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.

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...

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

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

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

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

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)

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.

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

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

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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.

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

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.

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

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.

Properties and Characterization of Kenaf-Filled Natural Rubber Latex Foam

Directory of Open Access Journals (Sweden)

Ahmad Fikri Abdul Karim

2015-12-01

Full Text Available Kenaf powder was incorporated with natural rubber latex (NRL compound and foamed to make natural rubber latex foam (NRLF by using a well known technique called the Dunlop method. Different loadings of kenaf powder were added to NRL compound and was foamed to make NRLF. The mechanical properties, density, compression, thermal, and micro-structural characterization of control NRLF and kenaf incorporated NRLF were studied. Increasing content of kenaf reduced the tensile strength, elongation at break, and compressive strength of a NRLF. Modulus at 100% elongation and density of the NRLF increased with an increase in filler loading. Higher kenaf loading indicated higher elasticity of kenaf-filled NRLF, but the recovery percentage of kenaf-filled NRLF decreased with increasing kenaf loading. From thermogravimetric analysis (TGA result, an increase in the amount of kenaf loading from 1 to 7 phr increased the thermal stability of kenaf-filled NRLF. Morphological and micro-structural characterization performed by using scanning electron microscopy (SEM showed that kenaf powder filled up the micro-sized pores in the open cell structure of kenaf-filled NRLF.

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

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.

Understanding the viscoelastic behavior of silica filled rubber

NARCIS (Netherlands)

de Castro, J.G.

2014-01-01

This thesis focuses on the understanding the viscoelastic behavior of silica filled Nitrile Butadiene Rubber (NBR) using different sizes/surface areas in three different regions of deformation that will be developed in 3 chapters. The characterization of the samples used in this work is described in

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.

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...

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.

Effect of filling surface-treated pyrolytic char on resistivity of rubber films

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Pattraporn Yamkaya

2015-03-01

Full Text Available In this research, natural rubber (NR films filled with pyrolytic tire char, carbon black N234 and N330 were compared for their electrical resistivity. The filler loading was varied to be 5, 10, 15, 20 and 25% of dry rubber content. The effect of surfactant which is 2 %w/v sodium dodecyl sulfate (SDS was also investigated. In the experiments, it was necessary to disperse the pyrolytic char in ethyl alcohol while disperse carbon black (CB in ammonium hydroxide solution prior to mixing with the rubber latex and the filled NR film was prepared by casting the mixture on a plate. It was found that increasing the amount of pyrolytic char in the NR film could lower its resistivity. The surfactant, SDS, could help better dispersion of both CB and pyrolytic char, thereby decreasing the resistivity. In a separate experiment where hexane vapor was absorbed in NR film without surfactant, in the first 30 seconds, the rate of increasing resistivity of the CB-filled film was not seen as clearly as that of pyrolytic-char-filled film. For the films with surfactant, the slow increase in resistivity of the NR films filled with N330 and pyrolytic char during adsorbing hexane vapor was observed.

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.

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

Application of mathematical planning in production of filled emulsion rubbers

Science.gov (United States)

Pugacheva, I. N.; Molokanova, L. V.; Popova, L. V.; Repin, P. S.

2018-05-01

The applicability of mathematical planning of experiment in the field of chemistry and chemical engineering, in particular in the industrial production of synthetic rubbers, is considered in the article. Possibility of using secondary material resources, which are waste products of light industry, in the production of elastomeric compositions is studied. The method of obtaining a powdered cellulose additive from wastes containing cellulose fiber is described. The best way of introducing the obtained additive into elastomeric compositions based on the emulsion rubber is established. Optimal conditions for obtaining filled emulsion rubber with the help of a powdered cellulose additive were established basing on the mathematical planning of experiment.

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.

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

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.

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.

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

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.

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.

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.)

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

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 ...

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.

Mechanical performance of styrene-butadiene-rubber filled with carbon nanoparticles prepared by mechanical mixing

Energy Technology Data Exchange (ETDEWEB)

Saatchi, M.M. [Department of Chemical and Petroleum Engineering, Sharif University of Technology, P.O. Box 11155-9465, Tehran (Iran, Islamic Republic of); Shojaei, A., E-mail: akbar.shojaei@sharif.edu [Department of Chemical and Petroleum Engineering, Sharif University of Technology, P.O. Box 11155-9465, Tehran (Iran, Islamic Republic of)

2011-09-15

Highlights: {yields} We compare influence of carbon blacks and carbon nanotube on properties of SBR. {yields} We model mechanical behavior of SBR nanocomposites by the micromechanical model. {yields} Mechanical properties of carbon black/SBR is greatly dominated by bound rubber. {yields} Mechanical properties of SBR/nanotube is governed by big aspect ratio of nanotube. - Abstract: Reinforcement of styrene-butadiene-rubber (SBR) was investigated using two different carbon blacks (CBs) with similar particle sizes, including highly structured CB and conventional CB, as well as multi-walled carbon nanotube (MWCNT) prepared by mechanical mixing. The attempts were made to examine reinforcing mechanism of these two different classes of carbon nanoparticles. Scanning electron microscopy and electrical conductivity measurement were used to investigate morphology. Tensile, cyclic tensile and stress relaxation analyses were performed. A modified Halpin-Tsai model based on the concept of an equivalent composite particle, consisting of rubber bound, occluded rubber and nanoparticle, was proposed. It was found that properties of CB filled SBR are significantly dominated by rubber shell and occluded rubber in which molecular mobility is strictly restricted. At low strains, these rubber constituents can contribute in hydrodynamic effects, leading to higher elastic modulus. However, at higher strains, they contribute in stress hardening resulting in higher elongation at break and higher tensile strength. These elastomeric regions can also influence stress relaxation behaviors of CB filled rubber. For SBR/MWCNT, the extremely great inherent mechanical properties of nanotube along with its big aspect ratio were postulated to be responsible for the reinforcement while their interfacial interaction was not so efficient.

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.

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

EBM Irradiation Modification of Palm Oil Biomass Filled Reclaimed Rubber-Mechanical Study

International Nuclear Information System (INIS)

Pairu Ibrahim; Ratnam, C.T.

2016-01-01

In this project, a study was done to evaluate the mechanical properties of reclaimed rubber filled with palm oil empty fruit bunch (EFB) as fillers. The purpose of filler is to help improve the properties of reclaim rubber and the addition of filler is fixed at 10 parts. Palm oil EFB was obtained from Malaysian Palm Oil Board (MPOB) and prepared at different size. Various samples were prepared with various sizes of filler blended with reclaim rubber using Haake Hot Mixer. The compounds were then compression-moulded at 120 degree Celsius using an electrically heated hydraulic press for their cure times. Dumbbell-shaped tensile and test specimens for hardness and impact test were punched out from the compression-moulded slabs along the mill grain direction. From the test result, it was found that the addition of fillers able to increase the mechanical properties of reclaim rubber and the smaller size of fillers added produced higher tensile properties. The study shows that the palm oil EFB suitable to be used as filler in reclaim rubber. (author)

Tensile properties of carbon black-filled natural rubber latex films using two different approaches of film preparation

Science.gov (United States)

Jarkasi, Siti Aisyah; Samsuri, Azemi; Hashim, M. Y. Amir; Kamarun, Dzaraini

2017-09-01

A study was structured to investigate the effects of two different approaches of black-filled NRL films preparation on tensile strengths and tensile stress at 100% strain (M100). In the "First Approach", carbon black dispersion was added into the NRL and mixed using mechanical stirrer. Then the black-filled NRL was coagulated with acetic acid and dried to form NR black-filled masterbatch. This black-filled NR masterbatch was then masticated and mixed with other compounding ingredients on the 2-roll mill. In the "Second Approach", carbon black dispersion was mixed with NRL plus all other compounding ingredients using a mechanical stirrer at high mechanical stirring speed (200 rpm) for 3 hrs. Tensile test-pieces from these two rubber specimens were tested according to ISO37. It was observed that the tensile strengths are affected by both methods. In the case of masticated latex masterbatch, the black-filled NRL films gave higher tensile strength (25-27 MPa) as compared to un-masticated black-filled NRL films (11-17 MPa). The optimum amount of filler loading for highest tensile strength in both approaches was 20 phr of carbon black. However these different approaches did not give significant effect to the elongation at break, EB and M100. SEM images of samples prepared from both approaches suggested that the dispersion of filler in the rubber matrix was better in the masticated samples compared to the un-masticated samples. The reason for the difference in the tensile strength between the two black-filled rubbers might be associated with the degree of dispersions and the uniformity of the dispersions within the rubber matrix. The first mixing approach involved high mechanical shearing action during mastication and mixing process on the 2-roll mill. The high shearing actions were able to breakdown filler aggregates efficiently and distributed the dispersed filler uniformly within the rubber matrix. In the second approach, the breakdown of filler aggregates relied on

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

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

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)

Hugoniot-based equations of state for two filled EPDM rubbers

Science.gov (United States)

Pacheco, Adam; Dattelbaum, Dana; Orler, E.; Gustavsen, R.

