Narbonne, F-31062 Toulouse Cedex 9 (France); Remaury, S. [CNES – French Aerospace Agency, 18 Avenue Edouard Belin, F-31401 Toulouse Cedex 9 (France); Solé, S.; Sierra, G. [MAP Coatings – ZI, 2 Rue Clément Ader, 09100 Pamiers (France); Baceiredo, A. [Université de Toulouse, UPS, and CNRS, LHFA, UMR 5069, 118 route de Narbonne, F-31062 Toulouse Cedex 9 (France); Guillaumon, O. [MAP Coatings – ZI, 2 Rue Clément Ader, 09100 Pamiers (France)

    2013-08-15

    Two different space grade silicone rubbers were irradiated by an electron flux of 400 keV. The irradiation impact strongly depends on the chemical structure of rubbers (one reinforced with MQ resins, and the other one functionalized with phenyl groups at the silicon atoms and reinforced with silica). The irradiated rubbers were studied by means of solvent swelling, solid-state {sup 29}Si NMR, and ATR–FTIR spectroscopy. Physical properties were evaluated by thermal (differential scanning calorimetry), mechanical (dynamic mechanical analysis), and thermo-optical (ultraviolet–visible–near infrared spectroscopy) analyses. The formation of silicium T units and Si–CH{sub 2}–Si networks were evidenced by {sup 29}Si NMR, and the increase of the glass transition temperature and of modulus reflect the substantial increase in the macromolecular chain rigidity of the irradiated material. Dramatic damages of mechanical properties were observed, depending on the reinforced materials used. Slight changes of thermo-optical properties were highlighted independently to the initial chemical structure. - Highlights: • Electron flux radiations generate chains cross-linking. • Cross-linking occurs by T and Si–CH{sub 2}–Si units formation. • The cross-linking rate is slightly faster for 2D rubber compared to 3D rubber. • Modulus increases much more significantly for 3D rubber.

  8. Flat-plate solar array project. Volume 3: Silicon sheet: Wafers and ribbons

    Science.gov (United States)

    Briglio, A.; Dumas, K.; Leipold, M.; Morrison, A.

    1986-01-01

    The primary objective of the Silicon Sheet Task of the Flat-Plate Solar Array (FSA) Project was the development of one or more low cost technologies for producing silicon sheet suitable for processing into cost-competitive solar cells. Silicon sheet refers to high purity crystalline silicon of size and thickness for fabrication into solar cells. Areas covered in the project were ingot growth and casting, wafering, ribbon growth, and other sheet technologies. The task made and fostered significant improvements in silicon sheet including processing of both ingot and ribbon technologies. An additional important outcome was the vastly improved understanding of the characteristics associated with high quality sheet, and the control of the parameters required for higher efficiency solar cells. Although significant sheet cost reductions were made, the technology advancements required to meet the task cost goals were not achieved.

  9. Orientation and Morphology Effects in Rapid Silicon Sheet Solidification

    Science.gov (United States)

    Ciszek, T. F.

    1984-01-01

    Radial growth anisotropies and equilibrium forms of point nucleated, dislocation free silicon sheets spreading horizontally on the free surface of a silicon melt were measured for (100), (110), (111), and (112) sheet planes. The growth process was recorded. Qualitative Wulff surface free energy polar plots were deduced from the equilibrium shapes for each sheet plane. Predicted geometries for the tip shape of unidirectional, dislocation free, horizontally grown sheets growing in various directions within the planes were analyzed. Polycrystalline sheets and dendrite propagation were analyzed. For dendrites, growth rates on the order of 2.5 m/min and growth rate anisotropies of 25 are measured.

  10. Biofunctionalization of silicone rubber with microgroove-patterned surface and carbon-ion implantation to enhance biocompatibility and reduce capsule formation

    Directory of Open Access Journals (Sweden)

    Lei ZY

    2016-10-01

    Full Text Available Ze-yuan Lei, Ting Liu, Wei-juan Li, Xiao-hua Shi, Dong-li Fan Department of Plastic and Cosmetic Surgery, XinQiao Hospital, The Third Military Medical University, ChongQing, People’s Republic of China Purpose: Silicone rubber implants have been widely used to repair soft tissue defects and deformities. However, poor biocompatibility can elicit capsule formation, usually resulting in prosthesis contracture and displacement in long-term usage. To overcome this problem, this study investigated the properties of silicone rubber materials with or without a microgroove-patterned surface and with or without carbon (C-ion implantation. Materials and methods: Atomic force microscopy, X-ray photoelectron spectroscopy, and a water contact angle test were used to characterize surface morphology and physicochemical properties. Cytocompatibility was investigated by a cell adhesion experiment, immunofluorescence staining, a Cell Counting Kit-8 assay, and scanning electron microscopy in vitro. Histocompatibility was evaluated by studying the inflammatory response and fiber capsule formation that developed after subcutaneous implantation in rats for 7 days, 15 days, and 30 days in vivo. Results: Parallel microgrooves were found on the surfaces of patterned silicone rubber (P-SR and patterned C-ion-implanted silicone rubber (PC-SR. Irregular larger peaks and deeper valleys were present on the surface of silicone rubber implanted with C ions (C-SR. The silicone rubber surfaces with microgroove patterns had stable physical and chemical properties and exhibited moderate hydrophobicity. PC-SR exhibited moderately increased dermal fibroblast cell adhesion and growth, and its surface microstructure promoted orderly cell growth. Histocompatibility experiments on animals showed that both the anti-inflammatory and antifibrosis properties of PC-SR were slightly better than those of the other materials, and there was also a lower capsular contracture rate and less

  11. Rubber pad forming - Efficient approach for the manufacturing of complex structured sheet metal blanks for food industry

    Science.gov (United States)

    Spoelstra, Paul; Djakow, Eugen; Homberg, Werner

    2017-10-01

    The production of complex organic shapes in sheet metals is gaining more importance in the food industry due to increasing functional and hygienic demands. Hence it is necessary to produce parts with complex geometries promoting cleanability and general sanitation leading to improvement of food safety. In this context, and especially when stainless steel has to be formed into highly complex geometries while maintaining desired surface properties, it is inevitable that alternative manufacturing processes will need to be used which meet these requirements. Rubber pad forming offers high potential when it comes to shaping complex parts with excellent surface quality, with virtually no tool marks and scratches. Especially in cases where only small series are to be produced, rubber pad forming processes offers both technological and economic advantages. Due to the flexible punch, variation in metal thickness can be used with the same forming tool. The investments to set-up Rubber pad forming is low in comparison to conventional sheet metal forming processes. The process facilitates production of shallow sheet metal parts with complex contours and bends. Different bending sequences in a multiple tool set-up can also be conducted. The planned contribution thus describes a brief overview of the rubber pad technology. It shows the prototype rubber pad forming machine which can be used to perform complex part geometries made from stainless steel (1.4301). Based on an analysis of the already existing systems and new machines for rubber pad forming processes, together with their process properties, influencing variables and areas of application, some relevant parts for the food industry are presented.

  12. The Efficacy of a Silicone Sheet in Postoperative Scar Management.

    Science.gov (United States)

    Kim, Jin Sam; Hong, Joon Pio; Choi, Jong Woo; Seo, Dong Kyo; Lee, Eun Sook; Lee, Ho Seong

    2016-09-01

    Silicone gel sheeting has been introduced to prevent scarring, but objective evidence for its usefulness in scar healing is limited. Therefore, the authors' objective was to examine the effectiveness of silicone gel sheeting by randomly applying it to only unilateral scars from a bilateral hallux valgus surgery with symmetrical closure. In a prospective randomized, blinded, intraindividual comparison study, the silicone gel sheeting was applied to 1 foot of a hallux valgus incision scar (an experiment group) for 12 weeks upon removal of the stitches, whereas the symmetrical scar from the other foot was left untreated (a control group). The scars were evaluated at 4 and 12 weeks after the silicon sheet application. The Vancouver Scar Scale was used to measure the vascularity, pigmentation, pliability, height, and length of the scars. Adverse effects were also evaluated, and they included pain, itchiness, rash, erythema, and skin softening. At weeks 4 and 12, the experiment group scored significantly better on the Vancouver Scar Scale in all items, except length (P sheet does not cause adverse effects (P sheet application did show a significant improvement in prevention of postoperative scarring.

  13. Silicone rubber curing by high intensity infrared radiation

    International Nuclear Information System (INIS)

    Huang, T.; Tsai, J.; Cherng, C.; Chen, J.

    1994-01-01

    A high-intensity (12 kW) and compact (80 cm) infrared heating oven for fast curing (12 seconds) of tube-like silicone rubber curing studies is reported. Quality inspection by DSC and DMA and results from pilot-scale curing oven all suggest that infrared heating provides a better way of vulcanization regarding to curing time, quality, cost, and spacing over conventional hot air heating. copyright 1995 American Institute of Physics

  14. Pneumatic artificial rubber muscle using shape-memory polymer sheet with embedded electrical heating wire

    Science.gov (United States)

    Takashima, Kazuto; Sugitani, Kazuhiro; Morimoto, Naohiro; Sakaguchi, Seiya; Noritsugu, Toshiro; Mukai, Toshiharu

    2014-12-01

    Shape-memory polymer (SMP) can be deformed by applying a small load above its glass transition temperature (Tg). Shape-memory polymer maintains its shape after it has cooled below Tg and returns to a predefined shape when subsequently heated above Tg. The reversible change in the elastic modulus between the glassy and rubbery states of an SMP can be on the order of several hundred times. Based on the change in stiffness of the SMP in relation to the change in temperature, the present study attempts to evaluate the application of the SMP to soft actuators of a robot. In order to control the temperature of the SMP, we developed an SMP sheet with an embedded electrical heating wire. We formed a uniform, thin SMP sheet without air bubbles using a heat press. The SMP sheet with a heating wire can be heated quickly and can be maintained at a constant temperature. Moreover, the effects of the embedded wire on the mechanical properties in bending and tensile tests were small. Then, we applied the SMP sheet with the embedded electrical heating wire to a pneumatic artificial rubber muscle. The enhanced versatility of SMP sheet applications is demonstrated through a series of experiments conducted using a prototype. The initial shape and bending displacement of the pneumatic artificial rubber muscle can be changed by controlling the temperature of the SMP sheet.

  15. Accurate control of oxygen level in cells during culture on silicone rubber membranes with application to stem cell differentiation.

    Science.gov (United States)

    Powers, Daryl E; Millman, Jeffrey R; Bonner-Weir, Susan; Rappel, Michael J; Colton, Clark K

    2010-01-01

    Oxygen level in mammalian cell culture is often controlled by placing culture vessels in humidified incubators with a defined gas phase partial pressure of oxygen (pO(2gas)). Because the cells are consuming oxygen supplied by diffusion, a difference between pO(2gas) and that experienced by the cells (pO(2cell)) arises, which is maximal when cells are cultured in vessels with little or no oxygen permeability. Here, we demonstrate theoretically that highly oxygen-permeable silicone rubber membranes can be used to control pO(2cell) during culture of cells in monolayers and aggregates much more accurately and can achieve more rapid transient response following a disturbance than on polystyrene and fluorinated ethylene-propylene copolymer membranes. Cell attachment on silicone rubber was achieved by physical adsorption of fibronectin or Matrigel. We use these membranes for the differentiation of mouse embryonic stem cells to cardiomyocytes and compare the results with culture on polystyrene or on silicone rubber on top of polystyrene. The fraction of cells that are cardiomyocyte-like increases with decreasing pO(2) only when using oxygen-permeable silicone membrane-based dishs, which contract on silicone rubber but not polystyrene. The high permeability of silicone rubber results in pO(2cell) being equal to pO(2gas) at the tissue-membrane interface. This, together with geometric information from histological sections, facilitates development of a model from which the pO(2) distribution within the resulting aggregates is computed. Silicone rubber membranes have significant advantages over polystyrene in controlling pO(2cell), and these results suggest they are a valuable tool for investigating pO(2) effects in many applications, such as stem cell differentiation. Copyright 2009 American Institute of Chemical Engineers

  16. Thermal and thermo-mechanical behavior of butyl based rubber exposed to silicon oil at elevated temperature

    International Nuclear Information System (INIS)

    Ali, S.; Ramzan, S.; Raza, R.; Ahmed, F.; Hussain, R.; Ullah, S.; Ali, S.

    2013-01-01

    Silica reinforced rubbers are used as chemical resistant seals at high temperature. In this study the effect of alkali and silicon oil on the thermal and thermo-mechanical properties of the silica reinforced butyl rubber exposed as an interface between two liquid media at elevated temperature is investigated. Rubber bladder containing alkaline solution was immersed in silicon oil at 195+-5 degree C for multiple cycles and loss in its thermal, thermo-mechanical and mechanical properties were studied by TGA, DMA and Tinius Olsen Testing Machine supported by FTIR and Optical microscopy. It was observed that the thermal and thermo-mechanical properties of butyl rubber were negatively affected due to leaching out of silica filler embedded in an organic matrix at elevated temperature. The thermal stability of exposed rubber was decreased around 200 degree C and the loss of storage modulus was observed up to 99.5% at -59 degree C. (author)

  17. A cheap and simple passive sampler using silicone rubber for the ...

    African Journals Online (AJOL)

    caffeine, personal care products, pharmaceuticals, pesticides and polycyclic aromatic hydrocarbons. Keywords: passive sampler, silicone rubber (PDMS) tubing, GCxGC-TOFMS, ..... concentrations may be derived by using performance reference compounds to determine in situ passive sampler sampling rates followed by ...

  18. Fabrication of Extrinsically Conductive Silicone Rubbers with High Elasticity and Analysis of Their Mechanical and Electrical Characteristics

    Directory of Open Access Journals (Sweden)

    Anjum Saleem

    2010-08-01

    Full Text Available Conductive plastics are attracting more and more interest in electronics due to their light weight and inability to rust, which are common problems associated with metals. The field of conducting plastics is not new. Much work has been done to impart electrical conductivity to mechanically strong polymers such as polypropylene, polycarbonate and epoxies, etc. However there is a need to fabricate more flexible and elastic conductive polymers such as conducting silicone rubbers for use in various applications. In this work silicone rubbers reinforced with conductive fillers have been fabricated for use as sensors in textiles to detect the resistance change produced by stretching or relaxing. The variations of electrical resistance have been investigated by stretching and releasing the strands of conductive rubbers as a function of time. Two types of silicone rubbers—addition cured and condensation cured—were compounded with different electrically conductive fillers, among which carbon fibers have shown the best results. The carbon fibers improved the electrical conductance of the rubbers, even in very low weight percentages. The increasing concentration of fillers decreases the elasticity of the rubber. In order to keep the original properties of silicones, the filler concentration was kept as low as possible to produce a significantly detectable signal. The fabricated compounds were analyzed for their mechanical properties by stress strain curves. Such materials find their applications in electronics, antistatic applications, sports and the automotive industry where they can be used as deformation sensors.

  19. Solvent-free functionalization of silicone rubber and efficacy of PAAm brushes grafted from an amino-PPX layer against bacterial adhesion

    NARCIS (Netherlands)

    Fundeanu, Irina; Klee, Doris; Schouten, Arend J.; Busscher, Henk J.; van der Mei, Henny C.

    Silicone rubber is a frequently employed biomaterial that is prone to bacterial adhesion and biofilm formation. In this study, the surface of silicone rubber was solvent-free functionalized by chemical vapor deposition (CVD) of poly(o-amino-p-xylylene-co-p-xylylene (amino-PPX). Subsequently, the

  20. Pneumatic artificial rubber muscle using shape-memory polymer sheet with embedded electrical heating wire

    International Nuclear Information System (INIS)

    Takashima, Kazuto; Sugitani, Kazuhiro; Morimoto, Naohiro; Sakaguchi, Seiya; Noritsugu, Toshiro; Mukai, Toshiharu

    2014-01-01

    Shape-memory polymer (SMP) can be deformed by applying a small load above its glass transition temperature (T g ). Shape-memory polymer maintains its shape after it has cooled below T g and returns to a predefined shape when subsequently heated above T g . The reversible change in the elastic modulus between the glassy and rubbery states of an SMP can be on the order of several hundred times. Based on the change in stiffness of the SMP in relation to the change in temperature, the present study attempts to evaluate the application of the SMP to soft actuators of a robot. In order to control the temperature of the SMP, we developed an SMP sheet with an embedded electrical heating wire. We formed a uniform, thin SMP sheet without air bubbles using a heat press. The SMP sheet with a heating wire can be heated quickly and can be maintained at a constant temperature. Moreover, the effects of the embedded wire on the mechanical properties in bending and tensile tests were small. Then, we applied the SMP sheet with the embedded electrical heating wire to a pneumatic artificial rubber muscle. The enhanced versatility of SMP sheet applications is demonstrated through a series of experiments conducted using a prototype. The initial shape and bending displacement of the pneumatic artificial rubber muscle can be changed by controlling the temperature of the SMP sheet. (paper)

  1. Experimental and numerical studies on the sensitivity of carbon fibre/silicone rubber composite sensors

    International Nuclear Information System (INIS)

    Yang, Lili; Ge, Yong; Zhu, Qinghua; Zhang, Ce; Wang, Zongpeng; Liu, Penghuan

    2012-01-01

    Flexible conductive composite sensors are of great importance for applications in structural monitoring due to their low cost, high durability and excellent compatibility. In this work, carbon fibre/silicone rubber composites were prepared and their sensitivity near the percolation threshold was investigated experimentally and theoretically. Results show that carbon fibre/silicone rubber composites have great mechanical and sensitivity even under high strain conditions. Two models based on the tunnelling effect and general effective medium theory were found to understand the sensitivity of composites with lower and higher fractions of carbon fibre. Moreover, the reversibility of the sensing performance is improved with the increase of carbon fibre addition. (paper)

  2. Hydrogen passivation of silicon sheet solar cells

    International Nuclear Information System (INIS)

    Tsuo, Y.S.; Milstein, J.B.

    1984-01-01

    Significant improvements in the efficiencies of dendritic web and edge-supported-pulling silicon sheet solar cells have been obtained after hydrogen ion beam passivation for a period of ten minutes or less. We have studied the effects of the hydrogen ion beam treatment with respect to silicon material damage, silicon sputter rate, introduction of impurities, and changes in reflectance. The silicon sputter rate for constant ion beam flux of 0.60 +- 0.05 mA/cm 2 exhibits a maximum at approximately 1400-eV ion beam energy

  3. Shock compression parameters for a boron-loaded, silicone-rubber composite

    International Nuclear Information System (INIS)

    Gust, W.H.; Van Thiel, M.; Gathers, G.R.

    1975-01-01

    Hugoniot parameters under uniaxial-shock-wave-loading from 0.03 to 0.6 Mbar are presented for a composite with 70 wt percent boron loaded in a silicone-rubber matrix. The plot of shock velocity vs particle velocity was found to be nonlinear. Equations that describe fits of the data are presented. (U.S.)

  4. Filled liquid silicone rubbers: Possibilities and challenges

    DEFF Research Database (Denmark)

    Yu, Liyun; Vudayagiri, Sindhu; Zakaria, Shamsul Bin

    2014-01-01

    to ensure better particle dispersion as well as folllowing for film formation properties. We show that the mechanical properties of the films as well as the electrical breakdown strength can be affected, and that the control of the amount of solvent throughout the coating process is essential for solvent......Liquid silicone rubbers (LSRs) have been shown to possess very favorable properties as dielectric electroactive polymers due to their very high breakdown strengths (up to 170 V/μm) combined with their fast response, relatively high tear strength, acceptable Young’s modulus as well as they can...

  5. Synergistic effect and mechanism of platinum catalyst and nitrogen-containing silane on the thermal stability of silicone rubber

    International Nuclear Information System (INIS)

    Chen, Wanjuan; Zeng, Xingrong; Lai, Xuejun; Li, Hongqiang; Fang, Weizhen; Liu, Tian

    2016-01-01

    Highlights: • Platinum (Pt) and nitrogen-containing silane (NS) were introduced into silicone rubber. • The thermal stability was improved by Pt/NS both under nitrogen and air atmosphere. • The TG-FTIR of evolved gases during degradation was performed. • The synergistic effect and mechanism of Pt and NS were proposed. - Abstract: Platinum (Pt) catalyst and nitrogen-containing silane (NS) were introduced to improve the thermal stability of silicone rubber. The effects of Pt and NS on thermal stability and degradation mechanism of silicone rubber were investigated by thermogravimetry (TG), thermogravimetry-Fourier transform infrared spectrometry (TG-FTIR), scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDXS) and Fourier transform infrared spectrometry (FTIR). A significant synergism was found between Pt and NS for improving the thermal stability of silicone rubber. When 6.67 ppm of Pt and 1.4 phr of NS were introduced, the temperature of 10% and 20% weight loss under nitrogen atmosphere were respectively increased by 36 °C and 119 °C. Meanwhile, the residue weight at 900 °C was doubled to 68% in the presence of Pt/NS. The synergistic mechanism might be that the nitrogen atom coordinated with Pt and improved the catalytic efficiency of Pt. Additionally, NS preserved the catalytic activity of Pt under air atmosphere. Hence, Pt/NS efficiently catalyzed thermal crosslinking and suppressed degradation of silicone chains. Moreover, it revealed that the presence of Pt/NS protected silicone chains from oxidation. Thus, the unzipping depolymerization by silanol groups was reduced significantly.

  6. Synergistic effect and mechanism of platinum catalyst and nitrogen-containing silane on the thermal stability of silicone rubber

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Wanjuan; Zeng, Xingrong, E-mail: psxrzeng@gmail.com; Lai, Xuejun; Li, Hongqiang; Fang, Weizhen; Liu, Tian

    2016-05-20

    Highlights: • Platinum (Pt) and nitrogen-containing silane (NS) were introduced into silicone rubber. • The thermal stability was improved by Pt/NS both under nitrogen and air atmosphere. • The TG-FTIR of evolved gases during degradation was performed. • The synergistic effect and mechanism of Pt and NS were proposed. - Abstract: Platinum (Pt) catalyst and nitrogen-containing silane (NS) were introduced to improve the thermal stability of silicone rubber. The effects of Pt and NS on thermal stability and degradation mechanism of silicone rubber were investigated by thermogravimetry (TG), thermogravimetry-Fourier transform infrared spectrometry (TG-FTIR), scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDXS) and Fourier transform infrared spectrometry (FTIR). A significant synergism was found between Pt and NS for improving the thermal stability of silicone rubber. When 6.67 ppm of Pt and 1.4 phr of NS were introduced, the temperature of 10% and 20% weight loss under nitrogen atmosphere were respectively increased by 36 °C and 119 °C. Meanwhile, the residue weight at 900 °C was doubled to 68% in the presence of Pt/NS. The synergistic mechanism might be that the nitrogen atom coordinated with Pt and improved the catalytic efficiency of Pt. Additionally, NS preserved the catalytic activity of Pt under air atmosphere. Hence, Pt/NS efficiently catalyzed thermal crosslinking and suppressed degradation of silicone chains. Moreover, it revealed that the presence of Pt/NS protected silicone chains from oxidation. Thus, the unzipping depolymerization by silanol groups was reduced significantly.

  7. Organic filler from golden apple snails shells to improve the silicone rubber insulator properties

    Science.gov (United States)

    Tepsila, Sujirat; Suksri, Amnart

    2018-02-01

    This paper investigates the effect of an addition of filler compound using golden apple snail shell as an organic filler to the silicone rubber insulator. The filler obtained from golden apple snail shell is found mostly contained calcium carbonate. The organic calcium carbonate (CaCO3) with particle size of 45, 75, 100 and 300 micron were prepared. Sample of silicone rubber that were filled with fillers were tested under ASTM D638-02a type standard for mechanical test. Also, electrical test such as I-V characteristics (ASTM D257-07) and dry arc test according to ASTM D495-14 have been performed. The results revealed that using larger particle size of organic filler obtained from the golden apple snail shell resulted to higher value of dielectric constant as well as higher dielectric strength. Also, the filler helps slow down the tracking activity at an insulator surface due to its crystals of calcium carbonate. However, when using excessive amount of filler, the sample will have a drawbacks in mechanical properties. By using agriculture waste as a filler compound, one can reduced the usage of commercial CaCO3 as an inorganic materials and to lower the investment cost to a final silicone rubber product.

  8. An original architectured NiTi silicone rubber structure for biomedical applications

    Czech Academy of Sciences Publication Activity Database

    Rey, T.; Le Cam, J.B.; Chagnon, G.; Favier, D.; Rebouah, M.; Razan, F.; Robin, E.; Didier, P.; Heller, Luděk; Faure, S.; Janouchová, Kateřina

    2014-01-01

    Roč. 45, Dec (2014), s. 184-190 ISSN 0928-4931 Institutional support: RVO:68378271 Keywords : adhesion * interface * NiTi * filled silicone rubber * biomedical applications * architectured composite Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 3.088, year: 2014

  9. Interfacial Adhesion and Damping Characteristics of Laminated Veneer Lumber Intercalated with Rubber Sheets

    Directory of Open Access Journals (Sweden)

    Jingquan Han

    2016-06-01

    Full Text Available Laminated wood veneer lumber intercalated with rubber sheets (LLVR was fabricated using a layered adhesive system composed of polyaryl polymethylene isocyanate (PAPI for wood-rubber inter-bonding and phenol formaldehyde (PF resin to glue the wood veneers. The optimized manufacturing process (chloroprene rubber: CR; PAPI: 80 g/m2; PF: 200 g/m2; and silane: 9.0 wt.% was determined. The process as developed was then utilized to fabricate nine-ply LLVRs of five balanced constructions with two or three CR laminates used as various layers. The physico-mechanical properties of the LLVRs were evaluated, and the results showed that LLVRs had strong shear strength, sound dimensional stability, decent bending strength, and favorable toughening and buffering performances. The newly developed product is an interesting potential alternative to traditional laminated veneer lumber or plywood.

  10. Effect of expanded graphite and PEI-co-Silicon Rubber on the thermo mechanical, morphological as well as rheological properties of in situ composites based on poly (ether imide) and liquid crystalline polymer

    Energy Technology Data Exchange (ETDEWEB)

    Hatui, Goutam, E-mail: hatui.goutam@gmail.com; Malas, Asish, E-mail: malasasish@gmail.com; Bhattacharya, Pallab; Dhibar, Saptarshi, E-mail: saptaaus2007@gmail.com; Kundu, Mrinal Kanti, E-mail: kanti.mrinal19@gmail.com; Kumar Das, Chapal, E-mail: chapal12@yahoo.co.in

    2015-01-15

    Highlights: • PEI/LCP/ PEI-co-Silicon Rubber/EG and PEI/LCP/MWCNT nano composites are prepared by melt blending method. • The dispersions of acid modified expanded graphite were improved in presence of PEI-co-Silicon Rubber. • Thermal stability was found to be highest for PLGC composite. • Storage modulus and Young’s modulus showed an upward trend with incorporation of only EG and EG in presence of PEI-co-Silicon Rubber. • Among the nano composites PLGC has highest viscosity. - Abstract: Nanocomposites of polyether imide (PEI) and liquid crystalline polymer (LCP) with either MWCNT, Expanded Graphite (EG) or in combination of both EG and PEI-co-Silicon Rubber were prepared by melt blending process. The compatibility between the polymeric phases (PEI and LCP) was observed to be increased by the addition of PEI-co-Silicon Rubber while the only MWCNT added system (PLC) resulted in smaller LCP droplets. A continuous morphology was produced in presence of both PEI-co-Silicon Rubber and EG both added system (PLGR). This was due to the compatibilizing effect of PEI-co-Silicon Rubber. FTIR analysis revealed interaction between PEI and LCP in presence of PEI-co-Silicon Rubber. Remarkable increment of storage modulus was observed with the addition of EG and PEI-co-Silicon Rubber. Transmission Electron Microscope (TEM) analysis showed better dispersion of multiple graphene layers of EG in presence of PEI-co-Silicon Rubber compatibilized system. Tensile and Young’s modulus both were highest for EG/ PEI-co-Silicon Rubber added system. This is due to flexible compatibilizing effect of PEI-co-Silicon Rubber which delayed the detachment of LCP domain from the PEI matrix and thus detains the fracture.

  11. Effect of expanded graphite and PEI-co-Silicon Rubber on the thermo mechanical, morphological as well as rheological properties of in situ composites based on poly (ether imide) and liquid crystalline polymer

    International Nuclear Information System (INIS)

    Hatui, Goutam; Malas, Asish; Bhattacharya, Pallab; Dhibar, Saptarshi; Kundu, Mrinal Kanti; Kumar Das, Chapal

    2015-01-01

    Highlights: • PEI/LCP/ PEI-co-Silicon Rubber/EG and PEI/LCP/MWCNT nano composites are prepared by melt blending method. • The dispersions of acid modified expanded graphite were improved in presence of PEI-co-Silicon Rubber. • Thermal stability was found to be highest for PLGC composite. • Storage modulus and Young’s modulus showed an upward trend with incorporation of only EG and EG in presence of PEI-co-Silicon Rubber. • Among the nano composites PLGC has highest viscosity. - Abstract: Nanocomposites of polyether imide (PEI) and liquid crystalline polymer (LCP) with either MWCNT, Expanded Graphite (EG) or in combination of both EG and PEI-co-Silicon Rubber were prepared by melt blending process. The compatibility between the polymeric phases (PEI and LCP) was observed to be increased by the addition of PEI-co-Silicon Rubber while the only MWCNT added system (PLC) resulted in smaller LCP droplets. A continuous morphology was produced in presence of both PEI-co-Silicon Rubber and EG both added system (PLGR). This was due to the compatibilizing effect of PEI-co-Silicon Rubber. FTIR analysis revealed interaction between PEI and LCP in presence of PEI-co-Silicon Rubber. Remarkable increment of storage modulus was observed with the addition of EG and PEI-co-Silicon Rubber. Transmission Electron Microscope (TEM) analysis showed better dispersion of multiple graphene layers of EG in presence of PEI-co-Silicon Rubber compatibilized system. Tensile and Young’s modulus both were highest for EG/ PEI-co-Silicon Rubber added system. This is due to flexible compatibilizing effect of PEI-co-Silicon Rubber which delayed the detachment of LCP domain from the PEI matrix and thus detains the fracture

  12. Biofilm formation and design features of indwelling silicone rubber tracheoesophageal voice prostheses - An electron microscopical study

    NARCIS (Netherlands)

    Leunisse, C; van Weissenbruch, R; Busscher, HJ; van der Mei, HC; Dijk, F; Albers, FWJ

    2001-01-01

    After total laryngectomy, voice can be restored with a silicone rubber tracheoesophageal voice prosthesis. However, biofilm formation and subsequent deterioration of the silicone material of the prosthesis will limit device life by impairing valve function. To simulate the natural process of biofilm

  13. Development of silicone rubber-type neutron shielding material

    International Nuclear Information System (INIS)

    Do, Jae Bum; Cho, Soo Hang; Kim, Ik Soo; Oh, Seung Chul; Hong, Soon Seok; Noh, Sung Ki; Jeong, Duk Yeon.

    1997-06-01

    Because the exposure to radiation in the nuclear facilities can be fatal to human, it is important to reduce the radiation dose level to a tolerable level. The purpose of this study is to develop highly effective neutron shielding materials for the shipping and storage cask of radioactive materials or in the nuclear/radiation facilities. On this study, we developed silicone rubber based neutron shielding materials and their various material properties, including neutron shielding ability, fire resistance, combustion characteristics, radiation resistance, thermal and mechanical properties were evaluated experimentally. (author). 16 tabs., 17 figs., 25 refs

  14. Capillaric penetration of etchant solution into swift heavy ion-irradiated silicone rubber

    International Nuclear Information System (INIS)

    Fink, D.; Mueller, M.

    2000-01-01

    There is growing evidence that etchants penetrate into latent ion tracks in polymers from the very beginning, i.e., even during the so-called 'incubation time' when no visible etchant attack is observed. The model of capillaric penetration of viscous liquids into sponge-like matter agrees with experimental values both in their parametric dependence as in the absolute values. Our experiments are based on LiOH etching of both pristine and swift heavy ion-irradiated silicone rubber foils. About five times more etchant penetrates into irradiated than into pristine silicone rubber. The overall etchant penetration is highest in tracks parallel to the surface normal, and decreases with increasing ion track tilt angle towards the surface normal. The etchant penetration into the tracks proceeds relatively slowly with an effective viscosity comparable to that of heavy machine oil. When swelling starts to predominate, the maximum etchant penetration depth comes to saturation, with the total etchant uptake even decreasing

  15. Relationship Between Cell Compatibility and Elastic Modulus of Silicone Rubber/Organoclay Nanobiocomposites

    Science.gov (United States)

    Hosseini, Motahare Sadat; Tazzoli-Shadpour, Mohammad; Amjadi, Issa; Haghighipour, Nooshin; Shokrgozar, Mohammad Ali; Ghafourian Boroujerdnia, Mehri

    2012-01-01

    Background Substrates in medical science are hydrophilic polymers undergoing volume expansion when exposed to culture medium that influenced on cell attachment. Although crosslinking by chemical agents could reduce water uptake and promote mechanical properties, these networks would release crosslinking agents. In order to overcome this weakness, silicone rubber is used and reinforced by nanoclay. Objectives Attempts have been made to prepare nanocomposites based on medical grade HTV silicone rubber (SR) and organo-modified montmorillonite (OMMT) nanoclay with varying amounts of clay compositions. Materials and Methods Incorporation of nanocilica platelets into SR matrix was carried out via melt mixing process taking advantage of a Brabender internal mixer. The tensile elastic modulus of nanocomposites was measured by performing tensile tests on the samples. Produced polydimetylsiloxane (PDMS) composites with different flexibilities and crosslink densities were employed as substrates to investigate biocompatibility, cell compaction, and differential behaviors. Results The results presented here revealed successful nanocomposite formation with SR and OMMT, resulting in strong PDMS-based materials. The results showed that viability, proliferation, and spreading of cells are governed by elastic modulus and stiffness of samples. Furthermore, adipose derived stem cells (ADSCs) cultured on PDMS and corresponding nanocomposites could retain differentiation potential of osteocytes in response to soluble factors, indicating that inclusion of OMMT would not prevent osteogenic differentiation. Moreover, better spread out and proliferation of cells was observed in nanocomposite samples. Conclusions Considering cell behavior and mechanical properties of nanobiocomposites it could be concluded that silicone rubber substrate filled by nanoclay are a good choice for further experiments in tissue engineering and medical regeneration due to its cell compatibility and differentiation

  16. Streptococcus thermophilus and its biosurfactants inhibit adhesion by Candida spp. on silicone rubber

    NARCIS (Netherlands)

    Busscher, HJ; vanHoogmoed, CG; GeertsemaDoornbusch, GI; vanderKuijlBooij, M; vanderMei, HC

    1997-01-01

    The adhesion of yeasts, two Candida albicans and two Candida tropicalis strains isolated from naturally colonized voice prostheses, to silicone rubber with and without a salivary conditioning film in the absence and presence of adhering Streptococcus thermophilus B, a biosurfactant-releasing dairy

  17. Improved hemocompatibility of silicone rubber extracorporeal tubing via solvent swelling-impregnation of S-nitroso-N-acetylpenicillamine (SNAP) and evaluation in rabbit thrombogenicity model.

    Science.gov (United States)

    Brisbois, Elizabeth J; Major, Terry C; Goudie, Marcus J; Bartlett, Robert H; Meyerhoff, Mark E; Handa, Hitesh

    2016-06-01

    Blood-contacting devices, including extracorporeal circulation (ECC) circuits, can suffer from complications due to platelet activation and thrombus formation. Development of nitric oxide (NO) releasing polymers is one method to improve hemocompatibility, taking advantage of the ability of low levels of NO to prevent platelet activation/adhesion. In this study a novel solvent swelling method is used to load the walls of silicone rubber tubing with the NO donor S-nitroso-N-acetylpenicillamine (SNAP). This SNAP-silicone rubber tubing exhibits an NO flux of ca. 1×10(-10)molcm(-2)min(-1), which mimics the range of NO release from the normal endothelium, which is stable for at least 4h. Images of the tubing before and after swelling, obtained via scanning electron microscopy, demonstrate that this swelling method has little effect on the surface properties of the tubing. The SNAP-loaded silicone rubber and silicone rubber control tubing are used to fabricate ECC circuits that are evaluated in a rabbit model of thrombogenicity. After 4h of blood flow, the SNAP-loaded silicone rubber circuits were able to preserve the blood platelet count at 64% of baseline (vs. 12% for silicone rubber control). A 67% reduction in the degree of thrombus formation within the thrombogenicity chamber was also observed. This study demonstrates the ability to improve the hemocompatibility of existing/commercial silicone rubber tubing via a simple solvent swelling-impregnation technique, which may also be applicable to other silicone-based blood-contacting devices. Localized nitric oxide (NO) release can be achieved from biomedical grade polymers doped with S-nitroso-N-acetylpenicillamine (SNAP). Despite the promising in vitro and in vivo biocompatibility results reported for these NO releasing polymers, many of these materials may face challenges in being translated to clinical applications, especially in the areas of polymer processing and manufacturing. In this study, we report a solvent

  18. Aligned carbon nanotube-silicon sheets: a novel nano-architecture for flexible lithium ion battery electrodes.

    Science.gov (United States)

    Fu, Kun; Yildiz, Ozkan; Bhanushali, Hardik; Wang, Yongxin; Stano, Kelly; Xue, Leigang; Zhang, Xiangwu; Bradford, Philip D

    2013-09-25

    Aligned carbon nanotube sheets provide an engineered scaffold for the deposition of a silicon active material for lithium ion battery anodes. The sheets are low-density, allowing uniform deposition of silicon thin films while the alignment allows unconstrained volumetric expansion of the silicon, facilitating stable cycling performance. The flat sheet morphology is desirable for battery construction. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Tissue response to silicone rubber when used as a root canal filling.

    Science.gov (United States)

    Kasman, F G; Goldman, M

    1977-04-01

    To test the tissue compatibility of silicone rubber when it is used as a root canal filler, excess material was intentionally forced into the apical tissues in primates. The tissue response was one of general acceptance, with the usual response being fibrotic encapsulation. A low degree of inflammation was noted. Further studies are in progress.

  20. INTRAVASAL INJECTION OF FORMED-IN-PLACE MEDICAL GRADE SILICONE-RUBBER FOR VAS OCCLUSION

    NARCIS (Netherlands)

    SOEBADI, DM; GARDJITO, W; MENSINK, HJA

    This paper describes two consecutive studies: a volume study and an efficacy study. The volume study determined the appropriate volume of Medical Grade Silicone Rubber (MSR) needed to achieve complete occlusion of the vas deferens. This was done by in-vitro testing of 130 human vas specimens

  1. Comparison between electron-beam and chemical crosslinking of silicone rubber

    Energy Technology Data Exchange (ETDEWEB)

    Frounchi, Masoud [Polymer Engineering Group, Department of Chemical and Petroleum Engineering, Sharif University of Technology, Azadi Ave, Tehran (Iran, Islamic Republic of)]. E-mail: frounchi@sharif.edu; Dadbin, Susan [Yazd Processing Center, Atomic Energy Organization of Iran, Tehran (Iran, Islamic Republic of); Panahinia, Farhad [Polymer Engineering Group, Department of Chemical and Petroleum Engineering, Sharif University of Technology, Azadi Ave, Tehran (Iran, Islamic Republic of)

    2006-02-15

    Silicone rubber (SR) was irradiated by electron beam over a dose range of 50-300 kGy in the absence of chemical reagents. Molecular weight between crosslinks (M {sub c}) in the network of SB was determined by two methods of solvent swelling and modulus of elasticity. The network structure of the elastomer crosslinked by electron beam irradiation and chemical vulcanization was compared. Mechanical tests were performed to determine shore hardness, tensile elongation, strength and modulus of the samples. It was found that SR is effectively crosslinked by electron beam irradiation. The tensile strength, hardness, modulus and elongation of irradiated SR were higher than peroxide-crosslinked SR. The optimum dose for the neat rubber was 150 kGy which reduced to 50 kGy with addition of 10 wt.% fumed silica. The synergistic effect of fumed silica was verified by M {sub c} measurements which showed a dramatic decrease in presence of fumed silica in the rubber. The synergism in properties was also verified by comparing the modulus values calculated from the Guth-Smallwood equation and experimental data. Absence of chemical reagents in irradiated SR samples makes them a proper choice for medical applications.

  2. A flexible piezoresistive carbon black network in silicone rubber for wide range deformation and strain sensing

    Science.gov (United States)

    Zhu, Jianxiong; Wang, Hai; Zhu, Yali

    2018-01-01

    This work presents the design, fabrication, and measurement of a piezoresistive device with a carbon black (CB) particle network in a highly flexible silicone rubber for large deformation and wide range strain sensing. The piezoresistive composite film was fabricated with a mixture of silicone rubber and CB filler particles. The test results showed that the CB particle network in the silicone rubber strongly affected the resistance of the device during the process of drawing and its recovery. We found that the 50% volume ratio of CB filler particles showed a lower relative resistance than the 33.3% volume ratio of CB filler particles, but with an advantage of good resistance recovery stability and a smaller perturbation error (smaller changed resistance) during the periodic back and forth linear motor test. With both having a 50% volume ratio of CB filler particles and a 33.3% volume ratio of CB filler particles, one can reach up to 200% strain with resistances 18 kΩ and 110 kΩ, respectively. We also found that the relative resistance increased in an approximately linear relationship corresponding to the value of step-increased instantaneous length for the reported device. Moreover, an application test through hand drawing was used to demonstrate the piezoresistive performance of the device, which showed that the reported device was capable of measuring the instantaneous length with large deformation.

  3. PLA and two components silicon rubber blends aiming for frozen foods packaging applications

    Science.gov (United States)

    Meekum, Utai; Khiansanoi, Apichart

    2018-03-01

    Designing of PLA and two components silicone rubber blends was studies. Frozen food packaging application is the main ultimate aim. The statistical method using 23 DOE was conducted. The standard testing methods, in particular impact testing at sub-zero temperature, were performed. The preliminary blend formula comprised 1.0 phr of silane and polyester polyols, respectively, was initially resolved. Then, the optimize the silicone portion in the blends was determined. Blending formula using 8.0 phr of silicone with respect to PLA matrix gave rise to the overall satisfactory properties. 3. TETA was used as the silicone curing agent and reactively blended onto the ingredients. TETA at 0.4 phr, with respect to the silicone, enhanced the mechanical properties, especially flexibility and toughness, of the PLA/silicone blend. Exceeding the optimal TETA loading would cause the chain scission and also the dilution effects. Hence, marginal inferior properties of the blends were be experienced. The preliminary biodegradability investigation found that the PLA/silicone blend initially triggered at the second week. Its degradation rate was likely to be faster than neat PLA.

  4. Effect of pyrolysis atmospheres on the morphology of polymer-derived silicon oxynitrocarbide ceramic films coated aluminum nitride surface and the thermal conductivity of silicone rubber composites

    Science.gov (United States)

    Chiu, Hsien T.; Sukachonmakul, Tanapon; Wang, Chen H.; Wattanakul, Karnthidaporn; Kuo, Ming T.; Wang, Yu H.

    2014-02-01

    Amorphous silicon oxycarbide (SiOC) and silicon oxynitrocarbide (SiONC) ceramic films coated aluminum nitride (AlN) were prepared by using preceramic-polysilazane (PSZ) with dip-coating method, followed by pyrolysis at 700 °C in different (air, Ar, N2 and NH3) atmospheres to converted PSZ into SiOCair and SiONC(Ar,N2andNH3) ceramic. The existence of amorphous SiOCair and SiONC(Ar,N2andNH3) ceramic films on AlN surface was characterized by FTIR, XRD and XPS. The interfacial adhesion between silicone rubber and AlN was significantly improved after the introduction of amorphous SiOCair and SiONC(Ar,N2andNH3) ceramic films on AlN surface. It can be observed from AFM that the pyrolysis of PSZ at different atmosphere strongly affected to films morphology on AlN surface as SiOCair and SiONCNH3 ceramic films were more flat and smooth than SiONCN2 and SiONCAr ceramic films. Besides, the enhancement of the thermal conductivity of silicone rubber composites was found to be related to the decrease in the surface roughness of SiOCair and SiONC(Ar,N2andNH3) ceramic films on AlN surface. This present work provided an alternative surface modification of thermally conductive fillers to improve the thermal conductivity of silicon rubber composites by coating with amorphous SiOCair and SiONC(Ar,N2andNH3) ceramic films.

  5. Air-flow resistances of silicone rubber voice prostheses after formation of bacterial and fungal biofilms

    NARCIS (Netherlands)

    Elving, GJ; van der Mei, HC; Busscher, HJ; van Weissenbruch, R; Albers, FWJ

    Laryngectomized patients use silicone rubber voice prostheses to rehabilitate their voice. However, biofilm formation limits the lifetime of voice prostheses by causing leakage or an increased air-flow resistance and the prosthesis has to be replaced. To determine which bacterial or yeast strains,

  6. Evaluation of diagnostic technique for degradation of low-voltage electric cables with silicone rubber insulator

    International Nuclear Information System (INIS)

    Mikami, Masao

    2005-01-01

    As a part of countermeasures against ageing problems of nuclear power plants, it is requested to establish non-destructive diagnostic technique for their degradation of low voltage electric cables and assessment standard of their life. Having aimed at investigating the degradation of low-voltage electric cable with silicone rubber insulator, change of its surface hardness at elevated temperature were measured by indenter modules. Moreover, we also measured the elongation at break, which is regarded as general degradation index of electric cables, and the surface hardness with a micro hardness meter. Consequently, it is seen that the indenter modulus measurement is (1) capable to obtain general feature of the thermal degradation of silicone rubber insulator, (2) applicable to diagnose the degree of degradation of the electric cable by converting the result to elongation at break, (3) well correlated with the hardness measurement of the electric cable with the micro hardness meter. (author)

  7. PLA and two components silicon rubber blends aiming for frozen foods packaging applications

    Directory of Open Access Journals (Sweden)

    Utai Meekum

    2018-03-01

    Full Text Available Designing of PLA and two components silicone rubber blends was studies. Frozen food packaging application is the main ultimate aim. The statistical method using 23 DOE was conducted. The standard testing methods, in particular impact testing at sub-zero temperature, were performed. The preliminary blend formula comprised 1.0 phr of silane and polyester polyols, respectively, was initially resolved. Then, the optimize the silicone portion in the blends was determined. Blending formula using 8.0 phr of silicone with respect to PLA matrix gave rise to the overall satisfactory properties. 3. TETA was used as the silicone curing agent and reactively blended onto the ingredients. TETA at 0.4 phr, with respect to the silicone, enhanced the mechanical properties, especially flexibility and toughness, of the PLA/silicone blend. Exceeding the optimal TETA loading would cause the chain scission and also the dilution effects. Hence, marginal inferior properties of the blends were be experienced. The preliminary biodegradability investigation found that the PLA/silicone blend initially triggered at the second week. Its degradation rate was likely to be faster than neat PLA. Keywords: PLA/silicone blends, Mechanical properties, Sub-zero impact strength

  8. Improving Mechanical Properties of Molded Silicone Rubber for Soft Robotics Through Fabric Compositing.

    Science.gov (United States)

    Wang, Yue; Gregory, Cherry; Minor, Mark A

    2018-06-01

    Molded silicone rubbers are common in manufacturing of soft robotic parts, but they are often prone to tears, punctures, and tensile failures when strained. In this article, we present a fabric compositing method for improving the mechanical properties of soft robotic parts by creating a fabric/rubber composite that increases the strength and durability of the molded rubber. Comprehensive ASTM material tests evaluating the strength, tear resistance, and puncture resistance are conducted on multiple composites embedded with different fabrics, including polyester, nylon, silk, cotton, rayon, and several blended fabrics. Results show that strong fabrics increase the strength and durability of the composite, valuable in pneumatic soft robotic applications, while elastic fabrics maintain elasticity and enhance tear strength, suitable for robotic skins or soft strain sensors. Two case studies then validate the proposed benefits of the fabric compositing for soft robotic pressure vessel applications and soft strain sensor applications. Evaluations of the fabric/rubber composite samples and devices indicate that such methods are effective for improving mechanical properties of soft robotic parts, resulting in parts that can have customized stiffness, strength, and vastly improved durability.

  9. Solvent-free functionalization of silicone rubber and efficacy of PAAm brushes grafted from an amino-PPX layer against bacterial adhesion.

    Science.gov (United States)

    Fundeanu, Irina; Klee, Doris; Schouten, Arend J; Busscher, Henk J; van der Mei, Henny C

    2010-11-01

    Silicone rubber is a frequently employed biomaterial that is prone to bacterial adhesion and biofilm formation. In this study, the surface of silicone rubber was solvent-free functionalized by chemical vapor deposition (CVD) of poly(o-amino-p-xylylene-co-p-xylylene (amino-PPX). Subsequently, the amino groups of the amino-PPX layer were used to introduce the initiator from a vapor phase for atom transfer radical polymerization of acrylamide to form polyacrylamide (PAAm) brushes. The modification steps were verified by means of X-ray photoelectron spectroscopy and attenuated total reflection-Fourier transform infrared spectroscopy. Adhesion of Staphylococcus aureus ATCC 12600 and Escherichia coli 3.14 to an amino-PPX-PAAm brush coating in a parallel plate flow chamber was strongly reduced with respect to non-coated silicone rubber - by 93% and 99%, respectively. For E. coli 3.14, this reduction is larger than that obtained for solvent functionalization of γ-aminopropyltriethoxysilane-PAAm brushes due to the higher density of amino groups introduced by the CVD of amino-PPX. Copyright © 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  10. Effect of silica particles modified by in-situ and ex-situ methods on the reinforcement of silicone rubber

    International Nuclear Information System (INIS)

    Song, Yingze; Yu, Jinhong; Dai, Dan; Song, Lixian; Jiang, Nan

    2014-01-01

    Highlights: • In-situ and ex-situ methods were applied to modify silica particles. • In-situ method was more beneficial to preparing silica particles with high BET surface area. • Silicone rubber filled with in-situ modified silica exhibits excellent mechanical and thermal properties. - Abstract: In-situ and ex-situ methods were applied to modify silica particles in order to investigate their effects on the reinforcement of silicone rubber. Surface area and pore analyzer, laser particle size analyzer, Fourier-transform infrared spectroscopy (FTIR), contact-angle instrument, and transmission electron microscope (TEM) were utilized to investigate the structure and properties of the modified silica particles. Dynamic mechanical thermal analyzer (DMTA) was employed to characterize the vulcanizing behavior and mechanical properties of the composites. Thermogravimetric analysis (TGA) was performed to test the thermal stability of the composites. FTIR and contact angle analysis indicated that silica particles were successfully modified by these two methods. The BET surface area and TEM results reflected that in-situ modification was more beneficial to preparing silica particles with irregular shape and higher BET surface area in comparison with ex-situ modification. The DMTA and TGA data revealed that compared with ex-situ modification, the in-situ modification produced positive influence on the reinforcement of silicone rubber

  11. Inhibition of uropathogenic biofilm growth on silicone rubber in human urine by lactobacilli - a teleologic approach

    NARCIS (Netherlands)

    Velraeds, MMC; van de Belt-Gritter, B; Busscher, HJ; Reid, G; van der Mei, HC

    2000-01-01

    The ability of three Lactobacillus strains to inhibit the adhesion and growth of naturally occurring uropathogens on silicone rubber was investigated in human urine. The importance of biosurfactant production by Lactobacillus in discouraging uropathogen growth was determined in relation to the

  12. Effects of transverse temperature field nonuniformity on stress in silicon sheet growth

    Science.gov (United States)

    Mataga, P. A.; Hutchinson, J. W.; Chalmers, B.; Bell, R. O.; Kalejs, J. P.

    1987-01-01

    Stress and strain rate distributions are calculated using finite element analysis for steady-state growth of thin silicon sheet temperature nonuniformities imposed in the transverse (sheet width) dimension. Significant reductions in residual stress are predicted to occur for the case where the sheet edge is cooled relative to its center provided plastic deformation with high creep rates is present.

  13. Rubber molds for investment casting

    International Nuclear Information System (INIS)

    Sibtain, S.N.

    2011-01-01

    The main objective of the project is to investigate different types of molding rubbers used for investment casting. The level of shape complexity which can be achieved by using these rubber molds is also studied. It was almost impossible to make complex shapes molds using metal molds, in that cases rubber molds are very important because they arc flexible and give accurate and precise part dimensions. Turbine blades are hi-tech components with air-foil geometries that have close dimensional tolerances. They are made of super-alloys and manufactured by investment casting. The final blade profile depends upon the dimensional accuracy in each of the processing steps. In the present work experimental study for the production of high quality low cost castings of turbine blades using rubber molds and injected wax patterns is presented. Natural Rubber molds and wax patterns from these molds were made. Different types of molding rubbers were studied including natural rubber, silicone rubber and liquid silicone rubber. It was found that by using rubber molds we can make most complex shape with very less finishing required. The shrinkage was 12% as compared to original master pattern. Rubber molds were made using laboratory hot press. Three layers of rubber above and below the master pattern. After that vulcanization was done by giving temperature and pressure. (author)

  14. Preliminary observations on influence of dairy products on biofilm removal from silicone rubber voice prostheses in vitro

    NARCIS (Netherlands)

    Busscher, HJ; Free, RH; Van Weissenbruch, R; Albers, FWJ; Van der Mei, HC

    We determined oropharyngeal biofilm removal from silicone rubber voice prostheses in an artificial throat after perfusion with different commercially available dairy products, including buttermilk, Lactobacillus casei Shirota fermented milk (Yakult, Yakult Netherlands BV, Almere, The Netherlands),

  15. Impacts of Different Functional Groups on the Kinetic Rates of α-Amine Ketoximesilanes Hydrolysis in the Preparation of Room Temperature Vulcanized Silicone Rubber.

    Science.gov (United States)

    Xu, Huihui; Liu, Zihou; Liu, Qingyang; Bei, Yiling; Zhu, Qingzeng

    2018-05-13

    α-Amine ketoximesilanes are proven to be effective crosslinkers in the preparation of ketone-oxime one-component room temperature vulcanized (RTV) silicone rubber without the use of toxic metal catalyst. This work aimed to investigate the hydrolysis kinetic of α-amine ketoximesilanes, which is vitally important for the preparation of RTV silicone rubber. Five kinds of α-amine ketoximesilanes, namely α-(N,N-diethyl)aminomethyltri(methylethylketoxime)silane (DEMOS), α-(N,N-di-n-butyl)aminomethyltri(methylethylketoxime)silane (DBMOS), α-(N-n-butyl)aminomethyltri(methylethylketoxime)silane (n-BMOS), α-(N-cyclohexyl)aminomethyltri(methylethylketoxime)silane (CMOS) and α-(β-aminomethyl)aminomethyltri(methylethylketoxime)silane (AEMOS), were successfully obtained and confirmed using Fourier transform infrared spectrometer (FT-IR) and hydrogen-1 nuclear magnetic resonance ( ¹H NMR). Kinetics of hydrolysis reactions were measured by FT-IR and conductivity. Our results illustrated that the kinetic constant rates ranged from 12.2 × 10 −4 s −1 to 7.6 × 10 −4 s −1 , with the decreasing order of DEMOS > n-BMOS > DBMOS > CMOS > AEMOS at the given temperature and humidity. Better performances of thermal stability could be achieved when using the α-amine ketoximesilanes as crosslinkers in the preparation of RTV silicon rubber than that of RTV silicone rubber with the use of methyltri(methylethylketoxime)silane (MOS) as a crosslinker and organic tin as a catalyst.

  16. Silylation of cellulose nanocrystals and their reinforcement of commercial silicone rubber

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Hou-Yong, E-mail: phdyu@zstu.edu.cn; Chen, Rui; Chen, Guo-Yin [Zhejiang Sci-Tech University, The Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Ministry of Education, College of Materials and Textile (China); Liu, Lin; Yang, Xiao-Gang; Yao, Ju-Ming, E-mail: yaoj@zstu.edu.cn [Zhejiang Sci-Tech University, National Engineering Lab for Textile Fiber Materials & Processing Technology (China)

    2015-09-15

    Poor interfacial compatibility between unmodified cellulose nanocrystals (CNCs) and rubber restricts the property enhancement of matrix materials. In this study, according to structural similarity, the silylated CNC (SCNC) with diameter of 5–30 nm were prepared and incorporated into commercial silicone rubber (SR) via two-roll mill-compounding and vulcanization processes. As expected, at the same loading levels, SCNC had stronger reinforcing effect on the SR matrix than CNC. Compared to neat SR, with only 0.3 wt% (0.3 phr) SCNC1 incorporated, the tensile strength, Young’s modulus, storage tensile modulus, and maximum decomposition temperature (T{sub max}) of the nanocomposite were improved by 72, 125, 66 %, and 110.8 °C, respectively. Meanwhile the nanocomposites showed an obvious decrease in water vapor permeability (67 %). These enhancements were attributed to good dispersion of SCNC within SR matrix, improved interfacial interaction, and high crosslinking density.

  17. Effects of aging on the structural, mechanical, and thermal properties of the silicone rubber current transformer insulation bushing for a 500 kV substation.

    Science.gov (United States)

    Wang, Zhigao; Zhang, Xinghai; Wang, Fangqiang; Lan, Xinsheng; Zhou, Yiqian

    2016-01-01

    In order to analyze the cracking and aging reason of the silicone rubber current transformer (CT) insulation bushing used for 8 years from a 500 kV alternating current substation, characteristics including Fourier transform infrared (FTIR) spectroscopy, mechanical properties analysis, hardness, and thermo gravimetric analysis have been carried out. The FTIR results indicated that the external surface of the silicone rubber CT insulation bushing suffered from more serious aging than the internal part, fracture of side chain Si-C bond was much more than the backbone. Mechanical properties and thermal stability results illustrated that the main aging reasons were the breakage of side chain Si-C bond and the excessive cross-linking reaction of the backbone. This study can provide valuable basis for evaluating degradation mechanism and aging state of the silicone rubber insulation bushing in electric power field.

  18. White light scanner-based repeatability of 3-dimensional digitizing of silicon rubber abutment teeth impressions.

    Science.gov (United States)

    Jeon, Jin-Hun; Lee, Kyung-Tak; Kim, Hae-Young; Kim, Ji-Hwan; Kim, Woong-Chul

    2013-11-01

    The aim of this study was to evaluate the repeatability of the digitizing of silicon rubber impressions of abutment teeth by using a white light scanner and compare differences in repeatability between different abutment teeth types. Silicon rubber impressions of a canine, premolar, and molar tooth were each digitized 8 times using a white light scanner, and 3D surface models were created using the point clouds. The size of any discrepancy between each model and the corresponding reference tooth were measured, and the distribution of these values was analyzed by an inspection software (PowerInspect 2012, Delcamplc., Birmingham, UK). Absolute values of discrepancies were analyzed by the Kruskal-Wallis test and multiple comparisons (α=.05). The discrepancy between the impressions for the canine, premolar, and molar teeth were 6.3 µm (95% confidence interval [CI], 5.4-7.2), 6.4 µm (95% CI, 5.3-7.6), and 8.9 µm (95% CI, 8.2-9.5), respectively. The discrepancy of the molar tooth impression was significantly higher than that of other tooth types. The largest variation (as mean [SD]) in discrepancies was seen in the premolar tooth impression scans: 26.7 µm (95% CI, 19.7-33.8); followed by canine and molar teeth impressions, 16.3 µm (95% CI, 15.3-17.3), and 14.0 µm (95% CI, 12.3-15.7), respectively. The repeatability of the digitizing abutment teeth's silicon rubber impressions by using a white light scanner was improved compared to that with a laser scanner, showing only a low mean discrepancy between 6.3 µm and 8.9 µm, which was in an clinically acceptable range. Premolar impression with a long and narrow shape showed a significantly larger discrepancy than canine and molar impressions. Further work is needed to increase the digitizing performance of the white light scanner for deep and slender impressions.

  19. Optical characterization of RTV615 silicone rubber compound

    International Nuclear Information System (INIS)

    Li, W; Huber, G M

    2014-01-01

    Room Temperature Vulcanized (RTV) silicone compounds are commonly used to bond optical components. For our application, we needed to identify an adhesive with good ultraviolet transmission characteristics, to couple photomultipliers to quartz windows in a Heavy Gas Čerenkov detector that is being constructed for Experimental Hall C of Jefferson Lab to provide π/K separation up to 11 GeV/c. To this end, we present the light transmission results for Momentive RTV615 silicone rubber compound for wavelengths between 195-400 nm, obtained with an adapted reflectivity apparatus at Jefferson Lab. All samples cured at room temperature have transmissions ∼ 93% for wavelengths between 360-400 nm and fall sharply below 230 nm. Wavelength dependent absorption coefficients were extracted with four samples of different thicknesses cured at normal temperature (25° C for 7 days). The absorption coefficient drops approximately two orders in magnitude from 220-400 nm, exhibiting distinct regions of flattening near 250 nm and 330 nm. We also investigated the effect of a high temperature curing method (100° C for 1 hour) and found 5-10% better transmission than with the normal method. The effect was more significant with larger sample thickness (3.35 mm) over the wavelength range of 220-280 nm

  20. Acrylamide graft over silicone rubber tubes by simultaneous irradiation in 60 Co source

    International Nuclear Information System (INIS)

    Julio, C.A.; Higa, O.Z.

    1992-01-01

    The synthesis of a hydrogel having silicone rubber tubes as support was carried out through the radiation grafting technique. The best conditions for the grafting development were determined in relation to the monomer and inhibitor concentration, dose rate and irradiation dose. The addition of cupric ions in the process inhibited the acrylamide homo polymerization and enhanced the grafting yield. The water content in the grafted tubes characterized the hydrophilic property of the material. (author)

  1. Biomaterial characteristics and application of silicone rubber and PVA hydrogels mimicked in organ groups for prostate brachytherapy.

    Science.gov (United States)

    Li, Pan; Jiang, Shan; Yu, Yan; Yang, Jun; Yang, Zhiyong

    2015-09-01

    It is definite that transparent material with similar structural characteristics and mechanical properties to human tissue is favorable for experimental study of prostate brachytherapy. In this paper, a kind of transparent polyvinyl alcohol (PVA) hydrogel and silicone rubber are developed as suitable substitutions for human soft tissue. Segmentation and 3D reconstruction of medical image are performed to manufacture the mould of organ groups through rapid prototyping technology. Micro-structure observation, force test and CCD deformation test have been conducted to investigate the structure and mechanical properties of PVA hydrogel used in organ group mockup. Scanning electron microscope (SEM) image comparison results show that PVA hydrogel consisting of 3 g PVA, 17 g de-ionized water, 80 g dimethyl-sulfoxide (DMSO), 4 g NaCl, 1.5 g NaOH, 3 g epichlorohydrin (ECH) and 7 freeze/thaw cycles reveals similar micro-structure to human prostate tissue. Through the insertion force comparison between organ group mockup and clinical prostate brachytherapy, PVA hydrogel and silicone rubber are found to have the same mechanical properties as prostate tissue and muscle. CCD deformation test results show that insertion force suffers a sharp decrease and a relaxation of tissue deformation appears when needle punctures the capsule of prostate model. The results exhibit that organ group mockup consisting of PVA hydrogel, silicone rubber, membrane and agarose satisfies the needs of prostate brachytherapy simulation in general and can be used to mimic the soft tissues in pelvic structure. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Butyl Rubber: Compound Development and Characterization

    National Research Council Canada - National Science Library

    Sloan, James

    2000-01-01

    ...), to develop the standard butyl rubber compound. The strategy of this work was to compound- and compression-mold high-quality, uniform butyl rubber experimental sheets and to evaluate their cure properties, mechanical properties...

  3. Dielectric and Carrier Transport Properties of Silicone Rubber Degraded by Gamma Irradiation

    Directory of Open Access Journals (Sweden)

    Daomin Min

    2017-10-01

    Full Text Available Silicone rubber (SiR is used as an insulating material for cables installed in a nuclear power plant. Gamma rays irradiated SiR sheets for various periods at temperatures of 145 and 185 °C, and the resultant changes were analyzed by examining complex permittivity spectra and surface potential decay characteristics. Three different processes, namely, instantaneous polarization, electrode polarization due to the accumulation of ions to form double charge layers at dielectric/electrode interfaces, and DC conduction caused by directional hopping of ions, contribute to the complex permittivity. By fitting the spectra to theoretical equations, we can obtain the dielectric constant at high frequencies, concentration and diffusion coefficient of ions and DC conductivity for the pristine and degraded samples. The instantaneous polarization becomes active with an increase of dose and ageing temperature. The thermal expansion coefficient estimated from the temperature dependence of dielectric constant at high frequencies becomes smaller with an increase in dose, which is in good agreement with the experimental results of the swelling ratio. Additionally, trap distributions are calculated from surface potential decay measurements and analyzed to explain the variation in conductivity. Trap energy increases firstly, and then decreases with an increase in dose, leading to a similar change in DC conductivity. It is concluded that generations of both oxidative products and mobile ions, as well as the occurrence of chain scission and crosslinking are simultaneously induced by gamma rays.

  4. Effect of the adhesive antibiotic TA on adhesion and initial growth of E-coli on silicone rubber

    NARCIS (Netherlands)

    Simhi, E; van der Mei, HC; Ron, EZ; Rosenberg, E; Busscher, HJ

    2000-01-01

    Catheter-associated urinary tract infection is the most common nosocomial infection, and contributes to patient morbidity and mortality. We investigated the effect that the TA adhesive antibiotic had on adhesion and initial growth in urine of Escherichia coli on silicone rubber. The TA antibiotic

  5. Facile surface modification of silicone rubber with zwitterionic polymers for improving blood compatibility

    International Nuclear Information System (INIS)

    Liu, Pingsheng; Chen, Qiang; Yuan, Bo; Chen, Mengzhou; Wu, Shishan; Lin, Sicong; Shen, Jian

    2013-01-01

    A facile approach to modify silicone rubber (SR) membrane for improving the blood compatibility was investigated. The hydrophobic SR surface was firstly activated by air plasma, after which an initiator was immobilized on the activated surface for atom transfer radical polymerization (ATRP). Three zwitterionic polymers were then grafted from SR membrane via surface-initiated atom transfer radical polymerization (SI-ATRP). The surface composition, wettability, and morphology of the membranes before and after modification were characterized by X-ray photoelectron spectroscopy (XPS), static water contact angle (WCA) measurement, and atomic force microscopy (AFM). Results showed that zwitterionic polymers were successfully grafted from SR surfaces, which remarkably improved the wettability of the SR surface. The blood compatibility of the membranes was evaluated by protein adsorption and platelet adhesion tests in vitro. As observed, all the zwitterionic polymer modified surfaces have improved resistance to nonspecific protein adsorption and have excellent resistance to platelet adhesion, showing significantly improved blood compatibility. This work should inspire many creative uses of SR based materials for biomedical applications such as vessel, catheter, and microfluidics. Highlights: • Facile surface modification of silicone rubber with functional brushes • Modified SR surfaces have improved resistance to nonspecific protein adsorption. • Modified SR surfaces have excellent resistance to platelet adhesion. • Zwitteironic surface significant improvement in blood compatibility • Could inspire many creative uses of SR based materials for biomedical

  6. Facile surface modification of silicone rubber with zwitterionic polymers for improving blood compatibility

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Pingsheng [School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (China); Chen, Qiang, E-mail: chem100@nju.edu.cn [School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (China); High Technology Research Institute of Nanjing University, Changzhou 213164 (China); Yuan, Bo; Chen, Mengzhou; Wu, Shishan; Lin, Sicong [School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (China); Shen, Jian, E-mail: shenj1957@yahoo.com.cn [School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (China)

    2013-10-15

    A facile approach to modify silicone rubber (SR) membrane for improving the blood compatibility was investigated. The hydrophobic SR surface was firstly activated by air plasma, after which an initiator was immobilized on the activated surface for atom transfer radical polymerization (ATRP). Three zwitterionic polymers were then grafted from SR membrane via surface-initiated atom transfer radical polymerization (SI-ATRP). The surface composition, wettability, and morphology of the membranes before and after modification were characterized by X-ray photoelectron spectroscopy (XPS), static water contact angle (WCA) measurement, and atomic force microscopy (AFM). Results showed that zwitterionic polymers were successfully grafted from SR surfaces, which remarkably improved the wettability of the SR surface. The blood compatibility of the membranes was evaluated by protein adsorption and platelet adhesion tests in vitro. As observed, all the zwitterionic polymer modified surfaces have improved resistance to nonspecific protein adsorption and have excellent resistance to platelet adhesion, showing significantly improved blood compatibility. This work should inspire many creative uses of SR based materials for biomedical applications such as vessel, catheter, and microfluidics. Highlights: • Facile surface modification of silicone rubber with functional brushes • Modified SR surfaces have improved resistance to nonspecific protein adsorption. • Modified SR surfaces have excellent resistance to platelet adhesion. • Zwitteironic surface significant improvement in blood compatibility • Could inspire many creative uses of SR based materials for biomedical.

  7. Thermal degradation mechanism of addition-cure liquid silicone rubber with urea-containing silane

    International Nuclear Information System (INIS)

    Fang, Weizhen; Zeng, Xingrong; Lai, Xuejun; Li, Hongqiang; Chen, Wanjuan; Zhang, Yajun

    2015-01-01

    Highlights: • The urea-containing silane was incorporated into addition-cure liquid silicone rubber (ALSR) via hydrosilylation reaction. • The thermal stability of the ALSR was improved by DEUPAS both in nitrogen and air • The TG–FTIR of evolved gases during degradation was performed. • The possible degradation mechanism of the ALSR samples was proposed. - Abstract: The reactive urea-containing silane, (γ-diethylureidopropyl) allyloxyethoxysilane (DEUPAS), was synthesized by the trans-etherification reaction. The chemical structure was characterized by Fourier transform infrared spectrometry (FTIR) and 1 H nuclear magnetic resonance spectrometry ( 1 H NMR). Subsequently, DEUPAS was incorporated into addition-cure liquid silicone rubber (ALSR) via hydrosilylation reaction. The thermal stability of the ALSR samples was investigated by thermogravimetry (TG) and thermogravimetry–Fourier transform infrared spectrometry (TG–FTIR). When DEUPAS was incorporated, the temperature of 10% weight loss and 20% weight loss under air atmosphere were respectively increased by 31 °C and 60 °C compared with those of the ALSR without DEUPAS. Meanwhile, the residual weight at 800 °C increased from 33.5% to 58.7%. It was found that the striking enhancement in thermal stability of the ALSR samples was likely attributed to the decomposition of the urea groups to isocyanic acid, which reacted with hydroxyl groups to inhibit the unzipping depolymerization

  8. Thermal degradation mechanism of addition-cure liquid silicone rubber with urea-containing silane

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Weizhen; Zeng, Xingrong, E-mail: psxrzeng@gmail.com; Lai, Xuejun; Li, Hongqiang; Chen, Wanjuan; Zhang, Yajun

    2015-04-10

    Highlights: • The urea-containing silane was incorporated into addition-cure liquid silicone rubber (ALSR) via hydrosilylation reaction. • The thermal stability of the ALSR was improved by DEUPAS both in nitrogen and air • The TG–FTIR of evolved gases during degradation was performed. • The possible degradation mechanism of the ALSR samples was proposed. - Abstract: The reactive urea-containing silane, (γ-diethylureidopropyl) allyloxyethoxysilane (DEUPAS), was synthesized by the trans-etherification reaction. The chemical structure was characterized by Fourier transform infrared spectrometry (FTIR) and {sup 1}H nuclear magnetic resonance spectrometry ({sup 1}H NMR). Subsequently, DEUPAS was incorporated into addition-cure liquid silicone rubber (ALSR) via hydrosilylation reaction. The thermal stability of the ALSR samples was investigated by thermogravimetry (TG) and thermogravimetry–Fourier transform infrared spectrometry (TG–FTIR). When DEUPAS was incorporated, the temperature of 10% weight loss and 20% weight loss under air atmosphere were respectively increased by 31 °C and 60 °C compared with those of the ALSR without DEUPAS. Meanwhile, the residual weight at 800 °C increased from 33.5% to 58.7%. It was found that the striking enhancement in thermal stability of the ALSR samples was likely attributed to the decomposition of the urea groups to isocyanic acid, which reacted with hydroxyl groups to inhibit the unzipping depolymerization.

  9. Interference in adhesion of bacteria and yeasts isolated from explanted voice prostheses to silicone rubber by rhamnolipid biosurfactants

    NARCIS (Netherlands)

    Rodrigues, LR; Banat, IM; van der Mei, HC; Teixeira, JA; Oliveira, R

    Aims: The effects and extent of adhesion of four different bacterial and two yeast strains isolated from explanted voice prostheses to silicone rubber with and without an adsorbed rhamnolipid biosurfactant layer obtained from Pseudomonasaeruginosa DS10-129 was studied. Methods and Results: The

  10. Determination of silicone rubber and low-density polyethylene diffusion and polymer/water partition coefficients for emerging contaminants.

    Science.gov (United States)

    Pintado-Herrera, Marina G; Lara-Martín, Pablo A; González-Mazo, Eduardo; Allan, Ian J

    2016-09-01

    There is a growing interest in assessing the concentration and distribution of new nonregulated organic compounds (emerging contaminants) in the environment. The measurement of freely dissolved concentrations using conventional approaches is challenging because of the low concentrations that may be encountered and their temporally variable emissions. Absorption-based passive sampling enables the estimation of freely dissolved concentrations of hydrophobic contaminants of emerging concern in water. In the present study, calibration was undertaken for 2 polymers, low-density polyethylene (LDPE) and silicone rubber for 11 fragrances, 5 endocrine-disrupting compounds, 7 ultraviolet (UV) filters, and 8 organophosphate flame retardant compounds. Batch experiments were performed to estimate contaminant diffusion coefficients in the polymers (Dp ), which in general decreased with increasing molecular weight. The values for fragrances, endocrine-disrupting compounds, and UV filters were in ranges similar to those previously reported for polycyclic aromatic hydrocarbons, but were 1 order of magnitude lower for organophosphate flame retardant compounds. Silicone rubber had higher Dp values than LDPE and was therefore selected for further experiments to calculate polymer/water partition coefficients (KPW ). The authors observed a positive correlation between log KPW and log octanol/water partition coefficient values. Field testing of silicone rubber passive samplers was undertaken though exposure in the River Alna (Norway) for an exposure time of 21 d to estimate freely dissolved concentration. Some fragrances and UV filters were predominant over other emerging and regulated contaminants, at levels up to 1600 ng L(-1) for galaxolide and 448 ng L(-1) for octocrylene. Environ Toxicol Chem 2016;35:2162-2172. © 2016 SETAC. © 2016 SETAC.

  11. Computational Simulation on Facial Expressions and Experimental Tensile Strength for Silicone Rubber as Artificial Skin

    Science.gov (United States)

    Amijoyo Mochtar, Andi

    2018-02-01

    Applications of robotics have become important for human life in recent years. There are many specification of robots that have been improved and encriched with the technology advances. One of them are humanoid robot with facial expression which closer with the human facial expression naturally. The purpose of this research is to make computation on facial expressions and conduct the tensile strength for silicone rubber as artificial skin. Facial expressions were calculated by determining dimension, material properties, number of node elements, boundary condition, force condition, and analysis type. A Facial expression robot is determined by the direction and the magnitude external force on the driven point. The expression face of robot is identical with the human facial expression where the muscle structure in face according to the human face anatomy. For developing facial expression robots, facial action coding system (FACS) in approached due to follow expression human. The tensile strength is conducting due to check the proportional force of artificial skin that can be applied on the future of robot facial expression. Combining of calculated and experimental results can generate reliable and sustainable robot facial expression that using silicone rubber as artificial skin.

  12. PLA and single component silicone rubber blends for sub-zero temperature blown film packaging applications

    Science.gov (United States)

    Meekum, Utai; Khiansanoi, Apichart

    2018-06-01

    The poly(lactic acid) (PLA) blend with single component silicone rubber in the presence of reactive amino silane coupling agent and polyester polyols plasticizer were studied. The manufacturing of film packaging for sub-zero temperature applications from the PLA blend was the main objective. The mechanical properties, especially the impact strengths, of PLA/silicone blends were significantly depended on the silicone loading. The outstanding impact strengths, tested at sub-zero temperature, of the blend having silicone content of 8.0 phr was achieved. It was chosen as the best candidate for the processability improvement. Adding the talc filler into the PLA/silicone blend to enhance the rheological properties was investigated. The ductility of the talc filled blends were decreased with increasing the filler contents. However, the shear viscosity of the blend was raised with talc loading. The blend loaded with 40 phr of talc filler was justified as the optimal formula for the blown film process testing and it was successfully performed with a few difficulties. The obtained blown film showed relative good flexibility in comparison with LDPE but it has low transparency.

  13. Tribological Properties of Silicone Rubber-Based Ceramizable Composites Destined for Wire Covers. Part I. Studies of Block-On-Ring Friction Contact

    Directory of Open Access Journals (Sweden)

    R. Anyszka

    2015-06-01

    Full Text Available Ceramizable composites of silicone rubber matrix become more and more popular materials destined for wire covers, what can enhance fire safety of building increasing operation time of important equipment or devices (eg fire sprinklers, elevators, alarms etc. Aim of the research was to examine tribological properties and wear of commercially available silicone rubber-based ceramizable composites against steel, in configuration – steel block on composite ring, under various load (5, 10, 15, 20, 25 and 30 N. Changes to friction force in time were monitored by a tribotester, whereas wear of the composite surfaces were determined using an optical microscope. Performed studies demonstrate, that tribological characteristics and wear of the composites depend significantly on the origin of material.

  14. Epoxidized Natural Rubber/Chitosan Network Binder for Silicon Anode in Lithium-Ion Battery.

    Science.gov (United States)

    Lee, Sang Ha; Lee, Jeong Hun; Nam, Dong Ho; Cho, Misuk; Kim, Jaehoon; Chanthad, Chalathorn; Lee, Youngkwan

    2018-05-16

    Polymeric binder is extremely important for Si-based anode in lithium-ion batteries due to large volume variation during charging/discharging process. Here, natural rubber-incorporated chitosan networks were designed as a binder material to obtain both adhesion and elasticity. Chitosan could strongly anchor Si particles through hydrogen bonding, while the natural rubber could stretch reversibly during the volume variation of Si particles, resulting in high cyclic performance. The prepared electrode exhibited the specific capacities of 1350 mAh/g after 1600 cycles at the current density of 8 A/g and 2310 mAh/g after 500 cycles at the current density of 1 A/g. Furthermore, the cycle test with limiting lithiation capacity was conducted to study the optimal binder properties at varying degree of the volume expansion of silicon, and it was found that the elastic property of binder material was strongly required when the large volume expansion of Si occurred.

  15. Durable Superomniphobic Surface on Cotton Fabrics via Coating of Silicone Rubber and Fluoropolymers

    Directory of Open Access Journals (Sweden)

    Arsheen Moiz

    2018-03-01

    Full Text Available Performance textiles that protect human from different threats and dangers from environment are in high demand, and the advancement in functionalization technology together with employing advanced materials have made this an area of research focus. In this work, silicone rubber and environmentally friendly fluoropolymers have been employed to explore superomniphobic surface on cotton fabrics without compromising comfort much. It has been found that a cross-linked network between the rubber membrane and the fluoropolymers has been formed. The surface appearance, morphology, handle, thickness and chemical components of the surface of cotton fabrics have been changed. The coated fabrics showed resistance to water, aqueous liquid, oil, chemicals and soil. The comfort of the coated fabrics is different to uncoated cotton fabrics due to the existence of coated layers on the surface of cotton fabrics. This work would benefit the development and design of the next generation of performance textiles with balanced performance and comfort.

  16. LSA Large Area Silicon Sheet Task Continuous Czochralski Process Development

    Science.gov (United States)

    Rea, S. N.

    1979-01-01

    A commercial Czochralski crystal growing furnace was converted to a continuous growth facility by installation of a small, in-situ premelter with attendant silicon storage and transport mechanisms. Using a vertical, cylindrical graphite heater containing a small fused quartz test tube linear from which the molten silicon flowed out the bottom, approximately 83 cm of nominal 5 cm diamter crystal was grown with continuous melt addition furnished by the test tube premelter. High perfection crystal was not obtained, however, due primarily to particulate contamination of the melt. A major contributor to the particulate problem was severe silicon oxide buildup on the premelter which would ultimately drop into the primary melt. Elimination of this oxide buildup will require extensive study and experimentation and the ultimate success of continuous Czochralski depends on a successful solution to this problem. Economically, the continuous Czochralski meets near-term cost goals for silicon sheet material.

  17. Temperature Effect on Electrical Treeing and Partial Discharge Characteristics of Silicone Rubber-Based Nanocomposites

    Directory of Open Access Journals (Sweden)

    Mohd Hafizi Ahmad

    2015-01-01

    Full Text Available This study investigated electrical treeing and its associated phase-resolved partial discharge (PD activities in room-temperature, vulcanized silicone rubber/organomontmorillonite nanocomposite sample materials over a range of temperatures in order to assess the effect of temperature on different filler concentrations under AC voltage. The samples were prepared with three levels of nanofiller content: 0% by weight (wt, 1% by wt, and 3% by wt. The electrical treeing and PD activities of these samples were investigated at temperatures of 20°C, 40°C, and 60°C. The results show that the characteristics of the electrical tree changed with increasing temperature. The tree inception times decreased at 20°C due to space charge dynamics, and the tree growth time increased at 40°C due to the increase in the number of cross-link network structures caused by the vulcanization process. At 60°C, more enhanced and reinforced properties of the silicone rubber-based nanocomposite samples occurred. This led to an increase in electrical tree inception time and electrical tree growth time. However, the PD characteristics, particularly the mean phase angle of occurrence of the positive and negative discharge distributions, were insensitive to variations in temperature. This reflects an enhanced stability in the nanocomposite electrical properties compared with the base polymer.

  18. Surface modification of aluminum nitride by polysilazane and its polymer-derived amorphous silicon oxycarbide ceramic for the enhancement of thermal conductivity in silicone rubber composite

    Science.gov (United States)

    Chiu, Hsien Tang; Sukachonmakul, Tanapon; Kuo, Ming Tai; Wang, Yu Hsiang; Wattanakul, Karnthidaporn

    2014-02-01

    Polysilazane (PSZ) and its polymer-derived amorphous silicon oxycarbide (SiOC) ceramic were coated on aluminum nitride (AlN) by using a dip-coating method to allow moisture-crosslinking of PSZ on AlN, followed by heat treatment at 700 °C in air to convert PSZ into SiOC on AlN. The results from FTIR, XPS and SEM indicated that the surface of AlN was successfully coated by PSZ and SiOC film. It was found that the introduction of PSZ and SiOC film help improve in the interfacial adhesion between the modified AlN (PSZ/AlN and SiOC/AlN) and silicone rubber lead to the increase in the thermal conductivity of the composites since the thermal boundary resistance at the filler-matrix interface was decreased. However, the introduction of SiOC as an intermediate layer between AlN and silicone rubber could help increase the thermal energy transport at the filler-matrix interface rather than using PSZ. This result was due to the decrease in the surface roughness and thickness of SiOC film after heat treatment at 700 °C in air. Thus, in the present work, a SiOC ceramic coating could provide a new surface modification for the improvement of the interfacial adhesion between the thermally conductive filler and the matrix in which can enhance the thermal conductivity of the composites.

  19. Safety of food contact silicone rubber: Liberation of volatile compounds from soothers and teats

    DEFF Research Database (Denmark)

    Lund, Kirsten H.; Petersen, Jens Højslev

    2002-01-01

    The release of volatile compounds from soothers and teats made from silicone rubber has been investigated. Firstly, measurements of the total release of volatiles were performed according to the method in the draft European standard (CEN). Weight losses of 0.17-0.80% after four hours at 200 degrees......C were observed using gravimetric measurements. One product had a weight loss above the proposed CEN limit of 0.5%. Secondly, the volatile compounds were identified using a thermal desorption/cold trap injector on a gas chromatograph equipped with infrared spectroscopic (IR) and mass spectrometric (MS...

  20. Replication of microstructures on three-dimensional geometries by injection moulding of liquid silicone rubber

    DEFF Research Database (Denmark)

    Zhang, Yang; Mischkot, Michael; Hansen, Hans Nørgaard

    2015-01-01

    In this paper, liquid silicon rubber (LSR) parts with micro pillars are studied. The LSR parts were produced by injection moulding and are used as anchoring device for electrode implants inside humans. Micro-structures with specific dimension on implant surfaces can reduce encapsulation...... by the human body, thereby improving implant performance. This paper presents a method of applying micro structure on 3D parts. A Ni-plate with micro holes on the surface was cut into inserts and stuck in a cavity for injection moulding. 1000 injection moulding cycles were performed. Key dimensions...

  1. Plasma surface oxidation of 316L stainless steel for improving adhesion strength of silicone rubber coating to metal substrate

    Energy Technology Data Exchange (ETDEWEB)

    Latifi, Afrooz, E-mail: afroozlatifi@yahoo.com [Department of Biomaterials, Biomedical Engineering Faculty, Science and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Imani, Mohammad [Novel Drug Delivery Systems Dept., Iran Polymer and Petrochemical Institute, P.O. Box 14965/115, Tehran (Iran, Islamic Republic of); Khorasani, Mohammad Taghi [Biomaterials Dept., Iran Polymer and Petrochemical Institute, P.O. Box 14965/159, Tehran (Iran, Islamic Republic of); Daliri Joupari, Morteza [Animal and Marine Biotechnology Dept., National Institute of Genetic Engineering and Biotechnology, P.O. Box 14965/161, Tehran (Iran, Islamic Republic of)

    2014-11-30

    Highlights: • Stainless steel 316L was surface modified by plasma surface oxidation (PSO) and silicone rubber (SR) coating. • On the PSO substrates, concentration of oxide species was increased ca. 2.5 times comparing to non-PSO substrates. • The surface wettability was improved to 12.5°, in terms of water contact angle, after PSO. • Adhesion strength of SR coating on the PSO substrates was improved by more than two times comparing to non-PSO ones. • After pull-off test, the fractured area patterns for SR coating were dependent on the type of surface modifications received. - Abstract: Stainless steel 316L is one of the most widely used materials for fabricating of biomedical devices hence, improving its surface properties is still of great interest and challenging in biomaterial sciences. Plasma oxidation, in comparison to the conventional chemical or mechanical methods, is one of the most efficient methods recently used for surface treatment of biomaterials. Here, stainless steel specimens were surface oxidized by radio-frequency plasma irradiation operating at 34 MHz under pure oxygen atmosphere. Surface chemical composition of the samples was significantly changed after plasma oxidation by appearance of the chromium and iron oxides on the plasma-oxidized surface. A wettable surface, possessing high surface energy (83.19 mN m{sup −1}), was observed after plasma oxidation. Upon completion of the surface modification process, silicone rubber was spray coated on the plasma-treated stainless steel surface. Morphology of the silicone rubber coating was investigated by scanning electron microscopy (SEM). A uniform coating was formed on the oxidized surface with no delamination at polymer–metal interface. Pull-off tests showed the lowest adhesion strength of coating to substrate (0.12 MPa) for untreated specimens and the highest (0.89 MPa) for plasma-oxidized ones.

  2. Endurance test report of rubber sealing materials for the containment vessel

    International Nuclear Information System (INIS)

    Yamamoto, R.; Watanabe, K.; Hanashima, K.

    2015-01-01

    In the event of a nuclear power plant accident such as a core meltdown and a cooling system failure, the containment contains radioactive materials released from the reactor pressure vessel to reduce the activity of the radioactive materials and the effects of radiation in the vicinity of the plant. Since high sealing performance and high pressure resistance are required of the containment, a silicone or EPDM rubber gasket with high heat and radiation resistance is used for the sealing of the sealing boundary of the containment. In recent years, it has been shown that a large amount of steam is released into the containment in the case of a severe accident. Consequently, radiation resistance at high temperature as well as steam resistance is required of the rubber gasket placed at the sealing boundary. However, the steam resistance of silicone rubber is not necessarily as good as that of EPDM rubber. Therefore, it is necessary to evaluate the sealing characteristics of rubber gaskets in such a degrading environment in a severe accident. O. Kato et al. [1] conducted a study on the degradation status of rubber gaskets and their application limits at high temperature. However, few studies have evaluated rubber gaskets in high-temperature radiation and steam environments. In this study, we degraded silicone rubber and EPDM rubber used for the containment in the high-temperature radiation and steam environments expected to occur in a severe accident and evaluated the useful life of the rubber as a sealing material by estimating the change in its performance as a sealing material from the change in permanent compressive strain in the rubber. (author)

  3. Voice Prosthetic Biofilm Formation and Candida Morphogenic Conversions in Absence and Presence of Different Bacterial Strains and Species on Silicone-Rubber

    NARCIS (Netherlands)

    van der Mei, Henny C.; Buijssen, Kevin J. D. A.; van der Laan, Bernard F. A. M.; Ovchinnikova, Ekatarina; Geertsema-Doornbusch, Gesinda I.; Atema-Smit, Jelly; van de Belt-Gritter, Betsy; Busscher, Henk J.

    2014-01-01

    Morphogenic conversion of Candida from a yeast to hyphal morphology plays a pivotal role in the pathogenicity of Candida species. Both Candida albicans and Candida tropicalis, in combination with a variety of different bacterial strains and species, appear in biofilms on silicone-rubber voice

  4. Synthesis and Characterization of Silicon Nanoparticles Inserted into Graphene Sheets as High Performance Anode Material for Lithium Ion Batteries

    Directory of Open Access Journals (Sweden)

    Yong Chen

    2014-01-01

    Full Text Available Silicon nanoparticles have been successfully inserted into graphene sheets via a novel method combining freeze-drying and thermal reduction. The structure, electrochemical performance, and cycling stability of this anode material were characterized by SEM, X-ray diffraction (XRD, charge/discharge cycling, and cyclic voltammetry (CV. CV showed that the Si/graphene nanocomposite exhibits remarkably enhanced cycling performance and rate performance compared with bare Si nanoparticles for lithium ion batteries. XRD and SEM showed that silicon nanoparticles inserted into graphene sheets were homogeneous and had better layered structure than the bare silicon nanoparticles. Graphene sheets improved high rate discharge capacity and long cycle-life performance. The initial capacity of the Si nanoparticles/graphene keeps above 850 mAhg−1 after 100 cycles at a rate of 100 mAg−1. The excellent cycle performances are caused by the good structure of the composites, which ensured uniform electronic conducting sheet and intensified the cohesion force of binder and collector, respectively.

  5. Hydrophobic recovery of repeatedly plasma-treated silicone rubber .2. A comparison of the hydrophobic recovery in air, water, or liquid nitrogen

    NARCIS (Netherlands)

    Everaert, EP; VanderMei, HC; Busscher, HJ

    1996-01-01

    Surfaces of medical grade silicone rubber (Q7-4750, Dow Coming) were modified by repeated (six times) RF plasma treatments using various discharge gases: oxygen, argon, carbon dioxide, and ammonia. The treated samples were stored for a period of 3 months in ambient air, water, or liquid nitrogen.

  6. Characterizing Grain-Oriented Silicon Steel Sheet Using Automated High-Resolution Laue X-ray Diffraction

    Science.gov (United States)

    Lynch, Peter; Barnett, Matthew; Stevenson, Andrew; Hutchinson, Bevis

    2017-11-01

    Controlling texture in grain-oriented (GO) silicon steel sheet is critical for optimization of its magnetization performance. A new automated laboratory system, based on X-ray Laue diffraction, is introduced as a rapid method for large scale grain orientation mapping and texture measurement in these materials. Wide area grain orientation maps are demonstrated for both macroetched and coated GO steel sheets. The large secondary grains contain uniform lattice rotations, the origins of which are discussed.

  7. Multilayer graphene rubber nanocomposites

    Science.gov (United States)

    Schartel, Bernhard; Frasca, Daniele; Schulze, Dietmar; Wachtendorf, Volker; Krafft, Bernd; Morys, Michael; Böhning, Martin; Rybak, Thomas

    2016-05-01

    Multilayer Graphene (MLG), a nanoparticle with a specific surface of BET = 250 m2/g and thus made of only approximately 10 graphene sheets, is proposed as a nanofiller for rubbers. When homogenously dispersed, it works at low loadings enabling the replacement of carbon black (CB), increase in efficiency, or reduction in filler concentration. Actually the appropriate preparation yielded nanocomposites in which just 3 phr are sufficient to significantly improve the rheological, curing and mechanical properties of different rubbers, as shown for Chlorine-Isobutylene-Isoprene Rubber (CIIR), Nitrile-Butadiene Rubber (NBR), Natural Rubber (NR), and Styrene-Butadiene Rubber (SBR). A mere 3 phr of MLG tripled the Young's modulus of CIIR, an effect equivalent to 20 phr of carbon black. Similar equivalents are observed for MLG/CB mixtures. MLG reduces gas permeability, increases thermal and electrical conductivities, and retards fire behavior. The later shown by the reduction in heat release rate in the cone calorimeter. The higher the nanofiller concentration is (3 phr, 5 phr, and 10 phr was investigated), the greater the improvement in the properties of the nanocomposites. Moreover, the MLG nanocomposites improve stability of mechanical properties against weathering. An increase in UV-absorption as well as a pronounced radical scavenging are proposed and were proved experimentally. To sum up, MLG is interesting as a multifunctional nanofiller and seems to be quite ready for rubber development.

  8. Radiation-grafting of acrylamide onto silicone rubber films for diclofenac delivery

    Science.gov (United States)

    Magaña, Hector; Palomino, Kenia; Cornejo-Bravo, Jose M.; Alvarez-Lorenzo, Carmen; Concheiro, Angel; Bucio, Emilio

    2015-02-01

    This work focuses on the pre-irradiation grafting of acrylamide (AAm) onto silicone rubber films (SR) and evaluates the effect of gamma-ray radiation conditions on the grafting yield, which in turn may influence the performance of the grafted materials as components of drug-eluting devices. Pristine and modified SR were characterized using FTIR-ATR, DSC, TGA, swelling, and water contact angle analysis in order to elucidate the effects of AAm grafting onto SR. Grafted films with content in AAm ranging from 0.81% to 22.20% showed excellent cytocompatibility against fibroblasts, and capability to uptake the anti-inflammatory drug diclofenac. Amount of drug loaded directly correlated with the grafting degree of the films. Drug release studies were performed at pH 7.4 and 37 °C (physiological conditions). Most grafted films released the drug in a sustained way for at least three hours.

  9. Boundary lubrication of glass: rubber sliding contacts

    NARCIS (Netherlands)

    Heide, E. van der; Lossie, C.M.; Bommel, K.J.C. van; Reinders, S.A.F.; Lenting, H.B.M.

    2009-01-01

    Polymer brush coatings represent a promising class of coatings for friction control [1], especially in a humid environment [2]. A study on the feasibility of a specific class of polymer brush coatings [5] was done for a sliding system that involves ‘silicon skin L7350’: a silicon rubber used by FIFA

  10. Study on wood vinegars for use as coagulating and antifungal agents on the production of natural rubber sheets

    Energy Technology Data Exchange (ETDEWEB)

    Baimark, Yodthong; Niamsa, Noi [Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Mahasarakham University, Mahasarakham 44150 (Thailand)

    2009-06-15

    Coagulating and antifungal properties of wood vinegars in the preparation process of Hevea brasiliensis natural rubber (NR) sheets were investigated and compared with those of formic and acetic acids. The wood vinegars produced from biomasses such as inner coconut shell, bamboo and Eucalyptus woods were evaluated. It was found that plasticity retention index, Mooney viscosity and mechanical properties of NR coagulated by wood vinegars were similar to those using acetic acid and better than using formic acid. The antifungal efficiency of coagulants determined from a fungi growth area on NR sheet surfaces was found in the following order: coconut shell wood vinegar > bamboo wood vinegar {approx} Eucalyptus wood vinegar > acetic acid {approx} formic acid. The antifungal efficiency of the wood vinegars was strongly depended upon their phenolic compound contents and confirmed through the inhibitory growth of the main fungi, Penicillium griseofulvum, on potato dextrose agar. (author)

  11. Effect of Ingredient Loading on Surface Migration Kinetics of Additives in Vulcanized Natural Rubber Compounds

    Directory of Open Access Journals (Sweden)

    Bryan B. Pajarito

    2014-12-01

    Full Text Available Surface migration kinetics of chemical additives in vulcanized natural rubber compounds were studied as function of ingredient loading. Rubber sheets were compounded according to a 212-8 fractional factorial design of experiment, where ingredients were treated as factors varied at two levels of loading. Amount of migrated additives in surface of rubber sheets was monitored through time at ambient conditions. The maximum amount and estimated rate of additive migration were determined from weight loss kinetic curves. Attenuated total reflection–Fourier transform infrared (ATR-FTIR spectroscopy and optical microscopy were used to characterize the chemical structure and surface morphology of sheet specimens during additive migration. ANOVA results showed that increased loading of reclaimed rubber, CaCO3, and paraffin wax signif icantly decreased the maximum amount of additive migration; by contrast, increased loading of used oil, asphalt, and mercaptobenzothiazole disulphide (MBTS increased the maximum amount. Increased loading of sulfur, diphenylguanidine (DPG, and paraffin wax significantly decreased the additive migration rate; increased loading of used oil, asphalt, and stearic acid elicited an opposite effect. Comparison of ATRFTIR spectra of migrated and cleaned rubber surfaces showed signif icant variation in intensity of specif ic absorbance bands that are also present in infrared spectra of migrating chemicals. Paraffin wax, used oil, stearic acid, MBTS, asphalt, and zinc stearate were identified to bloom and bleed in the rubber sheets. Optical micrographs of migrated rubber surfaces revealed formation of white precipitates due to blooming and of semi-transparent wet patches due to bleeding.

  12. Congenital cheek teratoma with temporo-mandibular joint ankylosis managed with ultra-thin silicone sheet interpositional arthroplasty.

    Science.gov (United States)

    Bhatnagar, Ankur; Verma, Vinay Kumar; Purohit, Vishal

    2013-01-01

    Primary cheek teratomas are rare with joint ankylosis (TMJA). The fundamental aim in the treatment of TMJA is the successful surgical resection of ankylotic bone, prevention of recurrence, and aesthetic improvement by ensuring functional occlusion. Early treatment is necessary to promote proper growth and function of mandible and to facilitate the positive psychological development of child. Inter-positional arthroplasty with ultra-thin silicone sheet was performed. Advantages include short operative time, less foreign material in the joint space leading to negligible foreign body reactions and least chances of implant extrusion. Instead of excising a large bony segment, a thin silicone sheet was interposed and then sutured ensuring preservation of mandibular height. Aggressive post-operative physiotherapy with custom made dynamic jaw exerciser was used to prevent recurrence.

  13. Covalent Bonding of Thermoplastics to Rubbers for Printable, Reel-to-Reel Processing in Soft Robotics and Microfluidics.

    Science.gov (United States)

    Taylor, Jay M; Perez-Toralla, Karla; Aispuro, Ruby; Morin, Stephen A

    2018-02-01

    The lamination of mechanically stiff structures to elastic materials is prevalent in biological systems and popular in many emerging synthetic systems, such as soft robotics, microfluidics, stretchable electronics, and pop-up assemblies. The disparate mechanical and chemical properties of these materials have made it challenging to develop universal synthetic procedures capable of reliably adhering to these classes of materials together. Herein, a simple and scalable procedure is described that is capable of covalently laminating a variety of commodity ("off-the-shelf") thermoplastic sheets to silicone rubber films. When combined with laser printing, the nonbonding sites can be "printed" onto the thermoplastic sheets, enabling the direct fabrication of microfluidic systems for actuation and liquid handling applications. The versatility of this approach in generating thin, multifunctional laminates is demonstrated through the fabrication of milliscale soft actuators and grippers with hinged articulation and microfluidic channels with built-in optical filtering and pressure-dependent geometries. This method of fabrication offers several advantages, including technical simplicity, process scalability, design versatility, and material diversity. The concepts and strategies presented herein are broadly applicable to the soft robotics, microfluidics, and advanced and additive manufacturing communities where hybrid rubber/plastic structures are prevalent. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Radiation-grafting of N-vinylimidazole onto silicone rubber for antimicrobial properties

    Science.gov (United States)

    Meléndez-Ortiz, H. Iván; Alvarez-Lorenzo, Carmen; Burillo, Guillermina; Magariños, Beatriz; Concheiro, Angel; Bucio, Emilio

    2015-05-01

    Poly(N-vinylimidazole) (PVIm) was grafted numbers onto silicone rubber (SR) with the aim of providing antimicrobial properties. The grafting was carried out by means of gamma rays using the direct method. The influence on the grafting yield of absorbed dose, monomer concentration, addition of FeSO4 salt, composition and type of solvent (H2O, MeOH, THF, and acetone) was investigated. Grafts onto SR between 10% and 90% were obtained at doses from 20 to 100 kGy and a dose rate 10.9 kGy h-1; grafting yield increased with monomer concentration and dose. The new graft copolymers were confirmed by Fourier transform infrared spectroscopy (FT-IR). Differential scanning calorimeter (DSC) showed glass transition at 149 and 159 °C for 38% and 88% grafting respectively. Thermogravimetry analysis (TGA) presented two decomposition temperatures for SR-g-VIm at 380 (PVIm) and 440 °C (SR). SR-g-VIm showed antibacterial activity against Pseudomonas aeruginosa.

  15. In-plane mechanics of soft architectured fibre-reinforced silicone rubber membranes.

    Science.gov (United States)

    Bailly, L; Toungara, M; Orgéas, L; Bertrand, E; Deplano, V; Geindreau, C

    2014-12-01

    Silicone rubber membranes reinforced with architectured fibre networks were processed with a dedicated apparatus, allowing a control of the fibre content and orientation. The membranes were subjected to tensile loadings combined with continuous and discrete kinematical field measurements (DIC and particle tracking). These tests show that the mechanical behaviour of the membranes is hyperelastic at the first order. They highlight the influence of the fibre content and orientation on both the membrane in-plane deformation and stress levels. They also prove that for the considered fibrous architectures and mechanical loadings, the motion and deformation of fibres is an affine function of the macroscale transformation. These trends are fairly well described by the micromechanical model proposed recently in Bailly et al. (JMBBM, 2012). This result proves that these materials are very good candidates for new biomimetic membranes, e.g. to improve aortic analogues used for in vitro experiments, or existing textiles used for vascular (endo)prostheses. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. High Performance Graphene Oxide Based Rubber Composites

    Science.gov (United States)

    Mao, Yingyan; Wen, Shipeng; Chen, Yulong; Zhang, Fazhong; Panine, Pierre; Chan, Tung W.; Zhang, Liqun; Liang, Yongri; Liu, Li

    2013-01-01

    In this paper, graphene oxide/styrene-butadiene rubber (GO/SBR) composites with complete exfoliation of GO sheets were prepared by aqueous-phase mixing of GO colloid with SBR latex and a small loading of butadiene-styrene-vinyl-pyridine rubber (VPR) latex, followed by their co-coagulation. During co-coagulation, VPR not only plays a key role in the prevention of aggregation of GO sheets but also acts as an interface-bridge between GO and SBR. The results demonstrated that the mechanical properties of the GO/SBR composite with 2.0 vol.% GO is comparable with those of the SBR composite reinforced with 13.1 vol.% of carbon black (CB), with a low mass density and a good gas barrier ability to boot. The present work also showed that GO-silica/SBR composite exhibited outstanding wear resistance and low-rolling resistance which make GO-silica/SBR very competitive for the green tire application, opening up enormous opportunities to prepare high performance rubber composites for future engineering applications. PMID:23974435

  17. Morphological and structural study of the incorporation of spinel Mn{sub 1-x}Zn{sub x}Fe{sub 2}O{sub 4} silicone rubber; Estudo morfologico e estrutural da incorporacao do espinelio Mn{sub 1-x}Zn{sub x}Fe{sub 2}O{sub 4} em borracha de silicone

    Energy Technology Data Exchange (ETDEWEB)

    Diniz, Veronica C.S.; Silveira Junior, Jose E.R.; Costa Junior, A.D.S.; Kiminami, Ruth H.A.; Costa, Ana Cristina F.M., E-mail: edsonrjunior1@gmail.com [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Departamento de Engenharia de Materiais

    2016-07-01

    The Mn-Zn ferrites are ceramic materials which have very attractive electromagnetic properties very attractive for the development of technologies of electronic ceramics, they have the versatility can be manufactured with different geometries, and used in the form of polycrystalline ferrite (sintered body) or a composite ferrite (adding powder suitable matrix). In this work we study the structural and morphological characteristics of incorporating Mn-Zn ferrites silicone rubber. The samples were characterized by X-ray diffraction, spectroscopy in the infrared region by Fourier Transform and scanning electron microscopy. Through the obtained results, there was evidence of the presence of ferrite in the silicone rubber, which have been incorporated with good uniformity within the silicone matrix independent of the composition used. (author)

  18. Nanosized graphene sheets enhanced photoelectric behavior of carbon film on p-silicon substrate

    Science.gov (United States)

    Yang, Lei; Hu, Gaijuan; Zhang, Dongqing; Diao, Dongfeng

    2016-07-01

    We found that nanosized graphene sheets enhanced the photoelectric behavior of graphene sheets embedded carbon (GSEC) film on p-silicon substrate, which was deposited under low energy electron irradiation in electron cyclotron resonance plasma. The GSEC/p-Si photodiode exhibited good photoelectric performance with photoresponsivity of 206 mA/W, rise and fall time of 2.2, and 4.3 μs for near-infrared (850 nm) light. The origin of the strong photoelectric behavior of GSEC film was ascribed to the appearance of graphene nanosheets, which led to higher barrier height and photoexcited electron-collection efficiency. This finding indicates that GSEC film has the potential for photoelectric applications.

  19. The Effect of Creep on the Residual Stresses Generated During Silicon Sheet Growth

    Science.gov (United States)

    Hutchinson, J. W.; Lambropoulos, J. C.

    1984-01-01

    The modeling of stresses generated during the growth of thin silicon sheets at high speeds is an important part of the EFG technique since the experimental measurement of the stresses is difficult and prohibitive. The residual stresses which arise in such a growth process lead to serious problems which make thin Si ribbons unsuitable for fabrication. The constitutive behavior is unrealistic because at high temperature (close to the melting point) Si exhibits considerable creep which significantly relaxes the residual stresses. The effect of creep on the residual stresses generated during the growth of Si sheets at high speeds was addressed and the basic qualitative effect of creep are reported.

  20. Osteopontin (OPN is an important protein to mediate improvements in the biocompatibility of C ion-implanted silicone rubber.

    Directory of Open Access Journals (Sweden)

    Shao-liang Wang

    Full Text Available Medical device implants are drawing increasing amounts of interest from modern medical practitioners. However, this attention is not evenly spread across all such devices; most of these implantable devices can cause adverse reactions such as inflammation, fibrosis, thrombosis, and infection. In this work, the biocompatibility of silicone rubber (SR was improved through carbon (C ion implantation. Scanning electron microscopy (SEM, atomic force microscopy (AFM, X-ray photoelectron spectroscopy (XPS, and X-ray diffraction (XRD results confirmed that these newly generated carbon-implanted silicone rubbers (C-SRs had large, irregular peaks and deep valleys on their surfaces. The water contact angle of the SR surface decreased significantly after C ion implantation. C ion implantation also changed the surface charge distribution, silicone oxygen rate, and chemical-element distribution of SR to favor cell attachment. The dermal fibroblasts cultured on the surface C-SR grew faster and showed more typical fibroblastic shapes. The expression levels of major adhesion proteins, including talin-1, zyxin, and vinculin, were significantly higher in dermal fibroblasts cultured on C-SR coated plates than in dermal fibroblasts cultured on SR. Those same dermal fibroblasts on C-SRs showed more pronounced adhesion and migration abilities. Osteopontin (OPN, a critical extracellular matrix (ECM protein, was up-regulated and secreted from dermal fibroblasts cultured on C-SR. Matrix metalloproteinase-9 (MMP-9 activity was also increased. These cells were highly mobile and were able to adhere to surfaces, but these abilities were inhibited by the monoclonal antibody against OPN, or by shRNA-mediated MMP-9 knockdown. Together, these results suggest that C ion implantation significantly improves SR biocompatibility, and that OPN is important to promote cell adhesion to the C-SR surface.

  1. Image Classification of Ribbed Smoked Sheet using Learning Vector Quantization

    Science.gov (United States)

    Rahmat, R. F.; Pulungan, A. F.; Faza, S.; Budiarto, R.

    2017-01-01

    Natural rubber is an important export commodity in Indonesia, which can be a major contributor to national economic development. One type of rubber used as rubber material exports is Ribbed Smoked Sheet (RSS). The quantity of RSS exports depends on the quality of RSS. RSS rubber quality has been assigned in SNI 06-001-1987 and the International Standards of Quality and Packing for Natural Rubber Grades (The Green Book). The determination of RSS quality is also known as the sorting process. In the rubber factones, the sorting process is still done manually by looking and detecting at the levels of air bubbles on the surface of the rubber sheet by naked eyes so that the result is subjective and not so good. Therefore, a method is required to classify RSS rubber automatically and precisely. We propose some image processing techniques for the pre-processing, zoning method for feature extraction and Learning Vector Quantization (LVQ) method for classifying RSS rubber into two grades, namely RSS1 and RSS3. We used 120 RSS images as training dataset and 60 RSS images as testing dataset. The result shows that our proposed method can give 89% of accuracy and the best perform epoch is in the fifteenth epoch.

  2. Magneto-hydrodynamics of coupled fluid–sheet interface with mass suction and blowing

    International Nuclear Information System (INIS)

    Ahmad, R.

    2016-01-01

    There are large number of studies which prescribe the kinematics of the sheet and ignore the sheet's mechanics. However, the current boundary layer analysis investigates the mechanics of both the electrically conducting fluid and a permeable sheet, which makes it distinct from the other studies in the literature. One of the objectives of the current study is to (i) examine the behaviour of magnetic field effect for both the surface and the electrically conducting fluid (ii) investigate the heat and mass transfer between a permeable sheet and the surrounding electrically conducting fluid across the hydro, thermal and mass boundary layers. Self-similar solutions are obtained by considering the RK45 technique. Analytical solution is also found for the stretching sheet case. The skin friction dual solutions are presented for various types of sheet. The influence of pertinent parameters on the dimensionless velocity, shear stress, temperature, mass concentration, heat and mass transfer rates on the fluid–sheet interface is presented graphically as well as numerically. The obtained results are of potential benefit for studying the electrically conducting flow over various soft surfaces such as synthetic plastics, soft silicone sheet and soft synthetic rubber sheet. These surfaces are easily deformed by thermal fluctuations or thermal stresses. - Highlights: • The momentum equation is modelled for both the surrounding MHD fluid and the sheet with the effects of mass suction and blowing. • The current study further investigates the heat and mass transfer characteristics between a permeable sheet and the surrounding electrically conducting fluid across the thermal and mass boundary layers. • Both the approximated and analytical techniques have been included for the purpose of comparison, and the perfect numerical agreements have been established with the previous studies. • Dual solutions for the skin friction coefficients are found for various categories of

  3. Calibration of silicone rubber rods as passive samplers for pesticides at two different flow velocities: Modeling of sampling rates under water boundary layer and polymer control.

    Science.gov (United States)

    Martin, Alexis; Margoum, Christelle; Jolivet, Antoine; Assoumani, Azziz; El Moujahid, Bachir; Randon, Jérôme; Coquery, Marina

    2018-04-01

    There is a need to determine time-weighted average concentrations of polar contaminants such as pesticides by passive sampling in environmental waters. Calibration data for silicone rubber-based passive samplers are lacking for this class of compounds. The calibration data, sampling rate (R s ), and partition coefficient between silicone rubber and water (K sw ) were precisely determined for 23 pesticides and 13 candidate performance reference compounds (PRCs) in a laboratory calibration system over 14 d for 2 water flow velocities, 5 and 20 cm s -1 . The results showed that an in situ exposure duration of 7 d left a silicone rubber rod passive sampler configuration in the linear or curvilinear uptake period for 19 of the pesticides studied. A change in the transport mechanism from polymer control to water boundary layer control was observed for pesticides with a log K sw of approximately 3.3. The PRC candidates were not fully relevant to correct the impact of water flow velocity on R s . We therefore propose an alternative method based on an overall resistance to mass transfer model to adjust R s from laboratory experiments to in situ hydrodynamic conditions. We estimated diffusion coefficients (D s ) and thickness of water boundary layer (δ w ) as adjustable model parameters. Log D s values ranged from -12.13 to -10.07 m 2  s -1 . The estimated δ w value showed a power function correlation with water flow velocity. Environ Toxicol Chem 2018;37:1208-1218. © 2017 SETAC. © 2017 SETAC.

  4. Nanosized graphene sheets enhanced photoelectric behavior of carbon film on p-silicon substrate

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Lei; Hu, Gaijuan; Zhang, Dongqing [Key Laboratory of Education Ministry for Modern Design and Rotor-Bearing System, School of Mechanical Engineering, Xi' an Jiaotong University, Xi' an 710049 (China); Diao, Dongfeng, E-mail: dfdiao@szu.edu.cn [Institute of Nanosurface Science and Engineering (INSE), Shenzhen University, Shenzhen 518060 (China)

    2016-07-18

    We found that nanosized graphene sheets enhanced the photoelectric behavior of graphene sheets embedded carbon (GSEC) film on p-silicon substrate, which was deposited under low energy electron irradiation in electron cyclotron resonance plasma. The GSEC/p-Si photodiode exhibited good photoelectric performance with photoresponsivity of 206 mA/W, rise and fall time of 2.2, and 4.3 μs for near-infrared (850 nm) light. The origin of the strong photoelectric behavior of GSEC film was ascribed to the appearance of graphene nanosheets, which led to higher barrier height and photoexcited electron-collection efficiency. This finding indicates that GSEC film has the potential for photoelectric applications.

  5. Nanosized graphene sheets enhanced photoelectric behavior of carbon film on p-silicon substrate

    International Nuclear Information System (INIS)

    Yang, Lei; Hu, Gaijuan; Zhang, Dongqing; Diao, Dongfeng

    2016-01-01

    We found that nanosized graphene sheets enhanced the photoelectric behavior of graphene sheets embedded carbon (GSEC) film on p-silicon substrate, which was deposited under low energy electron irradiation in electron cyclotron resonance plasma. The GSEC/p-Si photodiode exhibited good photoelectric performance with photoresponsivity of 206 mA/W, rise and fall time of 2.2, and 4.3 μs for near-infrared (850 nm) light. The origin of the strong photoelectric behavior of GSEC film was ascribed to the appearance of graphene nanosheets, which led to higher barrier height and photoexcited electron-collection efficiency. This finding indicates that GSEC film has the potential for photoelectric applications.

  6. 耐漏电起痕硅橡胶的制备及应用研究进展%Progress in the Preparation and Application of Tracking and Erosion Resistant Silicone Rubber

    Institute of Scientific and Technical Information of China (English)

    郭燕霞; 赖学军; 曾幸荣; 李红强; 张亚军; 方伟镇

    2017-01-01

    硅橡胶以其优异的电气绝缘性、憎水防污和耐污闪等性能而广泛应用于高压超高压电力电气设备及外绝缘领域.然而硅橡胶绝缘材料在长期使用过程中,在外界强电场放电作用下会发生漏电起痕破坏,致使材料失效甚至燃烧.这对电力系统与电气设备的安全运行,以及人们的生产和生活造成巨大的危害.因此,硅橡胶的耐漏电起痕研究吸引了越来越多研究者的关注.文中综述了近年来国内外关于耐漏电起痕硅橡胶的最新研究进展,分析了硅橡胶耐漏电起痕剂亟待解决的问题,并指出高效率、相容好、多功能的有机耐漏电起痕剂是耐电痕化硅橡胶的重要发展方向.%Silicone rubber is widely used in high-voltage and super-high voltage electrical equipments and outdoor insulation,due to its excellent electrical insulation,water-repellence and flashover resistance.However,when served for a long time,silicone rubber insulation materials may suffer from tracking and erosion,resulting in insulation failure and even fire,because of strong external discharges.This caused great harm to the safety of the operation of power transmission systems and electrical equipment,as well as the industrial production and daily life of human.Therefore,research on the tracking and erosion resistance of silicone rubber attracted more and more attention.This paper reviewed the latest progress in the research of tracking and erosion resistant silicone rubber and analyzes the problems needed to be solved.Finally,it is pointed out that versatile organic agent for tracking and erosion resistance of silicone rubber with high efficiency and good compatibility is one of the most important developmental trends.

  7. Experimental investigation into the coupling effects of magnetic field, temperature and pressure on electrical resistivity of non-oriented silicon steel sheet

    Science.gov (United States)

    Xiao, Lijun; Yu, Guodong; Zou, Jibin; Xu, Yongxiang

    2018-05-01

    In order to analyze the performance of magnetic device which operate at high temperature and high pressure, such as submersible motor, oil well transformer, the electrical resistivity of non-oriented silicon steel sheets is necessary for precise analysis. But the reports of the examination of the measuring method suitable for high temperature up to 180 °C and high pressure up to 140 MPa are few. In this paper, a measurement system based on four-probe method and Archimedes spiral shape measurement specimens is proposed. The measurement system is suitable for measuring the electrical resistivity of unconventional specimens under high temperature and high pressure and can simultaneously consider the influence of the magnetic field on the electrical resistivity. It can be seen that the electrical resistivity of the non-oriented silicon steel sheets will fluctuate instantaneously when the magnetic field perpendicular to the conductive path of the specimens is loaded or removed. The amplitude and direction of the fluctuation are not constant. Without considering the effects of fluctuations, the electrical resistivity of the non-oriented silicon steel sheets is the same when the magnetic field is loaded or removed. And the influence of temperature on the electrical resistivity of the non-oriented silicon steel sheet is still the greatest even though the temperature and the pressure are coupled together. The measurement results also show that the electrical resistivity varies linearly with temperature, so the temperature coefficient of resistivity is given in the paper.

  8. Evaluation of radiation-induced degradation of silicon '0' ring

    International Nuclear Information System (INIS)

    Ikeshima, Yoshiaki; Shiraishi; Tadao; Sato, Ryuichi; Tanaka, Isao; Ichihashi, Yoshinori; Ito, Masayuki.

    1990-12-01

    Currently there is too few available data on mechanical properties of an 'O' ring made of organic material, which is used over an extensive period of time under actual Nuclear Reactor environmental conditions. The 'O' rings which were evaluated were made of Silicon Rubber, and are used to provide water tightness. The 'O' rings also served as a pressure boundary within the nozzle of the in-reactor tube in the Water Loop-2 (OWL-2) at the JMTR in Oarai, Ibaraki. The 'O' rings were subjected to a constant penetrating radiation (up to 3.46 kGy) over a period of thirteen (13) years. The effects on the mechanical properties of a Silicon Rubber 'O' Ring were evaluated after having been used over an extensive period of time in an actual in-reactor tube within a radiation environment; a full thirteen years in durations. In making comparison of the properties of other Silicon Rubber 'O' Rings. It was also found that these other 'O' rings were subject to Gamma Rays for a shorter period, but with the same amount of radiation as the 'O' rings in the reactor were supposedly to have received. The evaluation showed that a Silicon Rubber 'O' Ring could have been used for a period, as much as forty (40) years even with a (absorbed) dose of about 300 kGy, before the life expectancy of such an 'O' ring is fully met. It was also discovered that the mechanical properties of an Ethylene Propylene 'O' Rings (currently used in the new OWL-2 in-reactor tube) were much superior to those of the Silicon Rubber 'O' Rings. The Ethylene Propylene 'O' Rings had a live expectancy which was about three times that of a Silicon Rubber 'O' Rings. (author)

  9. A bioactive metallurgical grade porous silicon-polytetrafluoroethylene sheet for guided bone regeneration applications.

    Science.gov (United States)

    Chadwick, E G; Clarkin, O M; Raghavendra, R; Tanner, D A

    2014-01-01

    The properties of porous silicon make it a promising material for a host of applications including drug delivery, molecular and cell-based biosensing, and tissue engineering. Porous silicon has previously shown its potential for the controlled release of pharmacological agents and in assisting bone healing. Hydroxyapatite, the principle constituent of bone, allows osteointegration in vivo, due to its chemical and physical similarities to bone. Synthetic hydroxyapatite is currently applied as a surface coating to medical devices and prosthetics, encouraging bone in-growth at their surface and improving osseointegration. This paper examines the potential for the use of an economically produced porous silicon particulate-polytetrafluoroethylene sheet for use as a guided bone regeneration device in periodontal and orthopaedic applications. The particulate sheet is comprised of a series of microparticles in a polytetrafluoroethylene matrix and is shown to produce a stable hydroxyapatite on its surface under simulated physiological conditions. The microstructure of the material is examined both before and after simulated body fluid experiments for a period of 1, 7, 14 and 30 days using Scanning Electron Microscopy. The composition is examined using a combination of Energy Dispersive X-ray Spectroscopy, Thin film X-ray diffraction, Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy and the uptake/release of constituents at the fluid-solid interface is explored using Inductively Coupled Plasma-Optical Emission Spectroscopy. Microstructural and compositional analysis reveals progressive growth of crystalline, 'bone-like' apatite on the surface of the material, indicating the likelihood of close bony apposition in vivo.

  10. Study on influence of irradiation vulcanization to silicon rubber autohesive tape's properties

    International Nuclear Information System (INIS)

    Chen Chun; Tang Jian; Wu Ling; Han Yingchun; Zhou Hong; Mo Yan; Fu Haijun

    2006-01-01

    After using 60 Co γ-ray to irradiate vulcanization silicon rubber autohesive tape, the effect of absorbed dose to the autohesive tape's tensile strength, elongation at break, autohesion and breakdown voltage strength and dose rate's effect to the autohesive tape's properties were studied. The results indicate that autohesive tape's tensile strength increases and the elongation at break decreases with the increasing dose. Under the dose of 25 kGy, the tape's autohesion increases with the increasing dose. When the dose is up to 25 kGy, the tape's autohesion achieves to the maximum, and then decreases with the increasing dose. Absorbed dose has no effect to the tape's breakdown voltage strength, and the dose rate has no effect to the autohesive tape's properties. (authors)

  11. Wavelength-shifting fiber signal readout from Transparent RUbber SheeT (TRUST) type LiCaAlF6 neutron scintillator

    International Nuclear Information System (INIS)

    Watanabe, Kenichi; Yamazaki, Takuya; Sugimoto, Dai; Yamazaki, Atsushi; Uritani, Akira; Iguchi, Tetsuo; Fukuda, Kentaro; Ishidu, Sumito; Yanagida, Takayuki; Fujimoto, Yutaka

    2015-01-01

    As an alternative to the standard 3 He neutron detector, we are developing the Transparent RUbber SheeT type (TRUST) Eu doped LiCaAlF 6 (Eu:LiCAF) scintillator. This type of neutron scintillator can easily be fabricated as a large area sheet. In order to take advantage of a large area detector, we try to readout scintillation photons using a wavelength-shifting fiber (WLSF) from a TRUST Eu:LiCAF scintillator. The TRUST Eu:LiCAF scintillator with the size of 50×50×5 mm 3 was mounted on the WLSF plate and the end of the WLSFs was connected with a PMT. In order to reject high pulse height events induced in the WLSFs, we applied the pulse shape discrimination technique. The gamma-ray intrinsic and neutron absolute detection efficiency is evaluated to be 8.8×10 −7 and 9×10 −3 cps/ng Cf (2 m) for the TRUST Eu:LiCAF scintillator with the size of 50×50×5 mm 3

  12. Facile preparation of carbon nanotubes-graphene hybrids and the effect of aspect ratio of carbon nanotubes on electrical and thermal properties of silicone rubber based composites

    Science.gov (United States)

    Zhao, Shizhen; Bai, Lu; Zheng, Junping

    2018-01-01

    Thermal exfoliation, as an effective and easily scalable method, was widely used to produce graphene (GE). In order to prevent the severe stacking of GE sheets after thermal exfoliation process, a facile technique was used to solve this problem through the barrier effect of carbon nanotubes (CNTs). Two kinds of CNTs with different aspect ratios (AR) were taken to prepare CNTs-GE hybrids using this technique, and then the effect of AR of CNTs (namely CNTs-L for low AR and CNTs-H for high AR) in the hybrids on the performance of silicone rubber (SR) composites was investigated. The results indicate that the presence of CNTs can effectively impede the stacking of GE sheets and the hybrids are dispersed uniformly in the SR matrix. With the addition of CNTs-GE hybrids, the resulted SR composites exhibit greatly improved electrical and thermal properties, especially for the composites filled with CNTs-H-GE hybrid. At the hybrids content of 3.0 wt%, the volume resistivity of CNTs-H-GE/SR composite is 5 × 104 Ω cm (about 10 orders of magnitude decrease compared with pure SR). And the thermal conductivity increases by 78% compared to the pure SR. But as for the CNTs-L-GE/SR composite, the corresponding values are 3 × 106 Ω cm and 59%, respectively. In terms of thermal stability, the CNTs-H-GE/SR composite containing 1.0 wt% hybrid exhibits the maximum improvement of initial degradation temperature (419 °C) compared with the CNTs-L-GE/SR composite (393 °C) and pure SR (365 °C).