2013-06-01

The shock response of silica filled and Kevlar filled ethylene-propylene-diene (EPDM) rubbers was studied using gas gun-driven plate impact experiments. Both materials are proprietary formulations made by Kirkhill-TA, Brea CA USA, and are used for ablative internal rocket motor insulation. Two types of experiments were performed. In the first, the filled-EPDM sample was mounted on the front of the projectile and impacted a Lithium Fluoride (LiF) window. The Hugoniot state was determined from the measured projectile velocity, the EPDM/LiF interface velocity (measured using VISAR) and impedance matching to LiF. In the second type of experiment, electromagnetic particle velocity gauges were embedded between layers of filled-EPDM. These provided in situ particle velocity and shock velocity measurements. Experiments covered a pressure range of 0.34 - 14 GPa. Hugoniot-based equations of state were obtained for both materials, and will be compared to those of other filled elastomers such as silica-filled polydimethylsiloxane and adiprene. Work performed while at Los Alamos National Laboratory.

Molecular Diffusion of Toluene through CaCO3-Filled Natural Rubber Composites

Directory of Open Access Journals (Sweden)

Hedayatollah Sadeghi Ghari

2012-12-01

Full Text Available The transport properties of liquids and gases through polymeric materialsplay a very important role in some areas of industrial applications. In thisstudy, natural rubber (NR/CaCO3 composites were prepared by melt mixingmethod. By equilibrium swelling test, the transport process of toluene in the prepared natural rubber composites was investigated. The diffusion and transport of toluene through calcium carbonate-filled natural rubber composites have been studied in the temperature range 25–45°C. The diffusion of toluene through these composites was studied with special reference to the effect of filler concentration and temperature.The transport coefficients such as diffusion, permeation and sorption coefficients were estimated from the swelling data. To find out the mechanism of diffusion in prepared composites, the results of swelling studies were applied to an empirical equation. In these composites, diffusion is approximately based on Fickian diffusion mechanism and by increases in temperature; diffusion mechanism is more close to Fickian mechanism. Increase of filler content in composite would result in decreased ultimateswelling and slower diffusion rate of solvent. The diffusion rate, diffusion coefficient and the permeability increased by temperature. The study of the diffusion of toluene through filled natural rubber indicated that the concentration of filler plays an important role in the diffusion, sorption and permeation coefficients. Also interfacial interactions in NR composites were checked by dynamic-mechanical analysis. The microstructure and dispersion of calcium carbonate particles in natural rubber matrix were studiedby field emission scanning electron microscopy (FE-SEM. In general, the results of swelling tests, dynamic-mechanical analysis and FE-SEM images show that the optimized value of filler in NR composites is equal to 10 phr calcium carbonate.

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 ...

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.

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

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)

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.)

Mechanical and morphological properties of kenaf powder filled natural rubber latex foam

Energy Technology Data Exchange (ETDEWEB)

Karim, Ahmad Fikri Abdul, E-mail: a.fikri-89@yahoo.com; Ariff, Zulkifli Mohamad [School of Materials and Mineral Resources Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Pulau Pinang (Malaysia); Ismail, Hanafi [Cluster for Polymer Composites (CPC), Science and Engineering Research Centre, Engineering Campus, Universiti Sains Malaysia,14300 Nibong Tebal, Pulau Pinang (Malaysia)

2015-07-22

This research is carried out by incorporate kenaf powder with natural rubber latex (NRL) compound and is foamed to make natural rubber latex foam (NRLF) by using a well known technique called Dunlop method. Different loading of kenaf powder was added to NRL compound and was foamed to make NRLF. The tensile properties, and morphology of kenaf filled NRLF was studied. Increase in kenaf loading reduced the tensile strength and elongation at break and of a compound. Modulus at 100% elongation of the compound increased with increased in filler loading. The morphological and micro structural characterization has been performed by using scanning electron microscopy (SEM)

Mechanical and morphological properties of kenaf powder filled natural rubber latex foam

International Nuclear Information System (INIS)

Karim, Ahmad Fikri Abdul; Ariff, Zulkifli Mohamad; Ismail, Hanafi

2015-01-01

This research is carried out by incorporate kenaf powder with natural rubber latex (NRL) compound and is foamed to make natural rubber latex foam (NRLF) by using a well known technique called Dunlop method. Different loading of kenaf powder was added to NRL compound and was foamed to make NRLF. The tensile properties, and morphology of kenaf filled NRLF was studied. Increase in kenaf loading reduced the tensile strength and elongation at break and of a compound. Modulus at 100% elongation of the compound increased with increased in filler loading. The morphological and micro structural characterization has been performed by using scanning electron microscopy (SEM)

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.

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.

Properties of Vulcanized Polyisoprene Rubber Composites Filled with Opalized White Tuff and Precipitated Silica

Directory of Open Access Journals (Sweden)

Suzana Samaržija-Jovanović

2014-01-01

Full Text Available Opalized white tuff (OWT with 40 μm average particle size and 39.3 m2/g specific surface area has been introduced into polyisoprene rubber (NR. Their reinforcing effects were evaluated by comparisons with those from precipitated silica (PSi. The cure characteristic, apparent activation energy of cross-link (Eac and reversion (Ear, and mechanical properties of a variety of composites based on these rubbers were studied. This was done using vulcanization techniques, mechanical testing, and scanning electron microscopy (SEM. The results showed that OWT can greatly improve the vulcanizing process by shortening the time of optimum cure (tc90 and the scorch time (ts2 of cross-linked rubber composites, which improves production efficiency and operational security. The rubber composites filled with 50 phr of OWT were found to have good mechanical and elastomeric properties. The tensile strengths of the NR/OWT composites are close to those of NR/PSi composites, but the tear strength and modulus are not as good as the corresponding properties of those containing precipitated silica. Morphology results revealed that the OWT is poorly dispersed in the rubber matrix. According to that, the lower interactions between OWT and polyisoprene rubber macromolecules are obtained, but similar mechanical properties of NR/OWT (100/50 rubber composites compared with NR/PSi (100/50 rubber composites are resulted.

Thermostability and surface morphology of nano- and micro-filled NBR/CSM and CR/CSM rubber blends

Directory of Open Access Journals (Sweden)

M. MARINOVIC-CINCOVIC

2004-02-01

Full Text Available Acrylonitrile-butadiene rubber (NBR, polychloroprene rubber (CR, chlorosulphonated polyethylene rubber (CSM and their blends were cross-linked with sulphur, ethylene-thiourea, magnesium oxide or their combination. The effect of nano- and micro- particle sized of 35 pphr SiO2 on the thermostability and surface morphology of all the crosslinked systems was investigated. Identification of the structure of nano- and micro- particle sized SiO2 filled NBR/CSM and CR/CSM crosslinked systems was carried out by Fourier transform infrared spectroscopy (FTIR with an attenuated total reflectance (ATR extension. The thermal stability of the nano- and micro- particle sized SiO2 filled NBR/CSM and CR/CSM crosslinked systems were carried out by thermogravimetric analysis (TGA. The glass transition temperature (Tg of the samples was determined by differential scanning calorimetry (DSC. The morphology of the fracture surface of the crosslinked systems was carried out by scanning electron microscope (SEM. The results show when filled with nano-particle sized of SiO2 NBR/CSM and CR/CSM polymer matrix have a strong peak from SiO–C at 1079 cm-1. This suggests the an interaction between the SiO2, which should lead to an increased thermal stability, higher values of Tg, better dispersion the nano-SiO2 and more polish, without cracks than micro-filled NBR/CSM and CR/CSM crosslinked systems.

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.

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

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

A comparative investigation on strain induced crystallization for graphene and carbon nanotubes filled natural rubber composites

Directory of Open Access Journals (Sweden)

D. H. Fu

2015-07-01

Full Text Available Natural rubber containing graphene and carbon nanotubes (CNTs composites were prepared by ultrasonicallyassisted latex mixing. Natural rubber filled by both graphene and CNTs show significant enhanced tensile strength, while graphene exhibits a better reinforcing effect than CNTs. Strain-induced crystallization in natural rubber composites during stretching was determined by synchrotron wide-angle X-ray diffraction. With the addition of CNTs or graphene, the crystallization for natural rubber occurs at a lower strain compared to unfilled natural rubber, and the strain amplification effects were observed. The incorporation of graphene results in a faster strain-induced crystallization rate and a higher crystallinity compared to CNTs. The entanglement-bound rubber tube model was used to analyze the chain network structure and determine the network parameters of composites. The results show that the addition of graphene or CNTs has an influence on the molecular network structure and improves the contribution of entanglement to the conformational constraint, while graphene has a more marked effect than CNTs.

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

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.

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

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

Preservative loss from silicone tubing during filling processes.

Science.gov (United States)

Saller, Verena; Matilainen, Julia; Rothkopf, Christian; Serafin, Daniel; Bechtold-Peters, Karoline; Mahler, Hanns-Christian; Friess, Wolfgang

2017-03-01

Significant loss of preservative was observed during filling of drug products during filling line stops. This study evaluated the losses of three commonly used preservatives in protein drugs, i.e. benzyl alcohol, phenol, and m-cresol. Concentration losses during static incubation were quantified and interpreted with regard to the potential driving forces for the underlying sorption, diffusion, and desorption steps. Partitioning from the solution into the silicone polymer was identified as the most decisive parameter for the extent of preservative loss. Additionally, the influence of tubing inner diameter, starting concentration as well as silicone tubing type was evaluated. Theoretical calculations assuming equilibrium between solution and tubing inner surface and one-directional diffusion following Fick's first law were used to approximate experimental data. Since significant losses were found already after few minutes, adequate measures must be taken to avoid deviations during filling of preservative-containing protein solutions that may impact product quality or antimicrobial efficacy. As a possible alternative to the highly permeable silicone tubing, a specific make of fluoropolymer tubing was identified being suitable for peristaltic pumps and not showing any preservative losses. Copyright © 2016 Elsevier B.V. All rights reserved.

A parylene-filled-trench technique for thermal isolation in silicon-based microdevices

International Nuclear Information System (INIS)

Lei Yinhua; Wang Wei; Li Ting; Jin Yufeng; Zhang Haixia; Li Zhihong; Yu Huaiqiang; Luo Yingcun

2009-01-01

Microdevices prepared in a silicon substrate have been widely used in versatile fields due to the matured silicon-based microfabrication technique and the excellent physical properties of silicon material. However, the high thermal conductivity of silicon restricts its application in most thermal microdevices, especially devices comprising different temperature zones. In this work, a parylene-filled-trench technique was optimized to realize high-quality thermal isolation in silicon-based microdevices. Parylene C, a heat transfer barricading material, was deposited on parallel high-aspect-ratio trenches, which surrounded the isolated target zones. After removing the remnant silicon beneath the trenches by deep reactive ion etching from the back side, a high-quality heat transfer barrier was obtained. By using narrow trenches, only 5 µm thick parylene was required for a complete filling, which facilitated multi-layer interconnection thereafter. The parylene filling performance inside the high-aspect-ratio trench was optimized by two approaches: multiple etch–deposition cycling and trench profile controlling. A 4 × 6 array, in which each unit was kept at a constant temperature and was well thermally isolated individually, was achieved on a silicon substrate by using the present parylene-filled-trench technique. The preliminary experimental results indicated that the present parylene-filled-trench structure exhibited excellent thermal isolation performance, with a very low power requirement of 0.134 mW (K mm 2 ) −1 for heating the isolated silicon unit and a high thermal isolation efficiency of 72.5% between two adjacent units. Accompanied with high-quality isolation performance, the microdevices embedded the present parylene-filled-trench structure to retain a strong mechanical connection larger than 400 kPa between two isolated zones, which is very important for a high-reliability-required micro-electro-mechanical-system (MEMS) device. Considering its room

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

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

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.

Complications of cataract surgery in eyes filled with silicone oil.

Science.gov (United States)

Kanclerz, Piotr; Grzybowski, Andrzej; Schwartz, Stephen G; Lipowski, Paweł

2018-03-01

The aim of the study was to evaluate complications of cataract surgery in eyes filled with silicone oil. This retrospective, noncomparative, consecutive case series analyzed medical files of patients with eyes filled with silicone oil undergoing cataract surgery. Phacoemulsification with posterior chamber intraocular lens implantation was conducted with or without concurrent silicone oil removal. In this study, 121 eyes of 120 patients were included. In 32 eyes (26.4%) with evident silicone oil microemulsification or silicone oil-associated open-angle glaucoma, silicone oil was removed prior to phacoemulsification through a pars plana incision and no cases of posterior capsular rupture occurred during the subsequent cataract surgery. In the remaining 89 eyes, phacoemulsification was performed with silicone oil in the vitreous cavity. In these eyes, the rate of posterior capsular rupture was 9/89 (10.1%) and the rate of silicone oil migration into the anterior chamber through an apparently intact posterior capsule was 5/89 (5.6%). In 94 eyes (77.7%), an intraocular lens was inserted into the capsular bag, in 3 eyes (2.5%) into the sulcus, and in 1 eye (0.8%) a transscleral suturing was performed. In this series, complications related to the silicone oil were not uncommon during cataract surgery. In the majority of patients without evident silicone oil microemulsification or silicone oil-associated open-angle glaucoma, cataract surgery and posterior chamber intraocular lens implantation were performed while leaving the silicone oil in place.

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.

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.

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.

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,

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)

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

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.

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.

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

Dynamic Moisture Sorption and Desorption in Fumed Silica-filled Silicone Foam

Energy Technology Data Exchange (ETDEWEB)

Trautschold, Olivia Carol [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2016-09-02

Characterizing dynamic moisture sorption and desorption in fumed silica-filled silicone foam is necessary for determining material compatibilities and life predictions, particularly in sealed environments that may be exposed to a range of environmental conditions. Thermogravimetric analysis (TGA) and near infrared spectroscopy (NIR) were performed on S5470 fumed silica-filled silicone foam to determine the weight percent of moisture at saturation. Additionally, TGA was used to determine the time, temperature, and relative humidity levels required for sorption and desorption of physisorbed moisture in S5470.

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)

Dynamics of Coarse-grained Model of Filled Rubber Composite under Deformation

Science.gov (United States)

Hagita, Katsumi; Ueno, Shinichi; Bito, Yasumasa; Takano, Hiroshi; Doi, Masao; Morita, Hiroshi

2010-03-01

We presented a result of coarse-grained Molecular Dynamics simulation of filled polymer melts with Sulfur-crosslink under deformation based on the Kremer-Grest Model. Because all polymer chains are connected to one network gel, the size of simulation box under periodic boundary conditions (PBC) is set to about 33nm. We put 4 fillers, 80 polymer chains of 1024 particles, and many crosslink into the PBC box. One filler consists of 1280 particles of the C1280 fullerene structure. A repulsive force from the center of the filler is applied to the particles of C1280 in order to make a sphere whose diameter is about 15nm. Some patterns of distribution of the fillers are examined. The stress-strain curves estimated by applying a deformation to the system in simulations qualitatively agree with those in experiments. It is successful to show hysteresis on the S-S curve between elongation / release of the filled rubber.

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),

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.

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.