  13. Radiation-grafting of acrylamide onto silicone rubber films for diclofenac delivery

    International Nuclear Information System (INIS)

    Magaña, Hector; Palomino, Kenia; Cornejo-Bravo, Jose M.; Alvarez- Lorenzo, Carmen; Concheiro, Angel; Bucio, Emilio

    2015-01-01

    This work focuses on the pre-irradiation grafting of acrylamide (AAm) onto silicone rubber films (SR) and evaluates the effect of gamma-ray radiation conditions on the grafting yield, which in turn may influence the performance of the grafted materials as components of drug-eluting devices. Pristine and modified SR were characterized using FTIR-ATR, DSC, TGA, swelling, and water contact angle analysis in order to elucidate the effects of AAm grafting onto SR. Grafted films with content in AAm ranging from 0.81% to 22.20% showed excellent cytocompatibility against fibroblasts, and capability to uptake the anti-inflammatory drug diclofenac. Amount of drug loaded directly correlated with the grafting degree of the films. Drug release studies were performed at pH 7.4 and 37 °C (physiological conditions). Most grafted films released the drug in a sustained way for at least three hours. - Highlights: • SR–g-AAm depends on dose, monomer concentration, and reaction time and temperature. • Diclofenac sodium salt is loaded and released in a sustained way from SR–g-AAm films. • SR–g-AAm films are cytocompatible and have potential as components of drug–device

  14. Electrical Tree Initiation and Growth in Silicone Rubber under Combined DC-Pulse Voltage

    Directory of Open Access Journals (Sweden)

    Tao Han

    2018-03-01

    Full Text Available Electrical tree is a serious threat to silicone rubber (SIR insulation and can even cause breakdown. Electrical trees under alternating current (AC and direct current (DC voltage have been widely researched. While there are pulses in high-voltage direct current (HVDC cables under operating conditions caused by lightning and operating overvoltage in the power system, little research has been reported about trees under combined DC-pulse voltage. Their inception and growth mechanism is still not clear. In this paper, electrical trees are studied under several types of combined DC-pulse voltage. The initiation and growth process was recorded by a digital microscope system. The experimental results indicate that the inception pulse voltage is different under each voltage type and is influenced by the combined DC. The initial tree has two structures, determined by the pulse polarity. With increased DC prestressing time, tree inception pulse voltage with the same polarity is clearly decreased. Moreover, a special initial bubble tree was observed after the prestressing DC.

  15. All-solid-state ion-selective silicone rubber membrane electrodes with a new conducting polymer

    International Nuclear Information System (INIS)

    Park, Eun Rang; Chung, Yeon Joon; Hwang, Sun Woo

    2012-01-01

    New conducting polymers containing heterocyclic rings with carbazole, ethylene dioxythiophene (EDOT) and benzobisthiazole were synthesized and the characterized by using organic spectroscopic methods. Potentiometric ion-selective membrane electrodes (ISMEs) have been extensively used for ion analysis in clinical, environmental, and industrial fields owing to their wide response range (4 to 7 orders of magnitude), no effect of sample turbidity, fast response time, and ease of miniaturization. Considerable attention has been given to alternative use of room-temperature vulcanizing (RTV)-type silicone rubber (SR) owing to its strong adhesion and high thermal durability. Unfortunately, the high membrane resistance of SR-based ion-selective membranes (ISMs) (2 to 3 higher orders of magnitude compared to those of poly(vinyl chloride)(PVC)-based ones) has significantly restricted their application. Herein, we demonstrate a new method to reduce the membrane resistance via addition of a new conducting polymer into the SR-based ISMs.

  16. Rubber membrane liner confines low level radioactive material

    International Nuclear Information System (INIS)

    Anon.

    1982-01-01

    One of the most sophisticated membrane lining projects in the world was undertaken in 1979 by the Cotter Corporation, Canon City, Colorado, producers of vanadium and uranium, when a new tailings pond was built to handle mill tailings and effluents. To comply with local, state and federal regulations, Cotter sought maximum protection for downstream residents. The lining was designed to keep leakage near zero and withstand tailings and water pressure at the deepest part of the pond. Other considerations were compatibility with alkalis and acids and durability and effectiveness of the lining beyond the life of the mill. ''We had to be sure the impoundment would outlast the mill because of the need for long-term isolation of the tailings,'' said Joseph McCluskey, Cotter's executive vice presient. Gotter chose an industrial grade sheeting made of Hypalon synthetic rubber, a chlorosulfonated polyethylene, that has an exposed life expectancy of 40 years; however, once covered with earth and tailings, it will last much longer. The sheeting consists of a reinforced scrim sandwiched between two sheets of Hypalon. The rubber comprises nearly 50 percent of the total linear weight, and the reinforcement is a 10' x 10' 1000D polyester scrim whose open weave allows the rubber to penetrate the fabric and create excellent adhesion between the layers. After two years, the impoundment contains approximately 1400 acre feet of liquid. Currently, about one half of the pond consists of run-off with tailings and liquids from the new mill making up the difference

  17. Wavelength-shifting fiber signal readout from Transparent RUbber SheeT (TRUST) type LiCaAlF{sub 6} neutron scintillator

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Kenichi, E-mail: k-watanabe@nucl.nagoya-u.ac.jp [Graduate School of Engineering, Nagoya University, Nagoya 464-8603 (Japan); Yamazaki, Takuya; Sugimoto, Dai; Yamazaki, Atsushi; Uritani, Akira; Iguchi, Tetsuo [Graduate School of Engineering, Nagoya University, Nagoya 464-8603 (Japan); Fukuda, Kentaro; Ishidu, Sumito [Tokuyama Corporation, Shunan 745-8648 (Japan); Yanagida, Takayuki; Fujimoto, Yutaka [Kyushu Institute of Technology, Kita-kyushu 808-0196 (Japan)

    2015-06-01

    As an alternative to the standard {sup 3}He neutron detector, we are developing the Transparent RUbber SheeT type (TRUST) Eu doped LiCaAlF{sub 6} (Eu:LiCAF) scintillator. This type of neutron scintillator can easily be fabricated as a large area sheet. In order to take advantage of a large area detector, we try to readout scintillation photons using a wavelength-shifting fiber (WLSF) from a TRUST Eu:LiCAF scintillator. The TRUST Eu:LiCAF scintillator with the size of 50×50×5 mm{sup 3} was mounted on the WLSF plate and the end of the WLSFs was connected with a PMT. In order to reject high pulse height events induced in the WLSFs, we applied the pulse shape discrimination technique. The gamma-ray intrinsic and neutron absolute detection efficiency is evaluated to be 8.8×10{sup −7} and 9×10{sup −3} cps/ng Cf (2 m) for the TRUST Eu:LiCAF scintillator with the size of 50×50×5 mm{sup 3}.

  18. Design, Construction, and Evaluation of Rubber Friction Tester

    Directory of Open Access Journals (Sweden)

    Mehdi Razzaghi Kashani

    2012-12-01

    Full Text Available Coeffcient of  friction  (COF  for  rubber parts  is one of  the key parameters in their interaction with solid rough surfaces (micrometer to millimeter scales,  such  as  tire-road  interactions. COF  of  rubber  depends  on  viscoelastic properties of rubber, roughness characteristics of the counter-part surface, and process variables such as contact nominal pressure and sliding speed. Due to the need for measuring COF  for  rubber,  a  new  friction  tester, with  continuous  variation  of nominal pressure and sliding speed, was designed and constructed in order to assess the effect of above mentioned parameters. Tire tread compounds, as the most common rubber part  in  the feld of  rubber  tribology, was used  for  this purpose. Viscoelastic properties of compounds were varied by changing composition of styrene-butadiene rubber (SBR and butadiene rubber (BR in the blend. Effect of surface roughness was evaluated by using silicon-carbide papers with different roughness parameters. By statistical analysis it was shown that the designed friction tester has high accuracy in measuring the coeffcient of friction of rubber and differentiating the effective parameters. Increasing the nominal pressure led to reduction of COF and increase in sliding speed forced it through a maximum. In conclusion, the loss factor of the compound and asymmetry in roughness distribution of the counter-surface are considered as the most effective parameters on COF of rubber.

  19. Single Stage Silicone Border Molded Closed Mouth Impression Technique-Part II.

    Science.gov (United States)

    Solomon, E G R

    2011-09-01

    Functioning of a complete denture depends to a great extent on the impression technique. Several impression techniques have been described in the literature since the turn of this century when Greene [Clinical courses in dental prothesis, 1916] brothers introduced the first scientific system of recording dental impression. Advocates of each technique have their own claim of superiority over the other. The introduction of elastomeric impression materials [Skinner and Cooper, J Am Dent Assoc 51:523-536, 1955] has made possible new techniques of recording impression for complete denture construction. These rubber like materials are of two types; one has a polysulfide base and is popularily known as polysulfide rubber (Thiokol and Mercaptan). The other variety has a silicone base known as silicone rubber or silicone elastomer. Silicone elastomers are available in four different consistencies; a thin easy flowing light bodied material,a creamy medium bodied material, a highly viscous heavy bodied material and a kneadable putty material. This paper describes an active closed mouth impression technique with one stage border molding using putty silicone material as a substitute for low fusing compound.

  20. A comprehensive study of the electrically conducting water based CuO and Al2O3 nanoparticles over coupled nanofluid-sheet interface

    International Nuclear Information System (INIS)

    Ahmad, R

    2016-01-01

    Many studies on nanofluid flow over a permeable/impermeable sheet prescribe the kinematics of the sheet and disregard the sheet’s mechanics. However, the current study is one of the infrequent contributions that anticipate the mechanics of both the electrically conducting nanofluid (a homogeneous mixture of nanoparticles and base fluid) and the sheet. Two types of nanoparticles, alumina and copper, with water as a base fluid over the sheet are considered. With the help of the similarity transformations, the corresponding partial differential equations for the coupled nanofluid-sheet interface are transformed into a system of ordinary differential equations. The simulations are done by using the experimentally verified results from the previous studies for viscosity and thermal conductivity. Self-similar solutions are attained by considering both analytical and numerical techniques. Dual skin friction coefficients are attained with different copper and alumina nanoparticles over both the stretching and viscous sheets. The influence of the Eckert number, magnetic and mass suction/blowing parameters on the dimensionless velocity, temperature, skin friction and heat transfer rates over the nanofluid-sheet interface are presented graphically as well as numerically. The obtained results are of potential benefit for studying nanofluid flow over various soft surfaces such as synthetic plastics, soft silicone sheet and soft synthetic rubber sheet. These surfaces are easily deformed by thermal fluctuations. (paper)

  1. Crystal growth for high-efficiency silicon solar cells workshop: Summary

    Science.gov (United States)

    Dumas, K. A.

    1985-01-01

    The state of the art in the growth of silicon crystals for high-efficiency solar cells are reviewed, sheet requirements are defined, and furture areas of research are identified. Silicon sheet material characteristics that limit cell efficiencies and yields were described as well as the criteria for the ideal sheet-growth method. The device engineers wish list to the material engineer included: silicon sheet with long minority carrier lifetime that is uniform throughout the sheet, and which doesn't change during processing; and sheet material that stays flat throughout device processing, has uniform good mechanical strength, and is low cost. Impurities in silicon solar cells depreciate cell performance by reducing diffusion length and degrading junctions. The impurity behavior, degradation mechanisms, and variations in degradation threshold with diffusion length for silicon solar cells were described.

  2. Novel Techniques for Characterizing and Understanding the Response of Rubbers and Rubber-Based Composites to Impact Loading

    Science.gov (United States)

    2016-09-30

    obtained from the drop -weight simulations at the temperature ranges from 60 to -12 °C and the given nitrile and silicone rubber relaxation curves...characterising the high rate properties of low impedance polymers. In particular, the difficulties of testing materials with low wavespeeds are...addressed using two different methods based on wave propagation: 1) Optical measurements of the evolution of displacement fields induced by stress wave

  3. Study on reducing radiation dose in dental radiography for children, 1. The seltering effects of lead content rubber sheet and ready-made apron

    Energy Technology Data Exchange (ETDEWEB)

    Shikone, Mitsuru; Tsuchida, Atsushi; Tateno, Hidemi; Uchimura, Noboru; Higaki, Morio; Kanno, Masanori; Higashi, Tomomitsu

    1986-12-01

    X-ray examination is one of the effective diagnoses in dentistry. And it is difficult to conduct a precise dental examination without X-ray films, especially in pedodontics. However, radiography may be attended with many radiation injury, and we must perform the complete protection of patients when taking X-ray radiography for children, because their tissues are much more sensitive to radiation than those of adult. Children have some radiosensitive immature organs such as the thyroid gland, eyes (crystalline lens), gonad etc., accordingly, it is very important to protect them from exposure of X-rey. It has been suggested that the thyroid gland is the most sensitive to radiation among many organs. We, therefore, establish a protector for children's thyroid gland as soon as possible. In this study, the auther had designed X-ray protecting rubber sheet which had various lead contents, for finding an optimum condition of the protector. Additionally, the sheltering effects were compared among ready-made protectors. 1. It was satisfactory for complete sheltering of direct beam that the rubber sheet contained 0.375 mmPb, 0.5 mmPb, and 0.75 mmPb, at the tubevoltage of 65 kVp, 70 kVp and 80 kVp, respectively. 2. The radiolucency ratio of Hagoromo Apron containing 0.25 mmPb was 0 % at 65 kVp, and that of X-ray Shield containing 0.50 mmPb was 0 % at 65, 70 kVp and 80 kVp too. 3. Among the ready-made aprons, there was one which had less lead content than the indicated value.

  4. The use of styrene-butadiene rubber waste as a potential filler in nitrile rubber: order of addition and size of waste particles

    Directory of Open Access Journals (Sweden)

    D. A. Baeta

    2009-03-01

    Full Text Available Styrene-butadiene rubber (SBR has large applications in the shoe industry, especially as expanded sheets used to produce insoles and inner soles. According to TG analysis, the rubber content in SBR residues (SBR-r was found to be around 26-wt%. Based on that data, a cost-effective technique for the reuse of SBR-r in Nitrile rubber (NBR was developed. Later, the effect of SBR-r on the cure behavior, mechanical performance, swelling, and crosslink density of reused rubber was investigated, with more emphasis placed on the effect of both particle size and loading of waste filler. Cure characteristics such as optimum cure time and scorch time were then reduced by the increasing amount of SBR-r filler. Owing to the reinforced nature of the largest particle size SBR-r, the best results for the mechanical properties of NBR were those in which SBR-r was added at the end of the cure process. The study has thus shown that SBR residue (SBR-r can be used as an economical alternative filler in NBR.

  5. Punchless Drawing of Magnesium Alloy Sheet under Cold Condition and its Computation

    International Nuclear Information System (INIS)

    Yamashita, Minoru; Hattori, Toshio; Sato, Joji

    2011-01-01

    The punchless drawing with Maslennikov's technique was applied to the circular cup drawing of magnesium alloy AZ31B sheet under cold condition. The elastic rubber ring was used instead of the 'hard' punch, where the compressed ring dragged the sheet inward the die cavity. Attainable circumferential strain of the blank was increased by this technique with repetitive drawing operation. Thickness of the rubber pad affected little the attainable strain. The shape appearance became better when a harder rubber was used. The cup forming by single drawing operation was also tested using a small die shoulder radius. The LDR of 1.250 was obtained with the straight cup wall. Further, the computation of the punchless drawing was also conducted for the single drawing operation. The computed deformation pattern was well consistent with the corresponding experimental result.

  6. Electrical treeing behaviors in silicone rubber under an impulse voltage considering high temperature

    Science.gov (United States)

    Yunxiao, ZHANG; Yuanxiang, ZHOU; Ling, ZHANG; Zhen, LIN; Jie, LIU; Zhongliu, ZHOU

    2018-05-01

    In this paper, work was conducted to reveal electrical tree behaviors (initiation and propagation) of silicone rubber (SIR) under an impulse voltage with high temperature. Impulse frequencies ranging from 10 Hz to 1 kHz were applied and the temperature was controlled between 30 °C and 90 °C. Experimental results show that tree initiation voltage decreases with increasing pulse frequency, and the descending amplitude is different in different frequency bands. As the pulse frequency increases, more frequent partial discharges occur in the channel, increasing the tree growth rate and the final shape intensity. As for temperature, the initiation voltage decreases and the tree shape becomes denser as the temperature gets higher. Based on differential scanning calorimetry results, we believe that partial segment relaxation of SIR at high temperature leads to a decrease in the initiation voltage. However, the tree growth rate decreases with increasing temperature. Carbonization deposition in the channel under high temperature was observed under microscope and proven by Raman analysis. Different tree growth models considering tree channel characteristics are proposed. It is believed that increasing the conductivity in the tree channel restrains the partial discharge, holding back the tree growth at high temperature.

  7. Electron beam cross-linking of natural rubber/linear-low density polyethylene blends

    International Nuclear Information System (INIS)

    Ahmad, A.; Mohd, D. H.; Abdullah, I.

    2005-01-01

    Effects of electron beam irradiation on the mechanical properties and morphological structure of natural rubber/linear-low density polyethylene blend was investigated The natural rubber/linear-low density polyethylene blend was prepared by melt blending in a Haake internal mixer at 140 d ig C , rotor speed of 50 rpm, and in 15 min Liquid natural rubber was incorporated into the blend as a compatibilizer Samples in the form of 1 mm sheets were exposed to 50-300 kGy of electron beam irradiation and analyzed for swelling index and gel content, tensile strength, and surface morphology. The result Indicated that gel content and mechanical properties of the samples increased with radiation dosage. The honey-comb structure of the surface morphology in low dosage irradiated samples slowly transformed into a continuous matrix on increasing radiation dose The variation of mechanical and physical properties was due to Increase in cross-linking density in the rubber and plastic phases and rubber-plastic Interaction on irradiation

  8. Effects of variation of oil and zinc oxide type on the gas barrier and mechanical properties of chlorobutyl rubber/epoxidised natural rubber blends

    International Nuclear Information System (INIS)

    Li, Lin; Zhang, Jin; Jo, Jae Ok; Datta, Sanjoy; Kim, Jin Kuk

    2013-01-01

    Highlights: ► A (90:10) blend of CIIR and ENR by weight was used as the base. ► Different process oil and ZnO were used to optimize the gas barrier property. ► The minimum oxygen permeability is obtained using sheet ZnO. - Abstract: In many polymer applications such as inner tire liners and fuel hoses, imparting excellent gas barrier property is of prime importance. Researches in this direction had been done based on a judicious choice of polymer type or a blend thereof and the compounding ingredients. Though butyl rubber has been the polymer of choice because of its excellent gas barrier property, yet researches were targeted to improve the same with further modification in the polymer type and variation in compounding ingredients. In this study, a (90:10) blend of chlorobutyl rubber (CIIR) and Epoxdised Natural Rubber (ENR) by weight was used as the base. Four different types of process oil and three different types of zinc oxide (ZnO) at fixed predetermined concentrations were used to optimize the gas barrier and mechanical properties. In this blend, recycled aromatic oil (RAE) and sheet zinc oxide were effective in imparting the best overall combination of properties. Scanning Electron Microscopic (SEM) studies of ZnO were done to understand the structure property relationship

  9. Contact of a spherical probe with a stretched rubber substrate

    Science.gov (United States)

    Frétigny, Christian; Chateauminois, Antoine

    2017-07-01

    We report on a theoretical and experimental investigation of the normal contact of stretched neo-Hookean substrates with rigid spherical probes. Starting from a published formulation of surface Green's function for incremental displacements on a prestretched, neo-Hookean, substrate [J. Mech. Phys. Solids 56, 2957 (2008), 10.1016/j.jmps.2008.07.002], a model is derived for both adhesive and nonadhesive contacts. The shape of the elliptical contact area together with the contact load and the contact stiffness are predicted as a function of the in-plane stretch ratios λx and λy of the substrate. The validity of this model is assessed by contact experiments carried out using an uniaxally stretched silicone rubber. For stretch ratio below about 1.25, a good agreement is observed between theory and experiments. Above this threshold, some deviations from the theoretical predictions are induced as a result of the departure of the mechanical response of the silicone rubber from the neo-Hokeean description embedded in the model.

  10. Mixed Matrix Silicone and Fluorosilicone/Zeolite 4A Membranes for Ethanol Dehydration by Pervaporation

    Science.gov (United States)

    The ability of homogeneous and mixed matrix membranes prepared using standard silicone rubber, poly(dimethylsiloxane) (PDMS), and fluorosilicone rubber, poly(trifluoropropylmethylsiloxane) (PTFPMS), to dehydrate ethanol by pervaporation was evaluated. Although PDMS is generally c...

  11. Etching kinetics of swift heavy ion irradiated silicone rubber with insoluble additives or reaction products

    International Nuclear Information System (INIS)

    Fink, D.; Mueller, M.; Petrov, A.; Farenzena, L.; Behar, M.; Papaleo, R.P.

    2003-01-01

    It is normally understood as a basic precondition of the etching of swift heavy ion tracks in polymers that both the additives and etching products are soluble in the etchant. If this is not given, the polymer surface may be gradually blocked by the deposition of the insoluble material that acts as a diffusion barrier for the penetration of fresh etchant into the tracks, and therefore the effective track etching speed will gradually be reduced. The etching kinetics is developed for that case, and the theory is compared with first experimental findings. For that purpose we have taken commercial silicone rubber foils as test materials, that were irradiated with GeV heavy ions through a mask at a fluence that corresponds to the onset of track overlapping. After etching with NaOH, the corresponding etching speed was recorded via the reduction of the foil thickness. The etching speed is seen to decrease with exposure time, in parallel to the development of an insoluble surface layer. It is discussed how to prevent that surface blocking, to maintain a high etching speed

  12. Abating coal tar seepage into surface water bodies using sheet piles with sealed interlocks

    International Nuclear Information System (INIS)

    Collingwood, B.I.; Boscardin, M.D.; Murdock, R.F.

    1995-01-01

    A former coal tar processing facility processed crude coal tar supplied from manufactured gas plants in the area. Coal-tar-contaminated ground water from the site was observed seeping through an existing timber bulkhead along a tidal river and producing a multicolored sheen on the surface of the river. As part of a short-term measure to abate the seepage into the river, 64-m long anchored sheet pile wall with sheet pile wing walls at each end was constructed inland of the of the timber bulkhead. The sheet piles extended to low-permeability soils at depth and the interlocks of the sheet piles were provided with polyurethane rubber seals. Based on postconstruction observations for leakage and sheens related to leakage, the steel sheet piles with polyurethane rubber interlock seals appeared to provide a successful seal and abate coal-tar-contaminated ground water seepage into the river. The tie rod penetration sealing proved to be a more problematic detail, but through several postconstruction grouting episodes, an effective seal was produced

  13. Visual nesting system for irregular cutting-stock problem based on rubber band packing algorithm

    Directory of Open Access Journals (Sweden)

    Xiaoping Liao

    2016-05-01

    Full Text Available This article deals with the packing problem of irregular items allocated into a rectangular sheet to minimize the waste. Conventional solution is not visual during the packing process. It obtains a reasonable and relatively satisfactory solution between the nesting time and nesting solution. This article adopts a physical method that uses rubber band packing algorithm to simulate a rubber band wrapping those packing irregular items. The simulation shows a visual and fast packing process. The resultant rubber band force is applied in the packing items to translate, rotate, and slide them to make the area decrease and obtain a high packing density. An improved analogy QuickHull algorithm is presented to obtain extreme points of rubber band convex hull. An adaptive module could set a variable rubber band force and a variable time step to make a proper convergence and no intersection. A quick convex decomposition method is used to solve the problem of concave polygon. A plural vector expression approach is adopted to calculate the resultant vector of the rubber band force. Several cases are compared with the benchmark problems to prove rubber band packing algorithm performance.

  14. Rubber industry

    Science.gov (United States)

    Staszak, Maciej

    2018-03-01

    Following chapter presents short introductory description of rubber and rubber industry. The main problem of rubber industry is the way of the usage of spent tires. Furthermore very important group of problems arise considering the metal and nonmetal additives which are significant component of the vulcanized rubber. The key attention is dedicated to typical ways of rubber usage in utilization and recovery of metals from spent rubber materials concentrating specifically on used tires processing. The method of recovery of rare metals from rubber tires was described. The rubber debris finds widest use in the field of waste metal solutions processing. The environmental pollution caused by metals poses serious threat to humans. Several applications of the use of waste rubber debris to remove metals from environmental waters were described. Moreover, the agriculture usage of waste tire rubber debris is described, presenting systems where the rubber material can be useful as a soil replacement.

  15. Temperature effects on the magnetic properties of silicon-steel sheets using standardized toroidal frame.

    Science.gov (United States)

    Wu, Cheng-Ju; Lin, Shih-Yu; Chou, Shang-Chin; Tsai, Chia-Yun; Yen, Jia-Yush

    2014-01-01

    This study designed a detachable and standardized toroidal test frame to measure the electromagnetic characteristic of toroidal laminated silicon steel specimens. The purpose of the design was to provide the measurements with standardized and controlled environment. The device also can withstand high temperatures (25-300°C) for short time period to allow high temperature tests. The accompanying driving circuit facilitates testing for high frequency (50-5,000 Hz) and high magnetic flux (0.2-1.8 T) conditions and produces both sinusoidal and nonsinusoidal test waveforms. The thickness of the stacked laminated silicon-steel sheets must be 30~31 mm, with an internal diameter of 72 mm and an outer diameter of 90 mm. With the standardized setup, it is possible to carry out tests for toroidal specimen in high temperature and high flux operation. The test results show that there is a tendency of increased iron loss under high temperature operation. The test results with various driving waveforms also provide references to the required consideration in engineering designs.

  16. Vacuum die casting of silicon sheet for photovoltaic applications. First quarterly report, March 16-June 30, 1979

    Energy Technology Data Exchange (ETDEWEB)

    None

    1979-01-01

    The obtective of this program is to develop a vacuum die-casting process for producing silicon sheet suitable for photovoltaic cells and to develop production techniques for optimization of polycrystallie silicon solar cell output. Efforts will examine process methods which are directed toward minimum cost processing of silicon into a quality suitable for producing solar cells with a terrestrial efficiency greater than 12% and having the potential to be scaled for large quantity production. In the vacuum die casting technique, silicon is melted under vacuum, and an evacuated die with a thin rectangular cavity is inserted into the melt. Liquid silicon is then injected into the die using a positive pressure of an inert gas. The major portion of the die casting work will be performed at Stanford Research Institute International under subcontract. The initial approach will follow parallel tracks: (1) obtain mechanical design parameters by using boron nitride, which has been shown to be non-wetting to silicon; (2) optimize silicon nitride material composition and coatings by sessile drop experiments; (3) test effectiveness of fluoride salt interfacial media with a graphite mold; and (4) test effect of surface finish using both boron nitride and graphite. Having established the material and mechanical boundary conditions, a finalized version of the prototype assembly will be constructed and the casting varibles determined. Polycrystalline silicon solar cells, with and without impurities, will be fabricated, characterized, and optimized at ARCCO Solar. The major activities will focus on the use of Wacker SILCO, HEM and in-house materials until vacuum die cast wafers are available. A baseline process with vacuum metallized contacts will be established and a reference mass production process with screen-printed metallization and high-throughput diffusions will also be obtained.

  17. Study on the properties of blend rubber prepared with grafted rubber and irradiated rubber by Gamma Rays

    International Nuclear Information System (INIS)

    Dafader, N. C.; Haque, M. E.; Islam, K. A.

    2004-05-01

    The blend rubbers were prepared by mixing γ-rays irradiated and monomer grafted rubbers. The monomers, methyl methacrylate (MMA) and styrene were used separately to prepare grafted rubber by exposure to radiation. The physico-chemical properties of the blend rubbers were evaluated. The tensile strength and elongation at break of the blend rubbers decrease whereas modulus at 500% elongation, swelling ratio and permanent set increase with the increased proportion of grafted rubber in the blend. The tear strength of the blend between irradiated and styrene grafted rubbers increases with the increased proportion of grafted rubber but that of the blend of irradiated and MMA grafted rubbers remains almost constant. The blend rubber could be used for special type of application like rubber thread, tube, catheter etc

  18. Preparation and Properties of EPDM/Silicone Alloy Using Maleated EPDM-polydimethylsiloxane Compatibilizer

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Doo Whan; Kim, Bum Jin [Hyperstructured Organic Materials Research Center, Department of Polymer Science and Engineering, Dankook University, Seoul (Korea); Shim, Dae Sup [Korea Electrotechnology Research Institute, Euiwang (Korea)

    2001-05-01

    EPDM used as an electrical insulating material was blended with silicone rubber and compatibilizer to improve weatherability, ozone resistance, and dielectric strength. The compatibilizer was prepared by imidizing maleated EPDM with {alpha},{omega}-aminopropyl polydimethylsiloxane. EPDM/ silicone alloy was prepared by blending EPDM and silicone rubber with weight ratio of 9/1, 7/3, 5/5, 3/7 and 1/9, maleated EPDM-polydimethylsiloxane copolymer, and dicumyl peroxide (DCP). The maximum tensile strength of 0.177 kgf/mm{sup 2}, elongation at break of 257%, and dielectric breakdown voltage 362.25 kV/cm were obtained from the alloy prepared with 9 to 1 weight ration of EPDM/silicone. The compatibility of the alloy was confirmed from the thermal characteristics measured using DMA and DSC. The morphology of the alloys was observed with SEM. 7 refs., 8 figs., 1 tab.

  19. Performance of composites made with polymers of silicone rubber and waste of lead on the properties of attenuation

    International Nuclear Information System (INIS)

    Barros, Frieda S.; Paredes, Ramon S.C.

    2009-01-01

    All facilities and personnel protection equipment which use ionizing radiation need protection. Based on this statement, several researchers have aimed their projects searching for new materials that present good behavior facing the attenuation properties. This research aims at the development of a composite by using the silicon rubber associated to the residue of lead in powder, obtained via the recycling of components of lead from automobile batteries. In this work , were checked the morphological physical - chemical properties of the materials isolated and associated, the calorimetrical properties of the performance of the composite related to the attenuation for X-Rays and gamma, through experimental rehearsals and computational simulation. For mixtures with 40% of lead residue, referential value in mass, favorable results were obtained about armor. In this way, it was allied the good performance of the composite with a reduction of an environmental passive to the process of recycling lead. (author)

  20. Developments in rubber technology 2 synthetic rubbers

    CERN Document Server

    Lee, K

    1981-01-01

    This book is intended for those people who have a knowledge or understanding of rubber materials and processes but who wish to update their knowledge. It should be read in conjunction with Developments in Rubber Technology-l as that volume discussed developments in natural rubber and selected special purpose synthetic rubbers as well as additives. The authors have been selected for their expertise in each particular field and we, as editors, would like to express our appreciation to the individual authors and also to their companies. Such a book would be impossible to produce without such active cooperation as we have received. Volumes 1 and 2 of Developments in Rubber Technology cover rubbers which are processed and vulcanised in the traditional manner. It is appreciated that the omission of non-vulcanised rubber materials (the so­ called thermoplastic elastomers) will be unwelcome to many readers but it is intended, because of the size of the subject, to cover these materials in a subsequent volume. A.W. K...

  1. Effects of nano-SiO{sub 2} particles on surface tracking characteristics of silicone rubber composites

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yong, E-mail: tjuliuyong@tju.edu.cn; Li, Zhonglei; Du, Boxue [Key Laboratory of Smart Grid of Ministry of Education (Tianjin University), School of Electrical Engineering and Automation, Tianjin University, Tianjin 300072 (China)

    2014-09-08

    Compared with neat silicone rubber composites (SiRCs), SiRCs filled with nano-sized SiO{sub 2} particles at weight ratios from 0.1 to 1.0 wt. % exhibit a higher surface flashover voltage and a greater resistance to surface tracking. Scanning electron microscopy images of tracking morphologies indicate that the SiO{sub 2} particles are situated in close proximity to the polymeric chains and act as bridges to stabilize the chains and maintain the structure of the composite. Higher concentrations of nano-sized SiO{sub 2} particles, however, (above 0.3 wt. %) produce defects in the molecular network which lead to reductions in both the surface flashover voltage and the resistance to surface tracking, although these reduced values are still superior to those of neat SiRCs. Therefore, SiRCs filled with nano-sized SiO{sub 2} particles, especially at an optimal weight ratio (0.1 to 0.3 wt. %), may have significant potential applications as outdoor insulators for power systems.

  2. Synthesis of Zirconium-Containing Polyhedral Oligometallasilsesquioxane as an Efficient Thermal Stabilizer for Silicone Rubber

    Directory of Open Access Journals (Sweden)

    Jiedong Qiu

    2018-05-01

    Full Text Available Free radicals play a negative role during the thermal degradation of silicone rubber (SR. Quenching free radicals is proposed to be an efficient way to improve the thermal-oxidative stability of SR. In this work, a novel zirconium-containing polyhedral oligometallasilsesquioxane (Zr-POSS with free-radical quenching capability was synthesized and characterized. The incorporation of Zr-POSS effectively improved the thermal-oxidative stability of SR. The T5 (temperature at 5% weight loss of SR/Zr-POSS significantly increased by 31.7 °C when compared to the unmodified SR. Notably, after aging 12 h at 280 °C, SR/Zr-POSS was still retaining about 65%, 60%, 75%, and 100% of the tensile strength, tear strength, elongation at break, and hardness before aging, respectively, while the mechanical properties of the unmodified SR were significantly decreased. The possible mechanism of Zr-POSS for improving the thermal-oxidative stability of SR was intensively studied and it was revealed that the POSS structure could act as a limiting point to suppress the random scission reaction of backbone. Furthermore, Zr could quench the free radicals by its empty orbital and transformation of valence states. Therefore, it effectively suppressed the thermal-oxidative degradation and crosslinking reaction of the side chains.

  3. Characterization of Hexsyn, a polyolefin rubber.

    Science.gov (United States)

    McMillin, C R

    1987-07-01

    Hexsyn is the Goodyear Tire and Rubber Company tradename for a polyolefin rubber synthesized from 1-hexene with 3-5% methylhexadiene as the source of residual double bonds for vulcanization. Under license from Goodyear, this same polymer has been manufactured by Lord Corporation for the hinge portion of finger joint prostheses using the tradename Bion. This rubber is currently licensed to the University of Akron and to the Cleveland Clinic Foundation for use in biomedical applications, and is being used primarily for biocompatible and highly fatigue resistant rubber components in ventricular assist and artificial heart systems. Results are presented from the physical, mechanical, and biological characterization of Hexsyn. Procedures are described for the synthesis, compounding, and post-molding extraction for Hexsyn. The physical testing of Hexsyn reported includes determinations of its density at 23 and 37 degrees C, initial hardness and hardness after aging in oxygen, blood, pseudoextracellular fluid and polyethylene glycol 600, typical molecular weights determined by gel permeation chromatography/low angle laser light scattering and intrinsic viscosity, thermal analyses by differential scanning calorimetry of Hexsyn gum, and vulcanized Hexsyn after exposure to blood and blood/fatigue conditions. Also reported are results of differential thermal analyses, thermomechanical analyses of virgin and annealed samples, and thermogravimetric analyses conducted in helium and in air. Dynamic mechanical analyses of Hexsyn include Clash-Berg and Rheovibron tests. Swelling was conducted to determine lot-to-lot and sheet-to-sheet variation for quality control and also a number of solvents were used so that the polymer-solvent interaction parameters could be determined. The permeability of Hexsyn to water, water vapor, and a variety of gases is reported. The permeability by contact angle measurements, refractive index, residual solvent analyses, migration of blood components

  4. Tribology study of reduced graphene oxide sheets on silicon substrate synthesized via covalent assembly.

    Science.gov (United States)

    Ou, Junfei; Wang, Jinqing; Liu, Sheng; Mu, Bo; Ren, Junfang; Wang, Honggang; Yang, Shengrong

    2010-10-19

    Reduced graphene oxide (RGO) sheets were covalently assembled onto silicon wafers via a multistep route based on the chemical adsorption and thermal reduction of graphene oxide (GO). The formation and microstructure of RGO were analyzed by X-ray photoelectron spectroscopy (XPS), attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, Raman spectroscopy, and water contact angle (WCA) measurements. Characterization by atomic force microscopy (AFM) was performed to evaluate the morphology and microtribological behaviors of the samples. Macrotribological performance was tested on a ball-on-plate tribometer. Results show that the assembled RGO possesses good friction reduction and antiwear ability, properties ascribed to its intrinsic structure, that is, the covalent bonding to the substrate and self-lubricating property of RGO.

  5. Low cost monocrystalline silicon sheet fabrication for solar cells by advanced ingot technology

    Science.gov (United States)

    Fiegl, G. F.; Bonora, A. C.

    1980-01-01

    The continuous liquid feed (CLF) Czochralski furnace and the enhanced I.D. slicing technology for the low-cost production of monocrystalline silicon sheets for solar cells are discussed. The incorporation of the CLF system is shown to improve ingot production rate significantly. As demonstrated in actual runs, higher than average solidification rates (75 to 100 mm/hr for 150 mm 1-0-0 crystals) can be achieved, when the system approaches steady-state conditions. The design characteristics of the CLF furnace are detailed, noting that it is capable of precise control of dopant impurity incorporation in the axial direction of the crystal. The crystal add-on cost is computed to be $11.88/sq m, considering a projected 1986 25-slice per cm conversion factor with an 86% crystal growth yield.

  6. Nano-reinforcement of tire rubbers: silica-technology for natural rubber : exploring the infuence of non-rubber constituents on the natural rubber-silica system

    NARCIS (Netherlands)

    Sarkawi, S.S.

    2013-01-01

    Natural rubber is a renewable resource material with outstanding properties which offers significant advantages over its counterparts, the fossil-resource synthetic rubbers. In fact, a natural rubber tree is an efficient carbon dioxide sequester. Since natural rubber is a natural product, it is

  7. Improving the Mechanical and Electrical Properties of Ceramizable Silicone Rubber/Halloysite Composites and Their Ceramic Residues by Incorporation of Different Borates

    Directory of Open Access Journals (Sweden)

    Jianhua Guo

    2018-04-01

    Full Text Available Ceramizable silicone rubber (MVQ/halloysite (HNT composites were fabricated by incorporation of three different borates, including sodium tetraborate decahydrate, ammonium pentaborate, and zinc borate into MVQ matrix, respectively. The composites without any borates were also prepared as control. The effect of the borates on the mechanical and electrical properties of MVQ/HNT composites was investigated. The ceramic residues were obtained from the decomposition of the composites after sintering at 1000 °C. The effect of the borates on the linear shrinkage, weight loss, and flexural and impact strength of the residues was also studied. The fracture surfaces of the composites and their corresponding residues were observed by SEM. The proposed ceramizable mechanism of the composites by incorporation of different borates was revealed by XRD analysis.

  8. Continuous Czochralski growth: Silicon sheet growth development of the large area sheet task of the low cost silicon solar array project

    Science.gov (United States)

    Johnson, C. M.

    1980-12-01

    The growth of 100 kg of silicon single crystal material, ten cm in diameter or greater, and 150 kg of silicon single crystal material 15 cm or greater utilizing one common silicon container material (one crucible) is investigated. A crystal grower that is recharged with a new supply of polysilicon material while still under vacuum and at temperatures above the melting point of silicon is developed. It accepts large polysilicon charges up to 30 kg, grows large crystal ingots (to 15 cm diameter and 25 kg in weight), and holds polysilicon material for recharging (rod or lump) while, at the same time, growing crystal ingots. Special equipment is designed to recharge polysilicon rods, recharge polysilicon lumps, and handle and store large, hot silicon crystal ingots. Many continuous crystal growth runs were performed lasting as long as 109 hours and producing as many as ten crystal ingots, 15 cm with weights progressing to 27 kg.

  9. Prediction of heat generation in rubber or rubber-metal springs

    Directory of Open Access Journals (Sweden)

    Banić Milan S.

    2012-01-01

    Full Text Available The temperature of rubber or rubber-metal springs increases under cyclic loading, due to hysteresis losses and low rubber thermal conductivity. Hysteresis losses correspond to energy dissipation from the rubber, which is primarily converted into heat. This well-known phenomenon, called heat build-up, is the primary reason for rubber aging. Increase in temperature within the rubber compound leads to degradation of its physical and chemical properties, increase in stiffness and loss of damping capability. This paper presents a novel procedure of heat generation prediction in rubber or rubber-metal springs. The procedure encompasses the prediction of hysteresis loss, i. e. dissipated energy within the rubber, by finite element analysis and application of a modern visco-plastic rubber constitutive model. The obtained dissipated energy was used as an input for transient thermal analysis. Verification of the proposed procedure was performed by comparison of simulation results with experimentally obtained data during the dynamic loading of the rubber specimen. The proposed procedure is highly computationally efficient and it enables time integration, which can be problematic in coupled mechanical thermal analysis. [Projekat Ministarstva nauke Republike Srbije, br. TR35005: Research and Development of New Generation of Wind Turbines of High Energy Efficiency

  10. Stable configurations of graphene on silicon

    Energy Technology Data Exchange (ETDEWEB)

    Javvaji, Brahmanandam; Shenoy, Bhamy Maithry [Department of Aerospace Engineering, Indian Institute of Science, Bangalore 560012 (India); Mahapatra, D. Roy, E-mail: droymahapatra@aero.iisc.ernet.in [Department of Aerospace Engineering, Indian Institute of Science, Bangalore 560012 (India); Ravikumar, Abhilash [Department of Metallurgical and Materials Engineering, National Institute of Technology Karnataka, Surathkal 575025 (India); Hegde, G.M. [Center for Nano Science and Engineering, Indian Institute of Science, Bangalore 560012 (India); Rizwan, M.R. [Department of Metallurgical and Materials Engineering, National Institute of Technology Karnataka, Surathkal 575025 (India)

    2017-08-31

    Highlights: • Simulations of epitaxial growth process for silicon–graphene system is performed. • Identified the most favourable orientation of graphene sheet on silicon substrate. • Atomic local strain due to the silicon–carbon bond formation is analyzed. - Abstract: Integration of graphene on silicon-based nanostructures is crucial in advancing graphene based nanoelectronic device technologies. The present paper provides a new insight on the combined effect of graphene structure and silicon (001) substrate on their two-dimensional anisotropic interface. Molecular dynamics simulations involving the sub-nanoscale interface reveal a most favourable set of temperature independent orientations of the monolayer graphene sheet with an angle of ∽15° between its armchair direction and [010] axis of the silicon substrate. While computing the favorable stable orientations, both the translation and the rotational vibrations of graphene are included. The possible interactions between the graphene atoms and the silicon atoms are identified from their coordination. Graphene sheet shows maximum bonding density with bond length 0.195 nm and minimum bond energy when interfaced with silicon substrate at 15° orientation. Local deformation analysis reveals probability distribution with maximum strain levels of 0.134, 0.047 and 0.029 for 900 K, 300 K and 100 K, respectively in silicon surface for 15° oriented graphene whereas the maximum probable strain in graphene is about 0.041 irrespective of temperature. Silicon–silicon dimer formation is changed due to silicon–carbon bonding. These results may help further in band structure engineering of silicon–graphene lattice.

  11. Principles and Application of Magnetic Rubber Testing for Crack Detection in High-Strength Steel Components: I. Active-Field Inspection

    Science.gov (United States)

    2014-12-01

    containing a dispersion of ferromagnetic particles to the surface of a magnetised steel component. Following curing of the rubber, any surface-breaking...concentration of black particles along the crack is clearly visible against the lighter pigments of the silicone rubber base. magnetic leakage flux due...other side of the black crack indication appear white because they contain a very low density of magnetic particles so that the underlying white pigment

  12. Gold nanorods-silicone hybrid material films and their optical limiting property

    Science.gov (United States)

    Li, Chunfang; Qi, Yanhai; Hao, Xiongwen; Peng, Xue; Li, Dongxiang

    2015-10-01

    As a kind of new optical limiting materials, gold nanoparticles have optical limiting property owing to their optical nonlinearities induced by surface plasmon resonance (SPR). Gold nanorods (GNRs) possess transversal SPR absorption and tunable longitudinal SPR absorption in the visible and near-infrared region, so they can be used as potential optical limiting materials against tunable laser pulses. In this letter, GNRs were prepared using seed-mediated growth method and surface-modified by silica coating to obtain good dispersion in polydimethylsiloxane prepolymers. Then the silicone rubber films doped with GNRs were prepared after vulcanization, whose optical limiting property and optical nonlinearity were investigated. The silicone rubber samples doped with more GNRs were found to exhibit better optical limiting performance.

  13. Rubber mixing process and its relationship with bound rubber and crosslink density

    Science.gov (United States)

    Hasan, A.; Rochmadi; Sulistyo, H.; Honggokusumo, S.

    2017-06-01

    This research studied the relationship between bound rubber and crosslink density based on rubber mixing process. Bound rubber was obtained after natural rubber was masticated and mixed with rubber chemicals and filler while crosslink density was collected after rubber compound was vulcanized. Four methods are used and each method refers to four ways of incorporating carbon black during mixing. The first method, after rubber was masticated for 5 minutes, the addition of rubber chemicals and filler was done simultaneously. Rubber was masticated for 1 minute and continued mixing of rubber chemicals and filler where mixing was different from first method. This was the second method. The third method was the same as the second method but the filler used N 660 while in the second method N 330. The last method is not the same as the first and second, the rubber is only masticated for 3 minutes and then mixed with filler and followed by rubber chemicals sequentially. The results showed that bound rubber and crosslink density were influenced by mixing and mastication process. Bound rubber dropped and crosslink density was relatively stable in the first three mixing methods for increasing carbon black at the beginning of the mixing process. Bound rubber and crosslink density stated opposite results in the fourth mixing method. The higher the bound rubber the lower the crosslink density. Without regard to mixing methods, there is a non-linear relationship between bound rubber formation and crosslink density determination

  14. Experimental study of laminated rubber bearings for earthquake isolation of buildings, 2

    International Nuclear Information System (INIS)

    Fujita, Takafumi; Fujita, Satoshi; Suzuki, Shigenobu; Yoshizawa, Toshikazu.

    1987-01-01

    Rubber bearings of 980 kN rated load were tested to investigate the characteristics of restoring forces of full scale bearings for earthquake isolation of buildings. These bearings comprising 27 natural rubber sheets of 6 mm thickness and 600 mm diameter bonded to steel plates were designed to provide a 100000 kg rated mass with a horizontal natural frequency of 0.51 Hz and a vertical one of 21 Hz and to accept a horizontal displacement larger than 300 mm. The static tests were carried out with satisfactory results. It was confirmed that the performance of the bearing met the specifications well. Furthermore, the vertical load distributions across the top plane of the bearing under various horizontal displacements were measured, and showed that they were always concentrated in the overlapping area of the top and bottom planes. This verified that the rubber bearing substantially supported the vertical load by the overlapping area. (author)

  15. Microstructure and texture evolution of ultra-thin grain-oriented silicon steel sheet fabricated using strip casting and three-stage cold rolling method

    Energy Technology Data Exchange (ETDEWEB)

    Song, Hong-Yu; Liu, Hai-Tao, E-mail: liuht@ral.neu.edu.cn; Wang, Yin-Ping; Wang, Guo-Dong

    2017-03-15

    A 0.1 mm-thick grain-oriented silicon steel sheet was successfully produced using strip casting and three-stage cold rolling method. The microstructure, texture and inhibitor evolution during the processing was briefly analyzed. It was found that Goss texture was absent in the hot rolled sheet because of the lack of shear deformation. After normalizing, a large number of dispersed MnS precipitates with the size range of 15–90 nm were produced. During first cold rolling, dense shear bands were generated in the deformed ferrite grains, resulting in the intense Goss texture after first intermediate annealing. The microstructure was further refined and homogenized during the subsequent cold rolling and annealing processes. After primary recrystallization annealing, a homogeneous microstructure consisting of fine and equiaxed grains was produced while the associated texture was characterized by a strong γ-fiber texture. Finally, a complete secondary recrystallization microstructure consisting of entirely large Goss grains was produced. The magnetic induction B{sub 8} and iron loss P{sub 10/400} was 1.79 T and 6.9 W/kg, respectively. - Highlights: • Ultra-thin grain-oriented silicon steel was produced by strip casting process. • Microstructure, texture and inhibitor evolution was briefly investigated. • Goss texture was absent in primary recrystallization annealed sheet. • MnS precipitates with a size range of 15–90 nm formed after normalizing. • A complete secondary recrystallization microstructure was produced.

  16. CT-assisted versus silicone rubber cast morphometry of the lower respiratory tract in healthy amazons (genus Amazona) and grey parrots (genus Psittacus)

    International Nuclear Information System (INIS)

    Krautwald-Junghanns, M.E.; Valerius, K.P.; Duncker, H.R.; Sohn, H.G.

    1998-01-01

    The objective of this study was to examine the normal respiratory tract of grey parrots and amazons by using two different methods. The lower respiratory tract of five amazons and four grey parrots, all healthy, were investigated applying computerised tomography (CT). Volumes and densities of the body, the body cavities, the normal lungs, and the airsacs in the living animals were defined as reference values of healthy birds to give a basis for future CT-diagnosis of respiratory diseases and their precise locations in parrots. In a parallel study, the lung and air sac volumes of six amazons and two grey parrots were measured using silicone rubber casts produced after the method described byH.-R. Duncker. Values for identical respiratory structures gained by these different methods were compared

  17. Silicone-Based Triboelectric Nanogenerator for Water Wave Energy Harvesting.

    Science.gov (United States)

    Xiao, Tian Xiao; Jiang, Tao; Zhu, Jian Xiong; Liang, Xi; Xu, Liang; Shao, Jia Jia; Zhang, Chun Lei; Wang, Jie; Wang, Zhong Lin

    2018-01-31

    Triboelectric nanogenerator (TENG) has been proven to be efficient for harvesting water wave energy, which is one of the most promising renewable energy sources. In this work, a TENG with a silicone rubber/carbon black composite electrode was designed for converting the water wave energy into electricity. The silicone-based electrode with a soft texture provides a better contact with the dielectric film. Furthermore, a spring structure is introduced to transform low-frequency water wave motions into high-frequency vibrations. They together improve the output performance and efficiency of TENG. The output performances of TENGs are further enhanced by optimizing the triboelectric material pair and tribo-surface area. A spring-assisted TENG device with the segmented silicone rubber-based electrode structure was sealed into a waterproof box, which delivers a maximum power density of 2.40 W m -3 , as triggered by the water waves. The present work provides a new strategy for fabricating high-performance TENG devices by coupling flexible electrodes and spring structure for harvesting water wave energy.

  18. Analysis of Silicones Released from Household Items and Baby Articles by Direct Analysis in Real Time-Mass Spectrometry

    Science.gov (United States)

    Gross, Jürgen H.

    2015-03-01

    Direct analysis in real time-mass spectrometry (DART-MS) enables screening of articles of daily use made of polydimethylsiloxanes (PDMS), commonly known as silicone rubber, to assess their tendency to release low molecular weight silicone oligomers. DART-MS analyses were performed on a Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometer. Flexible silicone baking molds, a watch band, and a dough scraper, as baby articles different brands of pacifiers, nipples, and a teething ring have been examined. While somewhat arbitrarily chosen, the set can be regarded as representative of household items, baby articles, and other objects made of silicone rubber. For comparison, two brands of silicone septa and as blanks a glass slide and a latex pacifier were included. Differences between the objects were mainly observed in terms of molecular weight distribution and occasional release of other compounds in addition to PDMS. Other than that, all objects made of silicone rubber released significant amounts of PDMS during DART analysis. To provide a coarse quantification, a calibration based on silicone oil was established, which delivered PDMS losses from 20 μg to >100 μg during the 16-s period per measurement. Also, the extraction of baking molds in rapeseed oil demonstrated a PDMS release at the level of 1 μg mg-1. These findings indicate a potential health hazard from frequent or long-term use of such items. This work does not intend to blame certain brands of such articles. Nonetheless, a higher level of awareness of this source of daily silicone intake is suggested.

  19. Research Progress about the Relationship between Nanoparticles Silicon Dioxide and Lung Cancer

    Directory of Open Access Journals (Sweden)

    Chun DAI

    2014-10-01

    Full Text Available Nano-silicon dioxide widely distributed in plastic, rubber, ceramics, paint, adhesives, and many other fields, and it is the product of coal combustion. A growing evidence shows that nano-silicon dioxide has certain correlation with respiratory system disease. In this paper, we synthesized existing researches of domestic and abroad, summarized the lung toxicity of nanoparticles. This article are reviewed from the physical and chemical properties of nanoparticles silicon dioxide, exposure conditions and environment, and the pathogenic mechanism of nano-silicon dioxide.

  20. Changes in Structure and Functioning of Protist (Testate Amoebae Communities Due to Conversion of Lowland Rainforest into Rubber and Oil Palm Plantations.

    Directory of Open Access Journals (Sweden)

    Valentyna Krashevska

    Full Text Available Large areas of tropical rainforest are being converted to agricultural and plantation land uses, but little is known of biodiversity and ecological functioning under these replacement land uses. We investigated the effects of conversion of rainforest into jungle rubber, intensive rubber and oil palm plantations on testate amoebae, diverse and functionally important protists in litter and soil. Living testate amoebae species richness, density and biomass were all lower in replacement land uses than in rainforest, with the impact being more pronounced in litter than in soil. Similar abundances of species of high and low trophic level in rainforest suggest that trophic interactions are more balanced, with a high number of functionally redundant species, than in rubber and oil palm. In contrast, plantations had a low density of high trophic level species indicating losses of functions. This was particularly so in oil palm plantations. In addition, the relative density of species with siliceous shells was >50% lower in the litter layer of oil palm and rubber compared to rainforest and jungle rubber. This difference suggests that rainforest conversion changes biogenic silicon pools and increases silicon losses. Overall, the lower species richness, density and biomass in plantations than in rainforest, and the changes in the functional composition of the testate amoebae community, indicate detrimental effects of rainforest conversion on the structure and functioning of microbial food webs.

  1. Changes in Structure and Functioning of Protist (Testate Amoebae) Communities Due to Conversion of Lowland Rainforest into Rubber and Oil Palm Plantations.

    Science.gov (United States)

    Krashevska, Valentyna; Klarner, Bernhard; Widyastuti, Rahayu; Maraun, Mark; Scheu, Stefan

    2016-01-01

    Large areas of tropical rainforest are being converted to agricultural and plantation land uses, but little is known of biodiversity and ecological functioning under these replacement land uses. We investigated the effects of conversion of rainforest into jungle rubber, intensive rubber and oil palm plantations on testate amoebae, diverse and functionally important protists in litter and soil. Living testate amoebae species richness, density and biomass were all lower in replacement land uses than in rainforest, with the impact being more pronounced in litter than in soil. Similar abundances of species of high and low trophic level in rainforest suggest that trophic interactions are more balanced, with a high number of functionally redundant species, than in rubber and oil palm. In contrast, plantations had a low density of high trophic level species indicating losses of functions. This was particularly so in oil palm plantations. In addition, the relative density of species with siliceous shells was >50% lower in the litter layer of oil palm and rubber compared to rainforest and jungle rubber. This difference suggests that rainforest conversion changes biogenic silicon pools and increases silicon losses. Overall, the lower species richness, density and biomass in plantations than in rainforest, and the changes in the functional composition of the testate amoebae community, indicate detrimental effects of rainforest conversion on the structure and functioning of microbial food webs.

  2. Rubber glove wearing device

    International Nuclear Information System (INIS)

    Nozaki, Tatsuo; Takada, Kaoru.

    1994-01-01

    Rubber groves are attached each to an upper end of a glove putting vessel having an air-sucking hole on the bottom by enlarging an opening end of the rubber glove and turning back the inside to the outside. When the sucking device is operated, air in the glove putting device is sucked and the rubber glove is expanded by an atmospheric pressure. After expansion of the rubber glove to some extent, the sucking device is stopped, and presence or absence of failures of the rubber glove is confirmed by shrinkage of the rubber glove and by an indication value of a pressure gauge for detecting the pressure change in the vessel. Then, a hand is inserted to the expanded rubber glove, and a detaching switch in the vessel is pushed by a finger tip. A detaching piece at the upper end of the vessel is protruded outwardly to enlarge the turned-back portion of the rubber glove to easily release the rubber glove from the putting vessel, and the rubber glove is put on. This enables to wear the rubber glove and conduct failure test simultaneously. Further, a user can put on the rubber glove without touching the outside of the rubber glove. (I.N.)

  3. Correlation of Electrical and Swelling Properties with Nano Free Volume Structure of Conductive Silicone Rubber Composites

    International Nuclear Information System (INIS)

    Abd-El Salam, M.H.; El-Gamal, S.; Abd El-Maqsoud, D.M.; Mohsen, M.

    2013-01-01

    The present study focuses on finding a correlation between the positron annihilation parameters in silicone rubber based on Poly dimethyl siloxane (PDMS) composites loaded with different conductive fillers and their swelling and electrical properties. Four types of conductive fillers have been used in this study: carbon black, graphite, copper, and nickel powders. The maximum degree of swelling Q m %, the penetration rate, P, as well as the diffusion coefficient, D, decrease with increasing the filler content due to the reduction of the size of free volume, as observed through a decrease of the probability of ortho-positronium (o-Ps) formation I 3 and the o-Ps lifetime Τ 3 , representing the size of free volume measured by the positron annihilation lifetime technique (PAL). The electrical conductivity ln (Σ) is positively correlated with the probability of free annihilation of positrons at interfaces I 2 , thus suggesting an increase in the electron density with the filler content. The activation energy of conduction, E a , is found to decrease with the increase in the loading of conductive filler and the particle size of the filler. A correlation between the free-volume V f , and the d.c. electrical conductivity ln (Σ) is found to be in accordance with Miyamoto and Shibayma model of ion conduction.

  4. Nanosílice como carga en la RTV SR usada para cubrir aisladores; Nanosilica as filler in the Room temperature vulcanized silicone rubber used to coat insulators

    Directory of Open Access Journals (Sweden)

    Ignat Pérez Almirall

    2014-04-01

    Full Text Available En el presente trabajo se realiza un estudio sobre la influencia que tiene agregar como carga nanosílice a la goma de silicona vulcanizada a temperatura ambiente (RTV SR, por sus siglas en inglés que es empleada para cubrir aisladores de vidrio o de porcelana. Con este objetivo se observó la dispersión de la nanosílice en la RTV SR por medio de microscopía electrónica de barrido (MEV, por sus siglas en inglés, se midió la permitividad de la RTV SR con y sin nanosílice para varias frecuencias y se evaluó la influencia que tiene la nanosílice en la resistencia a la erosión. Además fueron medidas las corrientes de fuga durante ensayos de niebla salina a aisladores de vidrio pintados con estos recubrimientos, analizando también la pérdida de hidrofobicidad que ocurre durante el ensayo y su recuperación una vez finalizado el mismo.  The present research work carries out a study on the influence of nanosilica on room temperature vulcanized silicone rubber (RTV SR used to coat insulators. Considering this objective, the dispersion of nanosilica was observed by means of scanning electron microscopy (MEV, the permittivity of the room temperature vulcanized silicone rubber was measured with and without nanosilica for different frequencies and the influence of nanosilica in erosion resistance. Leakage currents were also measured during salt spray tests to glass insulators covered with these coatings; the loss of hidrophobicity during the test was also measured and its recovery was analyzed the test was finished.

  5. Nanosílice como carga en la RTV SR usada para cubrir aisladores/ Nanosilica as filler in the Room temperature vulcanized silicone rubber used to coat insulators

    Directory of Open Access Journals (Sweden)

    Ignat Pérez Almirall

    2012-02-01

    Full Text Available En el presente trabajo se realiza un estudio sobre la influencia que tiene agregar como carga nanosílice a la goma de silicona vulcanizada a temperatura ambiente (RTV SR, por sus siglas en inglés que es empleada para cubrir aisladores de vidrio o de porcelana. Con este objetivo se observó la dispersión de la nanosílice en la RTV SR por medio de microscopía electrónica de barrido (MEV, por sus siglas en inglés, se midió la permitividad de la RTV SR con y sin nanosílice para varias frecuencias y se evaluó la influencia que tiene la nanosílice en la resistencia a la erosión. Además fueron medidas las corrientes de fuga durante ensayos de niebla salina a aisladores de vidrio pintados con estos recubrimientos, analizando también la pérdida de hidrofobicidad que ocurre durante el ensayo y su recuperación una vez finalizado el mismo.The present research work carries out a study on the influence of nanosilica on room temperature vulcanized silicone rubber (RTV SR used to coat insulators. Considering this objective, the dispersion of nanosilica was observed by means of scanning electron microscopy (MEV, the permittivity of the room temperature vulcanized silicone rubber was measured with and without nanosilica for different frequencies and the influence of nanosilica in erosion resistance. Leakage currents were also measured during salt spray tests to glass insulators covered with these coatings; the loss of hidrophobicity during the test was also measured and its recovery was analyzed the test was finished.

  6. Efficient 3D conducting networks built by graphene sheets and carbon nanoparticles for high-performance silicon anode.

    Science.gov (United States)

    Zhou, Xiaosi; Yin, Ya-Xia; Cao, An-Min; Wan, Li-Jun; Guo, Yu-Guo

    2012-05-01

    The utilization of silicon particles as anode materials for lithium-ion batteries is hindered by their low intrinsic electric conductivity and large volume changes during cycling. Here we report a novel Si nanoparticle-carbon nanoparticle/graphene composite, in which the addition of carbon nanoparticles can effectively alleviate the aggregation of Si nanoparticles by separating them from each other, and help graphene sheets build efficient 3D conducting networks for Si nanoparticles. Such Si-C/G composite shows much improved electrochemical properties in terms of specific capacity and cycling performance (ca. 1521 mA h g(-1) at 0.2 C after 200 cycles), as well as a favorable high-rate capability.