Investigations on the properties of NH4HCO3 filled natural rubber based magnetorheological elastomers (MREs)

Science.gov (United States)

Fan, Lili; Wang, Guoping; Wang, Wenju; Shi, Guanxin; Yang, Fufeng; Rui, Xiaoting

2018-04-01

Various anisotropic magnetorheological elastomers (MREs) were synthesized using the rubber mixing technique. Magnetic and temperature distributions of the experimental equipment and test instruments were analyzed by the ANSYS. NH4HCO3 was filled in the natural rubber matrix to modify properties of MREs. Microstructures and compositions of samples were studied by the scanning electron microscope (SEM), the energy dispersive x-ray spectroscopy (EDAX) analysis and x-ray powder diffraction (XRD). Via vibrating sample magnetometer (VSM) and density functional theory (DFT) method, the magnetic property of carbonyl iron (CI) was illuminated. The shear storage modulus and MR effect of MREs were investigated by the dynamic mechanical analyzer (DMA). It indicated that distributions of magnetic and temperature in the experimental and testing devices were uniform. Before vulcanization, CI particles were uniformly distributed in the matrix, while a CI chain structure was formed and embedded in the matrix after the vulcanization process. Moderate addition of NH4HCO3 accelerated the rubber vulcanization and enhanced the MR effect.

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.

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.

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

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)

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.

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.

Cure characteristics, crosslink density and degree of filler dispersion of kaolin-filled natural rubber compounds in the presence of alkanolamide

Science.gov (United States)

Surya, I.; Hayeemasae, N.; Ginting, M.

2018-03-01

The effects of alkanolamide (ALK) addition on cure characteristics, crosslink density and degree of filler dispersion of kaolin-filled natural rubber (NR) compounds were investigated. The kaolin filler was incorporated into NR compounds with a fixed loading, 30.0 phr. The ALK was prepared from Refined Bleached Deodorized Palm Stearin (RBDPS), a waste product of cooking oil production, and diethanolamine. The ALK is an oily material and added into the filled NR compounds as a rubber additive at different loadings, 0.0, 3.0, 5.0 and 7.0. The kaolin-filled NR compounds with and without ALK were vulcanized using a semi-efficient vulcanization system. It was found that ALK decreased the scorch and cure times and improved filler dispersion of the kaolin-filled NR compounds. The higher the ALK loading, the shorter were the scorch and cure times. It was also found that ALK increased the crosslink density of kaolin-filled NR compound up to 5.0 phr of loading. Due to its oily properties, The ALK acted as an internal plasticizer which decreased the minimum torque and improved the degree of kaolin dispersion in NR phases. The higher the ALK loading; the lower the minimum torque and better the filler dispersion.

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

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 ...

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...

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

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.

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

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.

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

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.

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.

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.

Electromechanical stability of electro-active silicone filled with high permittivity particles undergoing large deformation

International Nuclear Information System (INIS)

Liu, Liwu; Liu, Yanju; Zhang, Zhen; Leng, Jinsong; Li, Bo

2010-01-01

In this paper, an expression for the permittivity of electro-active silicone undergoing large deformation with high permittivity particles filled uniformly has been proposed. Two expressions are proposed for the permittivity, one based on experimental tests and the other based on the theory of composite material. By applying the thermodynamic model incorporating linear dielectric permittivity and nonlinear hyperelastic performance, the mechanical performance and electromechanical stability of the coupling system constituted by silicone filled with PMN–PT have been studied. The results show that the critical electric field decreases, namely the stability performance of the system declines when the content of PMN–PT c(v) increases and the electrostrictive coefficients increase. The results are beneficial for us to understand deeply the influence of the filled particle on the stability performance of silicone and to guide the design and manufacture of actuators and sensors based on dielectric elastomers

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.

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.

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.

Utilization of waste expanded polystyrene: Blends with silica-filled natural rubber

International Nuclear Information System (INIS)

Sekharan, Renju Vaikathusseril; Abraham, Beena Thattekatt; Thachil, Eby Thomas

2012-01-01

Highlights: ► Tensile strength of the silica filled blend is comparable with silica filled NR. ► Modulus and compression set were the best for compatibilized NR/EPS blends. ► Tear strength has increased by 25% for compatibilized blends. ► A 5% waste EPS can be incorporated into NR compounds as a waste management measure. -- Abstract: Expanded polystyrene (EPS) constitutes a considerable part of thermoplastic waste in the environment in terms of volume. In this study, this waste material has been utilized for blending with silica-reinforced natural rubber (NR). The NR/EPS (35/5) blends were prepared by melt mixing in a Brabender Plasticorder. Since NR and EPS are incompatible and immiscible a method has been devised to improve compatibility. For this, EPS and NR were initially grafted with maleic anhydride (MA) using dicumyl peroxide (DCP) to give a graft copolymer. Grafting was confirmed by Fourier Transform Infrared Spectroscopy (FTIR) spectroscopy. This grafted blend was subsequently blended with more of NR during mill compounding. Morphological studies using Scanning Electron Microscopy (SEM) showed better dispersion of EPS in the compatibilized blend compared to the noncompatibilized blend. By this technique, the tensile strength, elongation at break, modulus, tear strength, compression set and hardness of the blend were found to be either at par with or better than that of virgin silica filled NR compound. It is also noted that the thermal properties of the blends are equivalent with that of virgin NR. The study establishes the potential of this method for utilising waste EPS.

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.

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...

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...

Spin filling of valley-orbit states in a silicon quantum dot

Energy Technology Data Exchange (ETDEWEB)

Lim, W H; Yang, C H; Zwanenburg, F A; Dzurak, A S, E-mail: wee.lim@unsw.edu.au [Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, NSW 2052 (Australia)

2011-08-19

We report the demonstration of a low-disorder silicon metal-oxide-semiconductor (Si MOS) quantum dot containing a tunable number of electrons from zero to N = 27. The observed evolution of addition energies with parallel magnetic field reveals the spin filling of electrons into valley-orbit states. We find a splitting of 0.10 meV between the ground and first excited states, consistent with theory and placing a lower bound on the valley splitting. Our results provide optimism for the realisation in the near future of spin qubits based on silicon quantum dots.

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.

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)

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

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.

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.

Tensile, swelling and morphological properties of bentonite-filled acrylonitrile butadiene rubber composites

Science.gov (United States)

Lotfi, Muhamad Nadhli Amin; Ismail, Hanafi; Othman, Nadras

2017-10-01

Tensile, swelling and morphological properties of bentonite filled acrylonitrile butadiene rubber (NBR/Bt) composites were studied. The experiments were conducted at room temperature by using two rolled mill, universal testing machine (INSTRON), and American Standard Testing Method (ASTM) D471 for compounding, tensile testing, and swelling test, respectively. Results obtained indicated that a better tensile strength, elongation at break and tensile modulus were recorded as compared to the pure NBR particularly up to 90 phr of Bt loading. However, swelling (%) exhibited the opposite trend where the liquid uptake by the composites was indirectly proportional with the increasing of Bt loading. Scanning electron microscopy (SEM) used on the tensile fractured surface of the NBR/Bt composites have shown that the fillers were well embedded in the NBR matrix, for Bt loading up to 90 phr. The agglomeration of fillers occurred for Bt loading exceeding 90 phr.

Silicone rubbers for dielectric elastomers with improved dielectric and mechanical properties as a result of substituting silica with titanium dioxide

DEFF Research Database (Denmark)

Yu, Liyun; Skov, Anne Ladegaard

2016-01-01

One prominent method of modifying the properties of dielectric elastomers (DEs) is by adding suitable metal oxide fillers. However, almost all commercially available silicone elastomers are already heavily filled with silica to reinforce the otherwise rather weak silicone network and the resulting...... and dynamic viscosity. Filled silicone elastomers with high loadings of nano-sized titanium dioxide (TiO2) particles were also studied. The best overall performing formulation had 35 wt.% TiO2 nanoparticles in the POWERSIL® XLR LSR, where the excellent ensemble of relative dielectric permittivity of 4.9 at 0...

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).

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).

STUDIES ON NATURAL WEATHERING OF RATTAN POWDER-FILLED NATURAL RUBBER COMPOSITES

Directory of Open Access Journals (Sweden)

Komethi Muniandy,

2012-07-01

Full Text Available This article investigates the effect of natural weathering on mechanical and morphological properties of rattan powder-filled natural rubber (NR composites as a function of filler loading and silane coupling agent. The rattan powder samples in the range of 0 to 30 phr were compounded with NR using a laboratory size two-roll mill. The natural weathering test was carried out for six months. The degradation of the samples was evaluated by performing a tensile test, a Fourier transform infrared spectroscopy (FTIR, and a scanning electron microscopy (SEM test. The results indicated that after natural weathering, an increase in stress at 100% elongation (M100 can be seen for samples without the silane coupling agent, whilst M100 was reduced for samples with silane coupling agent. A drastic reduction in tensile strength and elongation at break were observed for all samples due to the photo-oxidation process that occurred during the degradation of the samples. The extent of degradation on the samples’ surfaces and the presence of oxygenated products were confirmed by SEM and FTIR studies, respectively.

Influence of fillers on mechanical properties of filled rubbers during ageing by irradiation

International Nuclear Information System (INIS)

Planes, Emilie

2008-01-01

The understanding of the evolution of mechanical properties and the prediction of the lifetime of material environment is a recurring problem. This question is very important to develop polymer formulations used for electrical cables in nuclear power plants. Thus it is important to know the evolution of materials when they are submitted to usual conditions in nuclear power plants. There are in literature some studies concerning the ageing by gamma irradiation of unfilled elastomer but the addition of fillers in the material can have consequences on the evolution of the mechanical properties during irradiation. Thus this work concerns the study of the ageing by gamma irradiation of filled rubbers and the identification of the role of fillers in the degradation mechanisms. The studied matrix, which commonly used for the type of application is EPDM. The fillers are: nano-scopic silica and aluminium trihydrate. Their surfaces have been treated in order to understand the role of filler-matrix interfaces during ageing. To evaluate the influence of fillers on the degradation mechanisms and on the evolution of the mechanical properties, the evolution during ageing of these materials filled or not has been studied for an ageing by irradiation: they have been physico-chemically, micro-structurally and mechanically characterized at various levels of ageing [fr

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.

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.

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.

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

EFFECTS.OF BORIC ACID ON THE CURE OF BORON-FILLED Y-3602 SILICONE GUM

Energy Technology Data Exchange (ETDEWEB)

Leichliter, G E

1974-10-01

The first two phases of a program designed to determine the effects of boric acid on the cure of Y-3602 silicone gum were conducted to evaluate extraction solvents and extraction time. The standard production formulation of B10-filled Y-3602 silicone gum was used in these evaluations. Results showed that the best solvent for reproducibility and high amine content was chloroform. The second phase indicated that extraction was essentially complete at the end of 4 hours.

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.

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.

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.

Characterization of the silicon nanopillar-surface filled and grafted with nanomaterials

International Nuclear Information System (INIS)

He, Yuan; Che, Xiangchen; Que, Long

2014-01-01

This paper reports the characterization of the silicon nanopillar-surface filled and grafted with nanomaterials. Usually a silicon nanopillar-surface contains nanopillars and air among them. The air is not a good medium to absorb and trap the incoming photons. In order to improve this capability, the air should be replaced with other material. To this end, copper sulfide–gold (CuS–Au) core–shell nanostructures and silver nanoplates are used as two representative substitutes for air among the nanopillars. Experiments find that the reflectance of the nanomaterial-coated nanopillar-surface can be reduced at least 50% compared to that of the bare nanopillar-surface. Different nanomaterial-coated nanopillar-surface can tune the optical reflectance and absorption profile, thereby trapping photons in different wavelength ranges. (paper)

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)

Polybenzoxazole-filled nitrile butadiene rubber compositions

Science.gov (United States)

Gajiwala, Himansu M. (Inventor); Guillot, David G. (Inventor)

2008-01-01

An insulation composition that comprises at least one nitrile butadiene rubber (NBR) having an acrylonitrile content that ranges from approximately 26% by weight to approximately 35% by weight and polybenzoxazole (PBO) fibers. The NBR may be a copolymer of acrylonitrile and butadiene and may be present in the insulation composition in a range of from approximately 45% by weight to approximately 56% by weight of a total weight of the insulation composition. The PBO fibers may be present in a range of from approximately 3% by weight to approximately 10% by weight of a total weight of the insulation composition. A rocket motor including the insulation composition and a method of insulating a rocket motor are also disclosed.

Alternative secondary accelerator for silica-filled natural rubber formulations

NARCIS (Netherlands)

Kaewsakul, Wisut; Sahakaro, Kannika; Dierkes, Wilma K.; Noordermeer, Jacobus W.M.

2013-01-01

Dithiophosphate (DTP) displays a good efficiency towards improved overall properties of silica-reinforced natural rubber compounds, when it is used as secondary accelerator in a sulfenamide primary accelerated sulfur vulcanization system. Comparing DTP with diphenylguanidine (DPG), DTP is more

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.

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.

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.

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.

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)

Verification of Interactions between Silica and Epoxidized Squalene as a Model for Epoxidized Natural Rubber

NARCIS (Netherlands)

Kaewsakul, Wisut; Sahakaro, Kannika; Dierkes, Wilma K.; Noordermeer, Jacobus W.M.

2014-01-01

Unmodified squalene (Sq) and epoxidised squalene (ESq), as models for natural rubber and epoxidised natural rubber, were mixed with silica in a reactor at 140 – 145ºC, which corresponds to the optimal mixing dump temperature of silica-filled natural rubber or epoxidised natural rubber compounds. The

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)

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

Effects of carbon blacks with various structures on vulcanization and reinforcement of filled ethylene-propylene-diene rubber

Directory of Open Access Journals (Sweden)

2008-10-01

Full Text Available The effects of carbon blacks on vulcanization and mechanical properties of filled ethylene-propylene-diene rubber (EPDM are investigated, by comparing with five types of rubber-grade carbon blacks. Curing kinetics is studied by rheometer and the results indicate that the curing characteristics are influenced by combination of surface area of carbon black and sulphur content on the filler surface, because the former one enhances the physical cross-linking and the latter one introduces the additional chemical cross-linking. Both the degree of cross-linking and cure rate increase with increasing surface area and sulphur content, whereas the optimum cure time and scorch time decrease. The reinforcing nature of the carbon black is assessed from mechanical measurements. It is suggested that the surface area of carbon blacks strongly affects the physical properties of EPDM/carbon black composites. Conductive carbon black (N472 can be used as desirable reinforcing filler due to the higher degree of cross-linking of EPDM with N472 than other EPDM/carbon black composites. The morphology and distribution of particles are studied by using scanning electron microscope. The sound reinforcing ability of N472 is also supported by scanning electron microscope due to the notable dispersibility of N472 within EPDM matrix. N472 ensures the EPDM/N472 composite the most conductive sample among the five composites.

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.

MEMS-based Porous Silicon Preconcentrators Filled with Carbopack-B for Explosives Detection

OpenAIRE

Camara , El Hadji Malik; James , Franck; Breuil , Philippe; Pijolat , Christophe; Briand , Danick; De Rooij , Nicolaas F

2014-01-01

International audience; In this paper we report the detection of explosive compounds using a miniaturized gas preconcentrator (μGP) made of porous silicon (PS) filled in with Carbopack B as an adsorbent material. The μGP includes also a platinum heater patterned at the backside and fluidic connectors sealed on the glass cover. Our μGP is designed and optimized through fluidic and thermal simulations for meeting the requirements of trace explosives detection. The thermal mass of the device was...

Analysis of Cement-Based Pastes Mixed with Waste Tire Rubber

Science.gov (United States)

Sola, O. C.; Ozyazgan, C.; Sayin, B.

2017-03-01

Using the methods of thermal gravimetry, differential thermal analysis, Furier transform infrared analysis, and capillary absorption, the properties of a cement composite produced by introducing waste tyre rubber into a cement mixture were investigated. It was found that the composite filled with the rubber had a much lower water absorption ability than the unfilled one.