  7. PROPERTIES TYRE TREAD RUBBERS DEPENDING ON PARTICULARITY OF RUBBER COMPOUND

    Directory of Open Access Journals (Sweden)

    Z. S. Shashok

    2014-01-01

    Full Text Available Summary. The results of studies of the elastomeric compositions based on natural rubber containing curatives different ratio "curing agent : vulcanization accelerator" listed in this article. Influence of the composition of the vulcanizing group on stress-strain and elastic- deformation properties of tire tread rubber was installed. It has been shown that a significant effect on thermo-oxidative aging of vulcanizates was the composition of the vulcanizing group. Results of studies resistance tread rubber to exposure to elevated temperatures were presented . Vulcanizates differing type and density by varying the cross-linking ratio of "curing agent : vulcanization accelerator" were obtained . Research results in the formation of rubber resistance and crack growth at different temperatures were presented. Revealed that the best education and resistance to tear propagation under normal conditions characterized by rubber ratio "curing agent : vulcanization accelerator" equal to 1.5:1. It has been established that a dynamic endurance study rubbers depends largely on the nature and concentration of the cross-linking cross-links and movable promote increase efficiency due to the grid and reduce the sulfidity rearrangement. During loading mode alternating deformations at elevated temperatures lability of polysulfide bonds negatively affects the performance of rubber, and the decisive role of providing strength and thermal cross-linking. It is shown that the performance of the spatial grid rubbers allow indirectly judge the dynamic vulcanizates endurance and predict performance rubbers at elevated temperatures under conditions of repeated cyclic deformation. Revealed that the vulcanizing system containing sulfur and vulcanization accelerator TBBS 1:2, promotes the formation of the optimal structure of vulcanized rubber , which provides the best resistance to repeated cyclic deformations in the operating temperatures of the tire.

  8. Multilayer Graphene/Carbon Black/Chlorine Isobutyl Isoprene Rubber Nanocomposites

    Directory of Open Access Journals (Sweden)

    Daniele Frasca

    2016-03-01

    Full Text Available High loadings of carbon black (CB are usually used to achieve the properties demanded of rubber compounds. In recent years, distinct nanoparticles have been investigated to replace CB in whole or in part, in order to reduce the necessary filler content or to improve performance. Multilayer graphene (MLG is a nanoparticle made of just 10 graphene sheets and has recently become commercially available for mass-product nanocomposites. Three phr (part for hundred rubbers of MLG are added to chlorine isobutyl isoprene rubber (CIIR/CB composites in order to replace part of the CB. The incorporation of just 3 phr MLG triples the Young’s modulus of CIIR; the same effect is obtained with 20 phr CB. The simultaneous presence of three MLG and CB also delivers remarkable properties, e.g. adding three MLG and 20 phr CB increased the hardness as much as adding 40 phr CB. A comprehensive study is presented, showing the influence on a variety of mechanical properties. The potential of the MLG/CB combination is illustrated to reduce the filler content or to boost performance, respectively. Apart from the remarkable mechanical properties, the CIIR/CB/MLG nanocomposites showed an increase in weathering resistance.

  9. In-depth proteome analysis of the rubber particle of Hevea brasiliensis (para rubber tree).

    Science.gov (United States)

    Dai, Longjun; Kang, Guijuan; Li, Yu; Nie, Zhiyi; Duan, Cuifang; Zeng, Rizhong

    2013-05-01

    The rubber particle is a special organelle in which natural rubber is synthesised and stored in the laticifers of Hevea brasiliensis. To better understand the biological functions of rubber particles and to identify the candidate rubber biosynthesis-related proteins, a comprehensive proteome analysis was performed on H. brasiliensis rubber particles using shotgun tandem mass spectrometry profiling approaches-resulting in a thorough report on the rubber particle proteins. A total of 186 rubber particle proteins were identified, with a range in relative molecular mass of 3.9-194.2 kDa and in isoelectric point values of 4.0-11.2. The rubber particle proteins were analysed for gene ontology and could be categorised into eight major groups according to their functions: including rubber biosynthesis, stress- or defence-related responses, protein processing and folding, signal transduction and cellular transport. In addition to well-known rubber biosynthesis-related proteins such as rubber elongation factor (REF), small rubber particle protein (SRPP) and cis-prenyl transferase (CPT), many proteins were firstly identified to be on the rubber particles, including cyclophilin, phospholipase D, cytochrome P450, small GTP-binding protein, clathrin, eukaryotic translation initiation factor, annexin, ABC transporter, translationally controlled tumour protein, ubiquitin-conjugating enzymes, and several homologues of REF, SRPP and CPT. A procedure of multiple reaction monitoring was established for further protein validation. This comprehensive proteome data of rubber particles would facilitate investigation into molecular mechanisms of biogenesis, self-homeostasis and rubber biosynthesis of the rubber particle, and might serve as valuable biomarkers in molecular breeding studies of H. brasiliensis and other alternative rubber-producing species.

  10. Fracture behavior of rubber powder modified rubber blends applied for conveying belt top covers

    OpenAIRE

    Euchler, Eric; Stocek, Radek; Gehde, Michael; Bunzel, Jörg-Michael; Saal, Wolfgang; Kipscholl, Reinhold

    2016-01-01

    The aim of this study is concentrated on the experimental investigation of wear resistance of rubber powder modified rubber blends. Styrene-Butadiene-Rubber (SBR) blends applied for conveying belt top covers have been modified by ground rubber (rubber powder) based on SBR. We theoretically described the rubber wear mechanism due to loading conditions occurring at conveyor belts in the field, to simulate wear behavior of top cover rubber materials. An own developed testing equipment based on g...

  11. Utility of Vaccum Pressed Silicon Sheet as a Bite Raising Appliance in the Management of TMJ Dysfunction Syndrome.

    Science.gov (United States)

    Datarkar, Abhay; Daware, Surendra; Dande, Ravi

    2017-09-01

    Temporomandibular disorders (TMDs) represent a group of painful conditions involving the muscles of mastication and the temporomandibular joint (TMJ) that frequently encountered in general clinical practice. This study is designed to assess the utility of vacuum pressed silicon sheet as a bite raising appliance in the management of TMJ dysfunction syndrome. The patients for this study were selected from those with the chief complaint of TMJ disorder. Out of 200 patients, 104 patients were diagnosed with subluxation and 96 patients were diagnosed with internal derangement of temporomandibular joint. All the reported cases were managed conservatively with physiotherapy and muscle relaxant therapy for one week period and followed with silicon bite raising appliance over both the arches in the subsequent period. All the patients had pain relief within six months duration as graded over verbal analog scale. ANOVA scale was used for comparision of VAS scores. The use of vacuum pressed bite raising appliance in the management of TMJ disorder was found to be satisfactorily effective in alleviation of pain symptom in our study group.

  12. Nitrile rubber and carboxylated nitrile rubber resistance to soybean biodiesel

    Directory of Open Access Journals (Sweden)

    Felipe Nunes Linhares

    2018-03-01

    Full Text Available Abstract Biodiesel has been considered a suitable substitute for petroleum diesel, but their chemical composition differs greatly. For this reason, biodiesel interacts differently than petroleum diesel with various materials, including rubbers. Therefore, the resistance of some elastomers should be thoroughly evaluated, specifically those which are commonly used in automotive industry. Nitrile rubber (NBR is widely used to produce vehicular parts that are constantly in contact with fuels. This paper aimed to assess the resistance of carboxylated nitrile rubber (XNBR with 28% of acrylonitrile content to soybean biodiesel in comparison with non-carboxylated nitrile rubber samples, with high and medium acrylonitrile content (33 and 45%. NBR with medium acrylonitrile content showed little resistance to biodiesel. However, carboxylated nitrile rubber even with low acrylonitrile content had similar performance to NBR with high acrylonitrile content.

  13. Microwave absorbing property of silicone rubber composites with added carbonyl iron particles and graphite platelet

    International Nuclear Information System (INIS)

    Xu, Yonggang; Zhang, Deyuan; Cai, Jun; Yuan, Liming; Zhang, Wenqiang

    2013-01-01

    Silicone rubber composites filled with carbonyl iron particles (CIPs) and graphite platelet (GP) were prepared using non-coating or coating processes. The complex permittivity and permeability of the composites were measured using a vector network analyzer in the frequency range of 1–18 GHz and dc electric conductivity was measured by the standard four-point contact method. The results showed that CIPs/GP composites fabricated in the coating process had the highest permittivity and permeability due to the particle orientation and interactions between the two absorbents. The coating process resulted in a decreased effective eccentricity of the absorbents, and the dc conductivity increased according to Neelakanta's equations. The reflection loss (RL) value showed that the composites had an excellent absorbing property in the L-band, minimum −11.85 dB at 1.5 mm and −15.02 dB at 2 mm. Thus, GP could be an effective additive in preparing thin absorbing composites in the L-band. - Highlights: ► The added GP increased the permittivity and permeability of composites filled with CIPs. ► The enhancement was owing to interactions of the two absorbents and the fabrication process. ► The coating process decreased the effective eccentricity of the particles, and increased the conductivity of the composites. ► The composites to which CIPs/GP were added in coating process had excellent absorbing properties in the L-band.

  14. Exposure to rubber fume and rubber process dust in the general rubber goods, tyre manufacturing and retread industries.

    Science.gov (United States)

    Dost, A A; Redman, D; Cox, G

    2000-08-01

    This study assesses the current patterns and levels of exposure to rubber fume and rubber process dust in the British rubber industry and compares and contrasts the data obtained from the general rubber goods (GRG), retread tire (RT) and new tire (NT) sectors. A total of 179 rubber companies were visited and data were obtained from 52 general rubber goods, 29 retread tire and 7 new tire manufacturers. The survey was conducted using a questionnaire and included a walk-through inspection of the workplace to assess the extent of use of control measures and the nature of work practices being employed. The most recent (predominantly 1995-97) exposure monitoring data for rubber fume and rubber process dust were obtained from these companies; no additional sampling was conducted for the purpose of this study. In addition to the assessment of exposure data, evaluation of occupational hygiene reports for the quality of information and advice was also carried out.A comparison of the median exposures for processes showed that the order of exposure to rubber fume (E, in mg m(-3)) is: E(moulding) (0.40) approximately E(extrusion) (0.33)>E(milling) (0.18) for GRG; E(press) (0. 32)>E(extrusion) (0.19)>E(autoclave) (0.10) for RT; and E(press) (0. 22) approximately E(all other) (0.22) for NT. The order of exposure to rubber fume between sectors was E(GRG) (0.40)>E(RT) (0.32)>E(NT) (0.22). Median exposures to rubber process dust in the GRG was E(weighing) (4.2)>E(mixing) (1.2) approximately E(milling) (0.8) approximately E(extrusion) (0.8) and no significant difference (P=0. 31) between GRG and NT sectors. The findings compare well with the study carried out in the Netherlands [Kromhout et al. (1994), Annals of Occupational Hygiene 38(1), 3-22], and it is suggested that the factors governing the significant differences noted between the three sectors relate principally to the production and task functions and also to the extent of controls employed. Evaluation of occupational

  15. Properties of rubber blends based on natural rubber loaded with different fillers and cured by gamma radiation

    International Nuclear Information System (INIS)

    Mohamed, R.M.

    2011-01-01

    In this investigation system styrene butadiene rubber (1502 type) and natural rubber were blended in different ratios namely, NR/SBR (0/100), NR/SBR (25/75), NR/SBR (50/50), NR/SBR (75/25) and NR/SBR (100/0). All the samples were subjected to gamma irradiation dose up to 250 kGy. The improvement in the mechanical properties, physico-mechanical properties and thermal properties was followed as a function of irradiation dose and blend ratio. The SBR /NR (50/50) blend with reasonable properties were filled with 40 p hr of Hisil (highly fined silicon), HAF carbon black (high abrasion furnace), TiO 2 titanium dioxide and clay; the reinforcing ability of these fillers was found to follow the order: Hisil > HAF carbon black > Clay > TiO 2 The effect of different kinds of enhancing agents (coagent) namely: N, N- methylene di acrylamide (MDA), trimethylol propane tri methacrylate (TMPTMA) and tetramethylol - methane tetraacrylate (TMMT) on the properties of the obtained composites as a function of irradiation dose was studied. The data obtained showed that the enhancement character of the co agents follow the order: TMMT >TMPTMA > MDA >unenhanced composites. This investigation showed also the effect of gamma irradiation on improving the above mentioned properties in the presence of filler and co agents. Moreover, radiation dose at 100 kGy is sufficient enough for obtained the desired properties. The obtaining composites can be used in many industrial applications such as radio controlled model race car tires to footwear applications; the SBR component adds the toughness while the natural rubber provides superior resilience and energy return when used in footwear.

  16. Preparation of sulfonic acid-containing rubbers from natural rubber vulcanizates

    Science.gov (United States)

    Poonsawat, Worapong; Poompradub, Sirilux; Ngamcharussrivichai, Chawalit

    2014-06-01

    In this work, a series of sulfonic acid-containing rubbers were prepared by aqueous phase oxidation of natural rubber vulcanizates in the presence of hydrogen peroxide (H2O2) and formic acid (HCOOH). The starting vulcanizates were neatly prepared via an efficient vulcanization (EV) system by varying mass ratio of N-cyclohexyl-2-benzothiazole sulfonamide (CBS), as an accelerator, to sulfur. The oxidation conditions were controlled at the molar ratio of H2O2: HCOOH = 1:1, the concentration of H2O2 = 15 wt.%, the temperature = 50 °C, and the reaction time = 3 h. The rubber materials before and after the oxidation were characterized for their physicochemical properties by using Fourier transform infrared spectroscopy, bomb calorimetry, acid-base titration and swelling measurements. The results indicated the presence of sulfonic acid group in the oxidized rubbers, generated by the oxidative cleaves of sulfide crosslinks in the rubber vulcanizates. The oxidation decreased the sulfur content of the rubber in which the level of sulfur loss was determined by the CBS/sulfur ratio. Moreover, the acidity of the oxidized products was correlated with the amount of sulfur remaining.

  17. Research of operational properties of compound based on high viscosity styrene-butadiene rubber SSBR-2560 TDAE HV

    Directory of Open Access Journals (Sweden)

    M. I. Falyakhov

    2016-01-01

    Full Text Available The article consider the influence of replacement of SSBR-2560 TDAE batch production on high viscosity SSBR-2560-TDAE HV in the tread recipe on the tire performance properties. Obtained samples were highly viscosity styrene butadiene rubber did not differ in the microstructure of the SSBR-2560 TDAE batch production. Increasing the molecular weight possible to increase the Mooney viscosity of the rubber, however, is known to one of adverse factors is the deterioration of processability of rubber compounds based on polymers. In this connection, investigated the behavior in the step mixing compound based on high viscosity SSBR rubber. We chose recipes tread of the tire with a high content of organic silicon filler. It is established that the equivalent replacement of the polymer in the tread recipe does not lead to significant changes in the basic parameters of rubber mixing. We observed a slight increase in the energy consumption for the preparation of the rubber compounds, as well as the discharge temperature at each stage. It was shown to improve the distribution of the filler in the polymer matrix for the compound based on SSBR-2560 TDAE HV. The results showed that compound based on high viscosity SSBR improves rolling resistance and traction characteristics, while maintaining abrasion in comparison with the SSBR-2560-M27 batch production. Recommended use this brand in the production of rubber car tires.

  18. Low cost silicon-on-ceramic photovoltaic solar cells

    Science.gov (United States)

    Koepke, B. G.; Heaps, J. D.; Grung, B. L.; Zook, J. D.; Sibold, J. D.; Leipold, M. H.

    1980-01-01

    A technique has been developed for coating low-cost mullite-based refractory substrates with thin layers of solar cell quality silicon. The technique involves first carbonizing one surface of the ceramic and then contacting it with molten silicon. The silicon wets the carbonized surface and, under the proper thermal conditions, solidifies as a large-grained sheet. Solar cells produced from this composite silicon-on-ceramic material have exhibited total area conversion efficiencies of ten percent.

  19. The Effect of Rubber Mixing Process on The Curing Characteristics of Natural Rubber

    Directory of Open Access Journals (Sweden)

    Abu Hasan

    2013-04-01

    Full Text Available This research is aimed at studying the relationship between rubber mixing processes and curing characteristics of natural rubber. The curing characteristic analysis was carried out through a natural rubber formula having been masticated and mixed, followed by curing. As many as four mastication methods were finely applied; each respected four sequences of rubber mixing process. In the first method, rubber was masticated for 5 minutes and then rubber chemicals and carbon black N 330 were  simultaneously added. In the second and the third methods, rubber was masticated for 1 minute and then carbon blacks and rubber chemicals were also simultaneously added but using different type of fillers. In the fourth method, rubber was masticated for 3 minutes and then rubber chemicals and carbon black were subsequently added. The additions of rubber chemicals and carbon blacks to the masticated rubber were distinguished by the sequence and time allocated for each mixing process. The carbon blacks were added in two stages by which 10 phr was added first and the remaining 40 phr was added later along with oil. In another method, ratios of the carbon blacks addition (as done in the first  and the second stages were 20:30, 30:20, and 40:10. The examination results showed that rubber mixing process gave an impact on the changes of curing characteristics. They were much affected by the method of carbon black addition. The mixing temperature also had an effect on both curing time and curing rate in which the higher the mixing temperature, the lower the curing time and curing rate. Vulcanization temperature also affected the curing time and curing rate in which the higher the vulcanization temperature, the lower the curing time and the higher the curing rate. Lastly, particle size of carbon black also gave an impact on the curing time and curing rate in which the smaller the particle size, the lower the curing time and the higher the curing rate.

  20. RTV silicone rubber surface modification for cell biocompatibility by negative-ion implantation

    International Nuclear Information System (INIS)

    Zheng, Chenlong; Wang, Guangfu; Chu, Yingjie; Xu, Ya; Qiu, Menglin; Xu, Mi

    2016-01-01

    Highlights: • The radiation effect has a greater influence than doping effect on the hydrophilicity of RTV SR. • The implanted ions result in a new surface atomic bonding state and morphology. • Generating hydrophilic functional groups is a reason for the improved cell biocompatibility. • The micro roughness makes the hydrophilicity should be reduced due to the lotus effect. • Cell culture demonstrates that negative-ion implantation can improve biocompatibility. - Abstract: A negative cluster ion implantation system was built on the injector of a GIC4117 tandem accelerator. Next, the system was used to study the surface modification of room temperature vulcanization silicone rubber (RTV SR) for cell biocompatibility. The water contact angle was observed to decrease from 117.6° to 99.3° as the C_1"− implantation dose was increased to 1 × 10"1"6 ions/cm"2, and the effects of C_1"−, C_2"− and O_1"− implantation result in only small differences in the water contact angle at 3 × 10"1"5 ions/cm"2. These findings indicate that the hydrophilicity of RTV SR improves as the dose is increased and that the radiation effect has a greater influence than the doping effect on the hydrophilicity. There are two factors influence hydrophilicity of RTV: (1) based on the XPS and ATR-FTIR results, it can be inferred that ion implantation breaks the hydrophobic functional groups (Si−CH_3, Si−O−Si, C−H) of RTV SR and generates hydrophilic functional groups (−COOH, −OH, Si−(O)_x (x = 3,4)). (2) SEM reveals that the implanted surface of RTV SR appears the micro roughness such as cracks and wrinkles. The hydrophilicity should be reduced due to the lotus effect (Zhou Rui et al., 2009). These two factors cancel each other out and make the C-implantation sample becomes more hydrophilic in general terms. Finally, cell culture demonstrates that negative ion-implantation is an effective method to improve the cell biocompatibility of RTV SR.

  1. Radiation vulcanization of rubbers

    Energy Technology Data Exchange (ETDEWEB)

    Makuuchi, Keizo [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2002-02-01

    An abstract of the radiation process of polymer materials and the polymer reaction by radiation is explained. Main radiation is 250 keV to 10 MeV of electron rays in the industry. Radiation cross-linked rubber has less the tensile strength than that by sulfur and organic peroxide crosslinking. The main origins of low tensile strength are caused by cut of backbone chain and ozone depend on radiation. Acceleration of crosslinking and short time of radiation are necessary to improve these defects. To accelerate crosslinking, we used crosslinking accelerators, for example, three poly-functional monomers (PFM). The maximum tensile strength of styrene-butadiene rubber (SBR) not added crosslinking accelerators showed 3 MPa at 110 kGy, but SBR added A-TMMT (tetramethylolmethane tetraacrylate) showed 5.5 MPa at 110 kGy. Radiation crosslinking of many kinds of rubber: isoprene (IR), SBR, CR, nitrile rubber (NBR), hydrogenated nitrile rubber (HNBR), butyl rubber (IIR), chlorinated butyl rubber (CIIR), EPM and TPE are explained. (S.Y.)

  2. Radiation vulcanization of rubbers

    International Nuclear Information System (INIS)

    Makuuchi, Keizo

    2002-01-01

    An abstract of the radiation process of polymer materials and the polymer reaction by radiation is explained. Main radiation is 250 keV to 10 MeV of electron rays in the industry. Radiation cross-linked rubber has less the tensile strength than that by sulfur and organic peroxide crosslinking. The main origins of low tensile strength are caused by cut of backbone chain and ozone depend on radiation. Acceleration of crosslinking and short time of radiation are necessary to improve these defects. To accelerate crosslinking, we used crosslinking accelerators, for example, three poly-functional monomers (PFM). The maximum tensile strength of styrene-butadiene rubber (SBR) not added crosslinking accelerators showed 3 MPa at 110 kGy, but SBR added A-TMMT (tetramethylolmethane tetraacrylate) showed 5.5 MPa at 110 kGy. Radiation crosslinking of many kinds of rubber: isoprene (IR), SBR, CR, nitrile rubber (NBR), hydrogenated nitrile rubber (HNBR), butyl rubber (IIR), chlorinated butyl rubber (CIIR), EPM and TPE are explained. (S.Y.)

  3. US rubber markets recover

    International Nuclear Information System (INIS)

    Wood, A.

    1993-01-01

    Synthetic rubber markets in North America bounced back in no uncertain terms last year, with demand climbing an impressive 9.5%, to 2.97 million m.t.; and, according to the International Institute of Synthetic Rubber Producers (IIS-RP; Houston) latest five-year forecast, producers can look forward to a 3.3% increase in demand during 1993. This growth rate outpaced out 1992 forecast and demonstrates the resilience of the synthetic rubber industry, says William E. Tessemer, managing director of IISRP. We expect demand in 1993 to surpass 1992 and level off at a 2%/year growth rate for synthetic rubber - 2.5% including thermoplastic elastomers [TPEs]-over the 1993-97 period. The improvement reflects signs of a recovery in North America, especially the pickup in the auto and tire industry. The two major tire rubbers - styrene butadiene and polybutadiene rubber - notched up double-digit gains, and other materials that have autos uses, such as nitrile rubber and many of the specialty elastomers, also advanced strongly

  4. Observation of double loop insertion of silicone rubber tube anastomosis method combined with "Z" flap repair in the treatment of lacrimal ductule laceration

    Directory of Open Access Journals (Sweden)

    Rui Hou

    2017-03-01

    Full Text Available AIM: To investigate the clinical curative effect of double loop insertion of silicone rubber tube combined with "Z" flap repair in the treatment of laceration of eyelid with canaliculus laceration. METHODS: The paper reviewed 45 cases of laceration of eyelid with laceration canaliculus, caused by trauma, which were treated in my hospital from January 2014 to January 2016. In the process of anastomosis of lacrimal duct and suture of eyelid laceration, either the method of single spinal anesthesia tube placement on skin contraposition suture or the method of dual annular silicone tube placement combined with the word "Z" flap repair was used. We compared the two methods and studied the possible complications like eyelid varus and valgus, lacrimal point valgus, eyelid scar, anastomotic dehiscence again. RESULTS: Out of the 22 cases in which the patients chose the single spinal anesthesia tube implantation on skin suture, 21 cases succeeded and patients received lacrimal duct patency results after extubation; and 1 case anastomosis failed. Complications: 20 cases had different degree of complications and the impact on their appearances were significant. Out of the 23 cases in which the patients chose double passage annular silicone tube joint prosthesis implantation Z flap, 23 received extubation results lacrimal patency or almost patency, the anastomosis of patients was successful. Complications: in two cases, patients had mild eyelid entropion and pomatum varus. Both eyelid deformity and severe wound tear did not occur in all cases again. Scar was not obvious. The success rate of anastomosis between the two groups was not significantly different(P=0.4889. To compare the rate of complications, there were significant differences(χ2=30.42, PCONCLUSION: The application of dual ring implantation silicon tube combined with the word "Z" flap repair in the treatment of lacrimal canaliculi laceration of eyelid laceration ensured the success rate of

  5. Temporomandibular joint arthroplasty for osteoarthrosis: A series of 24 patients that received a uni- or bilateral inter-positional silicone sheet.

    Science.gov (United States)

    Boutault, F; Cavallier, Z; Lauwers, F; Prevost, A

    2018-06-01

    To evaluate mid-term results from using a silicone sheet for inter-positional arthroplasty in moderate or severe cases of osteoarthrosis of the temporo-mandibular joint (TMJ). To also determine any remaining indications from this method. This retrospective study included patients that underwent surgery between 2008 and 2016. Pre- and post-operative mouth opening (MO), according to inter-incisal distance (mm) and pain score (PS: 0=no pain to 4=very severe pain) were recorded for 24 patients. Patients were divided according to thickness of the silicone sheet (group A: 1.0 mm, group B: 1.5 mm). The cohort included 22 females (92%). Mean age at surgery was 55 years±13 (26-80). Mean length of follow-up was 26 months±24 (6-80). Mean improvement in MO was 8.2 mm (+33%) and of PS was 1.7 (-68%). MO was not improved for two patients and worsened for one. PS score improved for all patients. No statistical difference was found between groups A and B. There was also a tendency for degradation of outcomes over time. The poor reputation of prosthetic discoplasty was not as evident in our series, even though anatomical and functional status seemed to deteriorate over time. This is because total-joint prosthetic replacement is often proposed instead. However, for elderly or fragile patients that have severe pain, and regarding cost-benefit aspects, conventional arthroplasty can still be discussed, especially since French national health-care insurance does not yet support TMJ prosthetic replacement for osteoarthrosis. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

  6. Process research on non-CZ silicon material

    Science.gov (United States)

    1982-01-01

    High risk, high payoff research areas associated with he process for producing photovoltaic modules using non-CZ sheet material are investigated. All investigations are being performed using dendritic web silicon, but all processes are directly applicable to other ribbon forms of sheet material. The technical feasibility of forming front and back junctions in non-CZ silicon using liquid dopant techniques was determined. Numerous commercially available liquid phosphorus and boron dopant solutions are investigated. Temperature-time profiles to achieve N(+) and P(+) sheet resistivities of 60 + or - 10 and 40 + or - s10 ohms per square centimeter respectively are established. A study of the optimal method of liquid dopant application is performed. The technical feasibility of forming a liquid applied diffusion mask to replace the more costly chemical vapor deposited SiO2 diffusion mask was also determined.

  7. Natural rubber: leather composites

    OpenAIRE

    Ravichandran,K.; Natchimuthu,N.

    2005-01-01

    Leather is a fibrous protein consisting of collagen in a three dimensionally crosslinked network. Chrome tanning of leather improves the appearance of leather but at the same time emits both solid and liquid chrome leather wastes. Scrap rubber recycling using untreated and neutralized leather fibrous particles in natural rubber has been studied. Vulcanization, mechanical, morphological and swelling properties of the natural rubber - scrap rubber composites containing neutralized leather have ...

  8. Rubber compounding and processing

    CSIR Research Space (South Africa)

    John, MJ

    2014-06-01

    Full Text Available This chapter presents an overview on the compounding and processing techniques of natural rubber compounds. The introductory portion deals with different types of rubbers and principles of rubber compounding. The primary and secondary fillers used...

  9. Natural rubber: leather composites

    Directory of Open Access Journals (Sweden)

    K. Ravichandran

    2005-06-01

    Full Text Available Leather is a fibrous protein consisting of collagen in a three dimensionally crosslinked network. Chrome tanning of leather improves the appearance of leather but at the same time emits both solid and liquid chrome leather wastes. Scrap rubber recycling using untreated and neutralized leather fibrous particles in natural rubber has been studied. Vulcanization, mechanical, morphological and swelling properties of the natural rubber - scrap rubber composites containing neutralized leather have been discussed. Use of chrome leather particles has been found to improve the consumption of scrap rubber powder in natural rubber formulations. Polymer composites based on leather wastes as fillers are reported to be useful for many applications such as in construction materials, automobile interior moldings, heat and sound insulating boards, shoe soles, flooring materials and moldings with good anti-static properties, air permeability and good appearances.

  10. Influence of biofilm lubricity on shear-induced transmission of staphylococcal biofilms from stainless steel to silicone rubber.

    Science.gov (United States)

    Gusnaniar, Niar; Sjollema, Jelmer; Jong, Ed D; Woudstra, Willem; de Vries, Joop; Nuryastuti, Titik; van der Mei, Henny C; Busscher, Henk J

    2017-11-01

    In real-life situations, bacteria are often transmitted from biofilms growing on donor surfaces to receiver ones. Bacterial transmission is more complex than adhesion, involving bacterial detachment from donor and subsequent adhesion to receiver surfaces. Here, we describe a new device to study shear-induced bacterial transmission from a (stainless steel) pipe to a (silicone rubber) tube and compare transmission of EPS-producing and non-EPS-producing staphylococci. Transmission of an entire biofilm from the donor to the receiver tube did not occur, indicative of cohesive failure in the biofilm rather than of adhesive failure at the donor-biofilm interface. Biofilm was gradually transmitted over an increasing length of receiver tube, occurring mostly to the first 50 cm of the receiver tube. Under high-shearing velocity, transmission of non-EPS-producing bacteria to the second half decreased non-linearly, likely due to rapid thinning of the lowly lubricious biofilm. Oppositely, transmission of EPS-producing strains to the second tube half was not affected by higher shearing velocity due to the high lubricity and stress relaxation of the EPS-rich biofilms, ensuring continued contact with the receiver. The non-linear decrease of ongoing bacterial transmission under high-shearing velocity is new and of relevance in for instance, high-speed food slicers and food packaging. © 2017 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

  11. Rubber

    Science.gov (United States)

    Graves, D. F.

    The word "rubber" immediately brings to mind materials that are highly flexible and will snap back to their original shape after being stretched. In this chapter a variety of materials are discussed that possess this odd characteristics. There will also be a discussion on the mechanism of this "elastic retractive force." Originally, rubber meant the gum collected from a tree growing in Brazil. The term "rubber" was coined for this material by the English chemist Joseph Priestley, who noted that it was effective for removing pencil marks from paper. Today, in addition to Priestley's natural product, many synthetic materials are made that possess these characteristics and many other properties. The common features of these materials are that they are made up of long-chain molecules that are amorphous (not crystalline), and the chains are above their glass transition temperature at room temperature.

  12. Carbon nanotube-coated silicone as a flexible and electrically conductive biomedical material

    International Nuclear Information System (INIS)

    Matsuoka, Makoto; Akasaka, Tsukasa; Totsuka, Yasunori; Watari, Fumio

    2012-01-01

    Artificial cell scaffolds that support cell adhesion, growth, and organization need to be fabricated for various purposes. Recently, there have been increasing reports of cell patterning using electrical fields. We fabricated scaffolds consisting of silicone sheets coated with single-walled (SW) or multi-walled (MW) carbon nanotubes (CNTs) and evaluated their electrical properties and biocompatibility. We also performed cell alignment with dielectrophoresis using CNT-coated sheets as electrodes. Silicone coated with 10 μg/cm 2 SWCNTs exhibited the least sheet resistance (0.8 kΩ/sq); its conductivity was maintained even after 100 stretching cycles. CNT coating also improved cell adhesion and proliferation. When an electric field was applied to the cell suspension introduced on the CNT-coated scaffold, the cells became aligned in a pearl-chain pattern. These results indicate that CNT coating not only provides electro-conductivity but also promotes cell adhesion to the silicone scaffold; cells seeded on the scaffold can be organized using electricity. These findings demonstrate that CNT-coated silicone can be useful as a biocompatible scaffold. - Highlights: ► We fabricated a CNT-coated silicone which has conductivity and biocompatibility. ► The conductivity was maintained after 100 cycles of stretching. ► CNT coatings enabled C2C12 cells adhere to the silicone surface. ► Cells were aligned with dielectrophoresis between CNT-coated silicone surfaces.

  13. Rubber particle proteins REF1 and SRPP1 interact differently with native lipids extracted from Hevea brasiliensis latex.

    Science.gov (United States)

    Wadeesirisak, Kanthida; Castano, Sabine; Berthelot, Karine; Vaysse, Laurent; Bonfils, Frédéric; Peruch, Frédéric; Rattanaporn, Kittipong; Liengprayoon, Siriluck; Lecomte, Sophie; Bottier, Céline

    2017-02-01

    Rubber particle membranes from the Hevea latex contain predominantly two proteins, REF1 and SRPP1 involved in poly(cis-1,4-isoprene) synthesis or rubber quality. The repartition of both proteins on the small or large rubber particles seems to differ, but their role in the irreversible coagulation of the rubber particle is still unknown. In this study we highlighted the different modes of interactions of both recombinant proteins with different classes of lipids extracted from Hevea brasiliensis latex, and defined as phospholipids (PL), glycolipids (GL) and neutral lipids (NL). We combined two biophysical methods, polarization modulated-infrared reflection adsorption spectroscopy (PM-IRRAS) and ellipsometry to elucidate their interactions with monolayers of each class of lipids. REF1 and SRPP1 interactions with native lipids are clearly different; SRPP1 interacts mostly in surface with PL, GL or NL, without modification of its structure. In contrast REF1 inserts deeply in the lipid monolayers with all lipid classes. With NL, REF1 is even able to switch from α-helice conformation to β-sheet structure, as in its aggregated form (amyloid form). Interaction between REF1 and NL may therefore have a specific role in the irreversible coagulation of rubber particles. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. A comparative study of natural rubber modified with ground tire rubber of truck

    OpenAIRE

    Binti Haridan, Ili Liyana

    2016-01-01

    The recycling of waste rubber has considerable significance in term of environmental protection and energy conservation. Considering that most of the relevant literature is concerned with tire recycling, the aim of this work was to develop and characterize the elastomeric samples of natural rubber (NR) composites filled with ground tire rubber of truck (GTR) devulcanized by microwave (DGTR). The tire rubber was ground under ambient conditions and subjected to microwave exposure for 3, 5 and ...

  15. Natural Rubber Modification For Upper Layer Of Rubberized Asphalt Paving Block AS Shock Absorber

    OpenAIRE

    Nasruddin, Nasruddin

    2017-01-01

    The research of rubber compounding modification for upper layer of rubberized asphalt paving block as shock absorber using natural rubber, styrene butadiene rubber (SBR) as synthetic rubber, fly ash as filler and also vegetable oil as plasticizer has been conducted. The research design was varying the filler Si-69, fly ash and palm oil. The five formulas A, B, C, D, and E designed by varying the amount of Si-69 (48.5; 50.75; 53.00; 55.25; and 57.50) phr; coal fly ash (4.75, 7.00, 9.25, 11.50 ...

  16. Fundamental studies on dynamic wear behavior of SBR rubber compounds modified by SBR rubber powder

    OpenAIRE

    Euchler, Eric; Heinrich, Gert; Michael, Hannes; Gehde, Michael; Stocek, Radek; Kratina, Ondrej; Kipscholl, Reinhold; Bunzel, Jörg-Michael; Saal, Wolfgang

    2016-01-01

    The aim of this study is focused on the experimental investigation of dynamic wear behavior of carbon black filled rubber compounds comprising pristine styrene butadiene rubber (SBR) together with incorporated SBR ground rubber (rubber powder). We also analyzed and described quantitatively the service conditions of some dynamically loaded rubber products, which are liable to wear (e.g. conveyor belts, tires). Beside the well-known standard test method to characterize wear resistance at steady...

  17. Vertically aligned nanowires on flexible silicone using a supported alumina template prepared by pulsed anodization

    DEFF Research Database (Denmark)

    Mátéfi-Tempfli, Stefan; Mátéfi-Tempfli, M.

    2009-01-01

    Carpets of vertically aligned nanowires on flexible substrates are successfully realized by a template method. Applying special pulsed anodization conditions, defect-free nanoporous alumina structures supported on polydimethylsiloxane (PDMS), a flexible silicone elastomer, are created. By using...... this template with nanopores ending on a conducting underlayer, a high-density nanowire array can be simply grown by direct DCelectrodeposition on the top of the silicone rubber....

  18. Injection molding of high precision optics for LED applications made of liquid silicone rubber

    Energy Technology Data Exchange (ETDEWEB)

    Hopmann, Christian; Röbig, Malte [Institute of Plastics Processing (IKV), RWTH Aachen University, Pontstraße 49, 52062 Aachen (Germany)

    2016-03-09

    Light Emitting Diodes (LED) conquer the growing global market of lighting technologies. Due to their advantages, they are increasingly used in consumer products, in lighting applications in the home and in the mobility sector as well as in industrial applications. Particularly, with regard to the increasing use of high-power LED (HP-LED) the materials in the surrounding area of the light emitting semiconductor chip are of utmost importance. While the materials behind the semiconductor chip are optimized for maximum heat dissipation, the materials currently used for the encapsulation of the semiconductor chip (primary optics) and the secondary optics encounter their limits due to the high temperatures. In addition certain amounts of blue UV radiation degrade the currently used materials such as epoxy resins or polyurethanes for primary optics. In the context of an ongoing joint research project with various partners from the industry, an innovative manufacturing method for high precision optics for LED applications made of liquid silicone rubber (LSR) is analyzed at the Institut of Plastics Processing (IKV), Aachen. The aim of this project is to utilize the material-specific advantages of high transparent LSR, especially the excellent high temperature resistance and the great freedom in design. Therefore, a high integrated injection molding process is developed. For the production of combined LED primary and secondary optics a LED board is placed in an injection mold and overmolded with LSR. Due to the integrated process and the reduction of subcomponents like the secondary optics the economics of the production process can be improved significantly. Furthermore combined LED optics offer an improved effectiveness, because there are no losses of the light power at the transition of the primary and secondary optics.

  19. The rubber tree genome reveals new insights into rubber production and species adaptation

    OpenAIRE

    Tang, Chaorong; Yang, Meng; Fang, Yongjun; Luo, Yingfeng; Gao, Shenghan; Xiao, Xiaohu; An, Zewei; Zhou, Binhui; Zhang, Bing; Tan, Xinyu; Yeang, Hoong Yeet; Qin, Yunxia; Yang, Jianghua; Lin, Qiang; Mei, Hailiang

    2016-01-01

    The Para rubber tree (Hevea brasiliensis) is an economically important tropical tree species that produces natural rubber, an essential industrial raw material. Here we present a high-quality genome assembly of this species (1.37 Gb, scaffold N50 = 1.28 Mb) that covers 93.8% of the genome (1.47 Gb) and harbours 43,792 predicted protein-coding genes. A striking expansion of the REF/SRPP (rubber elongation factor/small rubber particle protein) gene family and its divergence into several laticif...

  20. Radiation-induced deterioration of natural rubber and isoprene rubber vulcanizates

    International Nuclear Information System (INIS)

    Kohjiya, Shinzo; Matsumura, Yasushige; Yamashita, Shinzo; Matsuyama, Tomochika; Yamaoka, Hitoshi.

    1984-01-01

    Natural rubber (NR) and isoprene rubber (IR) were cured by sulfur and accelerator to give rubber vulcanizates. Both vulcanizates were subject to solvent extraction to purify them, followed by the γ-ray irradiation in air at room temperature. The deterioration by γ-ray (0-20 Mrad) was investigated by the changes of tensile properties, hardness, swelling, and ATR-IR spectra. The tensile strength decreased much by a few Mrad irradiation, which is elucidated due to the difficulty of stretch-induced crystallization of polyisoprene after the irradiation. Modulus at 50 % elongation, network-chain density, and hardness did not show significant variation with the γ-ray dose. These irradiation results suggest both degradation and crosslinking occur comparably in the rubber vulcanizates and the regularity of polyisoprene chains may be somewhat randomized to prevent them from crystallizing on stretching. (author)

  1. Effect of Temperature and Sheet Temper on Isothermal Solidification Kinetics in Clad Aluminum Brazing Sheet

    Science.gov (United States)

    Benoit, Michael J.; Whitney, Mark A.; Wells, Mary A.; Winkler, Sooky

    2016-09-01

    Isothermal solidification (IS) is a phenomenon observed in clad aluminum brazing sheets, wherein the amount of liquid clad metal is reduced by penetration of the liquid clad into the core. The objective of the current investigation is to quantify the rate of IS through the use of a previously derived parameter, the Interface Rate Constant (IRC). The effect of peak temperature and initial sheet temper on IS kinetics were investigated. The results demonstrated that IS is due to the diffusion of silicon (Si) from the liquid clad layer into the solid core. Reduced amounts of liquid clad at long liquid duration times, a roughened sheet surface, and differences in resolidified clad layer morphology between sheet tempers were observed. Increased IS kinetics were predicted at higher temperatures by an IRC model as well as by experimentally determined IRC values; however, the magnitudes of these values are not in good agreement due to deficiencies in the model when applied to alloys. IS kinetics were found to be higher for sheets in the fully annealed condition when compared with work-hardened sheets, due to the influence of core grain boundaries providing high diffusivity pathways for Si diffusion, resulting in more rapid liquid clad penetration.

  2. Rubber Reclamation

    Science.gov (United States)

    Williams, Kathryn R.

    2007-01-01

    The safety and health hazards related to recycling of used rubber, due to the scarcity and high price of virgin rubber are reported. Various threats like stagnant water pools trapped in tires leading to diseases and ignited tires, which become very difficult to extinguish and generating smoke that is extremely detrimental to the environment, have…

  3. Job safety analysis and hazard identification for work accident prevention in para rubber wood sawmills in southern Thailand.

    Science.gov (United States)

    Thepaksorn, Phayong; Thongjerm, Supawan; Incharoen, Salee; Siriwong, Wattasit; Harada, Kouji; Koizumi, Akio

    2017-11-25

    We utilized job safety analysis (JSA) and hazard identification for work accident prevention in Para rubber wood sawmills, which aimed to investigate occupational health risk exposures and assess the health hazards at sawmills in the Trang Province, located in southern Thailand. We conducted a cross-sectional study which included a walk-through survey, JSA, occupational risk assessment, and environmental samplings from March through September 2015 at four Para rubber wood sawmills. We identified potential occupational safety and health hazards associated with six main processes, including: 1) logging and cutting, 2) sawing the lumber into sheets, 3) planing and re-arranging, 4) vacuuming and wood preservation, 5) drying and planks re-arranging, and 6) grading, packing, and storing. Working in sawmills was associated with high risk of wood dust and noise exposure, occupational accidents injuring hands and feet, chemicals and fungicide exposure, and injury due to poor ergonomics or repetitive work. Several high-risk areas were identified from JSA and hazard identification of the working processes, especially high wood dust and noise exposure when sawing lumber into sheets and risk of occupational accidents of the hands and feet when struck by lumber. All workers were strongly recommended to use personal protective equipment in any working processes. Exposures should be controlled using local ventilation systems and reducing noise transmission. We recommend that the results from the risk assessment performed in this study be used to create an action plan for reducing occupational health hazards in Para rubber sawmills.

  4. Techniques for hot embossing microstructures on liquid silicone rubbers with fillers

    DEFF Research Database (Denmark)

    Vudayagiri, Sindhu; Yu, Liyun; Skov, Anne Ladegaard

    2015-01-01

    Embossing is an established process for the thermoplastic elastomers but not yet for the thermosetting elastomers. It has already been shown that hot embossing is a viable technology for imprinting microstructures in addition to curing thin silicone films at their gel point. It is one of the simp......Embossing is an established process for the thermoplastic elastomers but not yet for the thermosetting elastomers. It has already been shown that hot embossing is a viable technology for imprinting microstructures in addition to curing thin silicone films at their gel point. It is one...

  5. Effect of Recycled Rubber Particles and Silica on Tensile and Tear Properties of Natural Rubber Composites

    Directory of Open Access Journals (Sweden)

    Velu CHANDRAN

    2016-05-01

    Full Text Available Application of scrap rubber and worn out tires in natural rubber compounds has been studied. The scrap rubber can, however, be recycled and compounded with natural rubber and thus can be generated as a rubber composite. In this work, recycled rubber particles (RRP were prepared using pulverization process. Then, RRP was blended with natural rubber and silica compounds, and it was synthesized by two- roll mill and hydraulic press at specified operating conditions. The samples ranging from 0 to 40 phr of RRP loaded with silica were used as constant filler. The mechanical properties and morphological analysis were carried out. The results showed that tensile strength and elongation at break gradually decreased with increasing RRP loading in natural rubber and silica compounds. Tensile modulus went down at 10 phr of RRP and then showed an increasing trend. Hardness increased up to 30 phr of RRP and tear strength increased up to 20 phr of RRP. A comparative study was also carried out with virgin natural rubber vulcanizates. The incorporation of RRP and silica up to 20 phr in natural rubber did not lower the performance of rubber articles. Morphological studies revealed that better filler dispersion, interfacial adhesion, and cross link density could increase the tensile and tear strengths.DOI: http://dx.doi.org/10.5755/j01.ms.22.2.7330

  6. Nitric oxide releasing silicone rubbers with improved blood compatibility: preparation, characterization, and in vivo evaluation.

    Science.gov (United States)

    Zhang, Huiping; Annich, Gail M; Miskulin, Judiann; Osterholzer, Kathryn; Merz, Scott I; Bartlett, Robert H; Meyerhoff, Mark E

    2002-03-01

    Nitric oxide (NO) releasing silicone rubbers (SR) are prepared via a three-step reaction scheme. A diamino triaminoalkyltrimethoxysilane crosslinker is used to vulcanize hydroxyl terminated polydimethylsiloxane (PDMS) in the presence of ambient moisture and a dibutyltin dilaurate catalyst so that the respective diamine triamine groups are covalently linked to the cured SR structure. These amine sites are then diazeniumdiolated, in situ, when the cured SR is reacted with NO at elevated pressure (80 psi). Although nitrite species are also formed during the NO addition reaction, in most cases the diazeniumdiolated polymer is the major product within the final SR matrix. Temperature appears to be the major driving force for the dissociation of the attached diazeniumdiolate moieties, whereas the presence of bulk water bathing the SR materials has only minimal effect on the observed NO release rate owing to the low water uptake of the SR matrices. The resulting SR films/coatings release NO at ambient or physiological temperature for up to 20 d with average fluxes of at least 4 x 10(10) mol x cm(-2) x min(-1) (coating thickness > or = 600 microm) over first 4 h, comparable to the NO fluxes observed from stimulated human endothelial cells. The NO loading and concomitant NO release flux of the SR material are readily adjustable by altering the diamine triamine loading and film/coating thickness. The new NO releasing SR materials are shown to exhibit improved thromboresistance in vivo, as demonstrated via reduced platelet activation on the surface of these polymers when used to coat the inner walls of SR tubings employed for extracorporeal circulation in a rabbit model.

  7. Synthesis of a novel hydantoin-containing silane and its effect on the tracking and bacteria resistance of addition-cure liquid silicone rubber

    Science.gov (United States)

    Liu, Tian; Zeng, Xingrong; Fang, Weizhen; Lai, Xuejun; Li, Hongqiang

    2017-11-01

    A novel hydantoin-containing silane, [3-(5,5-dimethylhydantoinurethano) propyl] ethoxyallyloxysilane (DMHURPAS), was synthesized and the structure was characterized by FTIR and 1H NMR. The effect of DMHURPAS was investigated on the anti-tracking and antibacterial properties of addition-cure liquid silicone rubber (ALSR) after surface chlorination. It was found that ALSR containing only 1.5 phr of DMHURPAS passed 1A 4.5 kV level and erosion mass decreased from 0.843 g to 0.037 g. The thermal stability of ALSR was significantly improved and the mechanical properties were also enhanced. From thermogravimetry-Fourier transform infrared spectroscopy (TG-FTIR), ALSR/DMHURPAS showed significant decrease of carbonyl compounds and cyclic oligomers but increase of CH4 and CO2 during thermal degradation, indicating that DMHURPAS could inhibit oxidation of methyl groups and unzipping reaction, and promote the cleavage of methyl groups in ALSR. The antibacterial rates of ALSR containing 2.0 phr of DMHURPAS against Escherichia coli and Staphylococcus aureus were 95.7% and 83.4%, respectively.

  8. Efficient tunable luminescence of SiGe alloy sheet polymers

    International Nuclear Information System (INIS)

    Vogg, G.; Meyer, A. J.-P.; Miesner, C.; Brandt, M. S.; Stutzmann, M.

    2001-01-01

    Crystalline SiGe alloy sheet polymers were topotactically prepared from epitaxially grown calcium germanosilicide Ca(Si 1-x Ge x ) 2 precursor films in the whole composition range. These polygermanosilynes are found to be a well-defined mixture of the known siloxene and polygermyne sheet polymers with the OH groups exclusively bonded to silicon. The optical properties determined by photoluminescence and optical reflection measurements identify the mixed SiGe sheet polymers as direct semiconductors with efficient luminescence tunable in the energy range between 2.4 and 1.3 eV. [copyright] 2001 American Institute of Physics

  9. RTV silicone rubber surface modification for cell biocompatibility by negative-ion implantation

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Chenlong [Key Laboratory of Beam Technology and Material Modification Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University, 100875 Beijing (China); Wang, Guangfu, E-mail: 88088@bnu.edu.cn [Key Laboratory of Beam Technology and Material Modification Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University, 100875 Beijing (China); Beijing Radiation Center, 100875 Beijing (China); Chu, Yingjie; Xu, Ya; Qiu, Menglin; Xu, Mi [Key Laboratory of Beam Technology and Material Modification Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University, 100875 Beijing (China)

    2016-03-01

    Highlights: • The radiation effect has a greater influence than doping effect on the hydrophilicity of RTV SR. • The implanted ions result in a new surface atomic bonding state and morphology. • Generating hydrophilic functional groups is a reason for the improved cell biocompatibility. • The micro roughness makes the hydrophilicity should be reduced due to the lotus effect. • Cell culture demonstrates that negative-ion implantation can improve biocompatibility. - Abstract: A negative cluster ion implantation system was built on the injector of a GIC4117 tandem accelerator. Next, the system was used to study the surface modification of room temperature vulcanization silicone rubber (RTV SR) for cell biocompatibility. The water contact angle was observed to decrease from 117.6° to 99.3° as the C{sub 1}{sup −} implantation dose was increased to 1 × 10{sup 16} ions/cm{sup 2}, and the effects of C{sub 1}{sup −}, C{sub 2}{sup −} and O{sub 1}{sup −} implantation result in only small differences in the water contact angle at 3 × 10{sup 15} ions/cm{sup 2}. These findings indicate that the hydrophilicity of RTV SR improves as the dose is increased and that the radiation effect has a greater influence than the doping effect on the hydrophilicity. There are two factors influence hydrophilicity of RTV: (1) based on the XPS and ATR-FTIR results, it can be inferred that ion implantation breaks the hydrophobic functional groups (Si−CH{sub 3}, Si−O−Si, C−H) of RTV SR and generates hydrophilic functional groups (−COOH, −OH, Si−(O){sub x} (x = 3,4)). (2) SEM reveals that the implanted surface of RTV SR appears the micro roughness such as cracks and wrinkles. The hydrophilicity should be reduced due to the lotus effect (Zhou Rui et al., 2009). These two factors cancel each other out and make the C-implantation sample becomes more hydrophilic in general terms. Finally, cell culture demonstrates that negative ion-implantation is an effective method

  10. Floating Silicon Method

    Energy Technology Data Exchange (ETDEWEB)

    Kellerman, Peter

    2013-12-21

    The Floating Silicon Method (FSM) project at Applied Materials (formerly Varian Semiconductor Equipment Associates), has been funded, in part, by the DOE under a “Photovoltaic Supply Chain and Cross Cutting Technologies” grant (number DE-EE0000595) for the past four years. The original intent of the project was to develop the FSM process from concept to a commercially viable tool. This new manufacturing equipment would support the photovoltaic industry in following ways: eliminate kerf losses and the consumable costs associated with wafer sawing, allow optimal photovoltaic efficiency by producing high-quality silicon sheets, reduce the cost of assembling photovoltaic modules by creating large-area silicon cells which are free of micro-cracks, and would be a drop-in replacement in existing high efficiency cell production process thereby allowing rapid fan-out into the industry.

  11. Determination of adhesion between thermoplastic and liquid silicone rubbers in hard-soft-combinations via mechanical peeling test

    Science.gov (United States)

    Kühr, C.; Spörrer, A.; Altstädt, V.

    2014-05-01

    The production of hard-soft-combinations via multi injection molding gained more and more importance in the last years. This is attributed to different factors. One principle reason is that the use of two-component injection molding technique has many advantages such as cancelling subsequent and complex steps and shortening the process chain. Furthermore this technique allows the combination of the properties of the single components like the high stiffness of the hard component and the elastic properties of the soft component. Because of the incompatibility of some polymers the adhesion on the interface has to be determined. Thereby adhesion is not only influenced by the applied polymers, but also by the injection molding parameters and the characteristics of the mold. Besides already known combinations of thermoplastics with thermoplastic elastomers (TPE), there consists the possibility to apply liquid silicone rubber (LSR) as soft component. A thermoplastic/LSR combination gains in importance due to the specific advantages of LSR to TPE. The faintly adhesion between LSR and thermoplastics is currently one of the key challenges when dealing with those combinations. So it is coercively necessary to improve adhesion between the two components by adding an adhesion promoter. To determine the promoters influence, it is necessary to develop a suitable testing method to investigate e.g. the peel resistance. The current German standard "VDI Richtlinie 2019', which is actually only employed for thermoplastic/TPE combinations, can serve as a model to determine the adhesion of thermoplastic/LSR combinations.

  12. Advances in rubber/halloysite nanotubes nanocomposites.

    Science.gov (United States)

    Jia, Zhixin; Guo, Baochun; Jia, Demin

    2014-02-01

    The research advances in rubber/halloysite nanotubes (rubber/HNTs) nanocomposites are reviewed. HNTs are environmentally-friendly natural nanomaterials, which could be used to prepare the rubber-based nanocomposites with high performance and low cost. Unmodified HNTs could be adopted to prepare the rubber/HNTs composites with improved mechanical properties, however, the rubber/HNTs nanocomposites with fine morphology and excellent properties were chiefly prepared with various modifiers by in situ mixing method. A series of rubber/HNTs nanocomposites containing several rubbers (SBR, NR, xSBR, NBR, PU) and different modifiers (ENR, RH, Si69, SA, MAA, ILs) have been investigated. The results showed that all the rubber/HNTs nanocomposites achieved strong interfacial interaction via interfacial covalent bonds, hydrogen bonds or multiple interactions, realized significantly improved dispersion of HNTs at nanoscale and exhibited excellent mechanical performances and other properties.

  13. Electrospinning of PVC with natural rubber

    Science.gov (United States)

    Othman, Muhammad Hariz; Mohamed, Mahathir; Abdullah, Ibrahim

    2013-11-01

    Polyvinyl chloride (PVC) was mixed with natural rubbers which are liquid natural rubber (LNR), liquid epoxidised natural rubber (LENR) and liquid epoxidised natural rubber acrylate (LENRA) for a preparation of a fine non-woven fiber's mat. PVC and each natural rubbers(PVC:LENR, PVC:LNR and PVC:LENRA) were mixed based on ratio of 70:30. Electrospinning method was used to prepare the fiber. The results show that the spinnable concentration of PVC/ natural rubber/THF solution is 16 wt%. The morphology, diameter, structure and degradation temperature of electrospun fibers were investigated by scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). SEM photos showed that the morphology and diameter of the fibers were mainly affected by the addition of natural rubber. TGA results suggested that PVC electrospun fiber has higher degradation temperature than those electrospun fibers that contain natural rubber.

  14. Electrospinning of PVC with natural rubber

    International Nuclear Information System (INIS)

    Othman, Muhammad Hariz; Abdullah, Ibrahim; Mohamed, Mahathir

    2013-01-01

    Polyvinyl chloride (PVC) was mixed with natural rubbers which are liquid natural rubber (LNR), liquid epoxidised natural rubber (LENR) and liquid epoxidised natural rubber acrylate (LENRA) for a preparation of a fine non-woven fiber’s mat. PVC and each natural rubbers(PVC:LENR, PVC:LNR and PVC:LENRA) were mixed based on ratio of 70:30. Electrospinning method was used to prepare the fiber. The results show that the spinnable concentration of PVC/ natural rubber/THF solution is 16 wt%. The morphology, diameter, structure and degradation temperature of electrospun fibers were investigated by scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). SEM photos showed that the morphology and diameter of the fibers were mainly affected by the addition of natural rubber. TGA results suggested that PVC electrospun fiber has higher degradation temperature than those electrospun fibers that contain natural rubber

  15. Electrospinning of PVC with natural rubber

    Energy Technology Data Exchange (ETDEWEB)

    Othman, Muhammad Hariz; Abdullah, Ibrahim [Department of Chemistry, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); Mohamed, Mahathir [Radiation Processing Technology Division (BTS), Malaysian Nuclear Agency, Bangi, 43000, Kajang (Malaysia)

    2013-11-27

    Polyvinyl chloride (PVC) was mixed with natural rubbers which are liquid natural rubber (LNR), liquid epoxidised natural rubber (LENR) and liquid epoxidised natural rubber acrylate (LENRA) for a preparation of a fine non-woven fiber’s mat. PVC and each natural rubbers(PVC:LENR, PVC:LNR and PVC:LENRA) were mixed based on ratio of 70:30. Electrospinning method was used to prepare the fiber. The results show that the spinnable concentration of PVC/ natural rubber/THF solution is 16 wt%. The morphology, diameter, structure and degradation temperature of electrospun fibers were investigated by scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). SEM photos showed that the morphology and diameter of the fibers were mainly affected by the addition of natural rubber. TGA results suggested that PVC electrospun fiber has higher degradation temperature than those electrospun fibers that contain natural rubber.

  16. Degradation of blending vulcanized natural rubber and nitril rubber (NR/NBR) by dimethyl ether through variation of elastomer ratio

    Science.gov (United States)

    Saputra, A. H.; Juneva, S.; Sari, T. I.; Cifriadi, A.

    2018-04-01

    Dimethyl ether can cause degradation of the rubber material seal in some applications. In order to use of natural rubber in industry, research about a blending of natural rubber (NR) and nitrile rubber (NBR) to produce rubber to meet the standard seal material application were conducted. This study will observe the degradation mechanisms that occur in the blending natural rubber and nitrile rubber (NR/NBR) by dimethyl ether. Nitrile rubber types used in this study is medium quality nitrile rubber with 33% of acrylonitrile content (NBR33). The observed parameters are percent change in mass, mechanical properties and surface morphology. This study is limited to see the effect of variation vulcanized blending ratio (NR/NBR33) against to swelling. The increase of nitrile rubber (NBR33) ratio of blending rubber vulcanized can reduce the tensile strength and elongation. The best elastomer variation was obtained after comparing with the standard feasibility material of seal is rubber vulcanized blending (NR/NBR33) with ratio 40:60 NR: NBR.

  17. Biological Reclaiming of Recycled Rubber and Its Effect on Mechanical Properties of New Rubber Vulcanizates

    Directory of Open Access Journals (Sweden)

    Maryam Mansourirad

    2014-12-01

    Full Text Available Nowadays, due to environmental concerns, there has been great attention to recycling and reclaiming of tires. Different methods have been used for reclaiming or desulfurization of rubber. One of these methods, in which desulfurization of rubber happens with no damage to the polymer structure, is desulfurization by biological microorganisms. In this research the application and performance of thermophilic and sulfur oxidizing bacteria, Acidianus brierleyi for this purpose was investigated. Ground tire rubber was detoxified with organic solvents, and the optimum conditions for growing microorganisms in the existence of rubber powder in the shaker flasks were determined. In order to accelerate the process, the suitable conditions for growth of bacteria and desulfurization in the bioreactor were adopted. Fourier transfer infrared spectroscopy and scanning electron microscopy were employed to characterize desulfurization of bio-treated powder from bioreactor. The results indicated that morphological changes on powder surface and reduction of sulfur bonds have occurred. Samples from bioreactors, with and without bacteria and also untreated rubber powder were compounded with virgin styrene butadiene rubber. Tensile and dynamic properties were investigated using uni-direction tensile test and dynamic-mechanical-thermal analysis, respectively. Although some differences in dynamic-mechanical-thermal properties of samples pointed to stronger interaction between rubber matrix and treated rubber powder, no significant improvements in the mechanical properties of vulcanizates containing A.brierleyi-treated powder were observed. Low concentration of sulfur in rubber vulcanizates, chemical bonds of sulfur, and low efficiency of A. brierleyi in breaking sulfur bonds and reclaiming rubber were considered as the reasons for low efficiency of this treatment process.

  18. Robotically enhanced rubber hand illusion.

    Science.gov (United States)

    Arata, Jumpei; Hattori, Masashi; Ichikawa, Shohei; Sakaguchi, Masamichi

    2014-01-01

    The rubber hand illusion is a well-known multisensory illusion. In brief, watching a rubber hand being stroked by a paintbrush while one's own unseen hand is synchronously stroked causes the rubber hand to be attributed to one's own body and to "feel like it's my hand." The rubber hand illusion is thought to be triggered by the synchronized tactile stimulation of both the subject's hand and the fake hand. To extend the conventional rubber hand illusion, we introduce robotic technology in the form of a master-slave telemanipulator. The developed one degree-of-freedom master-slave system consists of an exoskeleton master equipped with an optical encoder that is worn on the subject's index finger and a motor-actuated index finger on the rubber hand, which allows the subject to perform unilateral telemanipulation. The moving rubber hand illusion has been studied by several researchers in the past with mechanically connected rigs between the subject's body and the fake limb. The robotic instruments let us investigate the moving rubber hand illusion with less constraints, thus behaving closer to the classic rubber hand illusion. In addition, the temporal delay between the body and the fake limb can be precisely manipulated. The experimental results revealed that the robotic instruments significantly enhance the rubber hand illusion. The time delay is significantly correlated with the effect of the multisensory illusion, and the effect significantly decreased at time delays over 100 ms. These findings can potentially contribute to the investigations of neural mechanisms in the field of neuroscience and of master-slave systems in the field of robotics.