Surface treated fly ash filled modified epoxy composites

Directory of Open Access Journals (Sweden)

Uma Dharmalingam

2015-01-01

Full Text Available Abstract Fly ash, an inorganic alumino silicate has been used as filler in epoxy matrix, but it reduces the mechanical properties due to its poor dispersion and interfacial bonding with the epoxy matrix. To improve its interfacial bonding with epoxy matrix, surface treatment of fly ash was done using surfactant sodium lauryl sulfate and silane coupling agent glycidoxy propyl trimethoxy silane. An attempt is also made to reduce the particle size of fly ash using high pressure pulverizer. To improve fly ash dispersion in epoxy matrix, the epoxy was modified by mixing with amine containing liquid silicone rubber (ACS. The effect of surface treated fly ash with varying filler loadings from 10 to 40% weight on the mechanical, morphological and thermal properties of modified epoxy composites was investigated. The surface treated fly ash was characterized by particle size analyzer and FTIR spectra. Morphological studies of surface treated fly ash filled modified epoxy composites indicate good dispersion of fillers in the modified epoxy matrix and improves its mechanical properties. Impact strength of the surface treated fly ash filled modified epoxy composites show more improvement than unmodified composites.

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.

Multiwall carbon nanotube-filled natural rubber: Electrical and mechanical properties

Directory of Open Access Journals (Sweden)

L. Bokobza

2012-03-01

Full Text Available The influence of multiwall carbon nanotube (MWNTs contents on electrical and mechanical properties of MWNTs-reinforced natural rubber (NR composites is studied. The volume resistivity of the composites decreases with increasing the MWNTs content and the electrical percolation threshold is reached at less than 1 phr of MWNTs (phr = parts of filler by weight per hundred parts of rubber. This is caused by the formation of conductive chains in the composites. Electrical measurements under uniaxial deformation of a composite carried out at a filler loading above the percolation threshold, indicate a gradual disconnection of the conducting network with the bulk deformation. The drop in the storage modulus G' with the shear strain amplitude (Payne effect is also attributed to a breakdown of the filler network. Considerable improvement in the stiffness is obtained upon incorporation of MWNTs in the polymer matrix but the main factor for reinforcement of NR by MWNTs appears to be their high aspect ratio rather than strong interfacial interaction with rubber. The tensile strength and the elongation at break of the composites are reduced with regard to the unfilled sample. This is probably due to the presence of some agglomerates that increase with the nanotube content. This hypothesis is confirmed by a cyclic loading of the composites where it is seen that the deformation at break occurs at a much higher level of strain in the second stretch than in the first one. The overall significant property improvements are the result of a better nanotube dispersion attributed to the combined use of tip sonication and cyclohexane as dispersion aids during composite processing.

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.

Pengaruh penggunaan nitril butadiene rubber dan pale crepe pada pembuatan sol karet untuk sepatu pengaman

OpenAIRE

Arum Yuniari

2010-01-01

Abstract Rubber sole for safety shoes was different on physical specification with general sole, especially on abrasion resistance and oil resistance. The objective of the study was to determine the effect of nitril butadiene rubber and pale crepe on physical properties of vulcanized rubber sole for safety shoes. Rubber sole for safety shoes was produced by blending pale crepe and nitril butadiene rubber with ratio of : 50/50; 60/40; 70/30 and 80/20 phr, respectively. Carbon black as fill...

Effect of various cross-linking types on the physical properties in carbon black-filled natural rubber compound

Energy Technology Data Exchange (ETDEWEB)

Park, B.H.; Jung, I.G.; Park, S.S. [Kumho Industry Co., Kwangju (Korea)

2001-01-01

The objective of this study was to investigate the effect of cure type on the processing and physical properties under conditions of similar stress-strain properties. On the carbon black filled natural rubber (NR) based compound, the induction time decreased, but the cure rate became fast with increasing loading of sulfur donor agent. Tensile strength was little affected on the curing type. However, elongation generally decreased with increasing accelerator. Effect of cure type on the blow-out properties was followings: CV[semi-EV][EV][hybrid bond][resin cure]. Version 1 and version 4 exhibited good cutting and chipping resistance compared to other cure systems. Especially, compounds with KA-9188 exhibited processing stability, good reversion and blow-out property without sacrificing tensile properties. It implies that sulfur cure system can be replaced with hybrid-cure system. (author). 9 refs., 6 tabs., 7 figs.

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.

Destiny rides again: the reappearance of silicone gel-filled breast implant toxicity.

Science.gov (United States)

Brawer, A E

2017-09-01

Background Twenty-five years ago attorneys representing ailing women in class action litigation against silicone breast implant manufacturers made the procedural error of defining silicone-induced toxicity in the courtroom before it was properly studied in the exam room. This aberrant methodology perverted the proper research process, rendered verification of any real disease elusive, and cemented the groundwork for a repeat public health crisis potentially affecting two million women in the USA who possess new silicone gel devices inserted over the past 10 years. Patients and methods Six women, previously well, aged 27 to 53 (mean 42), were recipients of the new generations of cohesive silicone gel-filled breast implants approved for general use by the Food and Drug Administration (FDA) since December of 2006. They averaged seven years of total implantation time, and none experienced implant rupture. Results All six became ill on average 3.5 years from the time of implantation. By seven years the women manifested multiple types of skin rashes, polyarthritis, fatigue, protracted AM stiffness, myalgias, headaches, photosensitivity, hair loss, paresthesias, tinnitus, lymphadenopathy, chest pain, cognitive dysfunction, dry eyes, skin pigment changes, itching, muscle twitching, dizziness, nausea, easy bruising, and odor and smell sensitivity. Three of the four who were explanted noted improvement and/or resolution of at least 50% of their total disease manifestations. Conclusions These six women are representative of over 70,000 other breast implant recipients who, over the past three years, have had their new silicone devices permanently removed because of alleged gel-induced toxicity. The recurrence of this public health crisis has been fueled by manufacturers' research fraud, FDA ineptness, faulty informed consent, patient abandonment, proprietary manufacturing secrecy, misleading advertising, physician indifference, aberrant research methodology, and lax

Effects of Blend Ratio and SBR Type on Properties of Carbon Black-Filled and Silica-Filled SBR/BR Tire Tread Compounds

Directory of Open Access Journals (Sweden)

Pongdhorn Sae-oui

2017-01-01

Full Text Available This work aimed at investigating the effects of blend ratio between styrene butadiene rubber (SBR and butadiene rubber (BR and SBR type (E-SBR and S-SBR on properties of SBR/BR tire tread compounds. Influences of these parameters on properties of the tread compounds reinforced by 80 parts per hundred rubber (phr of carbon black (CB and silica were also compared. Results reveal that hardness, strengths, and wet grip efficiency were impaired whereas rolling resistance was improved with increasing BR proportion. Surprisingly, the presence of BR imparted poorer abrasion resistance in most systems, except for the CB-filled E-SBR system in which an enhanced abrasion resistance was observed. Obviously, S-SBR gave superior properties (tire performance compared to E-SBR, particularly obvious in the silica-filled system. Compared with CB, silica gave comparable strengths, better wet grip efficiency, and lower rolling resistance. Carbon black, however, offered greater abrasion resistance than silica.

Styrene grafted natural rubber reinforced by in situ silica generated via sol–gel technique

Energy Technology Data Exchange (ETDEWEB)

Sittiphan, Torpong [Program of Petrochemistry and Polymer Sciences, Faculty of Science, Chulalongkorn University, Bangkok 10330 (Thailand); Prasassarakich, Pattarapan [Department of Chemical Technology, Faculty of Science, Chulalongkorn University, Bangkok 10330 (Thailand); Poompradub, Sirilux, E-mail: sirilux.p@chula.ac.th [Department of Chemical Technology, Faculty of Science, Chulalongkorn University, Bangkok 10330 (Thailand)

2014-02-15

Highlights: • Sol–gel reaction by NR latex was the absence of use of organic solvent and base catalyst. • Well dispersed in situ formed silica particles in the rubber matrix were obtained. • In situ silica was better to improve mechanical properties of rubber vulcanizates. -- Abstract: The filling of styrene graft natural rubber (ST-GNR) with in situ formed silica was performed using the sol–gel reaction via the latex solution method. The mechanical properties of ST-GNR/NR vulcanizate were improved when using the in situ formed silica to levels higher than those obtained with the commercial ex situ formed silica filled ST-GNR/NR vulcanizates at a comparable silica content of 12 parts by weight per hundred parts of rubber. Transmission electron microscopy analysis revealed that the in situ silica particles were small (∼40 nm diameter) and well dispersed, while the commercial silica particles were larger (∼60 nm diameter) and markedly agglomerated in the rubbery matrix. The mechanical properties of the composites prepared via both the solid rubber and latex solution methods were comparable.