  19. Structural characterization of rubber from jackfruit and euphorbia as a model of natural rubber.

    Science.gov (United States)

    Mekkriengkrai, Dararat; Ute, Koiichi; Swiezewska, Ewa; Chojnacki, Tadeusz; Tanaka, Yasuyuki; Sakdapipanich, Jitladda T

    2004-01-01

    A structural study of low molecular weight rubbers from Jackfruit (Artocarpus heterophyllus) and Painted spurge (Euphorbia heterophylla) was carried out as model compounds of natural rubber from Hevea brasiliensis. The rubber content of latex from Jackfruit was 0.4-0.7%, which is very low compared with that of 30-35% in the latex from Hevea tree. The rubber from Jackfruit latex was low molecular weight with narrow unimodal molecular weight distribution (MWD), whereas that obtained from E. heterophylla showed very broad MWD. The 1H and 13C NMR analyses showed that Jackfruit rubber consists of a dimethylallyl group and two trans-isoprene units connected to a long sequence of cis-isoprene units. The alpha-terminal group of Jackfruit rubber was presumed to be composed of a phosphate group based on the presence of 1H NMR signal at 4.08 ppm corresponding to the terminal =CH-CH2OP group.

  20. Magnetic rubber inspection (MRI)

    International Nuclear Information System (INIS)

    Carro, L.

    1997-01-01

    Magnetic Rubber Inspection (MRI) was developed to inspect for small cracks and flaws encountered in high performance aircraft. A formula of very fine magnetic particles immersed in a room temperature curing rubber is catalysed and poured into dams (retainers) on the surface of the part to be inspected. Inducing a magnetic field then causes the particles to be drawn to discontinuities in the component under test. These indicating particles are held to the discontinuity by magnetic attraction, as the rubber cures. The solid rubber cast (Replica) is then removed and examined under a microscope for indicating lines of particle concentrations. 3 refs., 6 figs

  1. New techniques used to realize silicon photocells

    International Nuclear Information System (INIS)

    Siffert, P.

    1978-01-01

    The techniques used to realize the terrestrial silicon solar cells being considered the possible improvements of these methods are discussed. The various approaches under development to prepare silicon sheets in a continuous way are considered for both self-supporting or substrate deposited layers. Finally, the various methods used or under investigation to obtain the surface potential barrier are considered; MIS, heterojunction and ion implantation [fr

  2. Comparative studies on the mechanical properties of natural rubber and natural rubber filled with multi-walled carbon nanotubes

    Science.gov (United States)

    Ismail, R.; Ibrahim, A.; Rusop, M.; Adnan, A.

    2018-05-01

    The present article compares the mechanical properties of natural rubber (NR) and carbon nanotubes (CNTs) filled natural rubber composites. Four types of nanocomposite specimens are fabricated with different MWCNT loadings: 0 wt% (pure natural rubber), 1 wt%, 3 wt%, and 5 wt%. The specimens are tested for their mechanical properties. It is observed that the tensile strength, hardness and elongation break of CNTs filled rubber composites are remarkably higher than that of raw rubber indicating the inherent reinforcing potential of CNTs. Percentage of the elongation at break of rubber CNTs composites is lower than that of raw rubber.

  3. The Effect of Gamma Irradiation on the Mechanical Properties of vulcanized Natural Rubber and Natural Rubber-Polyethylene Blends

    International Nuclear Information System (INIS)

    Sudradjat Iskandar

    2008-01-01

    To enhance the quality of vulcanized natural rubber and natural rubber-polyethylene blends, gamma irradiation has been done. The compound of natural rubber and natural rubber-polyethylene blends made by using roll mill machine. The mixed materials were antioxidant, anti ozon, plasticizer and vulcanisator. The natural rubber and natural rubber-polyethylene blends compound were vulcanizer and made a slab (film of sample) using hot and could press machine. The slabs produced were then gamma irradiated at irradiation dose of 75, 150 and 300 kGy. Before and after irradiation, the slab were characterized using strograph R1 machine. The results showed that the modulus 300 and hardness of vulcanized natural rubber and natural rubber-polyethylene blends were increasing; the tensile strength and tear strength were increasing to maximum level then decreasing with gamma irradiation, while the elongation at break was decreasing. The maximum tensile strength of vulcanized natural rubber and natural rubber-polyethylene blends were found at irradiation dose of 75 kGy. At the irradiation dose of 75 kGy, the tensile strength of vulcanized natural rubber increased from 17.6 MN/m 2 to 21.2 MN/m 2 , while the tensile strength of vulcanized natural rubber-polyethylene blends increased slightly from 18.7 MN/m 2 to 19.4 MN/m 2 . (author)

  4. Vulcanization of Rubber

    Indian Academy of Sciences (India)

    Temperature 140 -180°C. Sulfur. 2-3 parts per. 100 parts of rubber (phr). Accelerator 0.5-1.0 phr. ZnO ... out an experiment, he spilt a mixture of rubber and sulfur with other ingredients on a hot .... both carbon-sulfur and sulfur-nitrogen bonds -.

  5. Large area sheet task. Advanced dendritic web growth development. [silicon films

    Science.gov (United States)

    Duncan, C. S.; Seidensticker, R. G.; Mchugh, J. P.; Hopkins, R. H.; Meier, D.; Frantti, E.; Schruben, J.

    1981-01-01

    The development of a silicon dendritic web growth machine is discussed. Several refinements to the sensing and control equipment for melt replenishment during web growth are described and several areas for cost reduction in the components of the prototype automated web growth furnace are identified. A circuit designed to eliminate the sensitivity of the detector signal to the intensity of the reflected laser beam used to measure melt level is also described. A variable speed motor for the silicon feeder is discussed which allows pellet feeding to be accomplished at a rate programmed to match exactly the silicon removed by web growth.

  6. Application of gamma irradiation for incorporation of rubber powder in the formulations of EPDM and natural rubber

    International Nuclear Information System (INIS)

    Kiyan, Ludmila Y.P.; Parra, Duclerc Fernandes; Lugao, Ademar Benevolo

    2013-01-01

    The objective of this work was to study the behavior of the recycling of rubber burrs in form of powder, of the rubber industry from EPDM rubber powder and natural rubber with SBR. The rubber powder was irradiated and reused in rubber artifacts formulations for classical vulcanization. The processed material was irradiated using a 60 Co source in doses of 50, 100, 150 and 200 kGy and a dose rate of 5 kGy s-1 at room temperature. The radiation created devulcanization active sites for subsequent integration of the material (rubber powder) in formulations of commercial use. The processes were compared and their products characterized by analytical methods of the physical properties such as strength and elongation. Satisfactory results were found, noting a major spin-off of EPDM chain demonstrated by increased elongation

  7. Preparation of micro-pored silicone elastomer through radiation crosslinking

    International Nuclear Information System (INIS)

    Gao Xiaoling; Gu Mei; Xie Xubing; Huang Wei

    2013-01-01

    The radiation crosslinking was adopted to prepare the micro-pored silicone elastomer, which was performed by vulcanization and foaming respectively. Radiation crosslinking is a new method to prepare micro-pored material with high performance by use of radiation technology. Silicon dioxide was used as filler, and silicone elastomer was vulcanized by electron beams, then the micro-pored material was made by heating method at a high temperature. The effects of absorbed dose and filler content on the performance and morphology were investigated. The structure and distribution of pores were observed by SEM. The results show that the micro-pored silicon elastomer can be prepared successfully by controlling the absorbed dose and filler content. It has a smooth surface similar to a rubber meanwhile the pores are round and unconnected to each other with the minimum size of 14 μm. And the good mechanical performance can be suitable for further uses. (authors)

  8. Tribology Aspect of Rubber Shock Absorbers Development

    Directory of Open Access Journals (Sweden)

    M. Banić

    2013-09-01

    Full Text Available Rubber is a very flexible material with many desirable properties Which enable its broad use in engineering practice. Rubber or rubber-metal springs are widely used as anti-vibration or anti-shock components in technical systems. Rubber-metal springs are usually realized as a bonded assembly, however especially in shock absorbers, it is possible to realize free contacts between rubber and metal parts. In previous research it authors was observed that friction between rubber and metal in such case have a significant influence on the damping characteristics of shock absorber. This paper analyzes the development process of rubber or rubber-metal shock absorbers realized free contacts between the constitutive parts, starting from the design, construction, testing and operation, with special emphasis on the development of rubber-metal springs for the buffing and draw gear of railway vehicles.

  9. The role of linked phospholipids in the rubber-filler interaction in carbon nanotube (CNT) filler natural rubber (NR) composites

    NARCIS (Netherlands)

    Le, H.H.; Abhijeet, S.; Ilish, S.; Klehm, J.; Henning, S.; Beiner, M.; Sarkawi, S.S.; Dierkes, Wilma K.; Das, A.; Fischer, D.; Stöckelhuber, K.-W.; Wiessner, S.; Khatiwada, S.P.; Adhikari, R.; Pham, T.; Heinrich, G.; Radusch, H.-J.

    2014-01-01

    The aim of the present work is to evidence the role of the linked phospholipids of natural rubber (NR) in the rubber-carbon nanotube (CNT) interactions in rubber composites. Three rubbers namely NR, deproteinized NR (DPNR) and a synthetic rubber isoprene (IR) were used as matrix for CNTs. The

  10. Silencing the lettuce homologs of small rubber particle protein does not influence natural rubber biosynthesis in lettuce (Lactuca sativa).

    Science.gov (United States)

    Chakrabarty, Romit; Qu, Yang; Ro, Dae-Kyun

    2015-05-01

    Natural rubber, cis-1,4-polyisoprene, is an important raw material in chemical industries, but its biosynthetic mechanism remains elusive. Natural rubber is known to be synthesized in rubber particles suspended in laticifer cells in the Brazilian rubber tree (Hevea brasiliensis). In the rubber tree, rubber elongation factor (REF) and its homolog, small rubber particle protein (SRPP), were found to be the most abundant proteins in rubber particles, and they have been implicated in natural rubber biosynthesis. As lettuce (Lactuca sativa) can synthesize natural rubber, we utilized this annual, transformable plant to examine in planta roles of the lettuce REF/SRPP homologs by RNA interference. Among eight lettuce REF/SRPP homologs identified, transcripts of two genes (LsSRPP4 and LsSRPP8) accounted for more than 90% of total transcripts of REF/SRPP homologs in lettuce latex. LsSRPP4 displays a typical primary protein sequence as other REF/SRPP, while LsSRPP8 is twice as long as LsSRPP4. These two major LsSRPP transcripts were individually and simultaneously silenced by RNA interference, and relative abundance, polymer molecular weight, and polydispersity of natural rubber were analyzed from the LsSRPP4- and LsSRPP8-silenced transgenic lettuce. Despite previous data suggesting the implications of REF/SRPP in natural rubber biosynthesis, qualitative and quantitative alterations of natural rubber could not be observed in transgenic lettuce lines. It is concluded that lettuce REF/SRPP homologs are not critically important proteins in natural rubber biosynthesis in lettuce. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. OPTIMIZATION OF SURFACE RESISTIVITY AND RELATIVE PERMITTIVITY OF SILICONE RUBBER FOR HIGH VOLTAGE APPLICATION USING RESPONSE SURFACE METHODOLOGY

    Directory of Open Access Journals (Sweden)

    N.N. Ali

    2017-06-01

    Full Text Available Silicone Rubber (SiR is considered as one of the most established insulator in High Voltage (HV industry. SiR possess a great function ability such as its lighter weight, great heat resistance and substantial electrical insulation properties. Dynamic research were performed all around the world in order to explore the unique insulating behavior of SiR but very little are done on the optimization of SiR in term of their processing parameters and formulation. In this work, four materials and processing factors were introduced; A: Alumina Trihydrate (ATH, B: Dicumyl-Peroxide (DCP, C: mixing speed and D: mixing time in order to analyze its contribution towards improving the surface resistivity and relative permittivity of SIR rubber. The factors range were set based on prior screening and are defined as; ATH (10 – 50 pphr, Dicumyl Peroxide (0.50 -1.50 pphr, speed of mixer (40 – 70 rpm and mixing period (5 – 10 mins which were then varied accordingly to produce an overall 19 samples of SiR blends. The testing results were analyzed using statistical Design of Experiment (DOE by applying two level full factorial from Design Expert Software (v10 to discover the inter-correlation between the factors studied and benefaction of each factor in improving both surface resistivity and relative permittivity responses of produced SiR blends. The model analysis on surface resistivity shows the coefficient of determination R2 value of 88.72% while the one for relative permittivity shows R2 value of 82.34 %. Combination of both dependent variables had yielded an optimization suggestion for SiR formulation and processing strategy of ATH: 50 pphr, DCP: 0.50 pphr, mixing speed: 70 rpm and mixing period: 10 mins with the desirability level of 0.835. The optimized formulation had resulted in the production of SiR blend with the characteristic of surface resistivity of 1.02039x10^14 Ω/sq and relative permittivity of 4.0231, respectively. In conclusion, it can be

  12. LSSA large area silicon sheet task continuous Czochralski process development

    Science.gov (United States)

    Rea, S. N.

    1978-01-01

    A Czochralski crystal growing furnace was converted to a continuous growth facility by installation of a premelter to provide molten silicon flow into the primary crucible. The basic furnace is operational and several trial crystals were grown in the batch mode. Numerous premelter configurations were tested both in laboratory-scale equipment as well as in the actual furnace. The best arrangement tested to date is a vertical, cylindrical graphite heater containing small fused silicon test tube liner in which the incoming silicon is melted and flows into the primary crucible. Economic modeling of the continuous Czochralski process indicates that for 10 cm diameter crystal, 100 kg furnace runs of four or five crystals each are near-optimal. Costs tend to asymptote at the 100 kg level so little additional cost improvement occurs at larger runs. For these conditions, crystal cost in equivalent wafer area of around $20/sq m exclusive of polysilicon and slicing was obtained.

  13. Theoretical Investigation by Quantum Mechanics on the Tunnel Diode Effect of Electric Conductive Characteristics and Haptic Sensing in MCF Rubber

    Directory of Open Access Journals (Sweden)

    Kunio Shimada

    2010-01-01

    Full Text Available By applying our developed intelligent fluid, magnetic compound fluid (MCF, to silicon oil rubber, we have made the MCF rubber highly sensitive to temperature and electric conduction. MCF is useful as the element material in haptic robot sensors and other related devices. In the present paper, we clarified the relationship between the electric current and the voltage under a tensile strain by utilizing the quantum mechanics theory on the multibarrier potential problem. The experimental results could be qualitatively explained by our proposed theory. The electrons can be moved between the solid materials by the tunnel effect. The relation between voltage and electric current is affected by the formation of the clusters, and it is changed by the application of heat. We also clarified experimentally the present MCF rubber useful in haptic sensors. Because the motions of humans and robots are different, the sensing of the rubber is different, depending on the placement. However, as for both motions of human and robot, there is no quantitative difference in the electric resistance among kinetic energy, momentum, and force. The sensing is also different based on the stiffness of the surface to which the sensor is adhered.

  14. Physico-mecha-nical properties of rubber seed shell carbon – filled natural rubber compounds

    Directory of Open Access Journals (Sweden)

    L.O. Ekebafe

    2010-07-01

    Full Text Available Samples of rubber seed shells were carbonized at varying temperatures (100, 200, 300, 400, 500, 600, 700 and 800 °C for three hours each and sieved through a 150 μm screen. The portion of the rubber seed shell carbon that passed through the screen was characterized in terms of loss on ignition, surface area, moisture content, pH, bulk density, and metal content and used in compounding natural rubber. The characterization shows that the pH, conductivity, loss on ignition and the surface area increases with the increases of the heating temperature, unlike the bulk density which decreases. The compound mixes were cured using the efficient vulcanization system. Cure characteristics of compounds and physico-mechanical properties of the vulcanisates were measured as a function of filler loading along with that of N330 carbon-black filled natural rubbers. The results showed that the cure times, scorch times and the torque gradually increased, with increasing the filler content for rubber seed shell carbon-filled natural rubber, with the filler obtained at carbonizing temperature of 600 °C tending to show optimum cure indices. The physicomechanical properties of the vulcanisates increase with filler loading. The reinforcing potential of the carbonized rubber seed shell carbon was found to increase markedly for the filler obtained at the temperature range of 500-600 °C and then decreases with further increase in temperature.

  15. Constructing better roads with asphalt rubber

    Directory of Open Access Journals (Sweden)

    Pais Jorge C.

    2015-12-01

    Full Text Available Brazilians mixtures containing asphalt rubber were evaluated by mechanical laboratory tests. A conventional mixture with asphalt CAP-50/70 was produced as a mixture control. With the aim of compare the Brazilians mixtures performance, a Portuguese asphalt rubber mixture was tested as well. The testing set involved the determination of the mechanical properties, fatigue and permanent deformation, of asphalt rubber produced by wet process through two different systems: continuous blend and terminal blend. The asphalt rubber morphology was evaluated in order to determine the compatibility of the systems. The asphalt rubber mixtures exhibit good resistance to permanent deformation and prolonged fatigue life in relation to mixture control. Therefore it is concluded that the application of asphalt rubber alters the characteristics of asphalt mixture in a very beneficial way.

  16. Rubber modification of asphalt binders and mixes

    Energy Technology Data Exchange (ETDEWEB)

    Morrison, G.; Hesp, S.A.M. [Queen`s Univ., Kingston, ON (Canada). Dept. of Chemistry

    1995-12-31

    The physical properties of asphalt binders and concrete, modified with waste rubber tire, were examined. In an experiment designed to address the concern of waste disposal of scrap rubber, a control asphalt, devulcanized rubber modified asphalt and a crumb rubber modified asphalt were used to make asphalt concrete mixes. The three mixes were subjected to a thermal stress test to determine their low temperature fracture temperatures and strengths. Results were discussed in terms of the binder material used. At high service temperatures, the addition of 10% devulcanized rubber was found to have no beneficial effect, whereas the addition of 10% 80 mesh crumb rubber produced a modest improvement in performance. At low temperatures, the addition of devulcanized rubber produced increased resistance to cracking up to 90%. The addition of 10% 80 mesh crumb rubber increased fracture toughness by a factor of 3.3 times. 12 refs., 3 tabs.

  17. Solubility Study of Curatives in Various Rubbers

    NARCIS (Netherlands)

    Guo, R.; Talma, Auke; Datta, Rabin; Dierkes, Wilma K.; Noordermeer, Jacobus W.M.

    2008-01-01

    The previous works on solubility of curatives in rubbers were mainly carried out in natural rubber. Not too much information available on dissimilar rubbers and this is important because most of the compounds today are blends of dissimilar rubbers. Although solubility can be expected to certain

  18. Nitrile rubber and carboxylated nitrile rubber resistance to soybean biodiesel

    OpenAIRE

    Felipe Nunes Linhares; Cléverson Fernandes Senra Gabriel; Ana Maria Furtado de Sousa; Marcia Christina Amorim Moreira Leite; Cristina Russi Guimarães Furtado

    2018-01-01

    Abstract Biodiesel has been considered a suitable substitute for petroleum diesel, but their chemical composition differs greatly. For this reason, biodiesel interacts differently than petroleum diesel with various materials, including rubbers. Therefore, the resistance of some elastomers should be thoroughly evaluated, specifically those which are commonly used in automotive industry. Nitrile rubber (NBR) is widely used to produce vehicular parts that are constantly in contact with fuels. T...

  19. QENS investigation of filled rubbers

    CERN Document Server

    Triolo, A; Desmedt, A; Pieper, J K; Lo Celso, F; Triolo, R; Negroni, F; Arrighi, V; Qian, H; Frick, B

    2002-01-01

    The polymer segmental dynamics is investigated in a series of silica-filled rubbers. The presence of inert fillers in polymers greatly affects the mechanical and physical performance of the final materials. For example, silica has been proposed as a reinforcing agent of elastomers in tire production. Results from quasielastic neutron scattering and Dynamic Mechanical Thermal Analysis (DMTA) measurements are presented on styrene-ran-butadiene rubber filled with silica. A clear indication is obtained of the existence of a bimodal dynamics, which can be rationalized in terms of the relaxation of bulk rubber and the much slower relaxation of the rubber adsorbed on the filler surface. (orig.)

  20. Forming the stress state of a vibroisolated building in the process of mounting rubber steel vibration isolator

    Directory of Open Access Journals (Sweden)

    Dashevskiy Mikhail Aronovich

    2015-12-01

    Full Text Available The necessity to specificate the formation process of stress-strain state of buildings in the construction process is a new problem which requires including real production characteristics going beyond calculation models into calculation methods. Today the construction process lacks this specification. When mounting vibroisolators the stress-strein of a structure state is changing. The mounting method of vibroisolators is patented and consists in multistage successive compression loading of each vibroisolator with the constant speed and following fixation of this displacement. The specified engineering method of rubber-steel pads calculation in view of change of their form during deformation, nonlinearity, rheological processes is offered. Resilient pads look like rubber plates rectangular in plane reinforced on the basic surfaces with metal sheets. The influence of a time-variable static load and free vibrations of loaded pads are considered.

  1. Rubber elongation factor (REF, a major allergen component in Hevea brasiliensis latex has amyloid properties.

    Directory of Open Access Journals (Sweden)

    Karine Berthelot

    Full Text Available REF (Hevb1 and SRPP (Hevb3 are two major components of Hevea brasiliensis latex, well known for their allergenic properties. They are obviously taking part in the biosynthesis of natural rubber, but their exact function is still unclear. They could be involved in defense/stress mechanisms after tapping or directly acting on the isoprenoid biosynthetic pathway. The structure of these two proteins is still not described. In this work, it was discovered that REF has amyloid properties, contrary to SRPP. We investigated their structure by CD, TEM, ATR-FTIR and WAXS and neatly showed the presence of β-sheet organized aggregates for REF, whereas SRPP mainly fold as a helical protein. Both proteins are highly hydrophobic but differ in their interaction with lipid monolayers used to mimic the monomembrane surrounding the rubber particles. Ellipsometry experiments showed that REF seems to penetrate deeply into the monolayer and SRPP only binds to the lipid surface. These results could therefore clarify the role of these two paralogous proteins in latex production, either in the coagulation of natural rubber or in stress-related responses. To our knowledge, this is the first report of an amyloid formed from a plant protein. This suggests also the presence of functional amyloid in the plant kingdom.

  2. Silylated functionalized silicon-based composite as anode with excellent cyclic performance for lithium-ion battery

    Science.gov (United States)

    Li, Xiao; Tian, Xiaodong; Yang, Tao; Wang, Wei; Song, Yan; Guo, Quangui; Liu, Zhanjun

    2018-05-01

    Inferior cycling stability and rate performance respectively caused by rigorous volume change and poor electrical conductivity were the main challenge of state-of-the-art Silicon-based electrode. In this work, silylated functionalized exfoliated graphite oxide (EGO)/silicon@amorphous carbon (3-APTS-EGO/Si@C) was synthesized by adopting silane as intermediate to connect Si particles with EGO sheets followed by introduction of amorphous carbon. The result suggested that 3-Aminopropyltriethoxysilan connected the EGO sheets and Si nanoparticles via covalent bonds. Owing to the strong covalent interaction and the synergistic effect between the silicon, EGO sheets and amorphous carbon, 3-APTS-EGO/Si@C composite possessed a high capacity of 774 mAh g-1 even after 450 cycles at 0.4 A g-1 with the retention capacity of 97%. This work also provided an effective strategy to improve the long cycling life performance of Si-based electrode.

  3. Carboxy terminated rubber based on natural rubber grafted with acid anhydrides and its adhesion properties

    International Nuclear Information System (INIS)

    Klinpituksa, P; Kongkalai, P; Kaesaman, A

    2014-01-01

    The chemical modification of natural rubber by grafting of various polar functional molecules is an essential method, improving the versatility of rubber in applications. This research investigated the preparation of natural rubber-graft-citraconic anhydride (NR-g-CCA), natural rubber-graft-itaconic anhydride (NR-g-ICA), and natural rubber-graft-maleic anhydride (NR-g-MA), with the anhydrides grafted to natural rubber in toluene using benzoyl peroxide as an initiator. Variations of monomer content, initiator content, temperature and reaction time of the grafting copolymerization were investigated. The maximum degrees of grafting were 1.06% for NR-g-CCA, 4.66% for NR-g-ICA, and 5.03% for NR-g-MA, reached using 10 phr citraconic anhydride, 10 phr of itaconic anhydride, or 8 phr of maleic anhydride, 3 phr benzoyl peroxide, at 85, 80 and 80°C for 2, 2 and 3 hrs, respectively. Solvent-based wood adhesives were formulated from these copolymers with various contents of wood resin in the range 10-40 phr. The maximal 289 N/in cleavage peel and 245.7 KPa shear strength for NR-g-MA (5.03% grafting) were obtained at 40 phr wood resin

  4. Human islet viability and function is maintained during high density shipment in silicone rubber membrane vessels

    Science.gov (United States)

    Kitzmann, Jennifer P; Pepper, Andrew R; Lopez, Boris G; Pawlick, Rena; Kin, Tatsuya; O’Gorman, Doug; Mueller, Kathryn R; Gruessner, Angelika C; Avgoustiniatos, Efstathios S; Karatzas, Theodore; Szot, Greg L; Posselt, Andrew M; Stock, Peter G; Wilson, John R; Shapiro, AM; Papas, Klearchos K

    2014-01-01

    The shipment of human islets from processing centers to distant laboratories is beneficial for both research and clinical applications. The maintenance of islet viability and function in transit is critically important. Gas-permeable silicone rubber membrane (SRM) vessels reduce the risk of hypoxia-induced death or dysfunction during high-density islet culture or shipment. SRM vessels may offer additional advantages: they are cost-effective (fewer flasks, less labor needed), safer (lower contamination risk), and simpler (culture vessel can also be used for shipment). Human islets(IE) were isolated from two manufacturing centers and shipped in 10cm2 surface area SRM vessels in temperature and pressure controlled containers to a distant center following at least two days of culture (n = 6). Three conditions were examined: low density (LD), high density (HD), and a micro centrifuge tube negative control (NC). LD was designed to mimic the standard culture density for human islet preparations (200 IE/cm2), while HD was designed to have a 20-fold higher tissue density, which would enable the culture of an entire human isolation in 1–3 vessels. Upon receipt, islets were assessed for viability, measured by oxygen consumption rate normalized to DNA content (OCR/DNA), and quantity, measured by DNA, and, when possible, potency and function with dynamic glucose-stimulated insulin secretion (GSIS) measurements and transplants in immunodeficient B6 rag mice. Post-shipment OCR/DNA was not reduced in HD versus LD, and was substantially reduced in the NC condition. HD islets exhibited normal function post-shipment. Based on the data we conclude that entire islet isolations (up to 400,000 IE) may be shipped using a single, larger SRM vessel with no negative effect on viability and ex vivo and in vivo function. PMID:25131090

  5. Hyundai plans rubber unit despite overcapacity

    International Nuclear Information System (INIS)

    Hyoungjin Kim.

    1993-01-01

    Despite the oversupply of synthetic rubber in South Korea, the government has granted approval to Hyundai Petrochemical (Seoul) to build the country's second synthetic rubber unit, to be located alongside its petrochemical complex at Daesan. The plant is due for startup during second-half 1995, when the local market is expected to be in better balance. Hyundai will use Goodyear Tire ampersand Rubber technology for the plant, which will have annual capacities for 40,000 m.t. of polybutadiene rubber (BR), 30,000 m.t. of styrene butadiene rubber (SBR) and 12,000 m.t. of nitrile rubber (NBR). Styrene and butadiene requirements will be met from Hyundai's own production at Daesan. The current local producer of synthetic rubber is Korea Kumho Petrochemicals (Seoul), which has annual capacities for 150,000 m.t. of SBR, 95,000 m.t. of BR, and 10,000 m.t. of NBR. Korean SBR demand is about 141,000 m.t./year but is expected to increase to 161,000 m.t./year by 1996 and reach 194,000 m.t./year by the end of the decade

  6. Static friction in rubber-metal contacts with application to rubber pad forming processes

    NARCIS (Netherlands)

    Deladi, E.L.

    2006-01-01

    A static friction model suitable for rubber-metal contact is presented in this dissertation. In introduction, the motivation and the aims of the research are introduced together with the background regarding the related industrial application, which is the rubber pad forming process.

  7. Studies on the increased heat effect within the rubber tree rows of man-made rubber-tea community

    International Nuclear Information System (INIS)

    Ma Youxin

    1994-01-01

    Differences in the various components of thermal balance and the microclimatic factors within lower layers of rubber tree rows between a man-made rubber-tea community(RTC)and a pure rubber garden(PRG)in the coldest month were studied in Xishuangbanna,Yun-nan province

  8. Radiation induced graft copolymerization of acrylonitrile on natural rubber

    International Nuclear Information System (INIS)

    Claramma, N.M.; Mathew, N.M.; Thomas, E.V.

    1989-01-01

    Acrylonitrile graft natural rubber was prepared by initiating the polymerization of acrylonitrile in natural rubber field latex using γ-rays. The reaction was carried out at different rubber-monomer concentrations and the properties of the modified rubbers were compared with those of natural rubber and nitrile rubber. (author)

  9. Biodiversity in rubber agroforests

    NARCIS (Netherlands)

    Beukema, Hendrien

    2013-01-01

    Jungle rubber tuinen zijn extensieve rubber agroforests die qua structuur op secundaire bossen lijken, en waarin wilde soorten door de boer worden getolereerd. Met het verdwijnen van het laaglandregenwoud rijst de vraag of de begroeiing die ervoor in de plaats komt een aantal kenmerken en functies

  10. Enzymatic synthesis of rubber polymer in Hevea brasiliensis

    Energy Technology Data Exchange (ETDEWEB)

    Tang, F.; Hu, S.; Benedict, C.R. (Texas A and M Univ., College Station (United States))

    1991-05-01

    Light and Dennis purified serum soluble rubber transferase from Hevea latex to homogeneity. Prenyl transferase co-purified with rubber transferase. In the absence of washed rubber particles (WRP) the prenyl transferase catalyzed the formation of trans FPP from DMAPP and IPP. In the presence of WRP the transferase catalyzed cis additions of IPP to pre-existing rubber chains. Control mixtures of WRP, Mg{sup 2+} and FPP were not included to test for the contributions of the bound rubber transferase on WRP to the incorporation of IPP into polyisoprene. Bound rubber transferase catalyzes the repetitive addition of IPP to allylic-PP starter molecules to form polyisoprene. The order of utilization of allylic-PP starters was GGPP > FPP > GPP > DMAPP. The authors have shown that the polyisoprene enzymatically synthesized on WRP is a bimodal polymer consisting of different mol wt rubber chains similar to the polymeric characteristics of natural rubber. The bound rubber transferase was solubilized with Chaps and purified on DEAE-cellulose. The polymerization reaction catalyzed by the purified preparation showed a 98% requirement for pre-existing rubber chains. Results suggest that the prenyl transferase from Hevea serum may be part of the polymer starter system furnishing allylic-PP for the bound rubber transferase.

  11. Performance of self-compacting rubberized concrete

    Directory of Open Access Journals (Sweden)

    Hamza Bensaci

    2018-01-01

    Full Text Available Used tyre rubber wastes present a serious environmental problem of pollution and storage. The recycling of this waste in the industry of construction could be an appropriate solution to produce an eco-concrete and could contribute to the improvement of some of its properties. This paper aims to study the possibility of using tyre rubber waste as fine aggregate replacement in self-compacting concrete (SCC. Fines rubber particles of 0-2 mm of waste tyres were added SCC mixtures as a partial substitution of the total volume of sand at different percentages (5, 10, 15, 20 and 30%. The influence of fines rubber of used tyres on fresh and hardened properties of the SCC was investigated. The fresh properties of SCC were performed by using slump-flow, T50 flow time, L-box, V-funnel and segregation resistance tests. Characteristics of the hardened state were obtained by compressive strength and thermal conductivity. The experimental results showed that the inclusion of fines rubber in SCC decreases the workability, reduced its passing capacity and increases the possibility of blocking. A decrease in compressive strength is observed with the increase in rubber content. On the other hand, the incorporation of the rubber fines aggregates enhances in a remarkably way the thermal conductivity.

  12. Chlorinated rubbers with advanced properties for tire industry

    Science.gov (United States)

    Mikhaylov, I. A.; Sukhareva, K. V.; Andriasyan, Yu. O.; Popov, A. A.

    2017-12-01

    The paper investigates the production and processing of halide-modified chlorinated rubbers, such as isobutylene isoprene rubber and ethylene-propylene-diene-monomer rubber (IIR and EPDM), which are perspective in terms of application in rubber industry. Prospects for their production and application are determined by the specific properties of these rubbers (low gas permeability of IIR, high heat and ozone resistance of EPDM). These properties are governed by the structure of both initial IIR and EPDM and chlorinated rubbers (ChIIR and ChEPDM). A new alternative technology of obtaining chlorinated elastomers based on solid-phase mechanochemical halide modification is proposed. Novel chlorinated polyolefin rubbers obtained by the developed technology show good technological properties under industrial production conditions due to enhanced covulcanization.

  13. Production and performance of desulfurized rubber asphalt binder

    Directory of Open Access Journals (Sweden)

    Yanping Sheng

    2017-05-01

    Full Text Available Asphalt rubber binder typically exhibits disadvantages like segregation and high viscosity; however, this can be improved by the incorporation of desulfurized rubber powder. This study examined the swelling principle of desulfurized rubber asphalt (DRA. In addition, it evaluated the performance of DRA fabricated with various rubber powder contents under different shear conditions and development time. Superpave binders tests, including Brookfield viscosity, dynamic shear rheometer (DSR and bending beam rheometer (BBR tests, were applied on three control binders (i.e., neat, 20 mesh asphalt rubber binder, 40 mesh asphalt rubber binder and a DRA binder. Binder testing results indicated that rubber powder swelled into the base binder and resulted in enhanced stability. Optimum performance of the DRA binder was achieved by adding 20% (by weight of rubber powder into the base binder at shear rate, shear temperature, shear time and development time of 7000 r/min, 170 °C, 60 min and 45 min, respectively. Modified ranges of production conditions were also provided to widen the application of DRA in field construction. It appeared that DRA binder benefited from the recovered plasticity and viscosity of the rubber and consequently, exhibited superior performance over the neat and conventional asphalt rubber binders. Preliminary mixture evaluation was also conducted and the DRA binder was found to significantly improve the mixture resistance to permanent deformation and water damage. Overall, the DAR binder is encouraged to be used as a modified binder for flexible pavements. Keywords: Desulfurized rubber asphalt, Swelling model, Production process, Asphalt performance, Rubber asphalt

  14. In-house manufacturing of cylindrical silicone models for hemodynamic research

    Science.gov (United States)

    Denisenko, Nikita S.; Kulik, Viktor M.

    2017-10-01

    Laboratory studies of fluid motion in artificial vessels modeling a distinct part of circulatory system of human are of a great importance for fundamental biomechanics and for medical applications. In the medicine they are used for advancing known and developing new methods for curing cardiovascular diseases. In biomechanics, the phantoms of blood vessels are used for studying the fluid motion. However, they are quite expensive. Therefore, a development of technique for in-house manufacturing of phantoms is quite attractive. In this paper methods of manufacturing cylindrical channels of silicone rubbers (the model of the straight part of an artery) and determination of their elastic properties are described. A specially developed acrylic mold is used for this purpose. The phantoms are cast from a mixture of SKTN-A silicone and PMS-5 oil (Penta-91, Novosibirsk, Russia). The oil is used for changing elasticity properties of the silicone.

  15. Chemical modifications of liquid natural rubber

    Science.gov (United States)

    Azhar, Nur Hanis Adila; Rasid, Hamizah Md; Yusoff, Siti Fairus M.

    2016-11-01

    Liquid natural rubber (LNR) was synthesized via photosentisized degradation of natural rubber (NR). LNR was modified into epoxidized liquid natural rubber (LENR) and hydroxylated liquid natural rubber (LNR-OH) using Na2WO4/CH3COOH/H2O2 catalytic system. Chemical structures of LNR and modified LNRs were characterized using Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) and 1H Nuclear Magnetic Resonance (NMR) spectroscopies. Integration of 1H NMR was used to calculate the epoxy content (%) of LENR. 1H NMR detected the formation of LNR-OH after prolonged heating and increased of catalyst in oxidation reaction.

  16. The Cyclization of natural rubber

    International Nuclear Information System (INIS)

    Mirzataheri, M.

    2000-01-01

    The effect of solvent, temperature, time, weight percent of catalyst on the rate and mechanism of cyclization of natural rubber was studied in toluene and xylene solutions having tin tetra chloride catalyst (SnCl 4 ). Iodo metric titration show, with 8% SnCl 4 (based on polymer weight) cyclization occurs, leaving 27.4% of the total unsaturation. Infrared spectra of cyclized natural rubber show decreased absorption intensity at 840 and 780 cm -1 which are characteristic bands of the linear polymer and the appearance of absorption band at 890 cm -1 as cycles were formed. By using this chemical modification, natural rubber is transformed into a resinous thermoplastic, hard, non rubbery cyclized material with much less unsaturation than the original rubber, which could find commercial applications ad adhesives, printing inks, industrial and ship paints

  17. Process research of non-CZ silicon material

    Science.gov (United States)

    Campbell, R. B.

    1984-01-01

    Advanced processing techniques for non-CZ silicon sheet material that might improve the cost effectiveness of photovoltaic module production were investigated. Specifically, the simultaneous diffusion of liquid boron and liquid phosphorus organometallic precursors into n-type dendritic silicon web was examined. The simultaneous junction formation method for solar cells was compared with the sequential junction formation method. The electrical resistivity of the n-n and p-n junctions was discussed. Further research activities for this program along with a program documentation schedule are given.

  18. Use of rubber crumbs in cement concrete

    Science.gov (United States)

    Longvinenko, A. A.

    2018-03-01

    Rubber crumb obtained from worn out tires has been increasingly used over the last 15-20 years, especially in manufacture of asphalt and cement concrete mixtures. This review pays principal attention to application of the rubber crumb to cement concrete mixtures. Use of the rubber crumb in cement concrete is not as successful as in asphalt concrete mixtures, due to incompatibility problems linked to chemical composition and a significant difference in rigidity between the rubber crumb and concrete mixture aggregates. Different methods are proposed and studied to mitigate the adverse influence and increase the beneficial effects of the rubber crumb when added to cement concrete.

  19. Natural rubber (NR) biosynthesis: perspectives from polymer chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Barkakaty, Balaka [ORNL

    2014-01-01

    Natural rubber is an important strategic raw material for manufacturing a wide variety of industrial products. There are at least 2,500 different latex-producing plant species; however, only Hevea brasiliensis (the Brazilian rubber tree) is a commercial source. The chemical structure of natural rubber is cis-1,4-polyisoprene, but the exact structure of the head and end groups remains unknown. Since synthetic cis-1,4-polyisoprenes cannot match the superior properties of natural rubber, understanding the chemistry behind the biosynthetic process is key to finding a possible replacement. T his chapter summarizes our current understandings from the perspective of a polymer scientist by comparing synthetic polyisoprenes to natural rubber. The chapter also highlights biomimetic polymerization, research towards a synthetic match of natural rubber and the role of natural rubber in health care.

  20. Amphiphilic semi-interpenetrating polymer networks using pulverized rubber

    Science.gov (United States)

    Shahidi, Nima

    Scrap rubber materials provide a significant challenge to either reuse or safe disposal. Every year, millions of tires are discarded to landfills in the United States, consuming a staggering amount of land space, creating a high risk for large fires, breeding mosquitoes that spread diseases, and wasting the planet's natural resources. This situation cannot be sustained. The challenge of reusing scrap rubber materials is mainly due to the crosslinked structure of vulcanized rubber that prevent them from melting and further processing for reuse. The most feasible recycling approach is believed to be a process in which the vulcanized rubber is first pulverized into a fine powder and then incorporated into new products. The production of fine rubber particles is generally accomplished through the use of a cryogenic process that is costly. Therefore, development of a cost effective technology that utilizes a large quantity of the scrap rubber materials to produce high value added materials is an essential element in maintaining a sustainable solution to rubber recycling. In this research, a cost effective pulverization process, solid state shear extrusion (SSSE), was modified and used for continuous pulverization of the rubber into fine particles. In the modified SSSE process, pulverization takes place at high compressive shear forces and a controlled temperature. Furthermore, an innovative particle modification process was developed to enhance the chemical structure and surface properties of the rubber particles for manufacturing of high value added products. Modification of rubber particles was accomplished through the polymerization of a hydrophilic monomer mixture within the intermolecular structure of the hydrophobic rubber particles. The resulting composite particles are considered as amphiphilic particulate phase semi-interpenetrating polymer networks (PPSIPNs). The modified rubber particles are water dispersible and suitable for use in a variety of aqueous media

  1. Characterization of the natural rubber from new rubber tree clones of PB 300 series

    International Nuclear Information System (INIS)

    Silva, Maycon J.; Spinelli, Rafaela O.; Moreno, Rogerio M.B.; Mattoso, Luiz H.C.; Martins, Maria Alice; Scaloppi Junior, Erivaldo J.

    2015-01-01

    The natural rubber (NR) is present in more than 2500 species of plants, being the Hevea brasiliensis the most commercially exploited. It is a raw material of great importance to the Brazilian economy, but the country faces a production's deficit, having to import about 60% of its consumption. In this work , the latex obtained from rubber tree of new clones of PB series 300 (PB 311, PB 312, PB 314 , PB 326, PB 346 and PB 350 ) and RRIM 600 (control) were characterized by dry rubber content (DRC), total solids content, distribution of particle size, Zeta potential, thermogravimetry, differential scanning calorimetry, infrared in the spectroscopy (FTIR), nuclear magnetic resonance (NMR) and technological properties. The DRC values ranged from 33% to 40%, and total solids of 38% to 44%. All of the clones showed average particle diameter between 180.0 to 192.1 nm, excluding clones PB 326 and PB 346 with 150.0 nm and 157.9 nm, respectively. The NMR spectra and FTIR showed that the structure of the natural rubber from all clones studied is cis -1,4- polyisoprene. Natural rubber from the new clones showed good thermal stability up to 285 °C and glass transition temperature of -64 °C. (author)

  2. SUPPLY-CHAIN OF NATURAL RUBBER IN INDONESIA

    Directory of Open Access Journals (Sweden)

    Bustanul Arifin

    2011-08-01

    Full Text Available Normal 0 false false false MicrosoftInternetExplorer4 st1\\:*{behavior:url(#ieooui } /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-ansi-language:#0400; mso-fareast-language:#0400; mso-bidi-language:#0400;} The study examines the supply chain of natural rubber production in Indonesia and assessing the transmission of prices to rubber growers and provides recommendations for a suitable scheme that would help to ensure high production standards and a sustainable return for natural rubber production.  The frameworks to examine the performance of supply chain of rubber marketing rely mostly on the efficiency level of marketing system of natural rubbers, including the value chain principles in marketing margin, and revealed price transmission from consumers to growers. The results show that the roles of subdistrict middlemen are extremely crucial in moving up the slabs from the village level to urban areas, where trader-brokers are expecting the slabs to be forwarded directly to crumb-rubber factories.  Changes in world price, hence the profits being accumulated by traders and rubber factories, are not transmitted properly to rubber farmers and/or sharetappers. Information asymmetry, the access over price information, and immediate response of rubber growers to the change in world price could explain this non-cointegration in price data between growers and exporters.  In the near future, the policy reforms in supply chain of natural rubber marketing in Indonesia should carefully address these issues in a more comprehensive manner.  Finally, in order to contribute to the positive environmental and social benefits, the major challenge for natural rubber

  3. 75 FR 38119 - Polychloroprene Rubber From Japan

    Science.gov (United States)

    2010-07-01

    ... Rubber From Japan AGENCY: United States International Trade Commission. ACTION: Institution of a five-year review concerning the antidumping duty finding on polychloroprene rubber from Japan. SUMMARY: The... on polychloroprene rubber from Japan would be likely to lead to continuation or recurrence of...

  4. Zinc Leaching from Tire Crumb Rubber

    Science.gov (United States)

    Rhodes, E. P.; Ren, J.; Mays, D. C.

    2010-12-01

    Recent estimates indicate that more than 2 billion scrap tires are currently stockpiled in the United States and approximately 280 million more tires are added annually. Various engineering applications utilize recycled tires in the form of shredded tire crumb rubber. However, the use of tire crumb rubber may have negative environmental impacts, especially when the rubber comes into contact with water. A review of the literature indicates that leaching of zinc from tire crumb rubber is the most significant water quality concern associated with using this material. Zinc is generally used in tire manufacturing, representing approximately 1.3% of the final product by mass. This study will report results from the U.S. Environmental Protection Agency’s (EPA’s) Synthetic Precipitation Leaching Procedure, batch leaching tests, and column leaching tests performed to quantify the process by which zinc leaches from tire crumb rubber into water. Results are interpreted with a first-order kinetic attachment/detachment model, implemented with the U.S. Agricultural Research Service software HYDRUS-1D, in order to determine the circumstances when zinc leaching from tire crumb rubber would be expected to comply with the applicable discharge limits. One potential application for recycled tires is replacing sand with tire crumb rubber in granular media filters used for stormwater pollution control. For this to be a viable application, the total zinc in the stormwater discharge must be below the EPA’s benchmark value of 0.117 mg/L.

  5. 27 CFR 21.125 - Rubber hydrocarbon solvent.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Rubber hydrocarbon solvent. 21.125 Section 21.125 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU....125 Rubber hydrocarbon solvent. (a) Rubber hydrocarbon solvent is a petroleum derivative. (b...

  6. Synthesis of a pH- and Thermo- Responsive Binary Copolymer Poly(N-vinylimidazole-co-N-vinylcaprolactam Grafted onto Silicone Films

    Directory of Open Access Journals (Sweden)

    Ángela Obando-Mora

    2015-10-01

    Full Text Available This work focuses on the effects of gamma-ray irradiation conditions on the stimuli-responsiveness of silicone rubber (SR substrates grafted with N-vinylcaprolactam (NVCL and N-vinylimidazole (NVIM, modified by the simultaneously polymerization and grafting method, which is expected to result in valuable new applications in the near future. The modification of silicone rubber was carried out via γ-ray radiation in order to graft a binary copolymer, poly(N-vinylimidazole-co-N-vinylcaprolactam, by the pre-irradiation method, to obtain pH- and thermo-responsive materials. The grafting yield was found to be directly proportional to the dose and monomers concentration. The biomaterials were characterized by using Fourier-transform infrared attenuated total reflection (FTIR-ATR, differential scanning calorimetry (DSC, thermogravimetric analysis (TGA, and swelling; and their stimuli behavior was evaluated by lower critical solution temperature (LCST and pH critical studies.

  7. Application of gamma irradiation for incorporation of rubber powder in the formulations EPDM and NBR rubber

    International Nuclear Information System (INIS)

    Kiyan, Ludmila de Ysasa Pozzo

    2014-01-01

    The natural decomposition of rubber is a very slow process due to its three-dimensional network formed by vulcanized crosslinked structures becoming extremely difficult to reprocess this material. The present work aims to study the application of gamma irradiation as devulcanization process for material reuse/recycling. The interactions of elastomers with ionizing radiation of a gamma source were investigated and the changes in physicochemical properties of the materials were evaluated. Formulations of NBR (acrylonitrile - butadiene) and EPDM (ethylene - propylene - diene terpolymer) from the rubber industry were crosslinked by conventional sulfur-based mixing. Master - batch was processed with rubber powder (industrial waste) and virgin rubber. The raw material (master batch) was irradiated in 60 Co source at doses of 50, 100, 150 kGy and dose rate of 5 kGy h -1 at room temperature. The irradiated material was incorporated in classical sulfur-based formulations. The formulations were characterized by: infrared spectroscopy (FTIR), thermal analysis (TG and DTG), tensile strength, elongation at break, hardness, abrasion resistance, rheometry and swelling. The results showed a predominance of chain scission at a dose of 50 kGy for EPDM rubber. For nitrile predominance of chain scission was observed at a dose of 100 kGy. These results show the possibility of the use of gamma radiation for the reuse/recycling of EPDM and nitrile rubbers. (author)

  8. Recycling of rubber tires in electric arc furnace steelmaking: simultaneous combustion of metallurgical coke and rubber tyres blends

    Energy Technology Data Exchange (ETDEWEB)

    Magdalena Zaharia; Veena Sahajwalla; Byong-Chul Kim; Rita Khanna; N. Saha-Chaudhury; Paul O' Kane; Jonathan Dicker; Catherine Skidmore; David Knights [University of New South Wales, Sydney, NSW (Australia). School of Materials Science and Engineering

    2009-05-15

    The present study investigates the effect of addition of waste rubber tires on the combustion behavior of its blends with coke for carbon injection in electric arc furnace steelmaking. Waste rubber tires were mixed in different proportions with metallurgical coke (MC) (10:90, 20:80, 30:70) for combustion and pyrolysis at 1473 K in a drop tube furnace (DTF) and thermogravimetric analyzer (TGA), respectively. Under experimental conditions most of the rubber blends indicated higher combustion efficiencies compared to those of the constituent coke. In the early stage of combustion the weight loss rate of the blends is much faster compared to that of the raw coke due to the higher volatile yield of rubber. The presence of rubber in the blends may have had an impact upon the structure during the release and combustion of their high volatile matter (VM) and hence increased char burnout. Measurements of micropore surface area and bulk density of the chars collected after combustion support the higher combustion efficiency of the blends in comparison to coke alone. The surface morphology of the 30% rubber blend revealed pores in the residual char that might be attributed to volatile evolution during high temperature reaction in oxygen atmosphere. Physical properties and VM appear to have a major effect upon the measured combustion efficiency of rubber blends. The study demonstrates that waste rubber tires can be successfully co-injected with metallurgical coke in electric arc furnace steelmaking process to provide additional energy from combustion. 44 refs., 11 figs., 2 tabs.

  9. Natural rubber/nitrile butadiene rubber/hindered phenol composites with high-damping properties

    Directory of Open Access Journals (Sweden)

    Xiuying Zhao

    2015-10-01

    Full Text Available New natural rubber (NR/nitrile butadiene rubber (NBR/hindered phenol (AO-80 composites with high-damping properties were prepared in this study. The morphological, structural, and mechanical properties were characterized by atomic force microscopy (AFM, polarized Fourier transform infrared spectrometer (FTIR, dynamic mechanical thermal analyzer (DMTA, and a tensile tester. Each composite consisted of two phases: the NR phase and the NBR/AO-80 phase. There was partial compatibility between the NR phase and the NBR/AO-80 phase, and the NR/NBR/AO-80 (50/50/20 composite exhibited a co-continuous morphology. Strain-induced crystallization occurred in the NR phase at strains higher than 200%, and strain-induced orientation appeared in the NBR/AO-80 phase with the increase of strain from 100% to 500%. The composites had a special stress–strain behavior and mechanical properties because of the simultaneous strain-induced orientation and strain-induced crystallization. In the working temperature range of a seismic isolation bearing, the composites (especially the NR/NBR/AO-80 (50/50/20 composite presented a high loss factor, high area of loss peak (TA, and high hysteresis energy. Therefore, the NR/NBR/AO-80 rubber composites are expected to have important application as a high-performance damping material for rubber bearing.

  10. Low cost silicon solar array project large area silicon sheet task: Silicon web process development

    Science.gov (United States)

    Duncan, C. S.; Seidensticker, R. G.; Mchugh, J. P.; Blais, P. D.; Davis, J. R., Jr.

    1977-01-01

    Growth configurations were developed which produced crystals having low residual stress levels. The properties of a 106 mm diameter round crucible were evaluated and it was found that this design had greatly enhanced temperature fluctuations arising from convection in the melt. Thermal modeling efforts were directed to developing finite element models of the 106 mm round crucible and an elongated susceptor/crucible configuration. Also, the thermal model for the heat loss modes from the dendritic web was examined for guidance in reducing the thermal stress in the web. An economic analysis was prepared to evaluate the silicon web process in relation to price goals.

  11. Lignocellulosic fiber reinforced rubber composites

    CSIR Research Space (South Africa)

    Jacob John, Maya

    2009-04-01

    Full Text Available Natural Rubber (NR) is a naturally occurring elastomeric polymer of isoprene (2-methyl-1,3-butadiene). It can be extracted from latex of only one kind of tree, the Hevea braziliensis. Hevea rubber is produced in many tropical regions of Southeast...

  12. Development of advanced methods for continuous Czochralski growth. Silicon sheet growth development for the large area silicon sheet task of the low cost silicon solar array project

    Science.gov (United States)

    Wolfson, R. G.; Sibley, C. B.

    1978-01-01

    The three components required to modify the furnace for batch and continuous recharging with granular silicon were designed. The feasibility of extended growth cycles up to 40 hours long was demonstrated by a recharge simulation experiment; a 6 inch diameter crystal was pulled from a 20 kg charge, remelted, and pulled again for a total of four growth cycles, 59-1/8 inch of body length, and approximately 65 kg of calculated mass.

  13. A study on creep properties of laminated rubber bearings. Pt. 1. Creep properties and numerical simulations of thick rubber bearings

    International Nuclear Information System (INIS)

    Matsuda, Akihiro; Yabana, Shuichi

    2000-01-01

    In this report, to evaluate creep properties and effects of creep deformation on mechanical properties of thick rubber bearings for three-dimensional isolation system, we show results of compression creep test for rubber bearings of various rubber materials and shapes and development of numerical simulation method. Creep properties of thick rubber bearings were obtained from compression creep tests. The creep strain shows steady creep that have logarithmic relationships between strain and time and accelerated creep that have linear relationships. We make numerical model of a rubber material with nonlinear viscoelastic constitutional equations. Mechanical properties after creep loading test are simulated with enough accuracy. (author)

  14. Treatment of wastewater from rubber industry in Malaysia ...

    African Journals Online (AJOL)

    Treatment of wastewater from rubber industry in Malaysia. ... Discharge of untreated rubber effluent to waterways resulted in water pollution that affected the human health. ... Key words: Rubber industry, effluent, waste management, Malaysia.

  15. Presence of Polycyclic Aromatic Hydrocarbons in Rubber Packaging Materials and in Parenteral Formulations Stored in Bottles With Rubber Stoppers.

    Science.gov (United States)

    Bohrer, Denise; Viana, Carine; Barichello, Marcia M; de Moura, Juliane F; de Carvalho, Leandro M; Nascimento, Paulo C

    2017-08-01

    Rubber closures are the primary packaging material for sterile preparations intended for repeated use. Important features of rubber closures are achieved after additives are added to the elastomeric material that compounds the rubber. Among these additives is carbon black. Because of its origin, carbon black may contain polycyclic aromatic hydrocarbons (PAHs). The U.S. Environmental Protection Agency has identified 16 priority PAHs on the basis of concerns that they cause or might cause cancer in animals and humans. Regulatory agencies impose carbon black purity specifications based on limits for total PAHs (0.5 mg/kg) and benzo[a]pyrene (5 μg/kg) or benzo[a]pyrene only (250 μg/kg). PAHs in rubber packaging used for pharmaceutical formulations and in parenteral products stored in containers with rubber stoppers were investigated. To this end, the method proposed by the National Institute for Occupational Safety and Health-based on high-performance liquid chromatography with ultraviolet and fluorescence detection-was adapted to determine the levels of PAHs in rubber stoppers (gray and red) and in lipid emulsions and amino acid solutions stored in bottles with rubber stoppers. The rubber materials were shown to contain 12 PAHs, in concentrations ranging from 0.25-3.31 µg/g. Only 1 of 18 samples (11 amino acid solutions and 7 lipid emulsions) was uncontaminated. The most prevalent contaminants were pyrene, benzo[a]pyrene, and fluoranthene. The total PAH concentrations in the samples ranged from 0.11-5.96 µg/mL. Components of parenteral nutrition may be contaminated with PAHs, and rubber stoppers represent a potential source of these contaminants.

  16. Psychomotor Effects of Mixed Organic Solvents on Rubber Workers

    Directory of Open Access Journals (Sweden)

    O Aminian

    2014-04-01

    Full Text Available Background: Exposure to organic solvents is common among workers. Objective: To assess neurobehavioral effects of long-term exposure to organic solvents among rubber workers in Tehran, Iran. Methods: Across-sectional study was conducted on 223 employees of a rubber industry. The participants completed a data collection sheet on their occupational and medical history, and demographic characteristics including age, work experience, education level; they performed 6 psychiatric tests on the neurobehavioral core test battery (NCTB that measure simple reaction time, short-term memory (digit span, Benton, eye-hand coordination (Purdue pegboard, pursuit aiming, and perceptual speed (digit symbol. Results: Workers exposed and not exposed to organic solvents had similar age and education distribution. The mean work experience of the exposed and non-exposed workers was 5.9 and 4.4 years, respectively. The exposed workers had a lower performance compared to non-exposed workers in all psychomotor tests. After controlling for the confounders by logistic regression analysis, it was found that exposure to organic solvents had a significant effect on the results of digit symbols, digit span, Benton, aiming, and simple reaction time tests. No significant effect was observed in pegboard test. Conclusion: Occupational exposure to organic solvent can induce subtle neurobehavioral changes among workers exposed to organic solvents; therefore, periodical evaluation of the central nervous system by objective psychomotor tests is recommended among those who are chronically exposed to organic solvents.

  17. Rubber friction: role of the flash temperature

    International Nuclear Information System (INIS)

    Persson, B N J

    2006-01-01

    When a rubber block is sliding on a hard rough substrate, the substrate asperities will exert time-dependent deformations of the rubber surface resulting in viscoelastic energy dissipation in the rubber, which gives a contribution to the sliding friction. Most surfaces of solids have roughness on many different length scales, and when calculating the friction force it is necessary to include the viscoelastic deformations on all length scales. The energy dissipation will result in local heating of the rubber. Since the viscoelastic properties of rubber-like materials are extremely strongly temperature dependent, it is necessary to include the local temperature increase in the analysis. At very low sliding velocity the temperature increase is negligible because of heat diffusion, but already for velocities of order 10 -2 m s -1 the local heating may be very important. Here I study the influence of the local heating on the rubber friction, and I show that in a typical case the temperature increase results in a decrease in rubber friction with increasing sliding velocity for v>0.01 m s -1 . This may result in stick-slip instabilities, and is of crucial importance in many practical applications, e.g. for tyre-road friction and in particular for ABS braking systems

  18. Cryogenic Deflashing for Rubber Products

    Directory of Open Access Journals (Sweden)

    Abhilash M.

    2018-01-01

    Full Text Available Deflashing is the process of removal of excess flashes from the rubber products. Initially deflashing was a manual operation where dozen of workers, seated at small work stations would take each part and trim the excess rubber off with scissors, knives or by grinding. Still the same method is employed in most of the rubber industry. The drawbacks of this method are demand inconsistent and repeatable quality. Work done by hand is often inconsistent. There are commercially available cryogenic deflashing machine but they are too expensive hence cost effectiveness is also a prime factor. The objective of this paper is to develop a technique, to identify the media through which the flashes can be removed easily and effectively. Based on the test results obtained from testing of five different types of media, ABCUT Steel media gave best results. The testing of the ABCUT Steel media on rubber samples like O-rings, grommet tail door, bottom bush etc. shows good results.

  19. Characterization of crumb rubber modified by gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Faldini, Sonia B.; Terence, Mauro C.; Miranda, Leila F.; Munhoz, Antonio H.; Domingues, Leandro S.; Coghetto, Gregory, E-mail: sfaldini@yahoo.com.br, E-mail: mauroterence@yahoo.com.br [Universidade Presbiteriana Mackenzie (UPM), Sao Paulo, SP (Brazil). Escola de Engenharia. Engenharia de Materiais

    2013-07-01

    The use of crumb rubber from scrap tires has become a common practice in the construction of roads, leading to improved properties of the asphalt and decreasing the environmental pollution. In this study, crumb rubber was modified by gamma radiation to eventually incorporate it into the asphalt and verify potential improvements of their properties. The crumb rubber modified by gamma radiation in the dose 500 kGy and 1000kGy was characterized by thermal analysis, infrared spectroscopy and scanning electron microscopy. The dose of radiation used has no effect on degradation temperatures. It is observed that the IV spectra of untreated rubbers and rubbers irradiated have substantially the same profile. The results indicate that despite small morphological changes in the irradiated rubber, they do not influence its degradation temperature and composition. (author)

  20. Characterization of crumb rubber modified by gamma radiation

    International Nuclear Information System (INIS)

    Faldini, Sonia B.; Terence, Mauro C.; Miranda, Leila F.; Munhoz, Antonio H.; Domingues, Leandro S.; Coghetto, Gregory

    2013-01-01

    The use of crumb rubber from scrap tires has become a common practice in the construction of roads, leading to improved properties of the asphalt and decreasing the environmental pollution. In this study, crumb rubber was modified by gamma radiation to eventually incorporate it into the asphalt and verify potential improvements of their properties. The crumb rubber modified by gamma radiation in the dose 500 kGy and 1000kGy was characterized by thermal analysis, infrared spectroscopy and scanning electron microscopy. The dose of radiation used has no effect on degradation temperatures. It is observed that the IV spectra of untreated rubbers and rubbers irradiated have substantially the same profile. The results indicate that despite small morphological changes in the irradiated rubber, they do not influence its degradation temperature and composition. (author)

  1. Silane grafted natural rubber and its compatibilization effect on silica-reinforced rubber tire compounds

    NARCIS (Netherlands)

    Sengloyluan, K.; Sahakaro, K.; Dierkes, W. K.; Noordermeer, J. W.M.

    2017-01-01

    Natural Rubber (NR) grafted with 3-octanoylthio-1-propyltriethoxysilane (NXT) was prepared by melt mixing using 1,1′-di(tert-butylperoxy)-3,3,5-trimethylcyclohexane as initiator at 140 °C with NXT contents of 10 and 20 parts per hundred rubber [phr] and initiator 0.1 phr. The silane grafted on NR

  2. Alternative sources of natural rubber

    NARCIS (Netherlands)

    Mooibroek, H.; Cornish, K.

    2000-01-01

    Rubber (cis-1,4-polyisoprene) is one of the most important polymers naturally produced by plants because it is a strategic raw material used in more than 40,000 products, including more than 400 medical devices. The sole commercial source, at present, is natural rubber harvested from the Brazilian

  3. Geotechnical Properties of Rubber Tires and Sediments Mixtures

    Directory of Open Access Journals (Sweden)

    H. Sellaf

    2014-04-01

    Full Text Available An experimental work was undertaken to study the effect of rubber tires on the geotechnical properties of a dredged sediment, using a mixing ratio of large size. For comparison, two types of soil were studied (dredged sediment from Fergoug dam and Tizi Tuff from the north west of Algeria. Taking into account the high compressibility and the low water absorption of the rubber tires, grain size analysis, density, Atterberg limits analysis, chemical composition, direct shear tests, loading-unloading tests, modified Proctor and CBR tests are performed on the two soils and their mixtures with different scrap tire rubber (10, 20, 25 and 50%. The results show that liquid limits and plastic indexes decrease with the scrap tire rubber content and that the decrease is more significant for soil with high plasticity. Cohesion also decreases with scrap tire rubber content when the internal friction angle is vacillating. Compression and recompression indexes increase gradually with the scrap tire rubber content and the variation for compression index is more significant for the two soils. Compaction characteristics and CBR values decrease with scrap tire rubber content. The CBR values for W=3% are important compared to those with W=5% excepted for mixture with (75% tuff and 25% scrap tire rubber. The results show that the scrap tire rubber can be used as a reinforcement material for dredged soil, but with a content that should not highly affect the compressibility.

  4. Crack Velocities in Natural Rubber.

    Science.gov (United States)

    1982-05-01

    vulcanized natural rubber (3). The surprisingly low value for natural rubber was attributed to highly anisotropic elastic behavior at high strains...Dr. R.L. Rabie Hercules Incorporated WX-2, MS-952 Alleghany Ballistic Lab Los Alamos National Lab. P.O. Box 210 P.O. Box 1663 Washington, D.C. 21502

  5. Practical application of thermoreversibly Cross-linked rubber products

    Science.gov (United States)

    Polgar, L. M.; Picchioni, F.; de Ruiter, E.; van Duin, M.

    2017-07-01

    Currently, rubber products cannot simply be reprocessed after their product life, due to the irreversible cross-linking methods traditionally applied. The purpose of this work is to investigate how thermoreversible cross-linking of rubbers via Diels Alder chemistry can be used for the development of recyclable rubber products. Unfortunately, the applicability of the thermoreversible EPM-g-furan/BM system appears to be limited to room temperature applications, because of the rapid deterioration of the compression set at elevated temperatures compared to irreversibly cross-linked EPM. However, the use of EPM rubber modified with thiophene or cyclopentadiene moieties may extend the temperature application range and results in rubber products with acceptable properties. Finally, rubber products generally comprise fillers such as silica, carbon black or fibers. In this context, the reinforcing effect of short cut aramid fibers on the material properties of the newly developed thermoreversibly cross-linked EPM rubbers was also studied. The material properties of the resulting products were found to be comparable to those of a fiber reinforced, peroxide cured reference sample.

  6. Characterization of an amorphous silicon flat panel for controlling the positioning accuracy of sheet; Caracterizacion de un panel plano de silicio amorfo para control de la exactitud en el posicionamiento de laminas

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, J.; Gonzalez, V.; Gimeno, J.; Dolores, V. de los; Pastor, V.; Crispin, V.; Guardino, C.

    2011-07-01

    It has established a method for measuring the position of the blades in a multi leaf collimator (MLC) used to measure dose portal imaging device (EPID) of amorphous silicon, and verified its accuracy using radiochromic films and measures water with diode Cuba, techniques perfectly well validated in our institution. This dose profiles are studied for each sheet and determine their position at the point which has 50% of the dose in the open field.

  7. Biodiesel production methods of rubber seed oil: a review

    Science.gov (United States)

    Ulfah, M.; Mulyazmi; Burmawi; Praputri, E.; Sundari, E.; Firdaus

    2018-03-01

    The utilization of rubber seed as raw material of biodiesel production is seen highly potential in Indonesia. The availability of rubber seeds in Indonesia is estimated about 5 million tons per annum, which can yield rubber seed oil about 2 million tons per year. Due to the demand of edible oils as a food source is tremendous and the edible oil feedstock costs are far expensive to be used as fuel, production of biodiesel from non-edible oils such as rubber seed is an effective way to overcome all the associated problems with edible oils. Various methods for producing biodiesel from rubber seed oil have been reported. This paper introduces an optimum condition of biodiesel production methods from rubber seed oil. This article was written to be a reference in the selection of methods and the further development of biodiesel production from rubber seed oil. Biodiesel production methods for rubber seed oils has been developed by means of homogeneous catalysts, heterogeneous catalysts, supercritical method, ultrasound, in-situ and enzymatic processes. Production of biodiesel from rubber seed oil using clinker loaded sodium methoxide as catalyst is very interesting to be studied and developed further.

  8. Synergistic effect of plasma-modified halloysite nanotubes and carbon black in natural rubber-butadiene rubber blend

    NARCIS (Netherlands)

    Poikelispaa, Minna; Das, Amit; Dierkes, Wilma K.; Vuorinen, Jyrki

    2013-01-01

    Halloysite nanotubes (HNTs) were investigated concerning their suitability for rubber reinforcement. As they have geometrical similarity with carbon nanotubes, they were expected to impart a significant reinforcement effect on the rubber compounds but the dispersion of the nanofillers is difficult.

  9. Butterfly valve of all rubber lining type

    International Nuclear Information System (INIS)

    Shimada, Shosaku; Nakatsuma, Sumiya; Sasaki, Iwao; Aoki, Naoshi.

    1982-01-01

    The valves used for the circulating water pipes for condensers in nuclear and thermal power stations have become large with the increase of power output, and their specifications have become strict. The materials for the valves change from cast iron to steel plate construction. To cope with sea water corrosion, rubber lining has been applied to the internal surfaces of valve boxes, and the build-up welding of stainless steel has been made on the edges of valves. However, recently it is desired to develop butterfly valves, of which the whole valve disks are lined with hard rubber. For the purpose of confirming the performance of large bore valves, a 2600 mm bore butterfly valve of all rubber lining type was used, and the opening and closing test of 1100 times was carried out by applying thermal cycle and pressure difference and using artifical sea water. Also the bending test of hard rubber lining was performed with test pieces. Thus, it was confirmed that the butterfly valves of all rubber lining type have the performance exceeding that of the valves with build-up welding. The course of development of the valves of all rubber lining type, the construction and the items of confirmation by tests of these valves, and the tests of the valve and the hard rubber lining described above are reported. (Kako, I.)

  10. RoxB Is a Novel Type of Rubber Oxygenase That Combines Properties of Rubber Oxygenase RoxA and Latex Clearing Protein (Lcp).

    Science.gov (United States)

    Birke, Jakob; Röther, Wolf; Jendrossek, Dieter

    2017-07-15

    Only two types of rubber oxygenases, rubber oxygenase (RoxA) and latex clearing protein (Lcp), have been described so far. RoxA proteins (RoxAs) are c -type cytochromes of ≈70 kDa produced by Gram-negative rubber-degrading bacteria, and they cleave polyisoprene into 12-oxo-4,8-dimethyltrideca-4,8-diene-1-al (ODTD), a C 15 oligo-isoprenoid, as the major end product. Lcps are common among Gram-positive rubber degraders and do not share amino acid sequence similarities with RoxAs. Furthermore, Lcps have much smaller molecular masses (≈40 kDa), are b -type cytochromes, and cleave polyisoprene to a mixture of C 20 , C 25 , C 30 , and higher oligo-isoprenoids as end products. In this article, we purified a new type of rubber oxygenase, RoxB Xsp (RoxB of Xanthomonas sp. strain 35Y). RoxB Xsp is distantly related to RoxAs and resembles RoxAs with respect to molecular mass (70.3 kDa for mature protein) and cofactor content (2 c -type hemes). However, RoxB Xsp differs from all currently known RoxAs in having a distinctive product spectrum of C 20 , C 25 , C 30 , and higher oligo-isoprenoids that has been observed only for Lcps so far. Purified RoxB Xsp revealed the highest specific activity of 4.5 U/mg (at 23°C) of all currently known rubber oxygenases and exerts a synergistic effect on the efficiency of polyisoprene cleavage by RoxA Xsp RoxB homologs were identified in several other Gram-negative rubber-degrading species, pointing to a prominent function of RoxB for the biodegradation of rubber in Gram-negative bacteria. IMPORTANCE The enzymatic cleavage of rubber (polyisoprene) is of high environmental importance given that enormous amounts of rubber waste materials are permanently released (e.g., by abrasion of tires). Research from the last decade has discovered rubber oxygenase A, RoxA, and latex clearing protein (Lcp) as being responsible for the primary enzymatic attack on the hydrophobic and water-insoluble biopolymer poly( cis -1,4-isoprene) in Gram

  11. Greenhouse Gas Emissions from Rubber Industry in Thailand

    NARCIS (Netherlands)

    Jawjit, W.; Kroeze, C.; Rattanapan, S.

    2010-01-01

    Rubber production has been taking place in Thailand for many decades. Thailand is currently the world's largest natural rubber producer. We present emissions of greenhouse gases associated with the production of fresh latex, and three primary rubber products, including concentrated latex, block

  12. Minority carrier diffusion lengths and absorption coefficients in silicon sheet material

    Science.gov (United States)

    Dumas, K. A.; Swimm, R. T.

    1980-01-01

    Most of the methods which have been developed for the measurement of the minority carrier diffusion length of silicon wafers require that the material have either a Schottky or an ohmic contact. The surface photovoltage (SPV) technique is an exception. The SPV technique could, therefore, become a valuable diagnostic tool in connection with current efforts to develop low-cost processes for the production of solar cells. The technique depends on a knowledge of the optical absorption coefficient. The considered investigation is concerned with a reevaluation of the absorption coefficient as a function of silicon processing. A comparison of absorption coefficient values showed these values to be relatively consistent from sample to sample, and independent of the sample growth method.

  13. LSA Large Area Silicon Sheet Task. Continuous Liquid Feed Czochralski Growth. [for solar cell fabrication

    Science.gov (United States)

    Fiegl, G.

    1979-01-01

    The design and development of equipment and processes to demonstrate continuous growth of crystals by the Czochralski method suitable for producing single silicon crystals for use in solar cells is presented. The growth of at least 150 kg of mono silicon crystal, 150 mm in diameter is continuous from one growth container. A furnace with continuous liquid replenishment of the growth crucible, accomplished by a meltdown system with a continuous solid silicon feed mechanism and a liquid transfer system, with associated automatic feedback controls is discussed. Due to the silicon monoxide build up in the furnace and its retarding effect on crystal growth the furnace conversion for operation in the low pressure range is described. Development of systems for continuous solid recharging of the meltdown chamber for various forms of poly silicon is described.

  14. Development of rubber material for high radiation field

    International Nuclear Information System (INIS)

    Nakatsukasa, Sadayoshi; Tabasaki, Takeshi; Yoshida, Akihiro; Kadowaki, Yoshito

    2013-01-01

    Generally flexible polymeric materials exposed to radiation can't be used because they soften or harden remarkably in high radiation environment. Aromatic polymers such as PEEK, PI, and PES are also known as radiation-proof polymeric materials. Aromatic polymers are very hard, they can't be used for products like a packing where flexibility is required. We developed a new vulcanized rubber compound by the use of various additives and polymer blend. This developed rubber compound has a high radiation-proof performance by reaction balance of cross-linking and decomposition in this rubber. This rubber compound has a rubber elasticity even if exposed to radiation of MGy level, and its radiation proof is more than 5 times as high as conventional polymeric materials. This rubber compound is much more flexible than the aromatic polymers which are the used as conventional radiation-proof polymers. (author)

  15. Optimization of oxidation processes to improve crystalline silicon solar cell emitters

    Directory of Open Access Journals (Sweden)

    L. Shen

    2014-02-01

    Full Text Available Control of the oxidation process is one key issue in producing high-quality emitters for crystalline silicon solar cells. In this paper, the oxidation parameters of pre-oxidation time, oxygen concentration during pre-oxidation and pre-deposition and drive-in time were optimized by using orthogonal experiments. By analyzing experimental measurements of short-circuit current, open circuit voltage, series resistance and solar cell efficiency in solar cells with different sheet resistances which were produced by using different diffusion processes, we inferred that an emitter with a sheet resistance of approximately 70 Ω/□ performed best under the existing standard solar cell process. Further investigations were conducted on emitters with sheet resistances of approximately 70 Ω/□ that were obtained from different preparation processes. The results indicate that emitters with surface phosphorus concentrations between 4.96 × 1020 cm−3 and 7.78 × 1020 cm−3 and with junction depths between 0.46 μm and 0.55 μm possessed the best quality. With no extra processing, the final preparation of the crystalline silicon solar cell efficiency can reach 18.41%, which is an increase of 0.4%abs compared to conventional emitters with 50 Ω/□ sheet resistance.

  16. Crumb Rubber Recycling in Enhancing Damping Properties of Concrete

    Science.gov (United States)

    Sugapriya, P.; Ramkrishnan, R.

    2018-02-01

    Damping plays a major role in the design of roadside structures that gets affected due to vibrations transmitted from moving traffic. In this study, fine aggregates were partially replaced with crumb rubber in concrete, at varying percentages of 5, 10, 15 and 20% by weight. Three different sets of concrete, mixed with crumb rubber were prepared using raw rubber, treated rubber and treated rubber with partial replacement of cement. Cement was partially replaced with Ultra-Fine Ground Granulated Blast furnace Slag (UFGGBS) for this study. Samples were cast, cured and tested for various properties on the 7th and 28th day. The damping ratio and frequency of the peak value from a number of waves in rubber incorporated beams were found out using a FFT Analyser along with its Strength, Damping and Sorptivity characteristics. SEM analysis was conducted to analyse the micro structural bonding between rubber and concrete. The mode shapes of pavement slabs were modelled and analysed using a FEM tool, ANSYS. From the results, the behaviour of the three sets of rubberized concrete were compared and analysed, and an optimum percentage for crumb rubber and UFGGBS was proposed to achieve best possible damping without compromising the strength properties.

  17. Effect of air on speed of insulating material deterioration under simulated LOCA environment. [Gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Kusama, Yasuo; Yagi, Toshiaki; Ito, Masayuki; Okada, Sohei; Yoshikawa, Masato (Japan Atomic Energy Research Inst., Takasaki, Gunma. Takasaki Radiation Chemistry Research Establishment)

    1982-12-01

    To examine the quality approval testing method for the electric cables used for nuclear reactors, various covering insulating materials employed for the cables have been investigated from all angles. The factors which are considered to affect the deterioration of cable materials in a simulated LOCA (loss of coolant accident) environmental test are numerous. This paper reports on the result of investigation on the effect of air on the rate of deterioration of various organic materials usually used as the insulating and covering materials for the cables. Five kinds of polymer sheets (1 mm thick) used for reactor cables were employed as samples. The samples of both standard compounding ratio and the compounding ratio for practical reactor use were tested. As the deterioration prior to LOCA simulation, the thermal deterioration corresponding to 40 years aging (at 121 deg C for 7 days) was given, and subsequently, 50 Mrad gamma -irradiation at 1 Mrad/h was performed in the air. After that, the samples were subject to LOCA simulated environment. Since the results were different according to the kinds of samples, those are described separately for Hypalon, ethylene propylene rubber, cross-linked polyethylene, chloroprene and silicone rubber. The existence of air under LOCA environment accelerated the deterioration of insulation materials except silicone rubber, though its influence differed to the polymers. These materials swelled in the presence of air, and the degree of swelling increased with the temperature, having the close relation to oxidation deterioration. Polyethylene was more susceptible to the effect of air, and silicone rubber was rather stable. The samples of fire-retardant compounding ratio more swelled by water absorption than those of standard compounding ratio.

  18. Cream concentrated latex for foam rubber products

    Science.gov (United States)

    Suksup, R.; Imkaew, C.; Smitthipong, W.

    2017-12-01

    Fresh natural latex (around 40% rubber and 60% water) can be transformed to concentrated natural latex (around 60% rubber and 40% water) in order to realise economical transportation and easier latex product’s preparation. The concentrated natural latex is an extremely valuable material. It can be applied for many types of products, for example, foam rubber as pillow and mattress, elastic band, etc. Industrially, the concentrated natural latex can be prepared by centrifugation which requires an enormous expensive machine. From the eco-friendly products point of view, most of rubber entrepreneurs in the world try to develop a green rubber product. So, the main objective of this study is to prepare the cream concentrated latex without any sophisticated machine. Thus, we work on a simple, cheap and green method that does not use any expensive machine but uses water-based chemical as sodium alginate to prepare the cream concentrated latex. The optimal amount of sodium alginate in the latex was studied. The main characteristics of the cream concentrated latex were tested by various technics, such as alkalinity, total solid content (TSC), dry rubber content (DRC), etc. We found that there are no significant differences of results between fresh natural latex and cream concentrated latex, except for the TSC and DRC. The TSC and DRC of cream latex are higher than those of fresh natural latex. Finally, we propose a model of natural rubber particle and sodium alginate to form the cream concentrated latex.

  19. Compatibilization efficiency of carboxylated nitrile rubber and epoxy pre-polymer in nitrile/acrylic rubber blends

    Directory of Open Access Journals (Sweden)

    Micheli L. Celestin

    2013-01-01

    Full Text Available An investigation has been made of the effects from a compatibilizer, viz. carboxylated nitrile rubber (XNBR, on several properties of nitrile rubber (NBR and acrylic rubber (ACM blends, including curing characteristics, mechanical, dynamic mechanical and dielectric properties. The presence of XNBR until 10 phr resulted in an improvement of the ultimate tensile properties, especially elongation at break. The mechanical properties associated to the volume fraction of rubber in the network (Vr and torque values suggest the co-vulcanization phenomenon imparted by the compatibilization. The oil resistance of NBR/ACM (50:50 wt. (% blends (compatibilized and non compatibilized was similar to that observed for pure ACM and significantly higher than NBR. The addition of small amounts of epoxy pre-polymer in combination with XNBR resulted in an additional improvement of the tensile properties. The dynamic mechanical and dielectric properties of the blends were also investigated. The loss modulus values of the compatibilized blends were significantly lower indicating an increase of the elastic characteristics. All blends presented two dielectric relaxation peaks confirming the heterogeneity of the compatibilized blends

  20. Proceedings of the Rubber Association of Canada's 7. biennial 2006 rubber recycling symposium : changing concepts

    International Nuclear Information System (INIS)

    2006-01-01

    Rising energy costs and concerns over the environment have contributed to a renewed focus on recycling for many governments and industries. This conference examined recent trends affecting rubber recycling activities as well as the legislative environment and its impacts on future recycling activities. Major rubber recycling markets were reviewed, and emerging product ideas were evaluated. Industry stewardship model and governance models were discussed. The impacts of new advances in tire technology and manufacturing on the rubber recycling industry were also investigated. Issues concerning fixed tipping fees and incentive structures were discussed, and effective management strategies for the recycling of large off-the-road tires were evaluated. Tire-derived fuel (TDF) is the largest market in North America for scrap tires, and TDF may continue to grow as a result of rising fossil fuel costs. Issues and challenges related to the introduction of TDF to new communities were discussed. New developments in tire derived aggregates (TDA) and ground rubber were also reviewed. Twenty-eight presentations were given at this conference, 3 of which were catalogued separately for inclusion in this database. refs., tabs., figs

  1. Evapotranspiration of rubber ( Hevea brasiliensis ) cultivated at two plantation sites in Southeast Asia: RUBBER EVAPOTRANSPIRATION IN SE ASIA

    Energy Technology Data Exchange (ETDEWEB)

    Giambelluca, Thomas W. [Department of Geography, University of Hawai' i at Mānoa, Honolulu Hawai' i USA; Hydrospheric Atmospheric Research Center, Nagoya University, Nagoya Japan; Mudd, Ryan G. [Department of Geography, University of Hawai' i at Mānoa, Honolulu Hawai' i USA; Liu, Wen [Department of Geography, University of Hawai' i at Mānoa, Honolulu Hawai' i USA; Ziegler, Alan D. [Department of Geography, National University of Singapore, Singapore Singapore; Kobayashi, Nakako [Hydrospheric Atmospheric Research Center, Nagoya University, Nagoya Japan; Kumagai, Tomo' omi [Hydrospheric Atmospheric Research Center, Nagoya University, Nagoya Japan; Miyazawa, Yoshiyuki [Department of Geography, University of Hawai' i at Mānoa, Honolulu Hawai' i USA; Research Institute of East Asia Environments, Kyushu University, Fukuoka Japan; Lim, Tiva Khan [Cambodian Rubber Research Institute, Phnom Penh Cambodia; Huang, Maoyi [Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland Washington USA; Fox, Jefferson [East-West Center, Honolulu Hawai' i USA; Yin, Song [Cambodian Rubber Research Institute, Phnom Penh Cambodia; Mak, Sophea Veasna [Cambodian Rubber Research Institute, Phnom Penh Cambodia; Kasemsap, Poonpipope [Department of Horticulture, Kasetsart University, Bangkok Thailand

    2016-02-01

    The expansion of rubber (Hevea brasiliensis) cultivation to higher latitudes and higher elevations in southeast Asia is part of a dramatic shift in the direction of rural land cover change in the region toward more tree covered landscapes. To investigate the possible effects of increasing rubber cultivation in the region on ecosystem services including water cycling, eddy covariance towers were established to measure ecosystem fluxes within two rubber plantations, one each in Bueng Kan, northeastern Thailand, and Kampong Cham, central Cambodia. The results show that evapotranspiration (ET) at both sites is strongly related to variations in available energy and leaf area, and moderately controlled by soil moisture. Measured mean annual ET was 1128 and 1272 mm for the Thailand and Cambodia sites, respectively. After adjustment for energy closure, mean annual was estimated to be 1211 and 1459 mm yr at the Thailand and Cambodia sites, respectively. Based on these estimates and that of another site in Xishuangbanna, southwestern China, it appears that of rubber is higher than that of other tree dominated land covers in the region, including forest. While measurements by others in non rubber tropical ecosystems indicate that at high net radiation sites is at most only slightly higher than for sites with lower net radiation, mean annual rubber increases strongl with increasing net radiation across the three available rubber plantation observation sites. With the continued expansion of tree dominated land covers, including rubber cultivation, in southeast Asia, the possible association between commercially viable, fast growing tree crop species Giambelluca et al. Evapotranspiration of rubber (Havea brasiliensis) cultivated at two sites in southeast Asia and their relatively high water use raises concerns about potential effects on water and food security.

  2. Nylon-6/rubber blends: 6. Notched tensile impact testing of nylon-6(ethylene-propylene rubber) blends

    NARCIS (Netherlands)

    Dijkstra, Krijn; Dijkstra, K.; ter Laak, J.A.; ter Laak, J.; Gaymans, R.J.

    1994-01-01

    The deformation and fracture behaviour of nylon-6/EPR (ethylene-propylene rubber) blends is studied as a function of strain rate and rubber content. Therefore, tensile experiments are conducted on notched specimens over a broad range of draw speeds (including strain rates as encountered in normal

  3. Stimuli-responsive cement-reinforced rubber.

    Science.gov (United States)

    Musso, Simone; Robisson, Agathe; Maheshwar, Sudeep; Ulm, Franz-Josef

    2014-05-14

    In this work, we report the successful development of a cement-rubber reactive composite with reversible mechanical properties. Initially, the composite behaves like rubber containing inert filler, but when exposed to water, it increases in volume and reaches a stiffness that is intermediate between that of hydrogenated nitrile butadiene rubber (HNBR) and hydrated cement, while maintaining a relatively large ductility characteristic of rubber. After drying, the modulus increases even further up to 400 MPa. Wet/drying cycles prove that the elastic modulus can reversibly change between 150 and 400 MPa. Utilizing attenuated total reflection Fourier transform infrared spectroscopy), we demonstrate that the high pH produced by the hydration of cement triggers the hydrolysis of the rubber nitrile groups into carboxylate anions. Thus, the salt bridges, generated between the carboxylate anions of the elastomer and the cations of the filler, are responsible for the reversible variations in volume and elastic modulus of the composite as a consequence of environmental moisture exposure. These results reveal that cement nanoparticles can successfully be used to accomplish a twofold task: (a) achieve an original postpolymerization modification that allows one to work with carboxylate HNBR (HXNBR) not obtained by direct copolymerization of carboxylate monomers with butadiene, and (b) synthesize a stimuli-responsive polymeric composite. This new type of material, having an ideal behavior for sealing application, could be used as an alternative to cement for oil field zonal isolation applications.

  4. Microbial detoxification of waste rubber material by wood-rotting fungi.

    Science.gov (United States)

    Bredberg, Katarina; Andersson, B Erik; Landfors, Eva; Holst, Olle

    2002-07-01

    The extensive use of rubber products, mainly tires, and the difficulties to recycle those products, has resulted in world wide environmental problems. Microbial devulcanisation is a promising way to increase the recycling of rubber materials. One obstacle is that several microorganisms tested for devulcanisation are sensitive to rubber additives. A way to overcome this might be to detoxify the rubber material with fungi prior to the devulcanisation. In this study, 15 species of white-rot and brown-rot fungi have been screened with regard to their capacity to degrade an aromatic model compound in the presence of ground waste tire rubber. The most effective fungus, Resinicium bicolor, was used for detoxification of rubber material. Increase in growth of the desulfurising bacterium Thiobacillus ferrooxidans in presence of the rubber treated with Resinicium bicolor compared to untreated rubber demonstrated that detoxification with fungi is possible.

  5. Natural rubber producing plants: An overview

    African Journals Online (AJOL)

    User

    2013-03-20

    Mar 20, 2013 ... Currently, Hevea brasiliensis has been only one resource for commercial natural rubber production. ...... ADVANTAGES AND DISADVANTAGES ... polymer chain. Combinations of an amine antioxidant and a zinc dialkyldithiocarbamate have been used to counter these effects, improving guayule rubber ...

  6. Design of Self-Healing Supramolecular Rubbers by Introducing Ionic Cross-Links into Natural Rubber via a Controlled Vulcanization.

    Science.gov (United States)

    Xu, Chuanhui; Cao, Liming; Lin, Baofeng; Liang, Xingquan; Chen, Yukun

    2016-07-13

    Introducing ionic associations is one of the most effective approaches to realize a self-healing behavior for rubbers. However, most of commercial rubbers are nonpolar rubbers without now available functional groups to be converted into ionic groups. In this paper, our strategy was based on a controlled peroxide-induced vulcanization to generate massive ionic cross-links via polymerization of zinc dimethacrylate (ZDMA) in natural rubber (NR) and exploited it as a potential self-healable material. We controlled vulcanization process to retard the formation of covalent cross-link network, and successfully generated a reversible supramolecular network mainly constructed by ionic cross-links. Without the restriction of covalent cross-linkings, the NR chains in ionic supramolecular network had good flexibility and mobility. The nature that the ionic cross-links was easily reconstructed and rearranged facilitating the self-healing behavior, thereby enabling a fully cut sample to rejoin and retain to its original properties after a suitable self-healing process at ambient temperature. This study thus demonstrates a feasible approach to impart an ionic association induced self-healing function to commercial rubbers without ionic functional groups.

  7. [Total analysis of organic rubber additives].

    Science.gov (United States)

    He, Wen-Xuan; Robert, Shanks; You, Ye-Ming

    2010-03-01

    In the present paper, after middle pressure chromatograph separation using both positive phase and reversed-phase conditions, the organic additives in ethylene-propylene rubber were identified by infrared spectrometer. At the same time, by using solid phase extraction column to maintain the main component-fuel oil in organic additves to avoid its interfering with minor compounds, other organic additves were separated and analysed by GC/Ms. In addition, the remaining active compound such as benzoyl peroxide was identified by CC/Ms, through analyzing acetone extract directly. Using the above mentioned techniques, soften agents (fuel oil, plant oil and phthalte), curing agent (benzoylperoxide), vulcanizing accelerators (2-mercaptobenzothiazole, ethyl thiuram and butyl thiuram), and antiagers (2, 6-Di-tert-butyl-4-methyl phenol and styrenated phenol) in ethylene-propylene rubber were identified. Although the technique was established in ethylene-propylene rubber system, it can be used in other rubber system.

  8. Evaluation of three partially volatile neutron shields for high-performance shipping casks

    International Nuclear Information System (INIS)

    Rack, H.J.; Pearson, H.S.

    1981-02-01

    The thermal stability and mechanical behavior of three partially volatile candidate neutron shield materials have been evaluated. The results indicate that silicone based rubbers, impregnated with elemental boron or boron carbide, Boro-silicone 236 and Bisco NS-I respectively are more thermally stable than are borated beechwoods, e.g., Permali JN. Mechanical property measurements indicated however that the compressive strength of the borated beechwood is 10 to 48 times higher than that of the silicone-based rubbers. The compressive strengths of the borated beechwood and boron carbide impregnated silicone rubber were substantially more sensitive to test temperature than was the compressive strength of the boron impregnated silicone rubber. Finally the compressive strengths and energy absorbing capability of the boron impregnated silicone rubber is not affected by prior thermal exposure at 425 0 K for 1000h

  9. Investigation of surface halide modification of nitrile butadiene rubber

    Science.gov (United States)

    Sukhareva, K. V.; Mikhailov, I. A.; Andriasyan, Yu O.; Mastalygina, E. E.; Popov, A. A.

    2017-12-01

    The investigation is devoted to the novel technology of surface halide modification of rubber samples based on nitrile butadiene rubber (NBR). 1,1,2-trifluoro-1,2,2-trichlorethane was used as halide modifier. The developed technology is characterized by production stages reduction to one by means of treating the rubber compound with a halide modifier. The surface halide modification of compounds based on nitrile butadiene rubber (NBR) was determined to result in increase of resistance to thermal oxidation and aggressive media. The conducted research revealed the influence of modification time on chemical resistance and physical-mechanical properties of rubbers under investigation.

  10. Improving rubber concrete by waste organic sulfur compounds.

    Science.gov (United States)

    Chou, Liang-Hisng; Lin, Chun-Nan; Lu, Chun-Ku; Lee, Cheng-Haw; Lee, Maw-Tien

    2010-01-01

    In this study, the use of crumb tyres as additives to concrete was investigated. For some time, researchers have been studying the physical properties of concrete to determine why the inclusion of rubber particles causes the concrete to degrade. Several methods have been developed to improve the bonding between rubber particles and cement hydration products (C-S-H) with the hope of creating a product with an improvement in mechanical strength. In this study, the crumb tyres were treated with waste organic sulfur compounds from a petroleum refining factory in order to modify their surface properties. Organic sulfur compounds with amphiphilic properties can enhance the hydrophilic properties of the rubber and increase the intermolecular interaction forces between rubber and C-S-H. In the present study, a colloid probe of C-S-H was prepared to measure these intermolecular interaction forces by utilizing an atomic force microscope. Experimental results showed that rubber particles treated with waste organic sulfur compounds became more hydrophilic. In addition, the intermolecular interaction forces increased with the adsorption of waste organic sulfur compounds on the surface of the rubber particles. The compressive, tensile and flexural strengths of concrete samples that included rubber particles treated with organic sulfur compound also increased significantly.

  11. Circuit racing, track texture, temperature and rubber friction

    Science.gov (United States)

    Sharp, R. S.; Gruber, P.; Fina, E.

    2016-04-01

    Some general observations relating to tyre shear forces and road surfaces are followed by more specific considerations from circuit racing. The discussion then focuses on the mechanics of rubber friction. The classical experiments of Grosch are outlined and the interpretations that can be put on them are discussed. The interpretations involve rubber viscoelasticity, so that the vibration properties of rubber need to be considered. Adhesion and deformation mechanisms for energy dissipation at the interface between rubber and road and in the rubber itself are highlighted. The enquiry is concentrated on energy loss by deformation or hysteresis subsequently. Persson's deformation theory is outlined and the material properties necessary to apply the theory to Grosch's experiments are discussed. Predictions of the friction coefficient relating to one particular rubber compound and a rough surface are made using the theory and these are compared with the appropriate results from Grosch. Predictions from Persson's theory of the influence of nominal contact pressure on the friction coefficient are also examined. The extent of the agreement between theory and experiment is discussed. It is concluded that there is value in the theory but that it is far from complete. There is considerable scope for further research on the mechanics of rubber friction.

  12. Determination of the Mechanical Properties of Rubber by FT-NIR

    OpenAIRE

    Pornprasit, Rattapol; Pornprasit, Philaiwan; Boonma, Pruet; Natwichai, Juggapong

    2016-01-01

    Mechanical tests, for example, tensile and hardness tests, are usually used to evaluate the properties of rubber materials. In this work, mechanical properties of selected rubber materials, that is, natural rubber (NR), styrene butadiene rubber (SBR), nitrile butadiene rubber (NBR), and ethylene propylene diene monomer (EPDM), were evaluated using a near infrared (NIR) spectroscopy technique. Here, NR/NBR and NR/EPDM blends were first prepared. All of the samples were then scanned using a FT-...

  13. Ultraviolet curing of acrylated liquid natural rubber for surface coating application

    OpenAIRE

    Kannikar Kwanming; Pairote Klinpituksa; Wae-asae Waehamad

    2009-01-01

    Ultraviolet curable acrylated liquid natural rubber was prepared by grafting of photosensitive molecule onto liquid natural rubber for surface coating application. The liquid natural rubber (LNR) was firstly obtained by degradation of natural rubber latex with hydrogen peroxide and cobalt acetylacetonate at 65oC for 72 hrs. The preparation of acrylated natural rubber was carried out by the reaction of acrylic acid and epoxidized liquid natural rubber (ELNR) prior obtained from LNR with formic...

  14. Some Tribological Characterization of “EPDM” Rubber

    Directory of Open Access Journals (Sweden)

    A. Mukhopadhyay

    2014-06-01

    Full Text Available Ethylene Propylene Diene Monomer (EPDM rubber emerges as a dominant elastomer for major engineering applications. The major properties of EPDM are its outstanding heat, ozone and weather resistance ability. It has a good resistance to polar substances and steam condition too. In automobiles EPDM rubber has a common use as seals. This includes door seals, window seals, trunk seals and sometimes hood seals. Frequently these seals are the source of noise due to the movement of the door versus the car body. This is due to friction between the EPDM rubber parts and the mating surfaces. Thus, the contact iteration between the rubber sealing and the indenting object must be known to optimize the performance of rubber sealing. However, it is need less to mention that the behaviour of any viscoelastic material is very difficult to be predicted. In the present work various tribo-characteristics of EPDM rubber of different hardness have been evaluated utilizing the available laboratory test facilities in the Jadavpur University, Kolkata, India. Compression tests have been carried out using ‘Instron’ to determine the flow behaviour of EPDM rubber of different hardness both in dry as well as under different conditions of lubrication. The flow behaviour like load -vs.- elongation curves, true stress -vs.- elongation curves and true stress -vs.- true strain curves have been drawn from the experimental data. Abrasive wear behaviour has been evaluated using a two-body abrasion tester and the pattern abrasion has been appraised through SEM/EDAX study. Experimental results reveal that the hardness of EPDM rubber has significant effect on the flow behaviour and wear characteristics. The hardness, again, depends on the proportion of carbon black (CB content. Thus it can be stated that the flow behaviour can be governed by controlling the CB concentration in the EPDM rubber. Based on the experimental results conclusion has been drawn accordingly. Some of the

  15. Energy usage in the rubber industry

    Energy Technology Data Exchange (ETDEWEB)

    Soederstroem, M.

    1980-01-01

    The rubber industry has several energy-intensive steps, such as mastication of natural rubber, mixing and extrusion, and vulcanization. Opportunities for energy savings would be available with a continuous mixing process, heat recovery from cooling waters, and abandonment of thermal conduction in vulcanization. 6 figures. (DCK)

  16. Reaction sintering of two-dimensional silicon carbide fiber-reinforced silicon carbide composite by sheet stacking method

    International Nuclear Information System (INIS)

    Yoshida, Katsumi; Mukai, Hideki; Imai, Masamitsu; Hashimoto, Kazuaki; Toda, Yoshitomo; Hyuga, Hideki; Kondo, Naoki; Kita, Hideki; Yano, Toyohiko

    2007-01-01

    Two-dimensionally plain woven SiC fiber-reinforced SiC composite has been developed by reaction sintering using a sheet stacking method in order to further increase mechanical and thermal properties of the composite and to obtain flexibility of manufacturing process of 2D woven SiC/SiC composites which can be applied to the fabrication of larger parts. In addition, sinterability and mechanical properties of the composite were investigated. In this study, relative density of the composites was about 90-93% and a dense composite could be obtained by reaction sintering using the sheet stacking method. The bulk density and maximum bending strength of SiC/SiC composite with a C/SiC weight ratio of 0.6 were higher than that of the composite with C/SiC ratios of 0.5 or 0.7. The values were 2.9 g/cm 3 and 200 MPa, respectively. However, the composites obtained in this study fractured in almost brittle manner due to the lower fiber volume fraction

  17. Reinforcing effect of plasma modified halloysite nanotubes in a carbon black filled natural rubber-butadien rubber matrix

    NARCIS (Netherlands)

    Poikelispaa, Minna; Das, Amit; Dierkes, Wilma K.; Vuorinen, Jyrki

    2011-01-01

    Rubber composites are generally produced by the direct incorporation of fillers like carbon black and/or silica into the rubber matrix. The incorporation of different types of nanofillers is the subject of recent research with the aim of preparing composites with special compositions and properties.

  18. The enzymatic synthesis of rubber polymer in Parthenium argentatum Gray

    International Nuclear Information System (INIS)

    Benedict, C.R.; Madhavan, S.; Greenblatt, G.A.; Venkatachalam, K.V.; Foster, M.A.

    1990-01-01

    Washed rubber particles isolated from stem homogenates of Parthenium argentatum Gray by ultracentrifugation and gel filtration on columns of LKB Ultrogel AcA34 contain rubber transferase which catalyzes the polymerization of isopentenyl pyrophosphate into rubber polymer. The polymerization reaction requires Mg 2+ isopentenyl pyrophosphate, and an allylic pyrophosphate. The K m values for Mg 2+ , isopentenyl pyrophosphate, and dimethylallyl pyrophosphate were 5.2 x 10 -4 molar, 8.3 x 10 -5 molar, and 9.6 x 10 -5 molar, respectively. The molecular characteristics of the rubber polymer synthesized from [ 14 C]isopentenyl pyrophosphate were examined by gel permeation chromatography. The peak molecular weight of the radioactive polymer increased from 70,000 in 15 minutes to 750,000 in 3 hours. The weight average molecular weight of the polymer synthesized over a 3 hour period was 1.17 x 10 6 compared to 1.49 x 10 6 for the natural rubber polymer extracted from the rubber particles. Over 90% of the in vitro formation of the rubber polymer was de novo from dimethylallyl pyrophosphate and isopentenyl pyrophosphate. Treatment of the washed rubber particles with 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate solubilized the rubber transferase. The solubilized enzyme(s) catalyzed the polymerization of isopentenyl pyrophosphate into rubber polymer with a peak molecular weight of 1 x 10 5 after 3 hours of incubation with Mg 2+ and dimethylallyl pyrophosphate. The data support the conclusion that the soluble preparation of rubber transferase is capable of catalyzing the formation of a high molecular weight rubber polymer from an allylic pyrophosphate initiator and isopentenyl pyrophosphate monomer

  19. Fabrication of shape memory natural rubber using palmitic acid

    Directory of Open Access Journals (Sweden)

    Jeff Sze-Hua Wee

    2017-10-01

    Full Text Available This paper investigates the practicability of fabricating a shape memory natural rubber with the use of palmitic acid as the swelling agent. Strips of natural rubber samples were swollen in molten palmitic acid at 75 °C. Equilibrium swelling of natural rubber with palmitic acid was found to occur at approximately 50 min of swelling time. Under cooling effect, the palmitic acid crystallized to form a percolated crystalline platelet network. These networks allow fabricated shape memory natural rubber (SMNR to deform and recover its shape at a temperature above the melting point of palmitic acid. Under controlled uniaxial stress, the natural rubber sample with 0 parts per hundred rubber (phr carbon black loading exhibits fixity and recovery of 80 ± 10%. Motivation of this research is primarily on practicability of palmitic acid to be used as a swelling agent for shape memory properties. Results show that palmitic acid is a relatively good swelling agent to induce shape memory properties into natural rubber.

  20. Heterojunction Solar Cells Based on Silicon and Composite Films of Graphene Oxide and Carbon Nanotubes.

    Science.gov (United States)

    Yu, LePing; Tune, Daniel; Shearer, Cameron; Shapter, Joseph

    2015-09-07

    Graphene oxide (GO) sheets have been used as the surfactant to disperse single-walled carbon nanotubes (CNT) in water to prepare GO/CNT electrodes that are applied to silicon to form a heterojunction that can be used in solar cells. GO/CNT films with different ratios of the two components and with various thicknesses have been used as semitransparent electrodes, and the influence of both factors on the performance of the solar cell has been studied. The degradation rate of the GO/CNT-silicon devices under ambient conditions has also been explored. The influence of the film thickness on the device performance is related to the interplay of two competing factors, namely, sheet resistance and transmittance. CNTs help to improve the conductivity of the GO/CNT film, and GO is able to protect the silicon from oxidation in the atmosphere. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Fabrication of Wood-Rubber Composites Using Rubber Compound as a Bonding Agent Instead of Adhesives

    Directory of Open Access Journals (Sweden)

    Dongwei Shao

    2016-06-01

    Full Text Available Differing from the hot-pressing method in the manufacturing of traditional wood-rubber composites (WRCs, this study was aimed at fabricating WRCs using rubber processing to improve water resistance and mechanical properties. Three steps were used to make WRCs, namely, fiber-rubber mixing, tabletting, and the vulcanization molding process. Ninety-six WRC panels were made with wood fiber contents of 0%–50% at rotor rotational speeds of 15–45 rpm and filled coefficients of 0.55–0.75. Four regression equations, i.e., the tensile strength (Ts, elongation at break (Eb, hardness (Ha and rebound resilience (Rr as functions of fiber contents, rotational speed and filled coefficient, were derived and a nonlinear programming model were developed to obtain the optimum composite properties. Although the Ts, Eb and Rr of the panels were reduced, Ha was considerably increased by 17%–58% because of the wood fiber addition. Scanning electron microscope images indicated that fibers were well embedded in rubber matrix. The 24 h water absorption was only 1%–3%, which was much lower than commercial wood-based composites.

  2. Fabrication of Wood-Rubber Composites Using Rubber Compound as a Bonding Agent Instead of Adhesives.

    Science.gov (United States)

    Shao, Dongwei; Xu, Min; Cai, Liping; Shi, Sheldon Q

    2016-06-14

    Differing from the hot-pressing method in the manufacturing of traditional wood-rubber composites (WRCs), this study was aimed at fabricating WRCs using rubber processing to improve water resistance and mechanical properties. Three steps were used to make WRCs, namely, fiber-rubber mixing, tabletting, and the vulcanization molding process. Ninety-six WRC panels were made with wood fiber contents of 0%-50% at rotor rotational speeds of 15-45 rpm and filled coefficients of 0.55-0.75. Four regression equations, i.e. , the tensile strength ( T s), elongation at break ( E b), hardness ( H a) and rebound resilience ( R r) as functions of fiber contents, rotational speed and filled coefficient, were derived and a nonlinear programming model were developed to obtain the optimum composite properties. Although the T s, E b and R r of the panels were reduced, H a was considerably increased by 17%-58% because of the wood fiber addition. Scanning electron microscope images indicated that fibers were well embedded in rubber matrix. The 24 h water absorption was only 1%-3%, which was much lower than commercial wood-based composites.

  3. Dielectric strength behaviour and mechanical properties of transparent insulation materials suitable to optical monitoring of partial discharges

    International Nuclear Information System (INIS)

    Lothongkam, Chaiyaporn

    2014-01-01

    A novel optical detection method for partial discharge in HV/EHV cable terminations has been proposed. Optical sensor fibres integrated into the HV equipment provide high sensitivity as well as immunity to electromagnetic interference and enable therefore on-line monitoring in electromagnetically noisy environment. The availability of optically transparent silicone rubbers that meet strict dielectric and mechanical criteria is a crucial prerequisite for the implementation of this method. The optically transparent silicone rubbers can be applied for the fabrication of a modern rubber stress cone as well as for the development of a new optical sensing element sensitive to PD activities. In this thesis, AC dielectric strength behaviour and mechanical properties of three types of commercially available silicone rubbers were investigated. One of the characterized silicone rubbers was a translucent type whereas the two others were optically transparent types, however with different chemical curing reactions. The measurements of tensile strength and elongation at break were carried out according to the ISO 37 standard. For investigation of the dielectric strength E b behaviour of the virgin and modified silicone rubbers, a new methodology was developed. It is, at the same time, highly reliable and efficient, saves time and reduces material consumption in comparison to previously reported methodologies. The key component of this methodology is a specifically developed test facility. Furthermore, the methodology comprises determinations for easy preparation and handling of high-quality test specimens. This test method provides various advantages over other methods that have previously been used for measurement of the fundamental quantity E b value of silicone rubbers. Both technical and economic demands are satisfied. The new facility also enables cost-effective routine tests in material research laboratories. The high quality of the obtained test results was verified by

  4. Seismic isolation rubber bearings for nuclear facilities

    International Nuclear Information System (INIS)

    Fujita, Takafumi

    1991-01-01

    This paper describes results of biaxial breaking tests by compression and shear and by tension and shear for seismic isolation rubber bearings with bolted-type connections. The bearings used in the tests were low-damping rubber bearings, high-damping rubber bearings, and lead-rubber bearings. Three modes of failure of the bolted-type bearings were observed in the tests. They are the breaking failure by tension and shear; the breaking failure by compression and shear; and the buckling failure by compression and shear. The first and the second modes of failures are almost independent of the types and the sizes of the bearings. The breaking conditions of those failure modes are described in the axial-stress-shear-strain plane. This expression is useful for the evaluation of safety margins of the bearings. The paper outlines the basic design of the nuclear-grade bearings which were used for large-scale rubber bearing tests in a research project for seismic isolation of FBR plants. It also discusses the protection method against aging and the quality control which are important for implementation. (orig./HP)

  5. Seismic isolation rubber bearings for nuclear facilities

    International Nuclear Information System (INIS)

    Fujita, Takafumi

    1989-01-01

    This paper describes results of biaxial breaking tests by compression and shear and by tension and shear for seismic isolation rubber bearings with bolted-type connections. The bearings used in the tests were low-damping rubber bearings, high-damping rubber bearings, and lead-rubber bearings. Three modes of failure of the bolted-type bearings were observed in the tests. They are the breaking failure by tension and shear; the breaking failure by compression and shear; and the buckling failure by compression and shear. The first and the second modes of failures are almost independent of the types and the sizes of the bearings. The breaking conditions of those failure modes are described in the axial stress-shear strain plane. This expression is useful for the evaluation of safety margins of the bearings. The paper outlines the basic design of the nuclear-grade bearings which were used for large-scale rubber bearing tests in a research project for seismic isolation of fast breeder reactor (FBR) plants. The paper also discusses the protection method against aging and the quality control which are important for implementation

  6. Review of food toxicological issues associated in rubber products

    OpenAIRE

    Ng, Mei Xiang; Ong, S.P.; Hii, C.L.; Chuah, L.A.; Law, C.L.

    2014-01-01

    Over the centuries, rubber latex gained its popularity in machinery application due to its unique thermal properties, high elasticity and excellent impact resistance. It is widely accepted in food industry as rubber has good resistance to chemicals, including acids, alkalis and salts. For instance, rubber components comprise of couplings, shields, dust covers, gaskets and seals exist as group or standalone component in food manufacturing equipments or machinery. Even though most of the rubber...

  7. Rubber friction and tire dynamics

    International Nuclear Information System (INIS)

    Persson, B N J

    2011-01-01

    We propose a simple rubber friction law, which can be used, for example, in models of tire (and vehicle) dynamics. The friction law is tested by comparing numerical results to the full rubber friction theory (Persson 2006 J. Phys.: Condens. Matter 18 7789). Good agreement is found between the two theories. We describe a two-dimensional (2D) tire model which combines the rubber friction model with a simple mass-spring description of the tire body. The tire model is very flexible and can be used to accurately calculate μ-slip curves (and the self-aligning torque) for braking and cornering or combined motion (e.g. braking during cornering). We present numerical results which illustrate the theory. Simulations of anti-blocking system (ABS) braking are performed using two simple control algorithms.

  8. Rubber friction and tire dynamics.

    Science.gov (United States)

    Persson, B N J

    2011-01-12

    We propose a simple rubber friction law, which can be used, for example, in models of tire (and vehicle) dynamics. The friction law is tested by comparing numerical results to the full rubber friction theory (Persson 2006 J. Phys.: Condens. Matter 18 7789). Good agreement is found between the two theories. We describe a two-dimensional (2D) tire model which combines the rubber friction model with a simple mass-spring description of the tire body. The tire model is very flexible and can be used to accurately calculate μ-slip curves (and the self-aligning torque) for braking and cornering or combined motion (e.g. braking during cornering). We present numerical results which illustrate the theory. Simulations of anti-blocking system (ABS) braking are performed using two simple control algorithms.

  9. Laser-zone Growth in a Ribbon-to-ribbon (RTR) Process Silicon Sheet Growth Development for the Large Area Silicon Sheet Task of the Low Cost Solar Array Project

    Science.gov (United States)

    Baghdadi, A.; Gurtler, R. W.; Legge, R.; Sopori, B.; Rice, M. J.; Ellis, R. J.

    1979-01-01

    A technique for growing limited-length ribbons continually was demonstrated. This Rigid Edge technique can be used to recrystallize about 95% of the polyribbon feedstock. A major advantage of this method is that only a single, constant length silicon ribbon is handled throughout the entire process sequence; this may be accomplished using cassettes similar to those presently in use for processing Czochralski waters. Thus a transition from Cz to ribbon technology can be smoothly affected. The maximum size being considered, 3 inches x 24 inches, is half a square foot, and will generate 6 watts for 12% efficiency at 1 sun. Silicon dioxide has been demonstrated as an effective, practical diffusion barrier for use during the polyribbon formation.

  10. Forecasting Natural Rubber Price In Malaysia Using Arima

    Science.gov (United States)

    Zahari, Fatin Z.; Khalid, Kamil; Roslan, Rozaini; Sufahani, Suliadi; Mohamad, Mahathir; Saifullah Rusiman, Mohd; Ali, Maselan

    2018-04-01

    This paper contains introduction, materials and methods, results and discussions, conclusions and references. Based on the title mentioned, high volatility of the price of natural rubber nowadays will give the significant risk to the producers, traders, consumers, and others parties involved in the production of natural rubber. To help them in making decisions, forecasting is needed to predict the price of natural rubber. The main objective of the research is to forecast the upcoming price of natural rubber by using the reliable statistical method. The data are gathered from Malaysia Rubber Board which the data are from January 2000 until December 2015. In this research, average monthly price of Standard Malaysia Rubber 20 (SMR20) will be forecast by using Box-Jenkins approach. Time series plot is used to determine the pattern of the data. The data have trend pattern which indicates the data is non-stationary data and the data need to be transformed. By using the Box-Jenkins method, the best fit model for the time series data is ARIMA (1, 1, 0) which this model satisfy all the criteria needed. Hence, ARIMA (1, 1, 0) is the best fitted model and the model will be used to forecast the average monthly price of Standard Malaysia Rubber 20 (SMR20) for twelve months ahead.

  11. Fatigue life of automotive rubber jounce bumper

    International Nuclear Information System (INIS)

    Sidhu, R S; Ali, Aidy

    2010-01-01

    It is evident that most rubber components in the automotive industry are subjected to repetitive loading. Vigorous research is needed towards improving the safety and reliability of the components. The study was done on an automotive rubber jounce bumper with a rubber hardness of 60 IRHD. The test was conducted in displacement-controlled environment under compressive load. The existing models by Kim, Harbour, Woo and Li were adopted to predict the fatigue life. The experimental results show strong similarities with the predicted models.

  12. Recovery of indium-tin-oxide/silicon heterojunction solar cells by thermal annealing

    OpenAIRE

    Morales Vilches, Ana Belén; Voz Sánchez, Cristóbal; Colina Brito, Mónica Alejandra; López Rodríguez, Gema; Martín García, Isidro; Ortega Villasclaras, Pablo Rafael; Orpella García, Alberto; Alcubilla González, Ramón

    2014-01-01

    The emitter of silicon heterojunction solar cells consists of very thin hydrogenated amorphous silicon layers deposited at low temperature. The high sheet resistance of this type of emitter requires a transparent conductive oxide layer, which also acts as an effective antireflection coating. The deposition of this front electrode, typically by Sputtering, involves a relatively high energy ion bombardment at the surface that could degrade the emitter quality. The work function of the tra...

  13. LSA Large Area Silicon Sheet Task Continuous Liquid Feed Czochralski Growth

    Science.gov (United States)

    Fiegl, G.

    1979-01-01

    A process for the continuous growth of crystals by the Czochralski method, suitable for producing single silicon crystals for use in solar cells was studied. Continuous growth is the growth of 100 Kg of single silicon crystals, 10 cm in diameter, from one container. A furnace with continuous liquid replenishment of the growth crucible, accomplished by a melt-down system and a liquid transfer mechanism, with associated automatic feedback controls was developed. Elements of the transfer system were further developed and tested during actual transfer runs. Considerable simplification of the heating element of the transfer tube was achieved. Accuracy and reliability of the temperature sensor, which is part of the power input control system for the transfer tube, was improved. Electrical and thermal effectiveness were increased while assembly of the transfer tube system was further simplified.

  14. Determination of the Mechanical Properties of Rubber by FT-NIR

    Directory of Open Access Journals (Sweden)

    Rattapol Pornprasit

    2016-01-01

    Full Text Available Mechanical tests, for example, tensile and hardness tests, are usually used to evaluate the properties of rubber materials. In this work, mechanical properties of selected rubber materials, that is, natural rubber (NR, styrene butadiene rubber (SBR, nitrile butadiene rubber (NBR, and ethylene propylene diene monomer (EPDM, were evaluated using a near infrared (NIR spectroscopy technique. Here, NR/NBR and NR/EPDM blends were first prepared. All of the samples were then scanned using a FT-NIR spectrometer and fitted with an integration sphere working in a diffused reflectance mode. The spectra were correlated with hardness and tensile properties. Partial least square (PLS calibration models were built from the spectra datasets with preprocessing techniques, that is, smoothing and second derivative. This indicated that reasonably accurate models, that is, with a coefficient of determination [R2] of the validation greater than 0.9, could be achieved for the hardness and tensile properties of rubber materials. This study demonstrated that FT-NIR analysis can be applied to determine hardness and tensile values in rubbers and rubber blends effectively.

  15. Tailoring the Electronic and Magnetic Properties of Two-Dimensional Silicon Carbide Sheets and Ribbons by Fluorination

    KAUST Repository

    Shi, Zhiming

    2016-07-12

    Fluorination has been instrumental for tuning the properties of several two-dimensional (2D) materials, including graphene, h-BN, and MoS2. However, its potential application has not yet been explored in 2D silicon carbide (SiC), a promising material for nanoelectronic devices. We investigate the structural, electronic, and magnetic properties of fully and partially fluorinated 2D SiC sheets and nanoribbons by means of density functional theory combined with cluster expansion calculations. We find that fully fluorinated 2D SiC exhibits chair configurations and a nonmagnetic semiconducting behavior. Fluorination is shown to be an efficient approach for tuning the band gap. Four ground states of partially fluorinated SiC, SiCF2x with x = 0.0625, 0.25, 0.5, 0.75, are obtained by cluster expansion calculations. All of them exhibit nanoroad patterns, with the x = 0.5 structure identified as the most stable one. The x = 0.0625 structure is a nonmagnetic metal, while the other three are all ferromagnetic half-metals, whose properties are not affected by the edge states. We propose an effective approach for modulating the electronic and magnetic behavior of 2D SiC, paving the way to applications of SiC nanostructures in integrated multifunctional and spintronic nanodevices. © 2016 American Chemical Society.

  16. Tailoring the Electronic and Magnetic Properties of Two-Dimensional Silicon Carbide Sheets and Ribbons by Fluorination

    KAUST Repository

    Shi, Zhiming; Kutana, Alex; Yu, Guangtao; Chen, Wei; Yakobson, Boris I.; Schwingenschlö gl, Udo; Huang, Xuri

    2016-01-01

    Fluorination has been instrumental for tuning the properties of several two-dimensional (2D) materials, including graphene, h-BN, and MoS2. However, its potential application has not yet been explored in 2D silicon carbide (SiC), a promising material for nanoelectronic devices. We investigate the structural, electronic, and magnetic properties of fully and partially fluorinated 2D SiC sheets and nanoribbons by means of density functional theory combined with cluster expansion calculations. We find that fully fluorinated 2D SiC exhibits chair configurations and a nonmagnetic semiconducting behavior. Fluorination is shown to be an efficient approach for tuning the band gap. Four ground states of partially fluorinated SiC, SiCF2x with x = 0.0625, 0.25, 0.5, 0.75, are obtained by cluster expansion calculations. All of them exhibit nanoroad patterns, with the x = 0.5 structure identified as the most stable one. The x = 0.0625 structure is a nonmagnetic metal, while the other three are all ferromagnetic half-metals, whose properties are not affected by the edge states. We propose an effective approach for modulating the electronic and magnetic behavior of 2D SiC, paving the way to applications of SiC nanostructures in integrated multifunctional and spintronic nanodevices. © 2016 American Chemical Society.

  17. Application of gamma irradiation for incorporation of rubber powder in the formulations of acrylonitrile-butadiene rubber (NBR)

    International Nuclear Information System (INIS)

    Kiyan, Ludmila Y.P.; Parra, Duclerc Fernandes

    2013-01-01

    Full text: Polymeric materials do not decompose easily, disposal of waste polymers is a major environmental problem of global character. Recycling is an economical alternative and environmentally recommended for polymers consumed and discarded by society. As regards the rubber in object, its natural decomposition is much slower due to their highly crosslinked, in three-dimensional networks, structures which makes it an infusible and insoluble material. Moreover, these three dimensional structures entails several problems for their recovery and reprocessing. The aim of this paper was to study the behavior of NBR rubber recycle. It was used rubber powder from industry. The powder was irradiated in master-batch composition and used directly in classical formulations for rubber vulcanization. The master-batch processed was irradiated at doses of 50, 100 and 150kGy in 60 Co source at 5 kGy s -1 rate, at room temperature. Gamma radiation created active sites during devulcanization that promoted further integration of the rubber powder in formulations for commercial use. The processes were compared and their products were characterized by analytical methods of the physical properties such as tensile strength and elongation. The greatest change in the properties of polymeric materials by exposure to ionizing radiation resulted mainly of two main reactions occurring in the polymer molecule: chains scission (degradation) and crosslinking. Although these two processes occur simultaneously in all the polymers, the predominance of one or other effect depends mainly of the chemical structure of each polymer, and the irradiation conditions. In the results was observed the behavior of nitrile rubber under different doses and radiation improvement of the mechanical properties. (author)

  18. Application of gamma irradiation for incorporation of rubber powder in the formulations of acrylonitrile-butadiene rubber (NBR)

    Energy Technology Data Exchange (ETDEWEB)

    Kiyan, Ludmila Y.P.; Parra, Duclerc Fernandes, E-mail: ludmilapozzo@gmail.com [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Quimica e Meio Ambiente (CQMA)

    2013-07-01

    Full text: Polymeric materials do not decompose easily, disposal of waste polymers is a major environmental problem of global character. Recycling is an economical alternative and environmentally recommended for polymers consumed and discarded by society. As regards the rubber in object, its natural decomposition is much slower due to their highly crosslinked, in three-dimensional networks, structures which makes it an infusible and insoluble material. Moreover, these three dimensional structures entails several problems for their recovery and reprocessing. The aim of this paper was to study the behavior of NBR rubber recycle. It was used rubber powder from industry. The powder was irradiated in master-batch composition and used directly in classical formulations for rubber vulcanization. The master-batch processed was irradiated at doses of 50, 100 and 150kGy in {sup 60}Co source at 5 kGy s{sup -1} rate, at room temperature. Gamma radiation created active sites during devulcanization that promoted further integration of the rubber powder in formulations for commercial use. The processes were compared and their products were characterized by analytical methods of the physical properties such as tensile strength and elongation. The greatest change in the properties of polymeric materials by exposure to ionizing radiation resulted mainly of two main reactions occurring in the polymer molecule: chains scission (degradation) and crosslinking. Although these two processes occur simultaneously in all the polymers, the predominance of one or other effect depends mainly of the chemical structure of each polymer, and the irradiation conditions. In the results was observed the behavior of nitrile rubber under different doses and radiation improvement of the mechanical properties. (author)

  19. Properties of tire rubber with zinc-containing technological additives

    Directory of Open Access Journals (Sweden)

    S. N. Kayushnikov

    2017-01-01

    Full Text Available In this paper, we studied the influence of zinc-containing technological additives on partial replacement of zinc oxide and stearic acid on deformation-strength and performance properties of tire elastomeric compositions based on polyisoprene rubber and combination of oil-filled butadiene-styrene and polybutadiene rubbers. It was revealed that partial replacement of zinc oxide and stearic acid with zinc-containing technological additives does not significantly affect the basic physico-mechanical properties of rubbers based on synthetic rubbers of general use. It was determined that the introduction of zinc-containing technological additives SCC2 in combination with zinc oxide in all the studied ratios and SCC3 in combination with zinc oxide in 4: 1 and 3: 1 ratios leads to increase (up to 10.4% of the resistance of these rubbers under the action of temperature-force fields, which is probably due to a more even distribution of polar components of curing system in non-polar elastomeric matrix, as well as the type of cross-links formed during vulcanization under the action of surface-active additives. It has been found that the introduction of zinc-containing additives into the elastomeric compositions based on SRMS-30 ARKM-15 + SRD in combination with zinc oxide leads to increase to 6.3% of wear resistance of rubbers, which may be due to a lower defectiveness of vulcanization structure of these rubbers, concentration of stress centers in the material. For rubbers based on SRI-3, preservation of bond strength of rubber with a textile cord at a sufficiently high level is shown.

  20. Development of rubberized geopolymer interlocking bricks

    Directory of Open Access Journals (Sweden)

    Bashar S Mohammed

    2018-06-01

    Full Text Available Waste tires contribute badly to the environment on a huge scale as they are bulky, non-biodegradable, and prone to fire and being a shelter for mosquitos and other insects. This paper reports on a novel approach towards the development of rubberized brick by utilizing crumb rubber as the sole fine aggregate in the production of geopolymer interlocking bricks. The response surface methodology (RSM from Design Experts software has been used to determine the numbers of trial mixes and their corresponding ingredients. A total of thirteen trial mixes were carried out and tested for compressive strength and the RSM model was developed to predict the design mix based on the targeted compressive strength. The mix design was obtained to be an 18 M for NaOH and 0.8 solution to fly ash ratio. The geopolymer interlocking rubberized bricks were then produced and tested for compressive strength, dimension, modulus of rupture, water absorption, initial rate of absorption, and efflorescence. The geopolymer interlocking rubberised bricks presented a low compressive and flexural strength and a high-water absorption capacity. The bricks were rated as non-effloresced and classified as 3rd class bricks which can be used as non-load bearing material. It is recommended to utilize nano silica in order to increase the strength of the brick. Keywords: Rubberized bricks, Crumb rubber, Interlocking bricks, Geopolymer, Response surface methodology

  1. Recent developments in low cost silicon solar cells for terrestrial applications. [sheet production methods

    Science.gov (United States)

    Leipold, M. H.