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

Directory of Open Access Journals (Sweden)

K. Sengloyluan

2017-12-01

Full Text Available 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 molecules was confirmed by Fourier transform infrared (FTIR, proton nuclear magnetic resonance (1H-NMR and scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM-EDX. Based on 1H-NMR, the use of 10 and 20 phr (parts per hundred resin of silane resulted in grafted NXT onto NR of 0.66 and 1.32 mol%, respectively, or a grafting efficiency of approx. 38%. The use of NXT-grafted NR as compatibilizer in silica-filled NR compounds, to give a total amount of NXT in both grafted and non-grafted forms in the range of 0.8–6.1 wt% relative to the silica, decreases the Mooney viscosity and Payne effect of the compounds, improves filler-rubber interaction, and significantly increases the tensile properties of the silica-filled NR-compounds compared to the non-compatibilized one. At the same silane-content, the use of silane-grafted NR gives slightly better properties than the straight use of the same silane. With sulfur compensation, the use of NXT-grafted-NR with about 6 wt% NXT relative to the silica gives technical properties that reach the levels obtained for straight use of bis-(3-triethoxysilyl-propyltetrasulfide (TESPT at 8.6 wt% relative to the silica.

Nanocomposites of nitrile (NBR) rubber with multi-walled carbon nanotubes

Science.gov (United States)

Warasitthinon, Nuthathai

Nanotechnology offers the promise of creating new materials with enhanced performance. There are different kinds of fillers used in rubber nanocomposites, such as carbon black, silica, carbon fibers, and organoclays. Carbon nanotube reinforced elastomers have potential for improved rubber properties in aggressive environments. The first chapter is an introduction to the literature. The second chapter investigated the incorporation of multi-walled carbon nanotubes (MWCNTs) into rubber matrix for potential use in high temperature applications. The vulcanization kinetics of acrylonitrile butadiene rubber (NBR) reinforced with multi-walled carbon nanotubes was investigated. The vulcanized NBR rubber with different loading percentages of MWCNTs was also compared to NBR reinforced with carbon black N330. The optimum curing time at 170°C (T90) was found to decrease with increasing content of MWCNTs. Increased filler loading of both carbon black and MWCNTs gave higher modulus and strength. The MWCNTs filled materials gave better retention of modulus and tensile strength at high temperatures, but lower strength as compared to the carbon black filled samples. In the third chapter, carbon black (CB, 50phr) content in nitrile rubber (NBR) nanocomposites was partially replaced by multi-walled carbon nanotubes (MWCNTs). NBR/CB/CNTs nanocomposites with varying ratio of CB/CNTs (50/0 phr to 40/10 phr) were formulated via the melt-mixing method using an internal mixer. The reinforcing effect of single filler (CB) and mixture of fillers (CB and CNTs) on the properties of NBR nanocomposites was investigated. The cure kinetics and bound rubber content were analyzed using rheometry and solvent swelling method. In addition, mechanical behavior at both room temperature and high temperature (350°F/ 121°C) were examined. The scorch time and curing time values showed that there was no significant effect on the curing behavior of NBR nanocomposites after the partial replacement of CB with

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

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.

Microwave electromagnetic properties of carbonyl iron particles and Si/C/N nano-powder filled epoxy-silicone coating

International Nuclear Information System (INIS)

Qing Yuchang; Zhou Wancheng; Luo Fa; Zhu Dongmei

2010-01-01

The electromagnetic characteristics of carbonyl iron particles and Si/C/N nano-powder filled epoxy-silicone coatings were studied. The reflection loss of the coatings exceeds -10 dB at 8-18 GHz and -9 dB at 2-18 GHz when the coating thickness is 1 and 3 mm, respectively. The dielectric and magnetic absorbers filled coatings possess excellent microwave absorption, which could be attributed to the proper incorporate of the multi-polarization mechanisms as well as strong natural resonance. It is feasible to develop the thin and wideband microwave absorbing coatings using carbonyl iron particles and Si/C/N nano-powder.

Microwave electromagnetic properties of carbonyl iron particles and Si/C/N nano-powder filled epoxy-silicone coating

Science.gov (United States)

Qing, Yuchang; Zhou, Wancheng; Luo, Fa; Zhu, Dongmei

2010-02-01

The electromagnetic characteristics of carbonyl iron particles and Si/C/N nano-powder filled epoxy-silicone coatings were studied. The reflection loss of the coatings exceeds -10 dB at 8-18 GHz and -9 dB at 2-18 GHz when the coating thickness is 1 and 3 mm, respectively. The dielectric and magnetic absorbers filled coatings possess excellent microwave absorption, which could be attributed to the proper incorporate of the multi-polarization mechanisms as well as strong natural resonance. It is feasible to develop the thin and wideband microwave absorbing coatings using carbonyl iron particles and Si/C/N nano-powder.

Theory Of Dewetting In A Filled Elastomer Under Stress

Science.gov (United States)

Peng, Steven T. J.

1993-01-01

Report presents theoretical study of dewetting between elastomeric binder and filler particles of highly filled elastomer under multiaxial tension and resulting dilatation of elastomer. Study directed toward understanding and predicting nonlinear stress-vs.-strain behavior of filled elastomeric rocket propellant, also applicable to rubber in highly loaded tire or in damping pad.

Development of a Hybrid Piezo Natural Rubber Piezoelectricity and Piezoresistivity Sensor with Magnetic Clusters Made by Electric and Magnetic Field Assistance and Filling with Magnetic Compound Fluid.

Science.gov (United States)

Shimada, Kunio; Saga, Norihiko

2017-02-10

Piezoelements used in robotics require large elasticity and extensibility to be installed in an artificial robot skin. However, the piezoelements used until recently are vulnerable to large forces because of the thin solid materials employed. To resolve this issue, we utilized a natural rubber and applied our proposed new method of aiding with magnetic and electric fields as well as filling with magnetic compound fluid (MCF) and doping. We have verified the piezoproperties of the resulting MCF rubber. The effect of the created magnetic clusters is featured in a new two types of multilayered structures of the piezoelement. By measuring the piezoelectricity response to pressure, the synergetic effects of the magnetic clusters, the doping and the electric polymerization on the piezoelectric effect were clarified. In addition, by examining the relation between the piezoelectricity and the piezoresistivity created in the MCF piezo element, we propose a hybrid piezoelement.

Development of a Hybrid Piezo Natural Rubber Piezoelectricity and Piezoresistivity Sensor with Magnetic Clusters Made by Electric and Magnetic Field Assistance and Filling with Magnetic Compound Fluid

Science.gov (United States)

Shimada, Kunio; Saga, Norihiko

2017-01-01

Piezoelements used in robotics require large elasticity and extensibility to be installed in an artificial robot skin. However, the piezoelements used until recently are vulnerable to large forces because of the thin solid materials employed. To resolve this issue, we utilized a natural rubber and applied our proposed new method of aiding with magnetic and electric fields as well as filling with magnetic compound fluid (MCF) and doping. We have verified the piezoproperties of the resulting MCF rubber. The effect of the created magnetic clusters is featured in a new two types of multilayered structures of the piezoelement. By measuring the piezoelectricity response to pressure, the synergetic effects of the magnetic clusters, the doping and the electric polymerization on the piezoelectric effect were clarified. In addition, by examining the relation between the piezoelectricity and the piezoresistivity created in the MCF piezo element, we propose a hybrid piezoelement. PMID:28208625

Development of a Hybrid Piezo Natural Rubber Piezoelectricity and Piezoresistivity Sensor with Magnetic Clusters Made by Electric and Magnetic Field Assistance and Filling with Magnetic Compound Fluid

Directory of Open Access Journals (Sweden)

Kunio Shimada

2017-02-01

Full Text Available Piezoelements used in robotics require large elasticity and extensibility to be installed in an artificial robot skin. However, the piezoelements used until recently are vulnerable to large forces because of the thin solid materials employed. To resolve this issue, we utilized a natural rubber and applied our proposed new method of aiding with magnetic and electric fields as well as filling with magnetic compound fluid (MCF and doping. We have verified the piezoproperties of the resulting MCF rubber. The effect of the created magnetic clusters is featured in a new two types of multilayered structures of the piezoelement. By measuring the piezoelectricity response to pressure, the synergetic effects of the magnetic clusters, the doping and the electric polymerization on the piezoelectric effect were clarified. In addition, by examining the relation between the piezoelectricity and the piezoresistivity created in the MCF piezo element, we propose a hybrid piezoelement.