    1978-01-01

    A variety of techniques may be used for photovoltaic energy systems. Concentrated or not concentrated sunlight may be employed, and a number of materials can be used, including silicon, gallium arsenide, cadmium sulfide, and cadmium telluride. Most of the experience, however, has been obtained with silicon cells employed without sunlight concentration. An industrial base exists at present for producing solar cells at a price in the range from $15 to $30 per peak watt. A major federal program has the objective to reduce the price of power provided by silicon solar systems to approximately $1 per peak watt in the early 1980's and $0.50 per watt by 1986. The approaches considered for achieving this objective are discussed.

  2. Modification of rubber surface by UV surface grafting

    International Nuclear Information System (INIS)

    Shanmugharaj, A.M.; Kim, Jin Kuk; Ryu, Sung Hun

    2006-01-01

    Rubber surface is subjected to ultraviolet radiation (UV) in the presence of allylamine and radiation sensitizer benzophenone (BP). Fourier transform infrared spectral studies reveal the presence of allylamine on the surface. The presence of irregular needle shapes on the surface as observed in scanning electron micrographs also confirms the polymerized allylamine on the surface. Allylamine coatings have been further confirmed from atomic force microscopy (AFM) analysis. Thermogravimetric analysis (TGA) reveals that allylamine coating on the rubber surface lowers the thermal degradation rate. The contact angle between the water and rubber surface decreases for the modified rubber surface confirming the surface modification due to UV surface grafting

  3. Life assessment of rubber articles in fuels

    OpenAIRE

    Selldén, Emmy

    2013-01-01

    The choice of rubber material for use in sealings and hoses in the fuel system is of great importance. If a wrong type of rubber is used, premature failure during service may occur. This impacts the environmental performance, the safety during driving, uptime and economy of the transport. In this diploma work, rubbers for use in sealing and hoses in the fuel system have been evaluated to assess which materials have the potential to be used under long-term use in contact with commercial fuels....

  4. Research Progress in Graphene/Rubber Conducting Nanocomposites

    Directory of Open Access Journals (Sweden)

    DONG Hui-min

    2017-03-01

    Full Text Available The conductive mechanism of graphene/rubber nanocomposites was introduced.Advances in the synthesis and properties of graphene and its derivatives, modifications of graphene, along with its hybrid fillers, as well as fabrication of related rubber conducting nanocomposites were reviewed.Many factors affecting the electrical properties, such as fabrication method, vulcanization, temperature, pressure, frequency and media etc. were also summarized.It was pointed out that the further research should be focused on multi-component graphene/rubber nanocomposites and its double percolation phenomenon.

  5. Asphalt concrete modified by rubber crumbs in transport construction.

    Science.gov (United States)

    Duhovny, G. S.; Karpenko, AV

    2018-03-01

    High-temperature and low-temperature characteristics of the rubber-bitumen binder and rubber asphalt concrete based on it are researched. The determination method of binder’s low-temperature characteristics is offered. The estimation of binder’s and pavement’s stability against technological and operational aging is evaluated. Estimation of environmental and economic aspects of using rubber crumbs is made. The possibility of using rubber crumbs as modifier of organic binder for production of asphalt concrete on its base is justified.

  6. Thin film silicon photovoltaics: Architectural perspectives and technological issues

    Energy Technology Data Exchange (ETDEWEB)

    Mercaldo, Lucia Vittoria; Addonizio, Maria Luisa; Noce, Marco Della; Veneri, Paola Delli; Scognamiglio, Alessandra; Privato, Carlo [ENEA, Portici Research Center, Piazzale E. Fermi, 80055 Portici (Napoli) (Italy)

    2009-10-15

    Thin film photovoltaics is a particularly attractive technology for building integration. In this paper, we present our analysis on architectural issues and technological developments of thin film silicon photovoltaics. In particular, we focus on our activities related to transparent and conductive oxide (TCO) and thin film amorphous and microcrystalline silicon solar cells. The research on TCO films is mainly dedicated to large-area deposition of zinc oxide (ZnO) by low pressure-metallorganic chemical vapor deposition. ZnO material, with a low sheet resistance (<8 {omega}/sq) and with an excellent transmittance (>82%) in the whole wavelength range of photovoltaic interest, has been obtained. ''Micromorph'' tandem devices, consisting of an amorphous silicon top cell and a microcrystalline silicon bottom cell, are fabricated by using the very high frequency plasma enhanced chemical vapor deposition technique. An initial efficiency of 11.1% (>10% stabilized) has been obtained. (author)

  7. Complex permeability and permittivity variation of carbonyl iron rubber in the frequency range of 2 to 18 GHz

    Directory of Open Access Journals (Sweden)

    Adriana Medeiros Gama

    2010-04-01

    Full Text Available The complex dielectric permittivity (e and magnetic permeability (m of Radar Absorbing Materials (RAM based on metallic magnetic particles (carbonyl iron particles embedded in a dielectric matrix (silicon rubber have been studied in the frequency range of 2 to 18 GHz. The relative permeability and permittivity of carbonyl iron-silicon composites for various mass fractions are measured by the transmission/reflection method using a vector network analyzer. The concentration dependence of permittivity and permeability on the frequency is analyzed. In a general way, the results show that e´ parameter shows a more significant variation among the evaluated parameters (e”, m”, m’. The comparison of dielectric and magnetic loss tangents (e”/e” and m”/m’, respectively shows more clearly the variation of both parameters (e and m according to the frequency. It is also observed that higher carbonyl iron content fractions favor both dielectric and magnetic loss tangents.

  8. On the response of rubbers at high strain rates.

    Energy Technology Data Exchange (ETDEWEB)

    Niemczura, Johnathan Greenberg (University of Texas-Austin)

    2010-02-01

    In this report, we examine the propagation of tensile waves of finite deformation in rubbers through experiments and analysis. Attention is focused on the propagation of one-dimensional dispersive and shock waves in strips of latex and nitrile rubber. Tensile wave propagation experiments were conducted at high strain-rates by holding one end fixed and displacing the other end at a constant velocity. A high-speed video camera was used to monitor the motion and to determine the evolution of strain and particle velocity in the rubber strips. Analysis of the response through the theory of finite waves and quantitative matching between the experimental observations and analytical predictions was used to determine an appropriate instantaneous elastic response for the rubbers. This analysis also yields the tensile shock adiabat for rubber. Dispersive waves as well as shock waves are also observed in free-retraction experiments; these are used to quantify hysteretic effects in rubber.

  9. Biodiesel Production from Rubber Seed Oil via Esterification Process

    Directory of Open Access Journals (Sweden)

    W Widayat

    2012-07-01

    Full Text Available One promise source of alternative energy is biodiesel from rubber seed oil, because the raw materials available in plentiful quantities and can be renewed. In addition, the rubber seed is still lack of utilization, and Indonesia is one of the largest rubbers producing country in the world. The objective of this research is to studied on biodiesel production by esterification process. Parameters used in this study are the ratio of catalyst and temperature and its influence on the characteristics of the resulting biodiesel product. Characterization of rubber seed include acid content number analysis, saponification numbers, density, viscosity, iodine number, type of free fatty acids and triglyceride oils. The results of analysis showed that rubber seed oil content obtained is 50.5%. The results of the GCMS analysis showed that a free fatty acid level in rubber seed is very high. Conversion into bio-diesel oil is obtained by at most 59.91% and lowest 48.24%.

  10. The Rubber Hand Illusion Revisited: Visuotactile Integration and Self-Attribution

    Science.gov (United States)

    Tsakiris, Manos; Haggard, Patrick

    2005-01-01

    Watching a rubber hand being stroked, while one's own unseen hand is synchronously stroked, may cause the rubber hand to be attributed to one's own body, to "feel like it's my hand." A behavioral measure of the rubber hand illusion (RHI) is a drift of the perceived position of one's own hand toward the rubber hand. The authors investigated (a) the…

  11. Research on a haptic sensor made using MCF conductive rubber

    International Nuclear Information System (INIS)

    Zheng Yaoyang; Shimada, Kunio

    2008-01-01

    To provide a new composite material having a high electrical sensitivity in the fields of robotics and sensing, a magnetic rubber having network-like magnetic clusters was developed by utilizing a magnetic compound fluid (MCF). MCF rubber with small deformations can provide an effective sensor. In this paper, we report many experiments in which changes of the MCF rubber's resistance were observed when the rubber was compressed and a deformation was generated; we then made a trial haptic sensor using the MCF conductive rubber and performed many experiments to observe changes of the electrical resistance of the sensor. The results of experiments showed that the proposed sensor made with MCF conductive rubber is useful for sensing small amounts of pressure or small deformations

  12. Research on a haptic sensor made using MCF conductive rubber

    Energy Technology Data Exchange (ETDEWEB)

    Zheng Yaoyang; Shimada, Kunio [Faculty of Symbiotic Systems Science Fukushima University, 1 Kanayakawa, Fukushima 960-1296 (Japan)], E-mail: tei@sss.fukushima-u.ac.jp, E-mail: shimadakun@sss.fukushima-u.ac.jp

    2008-05-21

    To provide a new composite material having a high electrical sensitivity in the fields of robotics and sensing, a magnetic rubber having network-like magnetic clusters was developed by utilizing a magnetic compound fluid (MCF). MCF rubber with small deformations can provide an effective sensor. In this paper, we report many experiments in which changes of the MCF rubber's resistance were observed when the rubber was compressed and a deformation was generated; we then made a trial haptic sensor using the MCF conductive rubber and performed many experiments to observe changes of the electrical resistance of the sensor. The results of experiments showed that the proposed sensor made with MCF conductive rubber is useful for sensing small amounts of pressure or small deformations.

  13. Research on a haptic sensor made using MCF conductive rubber

    Science.gov (United States)

    Zheng, Yaoyang; Shimada, Kunio

    2008-05-01

    To provide a new composite material having a high electrical sensitivity in the fields of robotics and sensing, a magnetic rubber having network-like magnetic clusters was developed by utilizing a magnetic compound fluid (MCF). MCF rubber with small deformations can provide an effective sensor. In this paper, we report many experiments in which changes of the MCF rubber's resistance were observed when the rubber was compressed and a deformation was generated; we then made a trial haptic sensor using the MCF conductive rubber and performed many experiments to observe changes of the electrical resistance of the sensor. The results of experiments showed that the proposed sensor made with MCF conductive rubber is useful for sensing small amounts of pressure or small deformations.

  14. Contact allergy to rubber accelerators remains prevalent

    DEFF Research Database (Denmark)

    Schwensen, J F; Menné, T; Johansen, J D

    2016-01-01

    several clinical cases with allergic facial dermatitis to rubber. OBJECTIVES: To evaluate temporal trends of contact allergy to rubber accelerators from the European baseline series in a tertiary patch test clinic in Denmark, and examine associations with anatomical locations of dermatitis. METHODS: Patch...... test and clinical data collected in a Danish tertiary dermatology clinic in Gentofte, Herlev, Copenhagen between 1 January 2005 and 31 December 2014 were analysed. The following rubber accelerators or mixtures in petrolatum from the European baseline patch test series were included: thiuram mix 1.......0%, mercaptobenzothiazole 2.0% and mercapto mix 1.0%. RESULTS: The overall prevalence of contact allergy to rubber accelerators was 3.1% with no significant change during the study period (Ptrend = 0.667). Contact allergy to thiuram mix was the most prevalent and was significantly associated with occupational contact...

  15. Analysis of Work Design in Rubber Processing Plant

    Directory of Open Access Journals (Sweden)

    Wahyuni Dini

    2018-01-01

    Full Text Available The work design illustrates how structured jobs, tasks, and roles are defined and modified and their impact on individuals, groups, and organizations. If the work is not designed well, the company must pay greater costs for workers’ health, longer production processes or even penalties for not being able to meet the delivery schedule. This is visible to the condition in a rubber processing factory in North Sumatra. Work design aspects such as layouts, machinery and equipment, worker's physical working environment, work methods, and organizational policies have not been well-organized. Coagulum grinding machines into sheets are often damaged, resulting in 4 times the delay of product delivery in 2016, the presence of complaints of heat exposure submitted by workers, and workstation that has not been properly arranged is an indication of the need for work design. The research data will be collected through field observation, and distribution of questionnaires related aspects of work design. The result of the analysis depends on the respondent's answer from the distributed questionnaire regarding the 6 aspects studied.

  16. Analysis of Work Design in Rubber Processing Plant

    Science.gov (United States)

    Wahyuni, Dini; Nasution, Harmein; Budiman, Irwan; Wijaya, Khairini

    2018-02-01

    The work design illustrates how structured jobs, tasks, and roles are defined and modified and their impact on individuals, groups, and organizations. If the work is not designed well, the company must pay greater costs for workers' health, longer production processes or even penalties for not being able to meet the delivery schedule. This is visible to the condition in a rubber processing factory in North Sumatra. Work design aspects such as layouts, machinery and equipment, worker's physical working environment, work methods, and organizational policies have not been well-organized. Coagulum grinding machines into sheets are often damaged, resulting in 4 times the delay of product delivery in 2016, the presence of complaints of heat exposure submitted by workers, and workstation that has not been properly arranged is an indication of the need for work design. The research data will be collected through field observation, and distribution of questionnaires related aspects of work design. The result of the analysis depends on the respondent's answer from the distributed questionnaire regarding the 6 aspects studied.

  17. A flexible tactile sensitive sheet using a hetero-core fiber optic sensor

    Science.gov (United States)

    Fujino, S.; Yamazaki, H.; Hosoki, A.; Watanabe, K.

    2014-05-01

    In this report, we have designed a tactile sensitive sheet based on a hetero-core fiber-optic sensor, which realize an areal sensing by using single sensor potion in one optical fiber line. Recently, flexible and wide-area tactile sensing technology is expected to applied to acquired biological information in living space and robot achieve long-term care services such as welfare and nursing-care and humanoid technology. A hetero-core fiber-optic sensor has several advantages such as thin and flexible transmission line, immunity to EMI. Additionally this sensor is sensitive to moderate bending actions with optical loss changes and is independent of temperature fluctuation. Thus, the hetero-core fiber-optic sensor can be suitable for areal tactile sensing. We measure pressure characteristic of the proposed sensitive sheet by changing the pressure position and pinching characteristic on the surface. The proposed tactile sensitive sheet shows monotonic responses on the whole sensitive sheet surface although different sensitivity by the position is observed at the sensitive sheet surface. Moreover, the tactile sensitive sheet could sufficiently detect the pinching motion. In addition, in order to realize the discrimination between pressure and pinch, we fabricated a doubled-over sensor using a set of tactile sensitive sheets, which has different kinds of silicon robbers as a sensitive sheet surface. In conclusion, the flexible material could be given to the tactile sensation which is attached under proposed sensitive sheet.

  18. Sugarcane bagasse ash: new filler to natural rubber composite

    Directory of Open Access Journals (Sweden)

    Renivaldo José dos Santos

    2014-12-01

    Full Text Available Waste recycling has been the subject of numerous scientific researches regarding the environmental care. This paper reports the redirecting of sugarcane bagasse ash (SBA as new filler to natural rubber (NR/SBA. The NR/SBA composites were prepared using an opened cylinder mixer to incorporate the vulcanization agents and different proportions of residue (SBA. The ash contains about 70-90% of inorganic compounds, with silica (SiO2 being the main compound. The SBA incorporation improved the mechanical properties of the vulcanized rubber. Based on these results, a new use is proposed for the agro-industry organic waste to be implemented in the rubber vulcanization process, aimed at improving the rubber physical properties as well as decreasing the prices of natural rubber composites.

  19. Thermal properties of hydrogenated liquid natural rubber

    Science.gov (United States)

    Jamaluddin, Naharullah; Abdullah, Ibrahim; Yusoff, Siti Fairus M.

    2015-09-01

    Natural rubber (NR) was modified to form liquid natural rubber (LNR) via photooxidative degradation. Hydrogenated liquid natural rubber (HLNR) was synthesized by using diimide as source of hydrogen which the diimide is produced by thermolysis of p-toluenesulfonyl hydrazide (TSH). The structure of HLNR was characterized by determining the changes of main peaks in Fourier Transform infrared and nuclear magnetic resonance spectra after hydrogenation. Thermogravimetric analysis showed that the HLNR had higher decomposition temperature compared to LNR and the decomposition temperature is directly proportional to the percentage of conversion.

  20. Thermal properties of hydrogenated liquid natural rubber

    International Nuclear Information System (INIS)

    Jamaluddin, Naharullah; Abdullah, Ibrahim; Yusoff, Siti Fairus M.

    2015-01-01

    Natural rubber (NR) was modified to form liquid natural rubber (LNR) via photooxidative degradation. Hydrogenated liquid natural rubber (HLNR) was synthesized by using diimide as source of hydrogen which the diimide is produced by thermolysis of p-toluenesulfonyl hydrazide (TSH). The structure of HLNR was characterized by determining the changes of main peaks in Fourier Transform infrared and nuclear magnetic resonance spectra after hydrogenation. Thermogravimetric analysis showed that the HLNR had higher decomposition temperature compared to LNR and the decomposition temperature is directly proportional to the percentage of conversion

  1. Thermal properties of hydrogenated liquid natural rubber

    Energy Technology Data Exchange (ETDEWEB)

    Jamaluddin, Naharullah; Abdullah, Ibrahim; Yusoff, Siti Fairus M. [School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia)

    2015-09-25

    Natural rubber (NR) was modified to form liquid natural rubber (LNR) via photooxidative degradation. Hydrogenated liquid natural rubber (HLNR) was synthesized by using diimide as source of hydrogen which the diimide is produced by thermolysis of p-toluenesulfonyl hydrazide (TSH). The structure of HLNR was characterized by determining the changes of main peaks in Fourier Transform infrared and nuclear magnetic resonance spectra after hydrogenation. Thermogravimetric analysis showed that the HLNR had higher decomposition temperature compared to LNR and the decomposition temperature is directly proportional to the percentage of conversion.

  2. Record high efficiency of screen-printed silicon aluminum back surface field solar cell: 20.29%

    Science.gov (United States)

    Kim, Ki Hyung; Park, Chang Sub; Doo Lee, Jae; Youb Lim, Jong; Yeon, Je Min; Kim, Il Hwan; Lee, Eun Joo; Cho, Young Hyun

    2017-08-01

    We have achieved a record high cell efficiency of 20.29% for an industrial 6-in. p-type monocrystalline silicon solar cell with a full-area aluminum back surface field (Al-BSF) by simply modifying the cell structure and optimizing the process with the existing cell production line. The cell efficiency was independently confirmed by the Solar Energy Research Institute of Singapore (SERIS). To increase the cell efficiency, for example, in four busbars, double printing, a lightly doped emitter with a sheet resistance of 90 to 100 Ω/□, and front surface passivation by using silicon oxynitride (SiON) on top of a silicon nitride (SiN x ) antireflection layer were adopted. To optimize front side processing, PC1D simulation was carried out prior to cell fabrication. The resulting efficiency gain is 0.64% compared with that in the reference cells with three busbars, a single antireflection coating layer, and a low-sheet-resistance emitter.

  3. Natural rubber producing plants: An overview | Venkatachalam ...

    African Journals Online (AJOL)

    ... Hevea and also other natural rubber producing species for alternative source of latex production in the near future. Keywords: Alternative rubber sources, biotechnology, breeding, Hevea brasiliensis, Parthenium argentatum, Taraxacum koksaghyz, Ficus bengalensis, Lactuca serriola. African Journal of Biotechnology Vol.

  4. UTILISATION OF RUBBER SEED OL IN THE

    African Journals Online (AJOL)

    Thermal degradation studies on polyvinyl chloride in the presence of rubber seed oil, epoxidized rubber seed oil and metal ... Epoxidation of RSO was carried out at 29°C using peractic acid ..... impurities such as pigments, Vitamins, sterols ...

  5. Interfacial interaction between the epoxidized natural rubber and silica in natural rubber/silica composites

    Science.gov (United States)

    Xu, Tiwen; Jia, Zhixin; Luo, Yuanfang; Jia, Demin; Peng, Zheng

    2015-02-01

    The epoxidized natural rubber (ENR) as an interfacial modifier was used to improve the mechanical and dynamical mechanical properties of NR/silica composites. In order to reveal the interaction mechanism between ENR and silica, the ENR/Silica model compound was prepared by using an open mill and the interfacial interaction of ENR with silica was investigated by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), X-ray diffraction (XRD) and stress-strain testing. The results indicated that the ring-opening reaction occurs between the epoxy groups of ENR chains and Si-OH groups on the silica surfaces and the covalent bonds are formed between two phases, which can improve the dispersion of silica in the rubber matrix and enhance the interfacial combination between rubber and silica. The ring-opening reaction occurs not only in vulcanization process but also in mixing process, meanwhile, the latter seems to be more important due to the simultaneous effects of mechanical force and temperature.

  6. Mechanistic study of the rubber-brass adhesion interphase

    Science.gov (United States)

    Ashirgade, Akshay

    Brass-plated steel tire cords form an essential strengthening component of a radial automobile tire. Adhesion between rubber compound and brass-plated steel tire cord is crucial in governing the overall performance of tires. The rubber-brass interfacial adhesion is influenced by the chemical composition and thickness of the interfacial layer. It has been shown that the interfacial layer consists mainly of sulfides and oxides of copper and zinc. This thesis discusses the effect of changes in the chemical composition and the structure of the interfacial layers due to addition of adhesion promoter resins. Grazing incidence X-Ray Diffraction (GIXRD) experiments were run on sulfidized polished brass coupons previously bonded to six experimental rubber compounds. It was confirmed that heat and humidity conditions lead to physical and chemical changes of the rubber-steel tire cord interfacial layer, closely related to the degree of rubber-brass adhesion. Morphological transformation of the interfacial layer led to loss of adhesion after aging. The adhesion promoter resins inhibit unfavorable morphological changes in the interfacial layer thus stabilizing it during aging and prolonging failure. Tire cord adhesion tests illustrated that the one-component resins improved adhesion after aging using a rubber compound with lower cobalt loading. Based on the acquired diffraction profiles, these resins were also found to impede crystallization of the sulfide layer after aging leading to improved adhesion. Secondary Ion Mass Spectrometry (SIMS) depth profiles, SEM micrographs and AFM images strongly corroborated the findings from GIXRD. FTIR was utilized in a novel way to understand the degradation mechanism due to aging. A model for rubber and interfacial layer degradation is proposed to illustrate the effect of aging and the one-component resins. This interfacial analysis adds valuable new information to our understanding of the complex nature of the rubber-brass bonding

  7. 75 FR 57980 - Polychloroprene Rubber From Japan

    Science.gov (United States)

    2010-09-23

    ... INTERNATIONAL TRADE COMMISSION [Investigation No. AA1921-129 (Third Review)] Polychloroprene Rubber From Japan AGENCY: United States International Trade Commission. ACTION: Termination of five-year... of the antidumping duty finding on polychloroprene rubber from Japan would be likely to lead to...

  8. Experimental Investigation of the Mechanical and Durability Properties of Crumb Rubber Concrete.

    Science.gov (United States)

    Liu, Hanbing; Wang, Xianqiang; Jiao, Yubo; Sha, Tao

    2016-03-07

    Recycling waste tire rubber by incorporating it into concrete has become the preferred solution to dispose of waste tires. In this study, the effect of the volume content of crumb rubber and pretreatment methods on the performances of concrete was evaluated. Firstly, the fine aggregate and mixture were partly replaced by crumb rubber to produce crumb rubber concrete. Secondly, the mechanical and durability properties of crumb rubber concrete with different replacement forms and volume contents had been investigated. Finally, the crumb rubber after pretreatment by six modifiers was introduced into the concrete mixture. Corresponding tests were conducted to verify the effectiveness of pretreatment methods as compared to the concrete containing untreated crumb rubber. It was observed that the mechanical strength of crumb rubber concrete was reduced, while durability was improved with the increasing of crumb rubber content. 20% replacement of fine aggregate and 5% replacement of the total mixture exhibited acceptable properties for practical applications. In addition, the results indicated that the modifiers had a positive impact on the mechanical and durability properties of crumb rubber concrete. It avoided the disadvantage of crumb rubber concrete having lower strength and provides a reference for the production of modified crumb rubber concrete.

  9. Experimental Investigation of the Mechanical and Durability Properties of Crumb Rubber Concrete

    Directory of Open Access Journals (Sweden)

    Hanbing Liu

    2016-03-01

    Full Text Available Recycling waste tire rubber by incorporating it into concrete has become the preferred solution to dispose of waste tires. In this study, the effect of the volume content of crumb rubber and pretreatment methods on the performances of concrete was evaluated. Firstly, the fine aggregate and mixture were partly replaced by crumb rubber to produce crumb rubber concrete. Secondly, the mechanical and durability properties of crumb rubber concrete with different replacement forms and volume contents had been investigated. Finally, the crumb rubber after pretreatment by six modifiers was introduced into the concrete mixture. Corresponding tests were conducted to verify the effectiveness of pretreatment methods as compared to the concrete containing untreated crumb rubber. It was observed that the mechanical strength of crumb rubber concrete was reduced, while durability was improved with the increasing of crumb rubber content. 20% replacement of fine aggregate and 5% replacement of the total mixture exhibited acceptable properties for practical applications. In addition, the results indicated that the modifiers had a positive impact on the mechanical and durability properties of crumb rubber concrete. It avoided the disadvantage of crumb rubber concrete having lower strength and provides a reference for the production of modified crumb rubber concrete.

  10. Simulation work of fatigue life prediction of rubber automotive components

    International Nuclear Information System (INIS)

    Samad, M S A; Ali, Aidy

    2010-01-01

    The usage of rubbers has always been so important, especially in automotive industries. Rubbers have a hyper elastic behaviour which is the ability to withstand very large strain without failure. The normal applications for rubbers are used for shock absorption, sound isolation and mounting. In this study, the predictions of fatigue life of an engine mount of rubber automotive components were presented. The finite element analysis was performed to predict the critical part and the strain output were incorporated into fatigue model for prediction. The predicted result shows agreement in term of failure location of rubber mount.

  11. Performance Study of the Natural Rubber Composite with Clay Minerals

    International Nuclear Information System (INIS)

    Nyo Nyo Myint; Tin Tin Aye; Kyaw Myo Naing; Nyunt Wynn

    2008-03-01

    The preparation, characterization and some applications of natural rubber clay composite have been studied. This study investigated the possibility of natural rubber latex to replace some part of natural clays. In formulation of rubber clay composite from natural rubber latex and various clay minerals, three main steps were involved (i) preparation of latex cream (ii) prevulcanization of latex cream (iii) mixing vulcanized latex compound, with other ingredients. In each step, several parameters have been carefully investigated to optimize the performance of natural rubber clay composite production. The composite products were of better quality and can be considered to be more cost effective.

  12. Use of rubber crumb for preparation of asphalt-concrete mixtures

    Directory of Open Access Journals (Sweden)

    Yerbol Tileuberdi

    2012-03-01

    Full Text Available In this article use of rubber crumb from spent tire for preparation of rubber-bitumen compounds is investigated. Then the rubber-bitumen compositions are used in composition of asphalt concrete mixes .

  13. Proceedings of the Rubber Association of Canada's 7. biennial 2006 rubber recycling symposium : changing concepts

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-07-01

    Rising energy costs and concerns over the environment have contributed to a renewed focus on recycling for many governments and industries. This conference examined recent trends affecting rubber recycling activities as well as the legislative environment and its impacts on future recycling activities. Major rubber recycling markets were reviewed, and emerging product ideas were evaluated. Industry stewardship model and governance models were discussed. The impacts of new advances in tire technology and manufacturing on the rubber recycling industry were also investigated. Issues concerning fixed tipping fees and incentive structures were discussed, and effective management strategies for the recycling of large off-the-road tires were evaluated. Tire-derived fuel (TDF) is the largest market in North America for scrap tires, and TDF may continue to grow as a result of rising fossil fuel costs. Issues and challenges related to the introduction of TDF to new communities were discussed. New developments in tire derived aggregates (TDA) and ground rubber were also reviewed. Twenty-eight presentations were given at this conference, 3 of which were catalogued separately for inclusion in this database. refs., tabs., figs.

  14. The water-food nexus of natural rubber production

    Science.gov (United States)

    Chiarelli, D. D.; Rosa, L.; Rulli, M. C.; D'Odorico, P.

    2017-12-01

    The increasing global demand for natural rubber (100% increase in the last 15 years) is for most part met by Malaysia and Indonesia, and - to a lesser extent - other countries in south-east Asia and Africa. The consequent expansion of rubber plantation has often occurred at the expenses of agricultural land for staple food, particularly in southeast Asia, where most of the land suitable for agriculture is already harvested for food crops or other uses. Here we investigate the extent to which the ongoing increase in rubber production is competing with the food system and affecting the livelihoods of rural communities in the areas of production and their appropriation of natural resources, such as water. We also investigate to what extent the expansion of rubber plantations is taking place through large scale land acquisitions (LSLAs) and evaluate the impacts on rural communities. Our results show how rubber production has strong environmental, social and economic impacts. Despite their ability to bring employment and increase the average income of economically disadvantaged areas, rubber plantations may threaten the local water and food security and induce a loss of rural livelihoods, particularly when the new plantations result from LSLAs that displace semi-subsistence forms of production thereby forcing the local populations to depend on global markets.

  15. Aging Depth Test of Rubber Blocks by Accelerated Thermal Oxidation Test

    International Nuclear Information System (INIS)

    Park, Junhee; Choun, Young-Sun; Kim, Min Kyu

    2015-01-01

    In this study, the accelerated thermal oxidation tests of rubber block were performed to investigate the aging depth of rubber bearing. From the tests, it was found the critical aging depth in rubber block. Also the property variation of rubber was investigated along the depth. The deterioration pattern from the aging depth tests was found from surface to inside and the critical aging depth was to be about 10 mm. The analytical model for rubber bearing with aging can be developed based on the relationship between the property variation and aging depth investigated from this study. The mechanical properties of rubber bearings were changed with time. Because the aging effect of rubber material was generally higher than that of other structure materials it is needed that the aging properties of seismically isolators should be evaluated to ensure the safety of seismically isolated nuclear power plants (NPPs) over the lifetime. NRC and ASCE required the tests of seismically isolators for investigating the aging properties. JNES also required the seismic response analysis for the seismically isolated NPPs when the properties of seismically isolators were extremely changed. If the aging properties of seismically isolators such as rubber bearings are evaluated by analysis the analytical model of seismically isolators should be developed considering aging effect of rubber material. From the previous research, it was reported that the behavior of aged rubber material mainly affected by temperature and oxidation. The material properties between surface and inside can be different by the oxidation of rubber. Therefore, the aging depth should be investigated for exactly evaluating the seismic behavior of aged rubber bearing. The aging depth of rubber baring was not influenced by the size of seismically isolators but environment condition. Therefore, the detail analysis considering aging depth was not required for NPPs with large seismically isolators. But the seismic response

  16. 30 CFR 77.606-1 - Rubber gloves; minimum requirements.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Rubber gloves; minimum requirements. 77.606-1... COAL MINES Trailing Cables § 77.606-1 Rubber gloves; minimum requirements. (a) Rubber gloves (lineman's gloves) worn while handling high-voltage trailing cables shall be rated at least 20,000 volts and shall...

  17. Exposure of natural rubber to personal lubricants--swelling and stress relaxation as potential indicators of reduced seal integrity of non-lubricated male condoms.

    Science.gov (United States)

    Sarkar Das, Srilekha; Coburn, James C; Tack, Charles; Schwerin, Matthew R; Richardson, D Coleman

    2014-07-01

    Male condoms act as mechanical barriers to prevent passage of body fluids. For effective use of condoms the mechanical seal is also expected to remain intact under reasonable use conditions, including with personal lubricants. Absorption of low molecular weight lubricant components into the material of male condoms may initiate material changes leading to swelling and stress relaxation of the polymer network chains that could affect performance of the sealing function of the device. Swelling indicates both a rubber-solvent interaction and stress relaxation, the latter of which may indicate and/or result in a reduced seal pressure in the current context. Swelling and stress relaxation of natural rubber latex condoms were assessed in a laboratory model in the presence of silicone-, glycol-, and water-based lubricants. Within 15 minutes, significant swelling (≥6 %) and stress reduction (≥12 %) of condoms were observed with 2 out of 4 silicone-based lubricants tested, but neither was observed with glycol- or water-based lubricants tested. Under a given strain, reduction in stress was prominent during the swelling processes, but not after the process was complete. Lubricant induced swelling and stress relaxation may loosen the circumferential stress responsible for the mechanical seal. Swelling and stress relaxation behavior of latex condoms in the presence of personal lubricants may be useful tests to identify lubricant-rooted changes in condom-materials. For non-lubricated latex condoms, material characteristics--which are relevant to failure--may change in the presence of a few silicone-based personal lubricants. These changes may in turn induce a loss of condom seal during use, specifically at low strain conditions. Published by Elsevier Inc.

  18. Mixing formula for tissue-mimicking silicone phantoms in the near infrared

    Science.gov (United States)

    Böcklin, C.; Baumann, D.; Stuker, F.; Fröhlich, Jürg

    2015-03-01

    The knowledge of accurate optical parameters of materials is paramount in biomedical optics applications and numerical simulations of such systems. Phantom materials with variable but predefined parameters are needed to optimise these systems. An optimised integrating sphere measurement setup and reconstruction algorithm are presented in this work to determine the optical properties of silicone rubber based phantoms whose absorption and scattering properties are altered with TiO2 and carbon black particles. A mixing formula for all constituents is derived and allows to create phantoms with predefined optical properties.

  19. Recycling of rubber tires in asphalt paving materials

    Energy Technology Data Exchange (ETDEWEB)

    Piggott, M.R.; Woodhams, R.T.

    1979-01-01

    It has been known that the addition of rubber to asphalt used in paving will produced markedly superior road surfaces. Partly because of cost and because of the nonconventional paving techniques necessary, rubber has been largely ignored as a practical paving additive except in special cases. However, the large accumulation of old tires existing today provides a ready source for suitable rubber. If ground into a fine powder, this rubber can be mixed in a conventional pug mill along with sand, stone and asphalt to produce a hot mix which can be aplied in the normal manner without any special techniques. The extra cost of such modification is only 1% of a typical paving contract, whereas the advantages include lower maintenance cost, more durable road surface, and elimination of unwanted waste tires. This report has been prepared to assist civic and other authorities in the development of improved road surfacing formulations through the reuse of old tires. It includes the results of paving trials in Toronto and laboratory evaluations. These tests show that the addition of powdered rubber to asphalt paving materials markedly improves the durability and crack resistance, particularly at low temperatures. Additives in the rubber impart good strength retention in the presence of moisture. The toughness increases with age due to a slow interaction of the rubber with the asphalt which is accompanied by an increase in viscosity. As a result, performance is also enhanced at high temperatures and helps to minimize pavement distortions due to hot weather and traffic. 16 refs., 18 figs., 2 tabs.

  20. Chrome-tanned leather shavings as a filler of butadiene-acrylonitrile rubber.

    Science.gov (United States)

    Przepiórkowska, A; Chrońska, K; Zaborski, M

    2007-03-06

    The noxious wastes from the tanning industry such as chrome-tanned leather shavings were used as the only filler of rubber mixes containing carboxylated butadiene-acrylonitrile rubber (XNBR) or butadiene-acrylonitrile rubber (NBR), and a dispersing agent Limanol PEV (Schill & Seilacher). The best form addition of leather powder to the rubber mixes is mixed the waste protein with zinc oxide. The leather powder added to the rubber mixes improves the mechanical properties: tensile strength (T(s)), elongation at break (epsilon(b)) and increase the cross-linking density of carboxylated XNBR and NBR rubber mixes. Satisfactory results of these studies are presented in this work.

  1. Soft matter: rubber and networks

    Science.gov (United States)

    McKenna, Gregory B.

    2018-06-01

    Rubber networks are important and form the basis for materials with properties ranging from rubber tires to super absorbents and contact lenses. The development of the entropy ideas of rubber deformation thermodynamics provides a powerful framework from which to understand and to use these materials. In addition, swelling of the rubber in the presence of small molecule liquids or solvents leads to materials that are very soft and ‘gel’ like in nature. The review covers the thermodynamics of polymer networks and gels from the perspective of the thermodynamics and mechanics of the strain energy density function. Important relationships are presented and experimental results show that the continuum ideas contained in the phenomenological thermodynamics are valid, but that the molecular bases for some of them remain to be fully elucidated. This is particularly so in the case of the entropic gels or swollen networks. The review is concluded with some perspectives on other networks, ranging from entropic polymer networks such as thermoplastic elastomers to physical gels in which cross-link points are formed by glassy or crystalline domains. A discussion is provided for other physical gels in which the network forms a spinodal-like decomposition, both in thermoplastic polymers that form a glassy network upon phase separation and for colloidal gels that seem to have a similar behavior.

  2. Optical and Thermal Stability of Oligofluorene/Rubber Luminescent Blend.

    Science.gov (United States)

    Barbosa, Camila G; Faez, Roselena; Péres, Laura O

    2016-09-01

    This paper proposes to obtain homogeneous and stable blends of oligo(9,9-dioctylfluorene)-co-phenylene (OF), a conjugated oligomer with strong tendency of formation of excimers in the solid state, and nitrile rubber (NBR). This rubber protection reduces the formation of polymer excimers in the films. The fluorene oligomer was synthesized via Suzuki reaction and incorporated in the nitrile rubber. The films were formed by spin coating and casting techniques on the proportions of 1, 5, 10, 20 and 50 % (w/w) of OF in the nitrile rubber (NBR). The structural, optical and thermal properties of the films were evaluated with infrared, UV-Vis, fluorescence and thermogravimetry, respectively. The nitrile rubber proved to be essential for the preparation of homogeneous and stable films, since it was not possible to obtain films with only fluorene using the above-mentioned techniques. Furthermore, luminescent properties of OF are unchanged and the excimers formation in the solid state decrease suggesting the efficiency of nitrile rubber as the matrix for making films.

  3. Gamma-radiation effect on thermal ageing of butyl rubber compounds

    Energy Technology Data Exchange (ETDEWEB)

    Scagliusi, Sandra R.; Cardoso, Elizabeth C.L.; Lugao, Ademar B., E-mail: srscagliusi@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    Butyl rubber has a comprehensive use in sealing systems, especially in tires inner tubes, due to their low permeability to gases. So, it is required that butyl rubber compounds show a better performance, more and more. Butyl rubber is provided with excellent mechanical properties and oxidation resistance. Besides showing these properties, radiation exposures impart modifications in physical-chemical and morphological properties on butyl rubber materials. When exposed to gamma-radiation, rubbers suffer changes in their mechanical and physical properties, caused by material degradation. The major radiation effect in butyl rubbers is chain scission; besides, ageing promotes too the same effect with further build-up of free radicals. This work aims to the study of gamma-radiation in physical-chemical properties of butyl rubber subjected to thermal ageing. Doses used herein were: 25 kGy, 50 kGy, 100 kGy, 150 kGy and 200 KGy. Samples were evaluated before and after ageing according to traditional essays, such as: hardness, tensile strength and elongation at break. From accomplished assessments it is possible to affirm that at doses higher than 50 kGy it was observed a sharp decreasing in butyl rubber physical-chemical properties, before and after exposure to ageing. (author)

  4. Gamma-radiation effect on thermal ageing of butyl rubber compounds

    International Nuclear Information System (INIS)

    Scagliusi, Sandra R.; Cardoso, Elizabeth C.L.; Lugao, Ademar B.

    2015-01-01

    Butyl rubber has a comprehensive use in sealing systems, especially in tires inner tubes, due to their low permeability to gases. So, it is required that butyl rubber compounds show a better performance, more and more. Butyl rubber is provided with excellent mechanical properties and oxidation resistance. Besides showing these properties, radiation exposures impart modifications in physical-chemical and morphological properties on butyl rubber materials. When exposed to gamma-radiation, rubbers suffer changes in their mechanical and physical properties, caused by material degradation. The major radiation effect in butyl rubbers is chain scission; besides, ageing promotes too the same effect with further build-up of free radicals. This work aims to the study of gamma-radiation in physical-chemical properties of butyl rubber subjected to thermal ageing. Doses used herein were: 25 kGy, 50 kGy, 100 kGy, 150 kGy and 200 KGy. Samples were evaluated before and after ageing according to traditional essays, such as: hardness, tensile strength and elongation at break. From accomplished assessments it is possible to affirm that at doses higher than 50 kGy it was observed a sharp decreasing in butyl rubber physical-chemical properties, before and after exposure to ageing. (author)

  5. Preparation of vinyl acetate grafted natural rubber by irradiation method

    Energy Technology Data Exchange (ETDEWEB)

    Porntrairat, A.; Pattamaprom, C. [Center of Excellence on Natural Rubber Technology, Department of Chemical Engineering, Faculty of Engineering, Thammasat University, Pathumthani 12120 (Thailand)

    2016-03-09

    Improvement in properties of natural rubber could be done by several methods. In this research, gamma radiation technique, which is simple, accurate, easy to control and clean, was applied to enhance the properties of natural rubber (NR) in latex state. The purpose of this research is to study the appropriate condition for preparing grafted natural rubber latex by using irradiation method. Vinyl acetate monomers (VAc) were grafted onto natural rubber latex (NR-g-PVAc) at 0-10 kGys by gamma radiation from Cobalt-60 source at room temperature. Physical properties of grafted natural rubber such as chloroform number, swelling ratio and gel content were measured. The VAc content of NR-g-PVAc was investigated by titration and visualized by FTIR spectroscopy. The FTIR spectra of NR-g-PVAc prepared at 0-10 kGys showed characteristic peaks of the vinyl acetate confirming that VAc could be grafted onto natural rubber molecular chains effectively under appropriate irradiation conditions. From the result, radiation grafting was found to be a useful technique for grafting of vinyl acetate onto natural rubber.

  6. Rheological testing of crumb rubber modified bitumen

    CSIR Research Space (South Africa)

    Mturi, GAJ

    2011-08-01

    Full Text Available used to analyse crumb rubber modified (CRM) bitumen is that the specified gap setting in the configuration of the DSR between the upper and lower test platens is too small to accommodate crumb rubber particles. DSR testing of CRM bitumen therefore...

  7. New type of liquid rubber and compositions based on it.

    Science.gov (United States)

    Semikolenov, S V; Nartova, A V; Voronchikhin, V D; Dubkov, K A

    2014-11-01

    The new method for producing the functionalized polymers and oligomers containing carbonyl C=O groups is developed. The method is based on the noncatalytic oxidation of unsaturated rubbers by nitrous oxide (N2O) at 180-230 °С. The proposed method allows obtaining the new type of functionalized rubbers-liquid unsaturated polyketones with regulated molecular weight and concentration of C=O groups. The influence of the liquid polyketone addition on properties of rubber-based composites is investigated. The study indicates good prospects of using the liquid polyketones for the improvement of properties and operating characteristics of the various types of rubbers and the rubber-cord systems.

  8. Adaptive neuro-fuzzy inference system for forecasting rubber milk production

    Science.gov (United States)

    Rahmat, R. F.; Nurmawan; Sembiring, S.; Syahputra, M. F.; Fadli

    2018-02-01

    Natural Rubber is classified as the top export commodity in Indonesia. Its high production leads to a significant contribution to Indonesia’s foreign exchange. Before natural rubber ready to be exported to another country, the production of rubber milk becomes the primary concern. In this research, we use adaptive neuro-fuzzy inference system (ANFIS) to do rubber milk production forecasting. The data presented here is taken from PT. Anglo Eastern Plantation (AEP), which has high data variance and range for rubber milk production. Our data will span from January 2009 until December 2015. The best forecasting result is 1,182% in term of Mean Absolute Percentage Error (MAPE).

  9. Shear modulus and damping ratio of natural rubber containing carbon nanotubes

    Science.gov (United States)

    Ismail, R.; Ibrahim, A.; Rusop, M.; Adnan, A.

    2018-05-01

    This paper presents the results of an investigation into the potential application of Natural rubber (NR) containing Carbon Nanotubes (CNTs) by measuring its shear modulus and damping ratio. Four different types of rubber specimens which fabricated with different MWCNT loadings: 0 wt% (pure natural rubber), 1 wt%, 3 wt%, and 5 wt%. It is observed that the shear modulus and damping ratio of CNTs filled rubber composites are remarkably higher than that of raw rubber indicating the inherent reinforcing potential of CNTs.

  10. Magnetic whiskers of p-aminobenzoic acid and their use for preparation of filled and microchannel silicone rubbers

    International Nuclear Information System (INIS)

    Semenov, V. V.; Loginova, V. V.; Zolotareva, N. V.; Razov, E. N.; Kotomina, V. E.; Kruglov, A. V.

    2016-01-01

    A thin cobalt layer has been formed on the surface of p-aminobenzoic acid whiskers by chemical vapor deposition (CVD). The metallized crystals have been oriented in liquid polydimethylsiloxane rubber by applying a dc magnetic field. After vulcanization, the filler has been removed by processing in an alcohol solution of trifluoroacetic acid. The cobalt deposition on the surface of the organic compound and the properties of metallized whiskers are investigated by optical microscopy, scanning electron microscopy (SEM), and atomic force microscopy (AFM).

  11. Magnetic whiskers of p-aminobenzoic acid and their use for preparation of filled and microchannel silicone rubbers

    Energy Technology Data Exchange (ETDEWEB)

    Semenov, V. V., E-mail: vvsemenov@iomc.ras.ru; Loginova, V. V.; Zolotareva, N. V. [Russian Academy of Sciences, Razuvaev Institute of Organometallic Chemistry (Russian Federation); Razov, E. N. [Lobachevsky Nizhny Novgorod State University (Russian Federation); Kotomina, V. E.; Kruglov, A. V. [Lobachevsky Nizhny Novgorod State University, Physical‒Technical Research Institute (Russian Federation)

    2016-07-15

    A thin cobalt layer has been formed on the surface of p-aminobenzoic acid whiskers by chemical vapor deposition (CVD). The metallized crystals have been oriented in liquid polydimethylsiloxane rubber by applying a dc magnetic field. After vulcanization, the filler has been removed by processing in an alcohol solution of trifluoroacetic acid. The cobalt deposition on the surface of the organic compound and the properties of metallized whiskers are investigated by optical microscopy, scanning electron microscopy (SEM), and atomic force microscopy (AFM).

  12. Use of Diels-Alder Chemistry for Thermoreversible Cross-Linking of Rubbers : The Next Step toward Recycling of Rubber Products?

    NARCIS (Netherlands)

    Polgar, L. M.; van Duin, M.; Broekhuis, A. A.; Picchioni, F.

    2015-01-01

    A proof of principle for the use of Diels-Alder chemistry as a thermoreversible cross-linking tool for rubber products is demonstrated. A commercial ethylene-propylene rubber grafted with maleic anhydride has been thermoreversibly cross-linked in two steps. The pending anhydride rings were first

  13. Evaluation of rubber seal products for gamma facilities

    International Nuclear Information System (INIS)

    Sobhy, M.S.; Shafy, M.A.; Shahin, F.

    2005-01-01

    Ageing behavior by employing the prolonged exposures of high-energy radiation such as gamma-rays on the physicomechanical properties of some rubber seal products are studied. The proposed binary-rubber blends, SBR/NBR, EPDM/NBR and EPDM/EPM. have overcome their problem of inhomogeneity and incompatibility between the two rubber phases. Such enhancements are acquired by either the replacement of part of NBR by SBR during mastication, or the incorporation of maleic anhydride. Results show that the EPDM/EPM rubber blend has possessed the radiation resistance property towards the deterioration due to higher gamma-irradiation dose. The SEM images have c early observed the role of the used antioxidant, where a thin film is usually produced, degraded; with the appearance of surface cracks, and repaired with further gamma-irradiation up to high doses. Such enhancement is necessary for the definition of the requirements to be put on rubber seal materials. Finally, these products ought to assure the quality control in production and evaluate their application suitability that may employ in the pneumatic system in gamma facility

  14. Strength of mortar containing rubber tire particle

    Science.gov (United States)

    Jusoh, M. A.; Abdullah, S. R.; Adnan, S. H.

    2018-04-01

    The main focus in this investigation is to determine the strength consist compressive and tensile strength of mortar containing rubber tire particle. In fact, from the previous study, the strength of mortar containing waste rubber tire in mortar has a slightly decreases compare to normal mortar. In this study, rubber tire particle was replacing on volume of fine aggregate with 6%. 9% and 12%. The sample were indicated M0 (0%), M6 (6%), M9 (9%) and M12 (12%). In this study, two different size of sample used with cube 100mm x 100mm x 100mm for compressive strength and 40mm x 40mm x 160mm for flexural strength. Morphology test was conducted by using Scanning electron microscopic (SEM) were done after testing compressive strength test. The concrete sample were cured for day 3, 7 and 28 before testing. Results compressive strength and flexural strength of rubber mortar shown improved compare to normal mortar.

  15. Effects of preparation process on performance of rubber modified asphalt

    Science.gov (United States)

    Liu, Hanbing; Luo, Guobao; Wang, Xianqiang; Jiao, Yubo

    2015-06-01

    The rational utilization of waste rubber tire is essential for the environmental protection. Utilizing rubber particles to modify asphalt can not only improve asphalt performance, but also help the recycling of waste materials. Considering the effect of different preparation process parameters on the performance of rubber modified asphalt, this paper analyzes the effects of the shear temperature, shear time and shear rate on the performance of rubber modified asphalt, and provided a reference for its preparation.

  16. Characterizing Tire Crumb Rubber for Exposure Assessment

    Science.gov (United States)

    Tire crumb rubber derived from recycled tires is widely used as infill material in synthetic turf fields in the United States. An estimated 95% of the over 12,000 installed fields in the U.S. use tire crumb rubber infill alone or mixed with sand or alternative materials. Concerns...

  17. Effects of the Formulations of Silicon-Based Composite Anodes on their Mechanical, Storage, and Electrochemical Properties.

    Science.gov (United States)

    Assresahegn, Birhanu Desalegn; Bélanger, Daniel

    2017-10-23

    In this work, the effects of the formulation of silicon-based composite anodes on their mechanical, storage, and electrochemical properties were investigated. The electrode formulation was changed through the use of hydrogenated or modified (through the covalent attachment of a binding additive such as polyacrylic acid) silicon and acetylene black or graphene sheets as conducting additives. A composite anode with a covalently grafted binder had the highest elongation without breakages and strong adhesion to the current collector. These mechanical properties depend significantly on the conductive carbon additive used and the use of graphene sheets instead of acetylene black can improve elongation and adhesion significantly. After 180 days of storage under ambient conditions, the electronic conductivity and discharge capacity of the modified silicon electrode showed much smaller decreases in these properties than those of the hydrogenated silicon composite electrode, indicating that the modification can result in passivation and a constant composition of the active material. Moreover, the composite Si anode has a high packing density. Consequently, thin-film electrodes with very high material loadings can be prepared without decreased electrochemical performance. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Caltrans use of scrap tires in asphalt rubber products: a comprehensive review

    Directory of Open Access Journals (Sweden)

    Haiping Zhou

    2014-02-01

    Full Text Available The California Department of Transportation (Caltrans has been using scrap tire rubber in asphalt pavements since the 1970s in chip seals and the 1980s in rubberized hot mix asphalt(RHMA. Both the wet (field blend and dry processes were used in early trials. Caltrans has also used rubber modified binders containing both crumb rubber modifier and polymer modifier that could be manufactured at a refinery facility, a terminal blend wet process. Since the beginning of this century, Caltrans increased the use of scrap tire rubber in paving projects and invested considerable resources in developing technically sound, cost effective, and environmentally friendly strategies for using scrap tire rubber in roadway applications. By the end of year 2010, approximately 31%of all hot mix asphalt (HMA placed by Caltrans was rubberized HMA, roughly 1.2 million tons. Caltrans efforts in using asphalt rubber products were also demonstrated in its research and technology development. These included the construction of two full-scale field experiments, five warranty projects, and an accelerated pavement study using a heavy vehicle simulator. Additionally, terminal blend asphalt rubber and rubberized warm mix asphalts began to be experimented on trial basis. This paper provides a comprehensive review of Caltrans experience over four decades with asphalt rubber products. Current practices and future outlook are also discussed.

  19. Devulcanization of Waste Tire Rubber Using Amine Based Solvents and Ultrasonic Energy

    Directory of Open Access Journals (Sweden)

    Walvekar Rashmi

    2018-01-01

    Full Text Available This research project focuses on an alternative pathway of devulcanizing waste tire rubber by using amine based chemicals. Waste tire rubbers are known to be as toxic, non-degradable material due to their vulcanized crosslink carbon structure, and disposing of such waste could impose hazardous impacts on the environment. The current rubber recycling methods that are practiced today are rather uneconomical, non-environmentally friendly, and also producing recycled rubber with low quality due to the alteration in the main polymeric chains of waste rubber. This project aims to answer the question of whether the usage of amine can produce high quality rubber, where the properties of recycled rubber is almost the same as new/virgin rubber. With known potential of amine, it is a challenge for the chemical to selectively cleave the sulfur bonds without affecting the main carbon backbone chain in the rubber structure and diminishing much of the rubber properties. To study this research, amine-treated rubber must undergo devulcanisation process by applying heat and sonication energy. Then, the properties of the amine-treated rubber were determined through a set of characterization tests and analysis which are: gel content test to determine the weight of rubber before and after devulcanization, the thermogravimetric analysis (TGA to determine the thermal degradation and stability of rubber, and Fourier Transform Infrared Spectroscopy (FTIR to determine any structural change of the rubber. In this research so far, the first two preliminary analysis tests have been performed. The gel content test has shown that tertiary amine samples possessed a lower gel content (% of (77 – 63 %, compared to primary amine samples (falls within the range of 80%, as well as the TGA test in which tertiary amine samples degrade faster than primary amine samples (suggesting a higher degree of rubber structure breakdown. For each type of amine, the concertation of amine did

  20. Optical absorption in silicon layers in the presence of charge inversion/accumulation or ion implantation

    International Nuclear Information System (INIS)

    Alloatti, L.; Lauermann, M.; Koos, C.; Freude, W.; Sürgers, C.; Leuthold, J.

    2013-01-01

    We determine the optical losses in gate-induced charge accumulation/inversion layers at a Si/SiO 2 interface. Comparison between gate-induced charge layers and ion-implanted thin silicon films having an identical sheet resistance shows that optical losses can be significantly lower for gate-induced layers. For a given sheet resistance, holes produce higher optical loss than electrons. Measurements have been performed at λ = 1550 nm

  1. Effect of Graphite on the Properties of Natural Rubber

    Directory of Open Access Journals (Sweden)

    Auda jabber Braihi

    2016-09-01

    Full Text Available Natural rubber-graphite composites (0, 1, 2, 3, 4 pphr graphite were prepared on a laboratory two-roll mill. Swelling measurements were used to evaluate the impacts of graphite on the properties of natural rubber. Swelling results showed that the volume fraction of natural rubber in the swollen gel, the interaction parameter, and the cross-link density decreased by increasing graphite loadings, while the average molecular weight of natural rubber between cross-links increased. Vulcanization results showed that only scorch time parameter increased with increasing graphite loadings, while other parameters (Max. torque, Min. torque, cure rate and cure rate index decreased. Both thermal and AC conductivities increased.

  2. Rheological Properties of Rubber Compounds with Finely Divided Carbon Additives

    Science.gov (United States)

    Shashok, Zh. S.; Prokopchuk, N. R.; Vishnevskii, K. V.; Krauklis, A. V.; Borisevich, K. O.; Borisevich, I. O.

    2018-01-01

    A study has been made of the influence of three different nanomaterials: of the starting material, and also of those functionalized by amine and oxygen-containing groups, on the properties of elastomer compositions based on rubbers for special purposes. As the elastomer matrix, use was made in one case of a rubber compound based on BNKS-18 butadiene-nitrile rubber and in the other, of a combination of two grades of butadiene-nitrile rubber (BNKS-18 + BNKS-28 in a 50:50 ratio), which differed by the amount of the bound nitrile of acrylic acid. To determine the degree of interaction between the additives and the elastomer matrix, the authors carried out multiple tests of the rubber compounds. The indices of plastoelastic properties of the rubber compounds and the qualitative characteristics of distribution of the filler (elastic modulus at small deformation amplitudes and the shear modulus under large deformation) and the difference in these indices (complex dynamic modulus) alike have been determined.

  3. The Effects of Trans- Polyoctylene Rubber (TOR as a Compatibilizer on The Properties of Epoxidized Natural Rubber/Recycled Silicone Catheter (ENR-25/rSC Vulcanizate

    Directory of Open Access Journals (Sweden)

    Dahham Omar S.

    2016-01-01

    Full Text Available In this study, the influence of Trans- Polyoctylene Rubber (TOR as a compatibilizer on the cure characteristics, tensile and physical properties of ENR-25/rSC vulcanizate were determined. Five different loading of TOR (2, 4, 6, 8 and 10 phr were prepared and added into the vulcanizate. Results indicated that the scorch time (t2 and cure time (t90 bacame shorter as TOR increased, while minimum torque (ML and maximum torque (MH increased. The incorporation of TOR with the vulcanizates enhanced the tensile strength (Ts, modulus (M100 crosslinking density and hardness values. However, the elongation at break percentage of compatibilized vulcanizates became lower than uncompatibilized vulcanizates.

  4. Comparative Proteomics of Rubber Latex Revealed Multiple Protein Species of REF/SRPP Family Respond Diversely to Ethylene Stimulation among Different Rubber Tree Clones

    Directory of Open Access Journals (Sweden)

    Zheng Tong

    2017-05-01

    Full Text Available Rubber elongation factor (REF and small rubber particle protein (SRPP are two key factors for natural rubber biosynthesis. To further understand the roles of these proteins in rubber formation, six different genes for latex abundant REF or SRPP proteins, including REF138,175,258 and SRPP117,204,243, were characterized from Hevea brasiliensis Reyan (RY 7-33-97. Sequence analysis showed that REFs have a variable and long N-terminal, whereas SRPPs have a variable and long C-terminal beyond the REF domain, and REF258 has a β subunit of ATPase in its N-terminal. Through two-dimensional electrophoresis (2-DE, each REF/SRPP protein was separated into multiple protein spots on 2-DE gels, indicating they have multiple protein species. The abundance of REF/SRPP proteins was compared between ethylene and control treatments or among rubber tree clones with different levels of latex productivity by analyzing 2-DE gels. The total abundance of each REF/SRPP protein decreased or changed a little upon ethylene stimulation, whereas the abundance of multiple protein species of the same REF/SRPP changed diversely. Among the three rubber tree clones, the abundance of the protein species also differed significantly. Especially, two protein species of REF175 or REF258 were ethylene-responsive only in the high latex productivity clone RY 8-79 instead of in RY 7-33-97 and PR 107. Some individual protein species were positively related to ethylene stimulation and latex productivity. These results suggested that the specific protein species could be more important than others for rubber production and post-translational modifications might play important roles in rubber biosynthesis.

  5. FTIR spectra and mechanical strength analysis of some selected rubber derivatives

    Science.gov (United States)

    Gunasekaran, S.; Natarajan, R. K.; Kala, A.

    2007-10-01

    Rubber materials have wide range of commercial applications such as, infant diapers, famine hygiene products, drug delivery devices and incontinency products such as rubber tubes, tyres, etc. In the present work, studies on mechanical properties of some selected rubber materials viz., natural rubber (NR), styrene butadiene rubber (SBR), nitrile butadiene rubber (NBR) and ethylene propylene diene monomer (EPDM) have been carried out in three states viz., raw, vulcanized and reinforced. To enhance the quality of rubber elastomers, an attempt is made to prepare new elastomers called polyblends. In the present study an attempt is made to blend NR with NBR and with EPDM. We here report, a novel approach for the evaluation of various physico-mechanical properties such as mechanical strength, tensile strength, elongation and hardness. The method is simple, direct and fast and involves infrared spectral measurements for the evaluation of these properties. With the applications of modern infrared spectroscopy, the mechanical strength of these rubber materials have been analyzed by calculating the internal standards among the methyl and methylene group vibrational frequencies obtained from FTIR spectroscopy. Also the tensile strength measurements carried out by universal testing machine. The results pertaining physico-mechanical properties of the rubber derivatives undertaken in the present study obtained by IR-based method are in good agreement with data resulted from the standard methods.

  6. Study of the Properties of Polyurethane-waste Rubber Granulate Composites

    Institute of Scientific and Technical Information of China (English)

    W.W.Sulkowski; M.Moczy′ski; A.Sulkowska; A.Danch; J.Borek; S.Mistarz

    2007-01-01

    1 Results The production of rubber is very high and rises every year. Among other things it is directly connected with the growth of car production. Therefore, the processing of waste rubber and its management must be treated as a global problem. Used rubber may replace conventional fuel and, owing to its low price, can improve the economic effectiveness of combustion. Energy recovery by combustion of car tyres allows for rapid management of rubber waste. However, it is well-known that all kinds of wast...

  7. Buffing dust as a filler of carboxylated butadiene-acrylonitrile rubber and butadiene-acrylonitrile rubber.

    Science.gov (United States)

    Chronska, K; Przepiorkowska, A

    2008-03-01

    Buffing dust from chrome tanned leather is one of the difficult tannery wastes to manage. It is also hazardous to both human health and the environment. The scientific literature rarely reports studies on dust management, especially on its utilization as a filler for elastomers. In this connection we have made an attempt to use this leather waste as a filler for rubbers such as XNBR and NBR. The addition of the buffing dust to rubber mixes brought improvement in mechanical properties, and increase in resistance to thermal ageing as well as in electric conductivity and crosslink density of vulcalizates.

  8. Responses of rubber leaf phenology to climatic variations in Southwest China

    Science.gov (United States)

    Zhai, De-Li; Yu, Haiying; Chen, Si-Chong; Ranjitkar, Sailesh; Xu, Jianchu

    2017-11-01

    The phenology of rubber trees (Hevea brasiliensis) could be influenced by meteorological factors and exhibits significant changes under different geoclimates. In the sub-optimal environment in Xishuangbanna, rubber trees undergo lengthy periods of defoliation and refoliation. The timing of refoliation from budburst to leaf aging could be affected by powdery mildew disease (Oidium heveae), which negatively impacts seed and latex production. Rubber trees are most susceptible to powdery mildew disease at the copper and leaf changing stages. Understanding and predicting leaf phenology of rubber trees are helpful to develop effective means of controlling the disease. This research investigated the effect of several meteorological factors on different leaf phenological stages in a sub-optimal environment for rubber cultivation in Jinghong, Yunnan in Southwest China. Partial least square regression was used to quantify the relationship between meteorological factors and recorded rubber phenologies from 2003 to 2011. Minimum temperature in December was found to be the critical factor for the leaf phenology development of rubber trees. Comparing the delayed effects of minimum temperature, the maximum temperature, diurnal temperature range, and sunshine hours were found to advancing leaf phenologies. A comparatively lower minimum temperature in December would facilitate the advancing of leaf phenologies of rubber trees. Higher levels of precipitation in February delayed the light green and the entire process of leaf aging. Delayed leaf phenology was found to be related to severe rubber powdery mildew disease. These results were used to build predictive models that could be applied to early warning systems of rubber powdery mildew disease.

  9. Towards neuromorphic electronics: Memristors on foldable silicon fabric

    KAUST Repository

    Ghoneim, Mohamed T.

    2014-11-01

    The advantages associated with neuromorphic computation are rich areas of complex research. We address the fabrication challenge of building neuromorphic devices on structurally foldable platform with high integration density. We present a CMOS compatible fabrication process to demonstrate for the first time memristive devices fabricated on bulk monocrystalline silicon (100) which is next transformed into a flexible thin sheet of silicon fabric with all the pre-fabricated devices. This process preserves the ultra-high integration density advantage unachievable on other flexible substrates. In addition, the memristive devices are of the size of a motor neuron and the flexible/folded architectural form factor is critical to match brain cortex\\'s folded pattern for ultra-compact design.

  10. Recycling of Gamma Irradiated Inner Tubes in Butyl Based Rubber Compound

    International Nuclear Information System (INIS)

    Karaagac, B.

    2006-01-01

    Crosslinked elastomeric materials, such as tyres are of great challenge concerning the environmental and ecological reasons. Ionizing radiation seems to offer unique opportunities to tackle the problem of recycling of polymers and rubbers on account of its ability to cause chain scission and/or cross-linking of polymeric materials. There is only limited amount of work reported on the irradiation-induced degradation of rubbers. Unlike the majority of the elastomers with high levels of unsaturation, butyl rubber exhibits significant degradation by ionizing radiation action. In this study, recycling of gamma irradiated inner tubes made of butyl rubber in butyl based rubber compounds was studied. Used inner tubes were irradiated with gamma rays in air at 100 and 120 kGy absorbed doses. The compatibility of irradiated inner tubes with virgin butyl rubber was first investigated. Gamma irradiated inner tube wastes were replaced with butyl rubber up to 15 phr in the compound recipe. Similar recipes were also prepared by using the same quantity of commercial butyl rubber crumbs devulcanized by conventional methods. The rheological and mechanical properties and carbon black dispersion degree for both types of compounds prepared by using inner tubes scraps and commercial butyl crumbs were measured and were compared to the values of virgin butyl rubber compound. It is well known that mechanical properties are deteriorated when rubber crumb is added to the virgin compound. It was observed that the decrease in the mechanical properties was much lower for the compounds prepared from the tubes irradiated at 120 kGy than irradiated at 100 kGy. The better mechanical properties were obtained for the compounds prepared by recycling of irradiated inner tubes at 120 kGy than the compounds prepared by using commercial butyl crumbs. Almost similar carbon black distributions were observed for the all compounds studied. It has been concluded that gamma irradiated inner tubes are compatible

  11. Soil methane and CO2 fluxes in rainforest and rubber plantations

    Science.gov (United States)

    Lang, Rong; Blagodatsky, Sergey; Goldberg, Stefanie; Xu, Jianchu

    2017-04-01

    Expansion of rubber plantations in South-East Asia has been a land use transformation trend leading to losses of natural forest cover in the region. Besides impact on ecosystem carbon stocks, this conversion influences the dynamics of greenhouse gas fluxes from soil driven by microbial activity, which has been insufficiently studied. Aimed to understand how land use change affects the soil CO2 and CH4 fluxes, we measured surface gas fluxes, gas concentration gradient, and 13C signature in CH4 and soil organic matter in profiles in a transect in Xishuangbanna, including a rainforest site and three rubber plantation sites with age gradient. Gas fluxes were measured by static chamber method and open chamber respiration system. Soil gases were sampled from installed gas samplers at 5, 10, 30, and 75cm depth at representative time in dry and rainy season. The soil CO2 flux was comparable in rainforest and old rubber plantations, while young rubber plantation had the lowest rate. Total carbon content in the surface soil well explained the difference of soil CO2 flux between sites. All sites were CH4 sinks in dry season and uptake decreased in the order of rainforest, old rubber plantations and young rubber plantation. From dry season to rainy season, CH4 consumption decreased with increasing CH4 concentration in the soil profile at all depths. The enrichment of methane by 13CH4 shifted towards to lowerδ13C, being the evidence of enhanced CH4 production process while net surface methane flux reflected the consumption in wet condition. Increment of CH4 concentration in the profile from dry to rainy season was higher in old rubber plantation compared to rainforest, while the shifting of δ13CH4 was larger in rainforest than rubber sites. Turnover rates of soil CO2 and CH4 suggested that the 0-5 cm surface soil was the most active layer for gaseous carbon exchange. δ13C in soil organic matter and soil moisture increased from rainforest, young rubber plantation to old

  12. Liquefaction of ground tire rubber at low temperature.

    Science.gov (United States)

    Cheng, Xiangyun; Song, Pan; Zhao, Xinyu; Peng, Zonglin; Wang, Shifeng

    2018-01-01

    Low-temperature liquefaction has been investigated as a novel method for recycling ground tire rubber (GTR) into liquid using an environmentally benign process. The liquefaction was carried out at different temperatures (140, 160 and 180 °C) over variable time ranges (2-24 h) by blending the GTR with aromatic oil in a range from 0 to 100 parts per hundred rubber (phr). The liquefied GTR was separated into sol (the soluble fraction of rubber which can be extracted with toluene) and gel fractions (the solid fraction obtained after extraction) to evaluate the reclaiming efficiency. It was discovered that the percentage of the sol fraction increased with time, swelling ratio and temperature. Liquefied rubber was obtained with a high sol fraction (68.34 wt%) at 140 °C. Simultaneously, separation of nano-sized carbon black from the rubber networks occurred. The separation of carbon black from the network is the result of significant damage to the cross-linked-network that occurs throughout the liquefaction process. During liquefaction, a competitive reaction between main chain scission and cross-link bond breakage takes place. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Properties of concrete containing scrap-tire rubber--an overview.

    Science.gov (United States)

    Siddique, Rafat; Naik, Tarun R

    2004-01-01

    Solid waste management is one of the major environmental concerns in the United States. Over 5 billion tons of non-hazardous solid waste materials are generated in USA each year. Of these, more than 270 million scrap-tires (approximately 3.6 million tons) are generated each year. In addition to this, about 300 million scrap-tires have been stockpiled. Several studies have been carried out to reuse scrap-tires in a variety of rubber and plastic products, incineration for production of electricity, or as fuel for cement kilns, as well as in asphalt concrete. Studies show that workable rubberized concrete mixtures can be made with scrap-tire rubber. This paper presents an overview of some of the research published regarding the use of scrap-tires in portland cement concrete. The benefits of using magnesium oxychloride cement as a binder for rubberized concrete mixtures are also presented. The paper details the likely uses of rubberized concrete.

  14. Degrading radiation effects on properties of bromobutyl rubber compounds

    Energy Technology Data Exchange (ETDEWEB)

    Scagliusi, Sandra R.; Cardoso, Elisabeth C.L.; Pozenato, Cristina A.; Lugao, Ademar B., E-mail: srscagliusi@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2013-07-01

    The understanding of chemistry involved in degradation induced radiation is becoming more and more relevant in the re-use of polymeric materials, as well in beneficial radiation uses. Degrading radiation effects have been considered from viewpoint of controlled degradation for isoprene/isobutene in rubbers for recycling purposes. Bromobutyl rubber (BIIR) is an isobutylene/isoprene copolymer comprising 1.9 to 2.1% bromine and has a lot of applications including in tires air-chambers. In this work there were evaluated gamma-irradiation effects for re-use or recycling objectives in elastomeric bromobutyl compositions irradiated at 5, 15, 25, 50, 100,150 and 200 kGy. Mechanical properties, hardness and swelling were assessed in non-vulcanized and vulcanized rubber, non-irradiated and irradiated at different doses. The major gamma radiation effect in butyl rubber is the generation of free radicals along changes in mechanical properties. Irradiation effects in bromobutyl rubber compounds were comprehensively investigated, demonstrated and discussed. (author)

  15. Degrading radiation effects on properties of bromobutyl rubber compounds

    International Nuclear Information System (INIS)

    Scagliusi, Sandra R.; Cardoso, Elisabeth C.L.; Pozenato, Cristina A.; Lugao, Ademar B.

    2013-01-01

    The understanding of chemistry involved in degradation induced radiation is becoming more and more relevant in the re-use of polymeric materials, as well in beneficial radiation uses. Degrading radiation effects have been considered from viewpoint of controlled degradation for isoprene/isobutene in rubbers for recycling purposes. Bromobutyl rubber (BIIR) is an isobutylene/isoprene copolymer comprising 1.9 to 2.1% bromine and has a lot of applications including in tires air-chambers. In this work there were evaluated gamma-irradiation effects for re-use or recycling objectives in elastomeric bromobutyl compositions irradiated at 5, 15, 25, 50, 100,150 and 200 kGy. Mechanical properties, hardness and swelling were assessed in non-vulcanized and vulcanized rubber, non-irradiated and irradiated at different doses. The major gamma radiation effect in butyl rubber is the generation of free radicals along changes in mechanical properties. Irradiation effects in bromobutyl rubber compounds were comprehensively investigated, demonstrated and discussed. (author)

  16. HERBERT HOOVER, GREAT BRITAIN, AND THE RUBBER CRISIS, 1923-1926

    Directory of Open Access Journals (Sweden)

    Silvano A. Wueschner

    2000-01-01

    Full Text Available This paper examines the controversy arising out of Great Britain’s decision to implement the Stevenson plan. It examines, in particular, the role played by Herbert Hoover, both behind the scenes and in an effort to affect the repeal of the Stevenson scheme and at the same time to encourage and support the development of new sources of rubber under the control of American producers. During the period 1920-1922 rubber producing countries were confronted by the specter of overproduction. The existence of even a short term oversupply coupled with the business slump, a reaction from the war, led to a decline in the price of rubber. British producers succeeded in inducing the British Colonial authorities to support a scheme whereby rubber exports would be regulated in order to bring about an increase in the price of rubber. This plan, developed by the Stevenson Committee, called for a small minimum tax on all exports. Moreover, it soughtto limit production by establishing a quota based on the actual production of rubber during the 1919-1920 growing season. A progressive tax was applied to exports beyond standard production. American reaction to the scheme was varied. Secretary of Commerce Hoover, while publicly stating that the price of rubber had been low and was supportive of efforts to regulate production, behind the scenes showed a great deal of concern about the actions of the British government in regulating a commodity of which the United States was the single largest consumer. He was also linked, by some, to the idea that Great Britain sought to pay its war debt to the United States through the application of this tax. Much was made in American newspapers and the British press about Hoover’s criticism of British rubber restrictions. He was not opposed to regulating the supply of rubber, but only to the involvement of a government in the process, especially when it affected American producers and consumers. In response he proposed a scheme

  17. Silicon solar cells made by ion implantation and glow discharge

    International Nuclear Information System (INIS)

    Ponpon, J.P.; Siffert, P.

    1975-01-01

    Three different methods of silicon solar cell preparation are considered and investigated: low energy implantation, glow discharge and prebombarded Schottky barriers. The properties of the contact layers realized by these processes are compared in terms of junction depth and sheet resistance. Preliminary results show the usefulness of these techniques for terrestrial solar cell realization [fr

  18. STUDY ON HEAT DYNAMIC LOADING OF RUBBER

    Directory of Open Access Journals (Sweden)

    T. I. Igumenova

    2015-01-01

    Full Text Available A number of studies on heat buildup in tire rubber surface scan method samples using a thermal imaging camera. Investigated the exothermic chemical reaction mechanical destruction rubber when loading designs permanent cyclic stretching with deformation of the working zone 50%. Percentage of deformation of the working zone was chosen on the basis of the actual data on the stretch-compression zone "Rusk" tires, which is the maximum level difference of deformation during run-in. Experiment plan provided for periodic relaxation samples of at least 72 hours for more accurate simulation of operation process of structural products. Created and processed data on temperature changes in samples for bar and line profile for rubber compounds with the introduction of nanomodifiers (fulleren technical carbon in comparison with the control sample without him. The data obtained reflect the nature of heat depending on the composition of the compound. Identified common patterns of thermal nature of physico-chemical process mechanical destruction rubbers. For rubber with nanomodifikatorom there has been an increase in the temperature interval reaction from a minimum to a maximum 2 degrees that is also linked to the rise in the average temperature of the reaction on the histogram also at 2-3 degrees of deformation under the same conditions and the level of cyclic loading. However, the temperature in the control sample that is associated with the beginning of the formation of hardened rubber structures, economies of Mallinz-Petrikeev, occurs with delay twice compared with modified Fullerenes. Measurement of physic-mechanical indicators selected in the course of testing of samples showed the beginning of formation of structure with increased strength of samples in the sample temperature zone that corresponds to the thermal effect of èndotermičeskomu recombination reactions of macromolecules.

  19. Mechanical Properties of Graphene-Rubber Nanocomposites

    Science.gov (United States)

    Anhar, N. A. M.; Ramli, M. M.; Hambali, N. A. M. A.; Aziz, A. A.; Mat Isa, S. S.; Danial, N. S.; Abdullah, M. M. A. B.

    2017-11-01

    This research focused on development of wearable sensor device by using Prevulcanized Natural Rubber (PV) and Epoxidized Natural Rubber (ENR 50) latex incorporated with graphene oxide (GO), graphene paste, graphene powder and reduced graphene oxide (rGO) powder. The compounding formulation and calculation were based on phr (parts per hundred rubber) and all the samples were then tested for mechanical properties using Instron 5565 machine. It was found that the sonication effects on tensile strength may have better quality of tensile strength compared to non-sonicated GO. For PV incorporate GO, the optimum loading was best determined at loading 1.5 phr with or without sonication and similar result was recorded for PV/G. For ENR 50 incorporate graphene paste and rGO powder nanocomposite shows the best optimum was at 3.0 phr with 24 hours’ sonication.

  20. Chemi-microbial processing of waste tire rubber: A project overview

    International Nuclear Information System (INIS)

    Romine, R.A.; Snowden-Swan, L.

    1993-12-01

    PNL is developing a method to use thiophillic microorganisms to devulcanize (biodesulfurize) the surface of ground rubber particles, which will improve the bonding and adhesion of the ground tire rubber into the virgin tire rubber matrix. The Chemi-microbial processing approach, introduced in this paper, is targeted at alleviating the waste tire problem in an environmentally conscious manner; it may also be applied to improve asphaltic materials and rubber and polymeric wastes to facilite their recycling. This paper outlines the logic and technical methods that will be used

  1. Utilization of waste tire rubber in manufacture of oriented strandboard.

    Science.gov (United States)

    Ayrilmis, Nadir; Buyuksari, Umit; Avci, Erkan

    2009-09-01

    Some physical and mechanical properties of oriented strandboards (OSBs) containing waste tire rubber at various addition levels based on the oven-dry strand weight, using the same method as that used in the manufacture of OSB. Two resin types, phenol-formaldehyde (PF) and polyisocyanate, were used in the experiments. The manufacturing parameters were: a specific gravity of 0.65 and waste tire rubber content (10/90, 20/80 and 30/70 by wt.% of waste tire rubber/wood strand). Average internal bond values of PF-bonded OSB panels with rubber chips were between 17.6% and 48.5% lower than the average of the control samples while polyisocyanate bonded OSBs were 16.5-50.6%. However, water resistance and mechanical properties of OSBs made using polyisocyanate resin were found to comply with general-purpose OSB minimum property requirements of EN 300 Type 1 (1997) values for use in dry conditions at the lowest tire rubber loading level (10%) based on the oven-dry panel weight. The tire rubber improved water resistance of the OSB panel due to its almost hydrophobic property. Based on the findings obtained from this study, we concluded that waste tire rubber could be used for general-purpose OSB manufacturing up to 10% ratio based on the oven-dry panel weight.

  2. their use as Accelerator in Curing Process of Rubber Compounds

    Directory of Open Access Journals (Sweden)

    S. taghvaee

    2007-06-01

    Full Text Available In some special cases, rubber compounds with high amounts of unsaturated elastomer are recommended with organic sulfur donors instead of mineral sulfurs. In this condition, activated sulfur is produced in situ and curingprocess is facilitated without accelerators. Organic sulfur donor compounds have low thermal stability and in the vulcanization temperature produce free and activated sulfurs. The advantages of these compounds are:1. High effectiveness of curing agent in low quantities in rubber compounds manufacturing.2. Producing activated sulfurs in controlled condition and avoiding the over curing of rubber compounds.In this report the novel synthesis of some derivatives of diamino-disulfides which can be applied as sulfur donors in vulcanization of special rubber compounds is introduced. The key process is reaction of sulfurmonochloride with amines in petroleum ether as solvent in low temperature. Dithio-dimorpholine(DTDM, dithio-dipipyridyl (DTDP, dithio-bis dibutylamine (DTBDB and dithio-bisdiisopropyl amine (DTBDI were prepared according to this method. All products thus obtained were characterized by 1H and 13C-NMR spectroscopies. The effects of accelerating and sulfur donoring of all prepared agents were detected in rubber compounds with natural and synthetic rubber bases. All physical, chemical, reological and mechanical properties of rubber compounds based on prepared sulfur donors were characterized.

  3. The optimum content of rubber ash in concrete: flexural strength

    Science.gov (United States)

    Senin, M. S.; Shahidan, S.; Shamsuddin, S. M.; Ariffin, S. F. A.; Othman, N. H.; Rahman, R.; Khalid, F. S.; Nazri, F. M.

    2017-11-01

    Discarded scrap tyres have become one of the major environmental problems nowadays. Several studies have been carried out to reuse waste tires as an additive or sand replacement in concrete with appropriate percentages of tire rubber, called as rubberized concrete to solve this problem. The main objectives of this study are to investigate the flexural strength performance of concrete when adding the rubber ash and also to analyse the optimum content of rubber ash in concrete prisms. The performance total of 30 number of concrete prisms in size of 100mm x 100mm x 500 mm were investigated, by partially replacement of rubber ash with percentage of 0%, 3%, 5%, 7% and 9% from the volume of the sand. The flexural strength is increased when percentage of rubber ash is added 3% from control concrete prism, RA 0 for both concrete prism age, 7 days and 28 days with value 1.21% and 0.976% respectively. However, for RA 5, RA 7 and RA 9, the flexural strength was decreased compared to the control for both age, 7 days and 28 days. In conclusion, 3% is the optimum content of rubber ash in concrete prism for both concrete age

  4. Synthesis, characterization and degradation behavior of admicelled polyacrylate-natural rubber

    International Nuclear Information System (INIS)

    Pongpilaipruet, Angkana; Magaraphan, Rathanawan

    2015-01-01

    In order to improve weatherability of the cured natural rubber, the novel introduction of good ozone resistant polymers such as polyacrylates (poly(methyl acrylate) (PMA) or poly(methyl methacrylate) (PMMA)) into natural rubber (NR) by admicellar polymerization was investigated in this work. The admicellar polymerization to synthesize polyacrylate layer over the surface of NR latex particles was performed with varying monomer type (PMA and PMMA) and content (50 and 100 mM). The admicelled PMMA showed higher molecular weight than PMA. Fourier transform infrared spectra of the admicellar synthesized natural rubbers exhibited characteristic peaks of those polyacrylates. Micrographs from transmission electron and field emission scanning electron microscopes (FE-SEM) revealed the coatings of PMA and PMMA over the rubber particles, suggesting a core-shell structure. Thermogravimetric analysis revealed that the admicelled rubbers not only showed an improvement in heat stability but also a single decomposition temperature. After vulcanization, FE-SEM results showed the cured admicelled rubbers had phase transformation from core-shell to phase separation (aggregate domains of polyacrylate-rich phase) with smooth interface. This agreed well to their one glass transition temperature (∼−48 °C) which indicated good miscibility between NR and each polyacrylate. The cracks generated after exposure to ozone found in the admicelled rubbers were smaller than those in NR, suggesting better ozone resistance was achieved. Increasing monomer concentration led to less cracks or much better ozone resistance. Furthermore, changes in mechanical properties after ozone exposure of the admicelled PMA-NR were less than those of the admicelled PMMA-NR (having the same shell content) and the NR, respectively. - Highlights: • We use admicellar technique to add polyacrylates to NR in form of core-shell rubber. • This core-shell structure was physically formed as seen by the phase

  5. Synthesis, characterization and degradation behavior of admicelled polyacrylate-natural rubber

    Energy Technology Data Exchange (ETDEWEB)

    Pongpilaipruet, Angkana; Magaraphan, Rathanawan, E-mail: rathanawan.k@chula.ac.th

    2015-06-15

    In order to improve weatherability of the cured natural rubber, the novel introduction of good ozone resistant polymers such as polyacrylates (poly(methyl acrylate) (PMA) or poly(methyl methacrylate) (PMMA)) into natural rubber (NR) by admicellar polymerization was investigated in this work. The admicellar polymerization to synthesize polyacrylate layer over the surface of NR latex particles was performed with varying monomer type (PMA and PMMA) and content (50 and 100 mM). The admicelled PMMA showed higher molecular weight than PMA. Fourier transform infrared spectra of the admicellar synthesized natural rubbers exhibited characteristic peaks of those polyacrylates. Micrographs from transmission electron and field emission scanning electron microscopes (FE-SEM) revealed the coatings of PMA and PMMA over the rubber particles, suggesting a core-shell structure. Thermogravimetric analysis revealed that the admicelled rubbers not only showed an improvement in heat stability but also a single decomposition temperature. After vulcanization, FE-SEM results showed the cured admicelled rubbers had phase transformation from core-shell to phase separation (aggregate domains of polyacrylate-rich phase) with smooth interface. This agreed well to their one glass transition temperature (∼−48 °C) which indicated good miscibility between NR and each polyacrylate. The cracks generated after exposure to ozone found in the admicelled rubbers were smaller than those in NR, suggesting better ozone resistance was achieved. Increasing monomer concentration led to less cracks or much better ozone resistance. Furthermore, changes in mechanical properties after ozone exposure of the admicelled PMA-NR were less than those of the admicelled PMMA-NR (having the same shell content) and the NR, respectively. - Highlights: • We use admicellar technique to add polyacrylates to NR in form of core-shell rubber. • This core-shell structure was physically formed as seen by the phase

  6. Model fire tests on polyphosphazene rubber and polyvinyl chloride (PVC)/nitrile rubber foams

    Science.gov (United States)

    Widenor, W. M.

    1978-01-01

    A video tape record of model room fire tests was shown, comparing polyphosphazene (P-N) rubber and polyvinyl chloride (PVC)/nitrile rubber closed-cell foams as interior finish thermal insulation under conditions directly translatable to an actual fire situation. Flashover did not occur with the P-N foam and only moderate amounts of low density smoke were formed, whereas with the PVC/nitrile foam, flashover occurred quickly and large volumes of high density smoke were emitted. The P-N foam was produced in a pilot plant under carefully controlled conditions. The PVC/nitrile foam was a commercial product. A major phase of the overall program involved fire tests on P-N open-cell foam cushioning.

  7. Mechanical properties of concrete containing a high volume of tire-rubber particles.

    Science.gov (United States)

    Khaloo, Ali R; Dehestani, M; Rahmatabadi, P

    2008-12-01

    Due to the increasingly serious environmental problems presented by waste tires, the feasibility of using elastic and flexible tire-rubber particles as aggregate in concrete is investigated in this study. Tire-rubber particles composed of tire chips, crumb rubber, and a combination of tire chips and crumb rubber, were used to replace mineral aggregates in concrete. These particles were used to replace 12.5%, 25%, 37.5%, and 50% of the total mineral aggregate's volume in concrete. Cylindrical shape concrete specimens 15 cm in diameter and 30 cm in height were fabricated and cured. The fresh rubberized concrete exhibited lower unit weight and acceptable workability compared to plain concrete. The results of a uniaxial compressive strain control test conducted on hardened concrete specimens indicate large reductions in the strength and tangential modulus of elasticity. A significant decrease in the brittle behavior of concrete with increasing rubber content is also demonstrated using nonlinearity indices. The maximum toughness index, indicating the post failure strength of concrete, occurs in concretes with 25% rubber content. Unlike plain concrete, the failure state in rubberized concrete occurs gently and uniformly, and does not cause any separation in the specimen. Crack width and its propagation velocity in rubberized concrete are lower than those of plain concrete. Ultrasonic analysis reveals large reductions in the ultrasonic modulus and high sound absorption for tire-rubber concrete.

  8. Radiation vulcanization of natural rubber latex sensitized with commercial gases

    International Nuclear Information System (INIS)

    Chirinos, H.; Lugao, A.

    2002-01-01

    The industrial activities using natural rubber latex are fully compatible with rural areas in Amazon and other places in Brazil, as well as in other tropical countries. However the classical sulfur vulcanization presents many occupational problems for the workers in rural areas. Radiation vulcanization of natural rubber latex is a much more friendly process as sulfur compounds are not needed for crosslinking, although chemicals as acrylate monomers, particularly multifunctional acrylates are still used as sensitizers for radiation processes. Two commercial gases, acetylene and butadiene, were selected as sensitizers for the radiation vulcanization of natural rubber latex instead of acrylates. These gases accelerate the crosslinking rates of the cure process and lower the radiation dose required to achieve vulcanization of natural rubber latex and improve the mechanical properties to reduce the tackiness of rubber goods. (author)

  9. Radiation vulcanization of natural rubber latex sensitized with commercial gases

    Energy Technology Data Exchange (ETDEWEB)

    Chirinos, H.; Lugao, A. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)

    2002-07-01

    The industrial activities using natural rubber latex are fully compatible with rural areas in Amazon and other places in Brazil, as well as in other tropical countries. However the classical sulfur vulcanization presents many occupational problems for the workers in rural areas. Radiation vulcanization of natural rubber latex is a much more friendly process as sulfur compounds are not needed for crosslinking, although chemicals as acrylate monomers, particularly multifunctional acrylates are still used as sensitizers for radiation processes. Two commercial gases, acetylene and butadiene, were selected as sensitizers for the radiation vulcanization of natural rubber latex instead of acrylates. These gases accelerate the crosslinking rates of the cure process and lower the radiation dose required to achieve vulcanization of natural rubber latex and improve the mechanical properties to reduce the tackiness of rubber goods. (author)

  10. Ultraviolet curing of acrylated liquid natural rubber for surface coating application

    Directory of Open Access Journals (Sweden)

    Kannikar Kwanming

    2009-01-01

    Full Text Available Ultraviolet curable acrylated liquid natural rubber was prepared by grafting of photosensitive molecule onto liquid natural rubber for surface coating application. The liquid natural rubber (LNR was firstly obtained by degradation of natural rubber latex with hydrogen peroxide and cobalt acetylacetonate at 65oC for 72 hrs. The preparation of acrylated natural rubber was carried out by the reaction of acrylic acid and epoxidized liquid natural rubber (ELNR prior obtained from LNR with formic acid and hydrogen peroxide in the ratio of 2:1 by weight in toluene at 80oC for 6, 9, 12, 18, and 24 hrs. It was found that the percentage of acrylate grafted onto liquid natural rubber depended on the reaction time. Surface coating was performed by using acrylated liquid natural rubber and 1,6-hexanediol diacrylate (HDDA or tripropylene glycol diacrylate (TPGDA as a crosslinker and Irgarcure 184 or Irgarcure 651 as a photoinitiator under UV exposure for 30, 60, and 90 seconds. The hardness test of cured products was investigated using the Pencil hardness test at pencil level of 2B to 6H. It was found that the highest hardness of surface coating was at pencil level of 4H for the product using TPGDA and Irgacure 651 in the ratio of 80:10 parts per hundred of rubber (phr. The cured products were able to resist to 2% H2SO4 and distilled water for more than 24 hrs.

  11. Experimental Investigation on Damping Property of Coarse Aggregate Replaced Rubber Concrete

    Science.gov (United States)

    Sugapriya, P.; Ramkrishnan, R.; Keerthana, G.; Saravanamurugan, S.

    2018-02-01

    Rubber has good damping and vibrational characteristics and can reduce cracking significantly due to its elastic nature. This property of rubber can be incorporated in concrete to control vibrations and create better pavements. Crumb Rubber on being dumped in landfills has serious repercussions and causes soil and land pollution. An innovative use of waste tires is shredding them into small pieces and using them as a replacement for coarse aggregate. Crumb rubber is obtained by chopping scrap tires, and in this study it was added in two different sets named SET 1 - Treated Crumb Rubber and concrete, and SET 2 - Treated Crumb rubber with Ultra Fine GGBS as admixture in concrete. Coarse aggregate replaces Rubber in each of the 2 SET’s in proportions of 5, 10, 15 and 20%. Properties like Compressive Strength, Young’s Modulus, Direct and Semi direct Ultrasonic Pulse Velocity, Sorptivity, Damping ratio and Frequency were found out. Deformation and mode shape were studied with modal analysis and static analysis by applying a uniform pressure corresponding to the highest compressive strength of the slab, using ANSYS.

  12. Laboratory Evaluation of Ground Tire Rubber in Stone Mastic Asphalt

    Directory of Open Access Journals (Sweden)

    R. Muniandy

    2004-12-01

    Full Text Available Stone mastic asphalt (SMA is a gap-graded mix whereby stiffer asphalt cement is required to bind the stone matrix or arrangement of stones together. Although various asphalt additives are traditionally available, the use of rubber crumbs in SMA is still a new rresearch endeavor. Many countries around the world are facing serious problems on what to do with reject or discarded tires. In the present study, commercial truck tires, containing 70% natural rubber, were ground and pre-blended in 80-100 penetration asphalt for use in SMA mixtures. An assessment was made of the laboratory performance of rubberized SMA in terms of stability, resilent modulus, dynamic creep and tensile strength ratio. It was observed that the performance of SMA with ground tire rubber was for superior as compared to SMA mix with unmodified asphalt. Sulfur and Styrene Butadeline Rubber (SBR were used in rubberized SMA mixes as additives to test the sensitivity of SMA mixtures. As standard practice a 0.3% newly developed cellulose oil palm fiber was used in SMA to minimize the asphalt drain-down effects.

  13. Improved properties of dissimilar rubber-rubber blends using plasma polymer encapsulated curatives : a novel surface modification method to improve co-vulcanization

    NARCIS (Netherlands)

    Guo, R.

    2009-01-01

    In industrial applications, different rubber types are often blended to fine-tune or optimize the property portfolio required for successful performance of articles. Considering the complexity of a rubber blend compound, wherein numerous additives are involved, vulcanization or cure mismatch often

  14. Strength and microstructure characteristics of the recycled rubber tire-sand mixtures as lightweight backfill.

    Science.gov (United States)

    Zhang, Tao; Cai, Guojun; Duan, Weihong

    2018-02-01

    The disposal of scrap rubber tires has induced critical environmental issue worldwide due to the rapid increase in the number of vehicles. Recycled scrap tires as a construction material in civil engineering have significant environmental benefits from a waste management perspective. A systematic study that deals with strength and microstructure characteristics of the rubber-sand mixtures is initiated, and mechanical response of the mixtures is discussed in this investigation. Experiments were conducted to evaluate the effects of rubber fraction on the basic properties including mass density (ρ), stress-strain characteristics, shear strength, and unconfined compression strength (q u ) of the rubber-sand mixtures. Additionally, scanning electron microscopy (SEM) was carried out to reveal the microstructure characteristics of the mixtures with various rubber fractions. A discussion on the micromechanics of the mixtures also was conducted. This study demonstrates that the ρ, friction angle, and q u decrease linearly with an increase in rubber fraction, whereas shear strain at peak increases. The stress-strain characteristics of the rubber-sand mixtures shift from brittle to ductile as the rubber fraction increase. These changes are attributed to remarkably lower stiffness and higher compressibility of the rubber particle compared with those of the conventional mineral aggregates. With an increase in the rubber fraction, the mechanical response of rubber-sand mixtures exhibits two types: sand-like material and rubber-like material. Rubber particle possesses the capacity to prevent the contacted sand particles from sliding at lower rubber fraction, whereas it transmits the applied loadings as the rubber fraction increased. This outcome reinforces the practicability of using recycled rubber tire-sand mixtures as a lightweight backfill in subbase/base applications.

  15. A review on fatigue life prediction methods for anti-vibration rubber materials

    Directory of Open Access Journals (Sweden)

    Xiaoli WANG

    2016-08-01

    Full Text Available Anti-vibration rubber, because of its superior elasticity, plasticity, waterproof and trapping characteristics, is widely used in the automotive industry, national defense, construction and other fields. The theory and technology of predicting fatigue life is of great significance to improve the durability design and manufacturing of anti-vibration rubber products. According to the characteristics of the anti-vibration rubber products in service, the technical difficulties for analyzing fatigue properties of anti-vibration rubber materials are pointed out. The research progress of the fatigue properties of rubber materials is reviewed from three angles including methods of fatigue crack initiation, fatigue crack propagation and fatigue damage accumulation. It is put forward that some nonlinear characteristics of rubber under fatigue loading, including the Mullins effect, permanent deformation and cyclic stress softening, should be considered in the further study of rubber materials. Meanwhile, it is indicated that the fatigue damage accumulation method based on continuum damage mechanics might be more appropriate to solve fatigue damage and life prediction problems for complex rubber materials and structures under fatigue loading.

  16. Time series analysis of the behavior of brazilian natural rubber

    Directory of Open Access Journals (Sweden)

    Antônio Donizette de Oliveira

    2009-03-01

    Full Text Available The natural rubber is a non-wood product obtained of the coagulation of some lattices of forest species, being Hevea brasiliensis the main one. Native from the Amazon Region, this species was already known by the Indians before the discovery of America. The natural rubber became a product globally valued due to its multiple applications in the economy, being its almost perfect substitute the synthetic rubber derived from the petroleum. Similarly to what happens with other countless products the forecast of future prices of the natural rubber has been object of many studies. The use of models of forecast of univariate timeseries stands out as the more accurate and useful to reduce the uncertainty in the economic decision making process. This studyanalyzed the historical series of prices of the Brazilian natural rubber (R$/kg, in the Jan/99 - Jun/2006 period, in order tocharacterize the rubber price behavior in the domestic market; estimated a model for the time series of monthly natural rubberprices; and foresaw the domestic prices of the natural rubber, in the Jul/2006 - Jun/2007 period, based on the estimated models.The studied models were the ones belonging to the ARIMA family. The main results were: the domestic market of the natural rubberis expanding due to the growth of the world economy; among the adjusted models, the ARIMA (1,1,1 model provided the bestadjustment of the time series of prices of the natural rubber (R$/kg; the prognosis accomplished for the series supplied statistically adequate fittings.

  17. Application of gamma irradiation for incorporation of rubber powder in the formulations

    International Nuclear Information System (INIS)

    Kiyan, Ludmila Y.P.; Lugao, Ademar B.; Parra, Duclerc F.; Zaharescu, Traian

    2013-01-01

    The aim of this paper was to study the behavior of rubber recycle, in powder form of rubber industry. It was used EPDM rubber powder. The rubber powder was irradiated and used directly in classical formulations of rubber vulcanizate. The master-batch processed material was irradiated at doses of 50, 100 and 150kGy in 60 Co source at 5kGy s -1 rate, at room temperature. Gamma radiation created active sites devulcanization for further integration of the material (rubber powder) with facilities in formulations of commercial use. The processes were compared and their products were characterized by analytical methods of the physical properties such as tensile strength, elongation, hardness, rheology and abrasion tests. (author)

  18. Preparation of Natural Rubber (NR) Based Nano-Sized Materials Using Sol-Gel Technique

    International Nuclear Information System (INIS)

    Dahlan Mohd; Mahathir Mohamed

    2011-01-01

    The objectives of this project are to prepare nano-sized natural rubber-based hybrid coating material by sol-gel technique; to explore the possibility of producing ENR-Si (epoxidized natural rubber-silica) cramer with toughening effects; and to use it in radiation curing of surface coating. Since early 1960s Malaysia has introduced various forms of value-added natural rubber such as Standard Malaysian Rubber (SMR), methylmethacrylate-grafted natural rubber (MG rubber), followed by liquid natural rubber and epoxidized natural rubber (ENR). Products such as liquid epoxidized natural rubber acrylate (LENRA) and thermoplastic natural rubber (TPNR) are still on-going research projects in Nuclear Malaysia. The former has strong possibility to be used as radiation-sensitive comparabilities in TPNR blends, besides its original purpose for example in radiation curing of surface coating. But earlier findings indicated that, to make it (as for surface coating) more effective, reinforcement system is needed to be introduced. Strong candidate is silica by sol-gel technique, since common reinforcement filler for example carbon black has drawbacks in this particular case. This technique was introduced in late 1960s to produce metal oxides such as silica and titanium oxides in solution. (author)

  19. Mechanical properties of hexaferite based magnet composite of SrFe12019 and BaFe12O19 with natural rubber bonding agent

    International Nuclear Information System (INIS)

    Waluyo, T.; Herman, Y.A.; Sudirman; Ridwan

    2000-01-01

    Research on mechanical properties at magnet composite of SrFe 12 0 19 (SrM) and BaFe 12 O 19 (BaM)magnet powder with natural rubber bonding agent have been done. The natural rubber used was rubber made of latex without vulcanization, The SrM powder having average particle size of 1.6 μm and flat shaped. and the BaM powder having particle size of 1.2 μm and nodular shaped. The production of composite carried out in Labo Plastomill at 100 o C and mixer speed of 30 rpm for 7 minutes. The result obtained from Labo Plastomill then made into sheets. Mechanical properties of the composite tested were strain, elongation break and hardness, The results showed that the highest strain of the SrM composite obtained at composition of 70% vol of powder that is 2,22 MPa, and 3,84 MPa for BaM composite at 50% vol. of powder The elongation break of SrM composite decreased by increasing of powder volume fraction, that is 90% at the composition or 70% vol. of powder, and 370% for BaM composite at 50% vol. fraction of powder. The highest hardness for SrM composite obtained at composition of of 70% vol. of powder, that is 95 SHA. and for the BaM composite at 50% vol. of powder. that is 52 SHA

  20. The use of radiotracers in natural rubber research in Malaysia

    International Nuclear Information System (INIS)

    Lai, P.F.; Singh, M.M.

    1981-01-01

    Five main areas where radiotracers have been used in research on natural rubber are on studies on the uptake of plant nutrients by Hevea brasiliensis using 32 P, 86 Rb and 45 Ca as tracers; biosynthesis of Hevea rubber using 14 C or 3 H labelled intermediates; translocation and metabolism of 14 C. Ethephon in Hevea brasiliensis; use of radiotracers as analytical tools and adsorption of labelled fatty acid soaps on natural rubber lattices. These studies are discussed to show the powerful tool that radiotracers provide in agricultural, biochemical and chemical research on natural rubber. (author)

  1. Competitiveness and Exports Sustainability of the Indonesian Natural Rubber

    Directory of Open Access Journals (Sweden)

    Rumbiati Kamaludin

    2018-03-01

    Full Text Available This paper examines Indonesian competitiveness in export of natural rubber commodities by employing set of revealed comparative advantage (RCA and Export competitive index (ECI with respect to global trade. The market structure that is formed on natural rubber commodities is calculated using Herfindahl Index and Concentration Ratio analysis tools shows the oligopoly-shaped market structure. Calculation of comparative advantage with RCA analysis shows that the four countries exporting natural rubber, namely Thailand, Indonesia, Malaysia and Vietnam each have a comparative advantage. Where Indonesia has a better comparative advantage than Thailand in the period 2011 to 2015. This result is different from the calculations made on competitive advantage (ECI in which Indonesia's natural rubber commodities are not more competitive than Thailand

  2. Silver powder effectiveness and mechanism of silver paste on silicon solar cells

    International Nuclear Information System (INIS)

    Tsai, Jung-Ting; Lin, Shun-Tian

    2013-01-01

    Highlights: ► Optimizing the silver paste in 80–85 wt.%. ► Optimizing its particle size in 1–1.5 μm spherical powder. ► The sheet resistance is 4 mΩ/sq during the 860 °C sintering process. ► Redox reaction cause Ag crystallites to grow on the interface. ► A thin layer of silicon oxide (75–150 nm) was formed. - Abstract: Since the silver paste plays a major role in the mass production of silicon solar cells, this work has succeeded in optimizing the silver paste in 80–85 wt.% and optimizing its particle size in 1–1.5 μm spherical powder. As the firing temperature is increased, the growth trend of silver grain is improved. The result of this work has showed that the lowest sheet resistance is 4 mΩ/sq during the 860 °C sintering process. The scanning electron microscope (SEM) observation has showed that the formation of silver oxide is formed during the melting process of glass and triggered redox reaction of Ag crystallites to grow on the interface. It has proven by transmission electron microscope (TEM) that a thin layer of silicon oxide (75–150 nm) was formed, respectively.

  3. Rubber friction on road surfaces: Experiment and theory for low sliding speeds

    Energy Technology Data Exchange (ETDEWEB)

    Lorenz, B.; Persson, B. N. J. [PGI, FZ Jülich, 52425 Jülich (Germany); Oh, Y. R.; Nam, S. K.; Jeon, S. H. [Hankook Tire Co. LTD., 112 Gajeongbuk-ro, Yuseong-gu, Daejeon 305-725 (Korea, Republic of)

    2015-05-21

    We study rubber friction for tire tread compounds on asphalt road surfaces. The road surface topographies are measured using a stylus instrument and atomic force microscopy, and the surface roughness power spectra are calculated. The rubber viscoelastic modulus mastercurves are obtained from dynamic mechanical analysis measurements and the large-strain effective modulus is obtained from strain sweep data. The rubber friction is measured at different temperatures and sliding velocities, and is compared to the calculated data obtained using the Persson contact mechanics theory. We conclude that in addition to the viscoelastic deformations of the rubber surface by the road asperities, there is an important contribution to the rubber friction from shear processes in the area of contact. The analysis shows that the latter contribution may arise from rubber molecules (or patches of rubber) undergoing bonding-stretching-debonding cycles as discussed in a classic paper by Schallamach.

  4. Effect of electron beam irradiation on the properties of crosslinked rubbers

    Science.gov (United States)

    Banik, Indranil; Bhowmick, Anil K.

    2000-05-01

    Influence of electron beam (EB) irradiation on the mechanical and dynamic mechanical properties of crosslinked fluorocarbon (FKM) rubber, natural rubber (NR), ethylene propylene diene monomer (EPDM) rubber and nitrile rubber (NBR) has been investigated. The modulus, gel fraction, glass transition temperature ( Tg) and storage modulus increased, while the elongation at the break and the loss tangent (tan δ) Tg decreased. FKM and NBR vulcanizates have been shown to have EB radiation resistance up to 1500 kGy.

  5. Particle reinforced composites from acrylamide modified blend of styrene-butadiene and natural rubber

    Science.gov (United States)

    Blends of styrene-butadiene rubber and natural rubber that provide balanced properties were modified with acrylamide and reinforced with soy protein particles. The rubber composites show improved mechanical properties. Both modified rubber and composites showed a faster curing rate. The crosslinking...

  6. A review on the suitability of rubberized concrete for concrete bridge decks

    Science.gov (United States)

    Syamir Senin, Mohamad; Shahidan, Shahiron; Radziah Abdullah, Siti; Anting Guntor, Nickholas; Syazani Leman, Alif

    2017-11-01

    Road authorities manage a large population of ageing bridges, a substantial number of which fail to meet the current requirements either due to deterioration and other structural deficiencies or as a result of the escalating demands imposed by increased traffic. This problem is related to the dynamic load from vehicles. This problem can be solved by producing a type of concrete that can reduce the amplitude of oscillation or vibration such as rubberized concrete. Green construction has been a very important aspect in concrete production field in the last decade. One of the most problematic waste materials is scrap tires. The use of scrap tires in civil engineering is increasing by producing rubberized concrete. Rubberized concrete is a type of concrete that is mixed with rubber. The purpose of this review is to justify the suitability of rubberized concrete for concrete bridge decks. Several parameters named physical, chemical and mechanical properties were measured to ensure the suitability of rubberized concrete for concrete bridge decks. Rubberized concrete has similar workability to normal concrete. The rubber reduced the density and compressive strength of the concrete while increased the flexural strength, water absorption and damping ratio. The used of rubber in concrete beyond 20% is not recommended due to decreasing in compressive strength. Rubberized concrete recommended to be used in circumstances where vibration damping was required such as in bridge construction as shock-wave absorber.

  7. Piezoresistive pressure sensor using low-temperature aluminium induced crystallization of sputter-deposited amorphous silicon film

    International Nuclear Information System (INIS)

    Tiwari, Ruchi; Chandra, Sudhir

    2013-01-01

    In the present work, we have investigated the piezoresistive properties of silicon films prepared by the radio frequency magnetron sputtering technique, followed by the aluminium induced crystallization (AIC) process. Orientation and grain size of the polysilicon films were studied by x-ray diffraction analysis and found to be in the range 30–50 nm. Annealing of the Al–Si stack on an oxidized silicon substrate was performed in air ambient at 300–550 °C, resulting in layer exchange and transformation from amorphous to polysilicon phase. Van der Pauw and Hall measurement techniques were used to investigate the sheet resistance and carrier mobility of the resulting polycrystalline silicon film. The effect of Al thickness on the sheet resistance and mobility was also studied in the present work. A piezoresistive pressure sensor was fabricated on an oxidized silicon substrate in a Wheatstone bridge configuration, comprising of four piezoresistors made of polysilicon film obtained by the AIC process. The diaphragm was formed by the bulk-micromachining of silicon substrate. The response of the pressure sensor with applied negative pressure in 10–95 kPa range was studied. The gauge factor was estimated to be 5 and 18 for differently located piezoresistors on the diaphragm. The sensitivity of the pressure sensor was measured to be ∼ 30 mV MPa −1 , when the Wheatstone bridge was biased at 1 V input voltage. (paper)

  8. Surface improvement of EPDM rubber by plasma treatment

    Energy Technology Data Exchange (ETDEWEB)

    Moraes, J H [LPP, Physics Department, ITA, CTA, Pca Mal Eduardo Gomes 50, 12228-900 Sao Jose dos Campos, S.P. (Brazil); Silva Sobrinho, A S da [LPP, Physics Department, ITA, CTA, Pca Mal Eduardo Gomes 50, 12228-900 Sao Jose dos Campos, S.P. (Brazil); Maciel, H S [LPP, Physics Department, ITA, CTA, Pca Mal Eduardo Gomes 50, 12228-900 Sao Jose dos Campos, S.P. (Brazil); Dutra, J C N [EBO, Chemistry Division, IAE, CTA, Pca Mal Eduardo Gomes 50, 12228-904 Sao Jose dos Campos, S.P. (Brazil); Massi, M [LPP, Physics Department, ITA, CTA, Pca Mal Eduardo Gomes 50, 12228-900 Sao Jose dos Campos, S.P. (Brazil); Mello, S A C [EBO, Chemistry Division, IAE, CTA, Pca Mal Eduardo Gomes 50, 12228-904 Sao Jose dos Campos, S.P. (Brazil); Schreiner, W H [Physics Department, UFPR, Centro Politecnico, 80060-000 Curitiba, P.R. (Brazil)

    2007-12-21

    The surface of ethylene-propylene-diene monomer (EPDM) rubber was treated in N{sub 2}/Ar and N{sub 2}/H{sub 2}/Ar RF plasmas in order to achieve similar or better adhesion properties than NBR (acrylonitrile-butadiene) rubber, nowadays used as thermal protection of rocket chambers. The surface properties were studied by contact angle measurements and by x-ray photoelectron spectroscopy (XPS). The treated surfaces of the EPDM samples show a significant reduction in the contact angle measurement, indicating an increase in the surface energy. XPS analyses show the incorporation of polar nitrogen- and oxygen-containing groups on the rubber surface. After plasma treatment the presence of oxygen is observed due to surface oxidation which occurs when the samples are exposed to the air. Atomic force microscopy and scanning electron microscopy analyses indicate a decrease in the EPDM rubber surface roughness, promoted by surface etching during the plasma treatment. Strength tests indicate improvement of about 30% and 110% in the adhesion strength for the plasma treated EPDM/polyurethane liner interface and for the EPDM/epoxy adhesive interface, respectively. The adhesion strength of the EPDM/liner is similar to that obtained for the NBR/liner, which indicates that EPDM rubber can safely be used as thermal protection of the solid propellant rocket chamber.

  9. Surface improvement of EPDM rubber by plasma treatment

    International Nuclear Information System (INIS)

    Moraes, J H; Silva Sobrinho, A S da; Maciel, H S; Dutra, J C N; Massi, M; Mello, S A C; Schreiner, W H

    2007-01-01

    The surface of ethylene-propylene-diene monomer (EPDM) rubber was treated in N 2 /Ar and N 2 /H 2 /Ar RF plasmas in order to achieve similar or better adhesion properties than NBR (acrylonitrile-butadiene) rubber, nowadays used as thermal protection of rocket chambers. The surface properties were studied by contact angle measurements and by x-ray photoelectron spectroscopy (XPS). The treated surfaces of the EPDM samples show a significant reduction in the contact angle measurement, indicating an increase in the surface energy. XPS analyses show the incorporation of polar nitrogen- and oxygen-containing groups on the rubber surface. After plasma treatment the presence of oxygen is observed due to surface oxidation which occurs when the samples are exposed to the air. Atomic force microscopy and scanning electron microscopy analyses indicate a decrease in the EPDM rubber surface roughness, promoted by surface etching during the plasma treatment. Strength tests indicate improvement of about 30% and 110% in the adhesion strength for the plasma treated EPDM/polyurethane liner interface and for the EPDM/epoxy adhesive interface, respectively. The adhesion strength of the EPDM/liner is similar to that obtained for the NBR/liner, which indicates that EPDM rubber can safely be used as thermal protection of the solid propellant rocket chamber

  10. Surface improvement of EPDM rubber by plasma treatment

    Science.gov (United States)

    Moraes, J. H.; da Silva Sobrinho, A. S.; Maciel, H. S.; Dutra, J. C. N.; Massi, M.; Mello, S. A. C.; Schreiner, W. H.

    2007-12-01

    The surface of ethylene-propylene-diene monomer (EPDM) rubber was treated in N2/Ar and N2/H2/Ar RF plasmas in order to achieve similar or better adhesion properties than NBR (acrylonitrile-butadiene) rubber, nowadays used as thermal protection of rocket chambers. The surface properties were studied by contact angle measurements and by x-ray photoelectron spectroscopy (XPS). The treated surfaces of the EPDM samples show a significant reduction in the contact angle measurement, indicating an increase in the surface energy. XPS analyses show the incorporation of polar nitrogen- and oxygen-containing groups on the rubber surface. After plasma treatment the presence of oxygen is observed due to surface oxidation which occurs when the samples are exposed to the air. Atomic force microscopy and scanning electron microscopy analyses indicate a decrease in the EPDM rubber surface roughness, promoted by surface etching during the plasma treatment. Strength tests indicate improvement of about 30% and 110% in the adhesion strength for the plasma treated EPDM/polyurethane liner interface and for the EPDM/epoxy adhesive interface, respectively. The adhesion strength of the EPDM/liner is similar to that obtained for the NBR/liner, which indicates that EPDM rubber can safely be used as thermal protection of the solid propellant rocket chamber.

  11. Formation of shallow boron emitters in crystalline silicon using flash lamp annealing: Role of excess silicon interstitials

    Energy Technology Data Exchange (ETDEWEB)

    Riise, Heine Nygard, E-mail: h.n.riise@fys.uio.no; Azarov, Alexander; Svensson, Bengt G.; Monakhov, Edouard [Department of Physics/Centre for Materials Science and Nanotechnology, University of Oslo, P. O. Box 1048 Blindern, N-0316 Oslo (Norway); Schumann, Thomas; Hübner, Renè; Skorupa, Wolfgang [Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, P. O. Box 510119, 01314 Dresden (Germany)

    2015-07-13

    Shallow, Boron (B)-doped p{sup +} emitters have been realized using spin-on deposition and Flash Lamp Annealing (FLA) to diffuse B into monocrystalline float zone Silicon (Si). The emitters extend between 50 and 140 nm in depth below the surface, have peak concentrations between 9 × 10{sup 19 }cm{sup –3} and 3 × 10{sup 20 }cm{sup –3}, and exhibit sheet resistances between 70 and 3000 Ω/□. An exceptionally large increase in B diffusion occurs for FLA energy densities exceeding ∼93 J/cm{sup 2} irrespective of 10 or 20 ms pulse duration. The effect is attributed to enhanced diffusion of B caused by Si interstitial injection following a thermally activated reaction between the spin-on diffusant film and the silicon wafer.

  12. Development of rubber gloves by radiation vulcanization

    International Nuclear Information System (INIS)

    Makuuchi, K.; Yoshii, F.; Ishigaki, I.; Mogi, M.; Saito, T.

    1990-01-01

    The processes of radiation vulcanization and production of protective rubber gloves for radioactive contamination are described. A newly developed sensitizing system consisting of 5 phr 2-ethylhexyl acrylate and 1 phr carbon tetrachloride was used to vulcanize natural rubber latex at 12 kGy. Transparent and soft gloves were obtained from the radiation vulcanized latex by a coagulant dipping process. The mechanical properties of the gloves meet Japanese Industrial Standard specification for protective gloves. Combustion analysis of the gloves revealed that the amount of evolved sulfur dioxide and remaining ashes are less than those from commercially available rubber gloves. A trial usage of the gloves at a nuclear power plant showed that the gloves were easy to use for delicate work without undergoing fatigue. (author)

  13. Synthesis and characterization of silver nanoparticles in natural rubber

    International Nuclear Information System (INIS)

    Abu Bakar, N.H.H.; Ismail, J.; Abu Bakar, M.

    2007-01-01

    Silver nanoparticles are formed in natural rubber matrix via photo reduction of film cast from natural rubber latex (NRL) containing silver salt. The resulting NR-Ag nanocomposite is characterized using TEM, XRD and UV spectroscopic techniques. The nanoparticles, diameter ranging between 4 and 10 nm, are dispersed within distinct interfaces which correspond to the inter-particle boundaries of the NRL particles that form the matrix. The average width of the interfaces is 8 nm. X-ray diffraction (XRD) analysis confirms the nanoparticles as metallic silver of the face-centered cubic type. UV-vis absorption spectra show peaks characteristic of the surface plasmon resonance of nano-sized silver. A comparison with the results of formation of silver, obtained under similar reduction condition, in a series of matrices namely de-proteinized natural rubber latex (DNRL), NRL containing sodium dodecyl sulfate (SDS), aqueous solutions of bovain serum albumin and SDS, suggests that the protein in natural rubber is responsible for the formation of stable silver nanoparticles in the natural rubber (NR) matrix

  14. Review on Parameters Influencing the Rice Breakage and Rubber Roll Wear in Sheller

    Directory of Open Access Journals (Sweden)

    Prabhakaran P.

    2017-09-01

    Full Text Available The present review deals with parameters influencing the rice breakage during rice milling operations and the effect of rubber roll Sheller in rice husk removal process. The main objective of rice milling system is to remove the husk and bran layer to produce the white rice. In this process, rubber roll sheller is used to remove husk from the grains by friction process. If the rubber material is too soft, there may not be sufficient shear force to husk the paddy. Wear will be minimum for rubber material with high hardness but indeed it pronounce the breakage of rice. Hence, for efficient husking the rubber roll material should possess the balance of physico-mechanical properties. Rice breakage depends on several other parameters like the type of harvest, drying temperature, drying methods, physical characteristics of paddy, husking characteristics, paddy moisture content, rubber roller speed, rubber roll pressure, paddy feed rate and fissures. Rubber roll wear depends on the type of rubber material attached to the roller, feed rate, roller speed, pressure etc.

  15. Polybutadiene and Styrene-Butadiene rubbers for high-dose dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Lucas N. [Instituto Federal de Educacao, Ciencia e Tecnologia de Goias-IFG,Campus Goiania, Goiania -GO (Brazil); Instituto de Pesquisas Energeticas e Nucleares -IPEN, Sao Paulo-SP (Brazil); Vieira, Silvio L. [Instituto de Fisica, Universidade Federal de Goias-UFG, Campus Samambaia, Goiania-GO (Brazil); Schimidt, Fernando [Instituto Federal de Educacao, Ciencia e Tecnologia de Goias-IFG,Campus Inhumas, Inhumas-GO (Brazil); Antonio, Patricia L.; Caldas, Linda V.E. [Instituto de Pesquisas Energeticas e Nucleares -IPEN, Sao Paulo-SP (Brazil)

    2015-07-01

    Polybutadiene and Styrene-Butadiene are synthetical rubbers used widely for pneumatic tires manufacturing. In this research, the dosimeter characteristics of those rubbers were studied for application in high-dose dosimetry. The rubber samples were irradiated with doses of 10 Gy up to 10 kGy, using a {sup 60}Co Gamma Cell-220 system (dose rate of 1.089 kGy/h) and their readings were taken on a Fourier Transform Infrared Spectroscopy-FTIR system (model Frontier/Perkin Elmer). The ratios of two absorbance peaks were taken for each kind of rubber spectrum, Polybutadiene (1306/1130 cm{sup -1}) and Styrene-Butadiene (1449/1306 cm{sup -1}). The ratio calculated was used as the response to the irradiation, and is not uniform across the sample. From the results, it can be concluded for both rubbers: a) the dose-response curves may be useful for high-dose dosimetry (greater than 250 Gy); b) their response for reproducibility presented standard deviations lower than 2.5%; c) the relative sensitivity was higher for Styrene-Butadiene (1.86 kGy{sup -1}) than for Polybutadiene (1.81 kGy{sup -1}), d) for doses of 10 kGy to 200 kGy, there was no variation in the dosimetric response. Both types of rubber samples showed usefulness as high-dose dosimeters. (authors)

  16. Study on a Haptic Sensor Using MCF (Magnetic Compound Fluid) Electric Conductive Rubber

    Science.gov (United States)

    Zheng, Yaoyang; Shimada, Kunio

    To provide a new composite material having a high degree of sensitivity regarding both electrical conduction and temperature for the field of robotics or sensing, we have developed magnetic rubber that contains a network-like magnetic cluster. We compared the temperature response of MCF rubber with others rubbers made under various experimental conditions, allowing us to find an optimum condition for making MCF rubber. The temperature response was obtained by an experimental equation. We also compared the electric conductivity of MCF rubber with that of ordinary electric conductive rubber and found that its electric sensitivity was lower at a small deformation, but increased at larger deformations. Therefore, MCF rubber has proven itself effective as a switching sensor when a small deformation is applied.

  17. Rubber lining design for grinding mills: influence on economy and capacity

    Energy Technology Data Exchange (ETDEWEB)

    Nillson, G

    1979-11-01

    There is a difference in design parameters between steel linings and rubber linings for grinding mills. The basic design parameters for rubber are described and a comparison is made between steel and rubber in different applications. If a rubber lining is correctly designed, it will give at least the same capacity as any other type of lining. A rubber lining can often be made thinner than other types of lining and, in such cases, the increased mill diameter will increase the capacity. What has been said above regarding capacity applies equally to grinding efficiency. The grind can sometimes be changed by altering the lifter height and lifter profile. Rubber linings of the correct quality and design will always give improved lining economy, except for large primary ball mills. We trust that new designs and rubber qualities will change the picture in the future. What is said about lining economy is especially true when taking reduced downtime and maintenance into consideration. The lining must be designed to reduce sliding over the shell, which leads to heavy wear. When used for dry grinding, the adverse effects of temperature must be observed.

  18. Basic design of on-line analyzer for sheet paper using X-ray fluorescence (XRF) technique

    International Nuclear Information System (INIS)

    Rony Djokorayono; Ahmad Suntoro; Ikhsan Shobari; Usep Setia Gunawan

    2016-01-01

    Basic design of on-line analyzer for sheet paper using X-ray fluorescence technique has been carried out. Compared with sampling technique, this X-ray fluorescence technique has some advantages in term of analysis accuracy and time. The design activities performed including the establishment of design requirements, functional requirements, technical requirements, technical specification, detection sub-system design, data acquisition sub-system design, and operator computer console design. This program will use silicon drift or CdTe X-ray detector to detect X-ray fluorescence emitted by elements in sheet paper due to X-ray interaction of a X-ray source, 55 Fe (Ferro-55).This basic design of on-line analyzer for sheet paper using X-ray fluorescence technique should be followed up with the development of detailed design, prototype construction, and field testing. (author)

  19. Effect of electron beam irradiation on the properties of crosslinked rubbers

    Energy Technology Data Exchange (ETDEWEB)

    Banik, Indranil; Bhowmick, Anil K. E-mail: anilkb@rtc.iitkgp.ernet.in

    2000-05-01

    Influence of electron beam (EB) irradiation on the mechanical and dynamic mechanical properties of crosslinked fluorocarbon (FKM) rubber, natural rubber (NR), ethylene propylene diene monomer (EPDM) rubber and nitrile rubber (NBR) has been investigated. The modulus, gel fraction, glass transition temperature (T{sub g}) and storage modulus increased, while the elongation at the break and the loss tangent (tan {delta}){sub T{sub g}} decreased. FKM and NBR vulcanizates have been shown to have EB radiation resistance up to 1500 kGy. (author)

  20. Effect of electron beam irradiation on the properties of crosslinked rubbers

    International Nuclear Information System (INIS)

    Banik, Indranil; Bhowmick, Anil K.

    2000-01-01

    Influence of electron beam (EB) irradiation on the mechanical and dynamic mechanical properties of crosslinked fluorocarbon (FKM) rubber, natural rubber (NR), ethylene propylene diene monomer (EPDM) rubber and nitrile rubber (NBR) has been investigated. The modulus, gel fraction, glass transition temperature (T g ) and storage modulus increased, while the elongation at the break and the loss tangent (tan δ) T g decreased. FKM and NBR vulcanizates have been shown to have EB radiation resistance up to 1500 kGy. (author)