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.

Properties of tire rubber with zinc-containing technological additives

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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.

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...

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

Infrared Spectroscopic Study on Structural Change and Interfacial Interaction in Rubber Composites Filled with Silica-Kaolin Hybrid Fillers

Science.gov (United States)

Chen, Y.; Guan, J.; Hu, H.; Gao, H.; Zhang, L.

2016-07-01

A series of natural rubber/styrene butadiene rubber/polybutadiene rubber composites was prepared with nanometer silica and micron kaolin by a dry modification process, mechanical compounding, and mold vulcanization. Fourier transform infrared spectroscopy and a scanning electron microscope were used to investigate the structural changes and interfacial interactions in composites. The results showed that the "seesaw" structure was formed particularly with the incorporation of silica particles in the preparation process, which would be beneficial to the dispersibility of fillers in the rubber matrix. The kaolinite platelets were generally arranged in directional alignment. Kaolinite with smaller particle size and low-defect structure was more stable in preparation, but kaolinite with larger particle size and high defect structure tended to change the crystal structure. The composite prepared in this research exhibited excellent mechanical and thermal properties.

An investigation on chloroprene-compatibilized acrylonitrile butadiene rubber/high density polyethylene blends.

Science.gov (United States)

Ahmed, Khalil

2015-11-01

Blends of acrylonitrile butadiene rubber/high density polyethylene (NBR/HDPE) compatibilized by Chloroprene rubber (CR) were prepared. A fixed quantity of industrial waste such as marble waste (MW, 40 phr) was also included. The effect of the blend ratio and CR on cure characteristics, mechanical and swelling properties of MW-filled NBR/HDPE blends was investigated. The results showed that the MW-filled NBR/HDPE blends revealed an increase in tensile strength, tear, modulus, hardness and cross-link density for increasing weight ratio of HDPE. The minimum torque (M L) and maximum torque (M H) of blends increased with increasing weight ratio of HDPE while scorch time (ts2) cure time (tc90), compression set and abrasion loss of blends decreased with increasing weight ratio of HDPE. The blends also showed a continuous reduction in elongation at break as well as swelling coefficient with increasing HDPE amount in blends. MW filled blends based on CR provided the most encouraging balance values of overall properties.

An investigation on chloroprene-compatibilized acrylonitrile butadiene rubber/high density polyethylene blends

Directory of Open Access Journals (Sweden)

Khalil Ahmed

2015-11-01

Full Text Available Blends of acrylonitrile butadiene rubber/high density polyethylene (NBR/HDPE compatibilized by Chloroprene rubber (CR were prepared. A fixed quantity of industrial waste such as marble waste (MW, 40 phr was also included. The effect of the blend ratio and CR on cure characteristics, mechanical and swelling properties of MW-filled NBR/HDPE blends was investigated. The results showed that the MW-filled NBR/HDPE blends revealed an increase in tensile strength, tear, modulus, hardness and cross-link density for increasing weight ratio of HDPE. The minimum torque (ML and maximum torque (MH of blends increased with increasing weight ratio of HDPE while scorch time (ts2 cure time (tc90, compression set and abrasion loss of blends decreased with increasing weight ratio of HDPE. The blends also showed a continuous reduction in elongation at break as well as swelling coefficient with increasing HDPE amount in blends. MW filled blends based on CR provided the most encouraging balance values of overall properties.

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.

Novel in situ coordinated cerium salt/acrylonitrile-butadiene rubber composite

International Nuclear Information System (INIS)

Han, Jianjun; Lu, Haifeng; Zhang, Jie; Feng, Shengyu

2012-01-01

A novel rubber composite of acrylonitrile-butadiene rubber (NBR) filled with cerium salt particles was vulcanized via in situ coordination for the first time. The resulting materials exhibit good mechanical properties. Curing characteristics analysis, differential scanning calorimetry, X-ray photoelectron spectroscopy, tensile testing, and an equilibrium swelling method were used for the characterization of the composite. The results in this paper indicate that the composite is a kind of elastomer based on the in situ coordination crosslinking interactions between the nitrile groups (–CN) of NBR and cerium ions. The mechanical properties of vulcanized cerium salt/ NBR rubber are altered when changing the sorts of cerium salt. Moreover, these materials show good irradiation resistance because of the introduction of the cerium salt. -- Highlights: ► Cerium salts were firstly used to vulcanize the acrylonitrile-butadiene rubber. ► Cerium salts act as not only crosslink agents but also reinforcing fillers in the matrix. ► These materials show good irradiation resistance and mechanical properties at same time.

MECHANICAL PROPERTIES AND WATER ABSORPTION OF KENAF POWDER FILLED RECYCLED HIGH DENSITY POLYETHYLENE/NATURAL RUBBER BIOCOMPOSITES USING MAPE AS A COMPATIBILIZER

Directory of Open Access Journals (Sweden)

Azura A. Rashid

2011-06-01

Full Text Available The performance of kenaf powder (KP filled recycled high density polyethylene (rHDPE /natural rubber (NR blends with and without a compatibilizer, maleic anhydride grafted polyethylene (MAPE, were investigated. The composites with different filler loading (0 to 40 phr were prepared with a Haake internal mixer. Increasing the KP loading in rHDPE/NR/KP biocomposites reduced the tensile strength and the elongation at break but increased the stabilization torque and the tensile modulus. The addition of MAPE as a compatibilizer increased the tensile strength, elongation at break, and modulus of the composites. This might be attributed to the enhanced adhesion between the filler and polymer matrix, as evidenced from the morphology, using scanning electron microscopy. The incorporation of compatibilizer also reduced the water absorption of the composites.

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

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.

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

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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.

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)

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...

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.

Efeito do óleo de mamona em composições de borracha natural contendo sílica Effects from the castor oil on silica-filled natural rubber compounds

Directory of Open Access Journals (Sweden)

Helson M. da Costa

2004-03-01

Full Text Available O potencial do óleo de mamona como um ativador para a vulcanização de composições de borracha natural (NR contendo sílica foi investigado. Utilizando-se um planejamento de experimentos adequado, manteve-se a concentração de sílica e outros aditivos constantes enquanto as quantidades de ácido esteárico, óleo de mamona e poli(etileno-glicol foram variadas. A cura foi conduzida em um reômetro de disco oscilatório TI-100 e a variável de controle escolhida foi a resistência à tração. Os resultados demonstraram que o óleo de mamona sozinho não exerce influência considerável sobre o desempenho mecânico da borracha natural em presença de sílica.The possible use of castor oil fatty acid as an activator for the vulcanization reaction in silica-filled natural rubber (NR compounds was investigated. The design and analysis of the experiments were carried out by keeping constant the concentration of silica and the other ingredients while the amounts of stearic acid, castor oil and poly(ethylene glycol were varied. Cure was carried out on a TI-100 oscillating disk rheometer, and the tensile strength was chosen as the control variable. The results show that the addition of castor oil does not significantly change the mechanical performance of silica-filled natural rubber compounds.

Doping porous silicon with erbium: pores filling as a method to limit the Er-clustering effects and increasing its light emission

KAUST Repository

Mula, Guido

2017-07-14

Er clustering plays a major role in hindering sufficient optical gain in Er-doped Si materials. For porous Si, the long-standing failure to govern the clustering has been attributed to insufficient knowledge of the several, concomitant and complex processes occurring during the electrochemical Er-doping. We propose here an alternative road to solve the issue: instead of looking for an equilibrium between Er content and light emission using 1-2% Er, we propose to significantly increase the electrochemical doping level to reach the filling the porous silicon pores with luminescent Er-rich material. To better understand the intricate and superposing phenomena of this process, we exploit an original approach based on needle electron tomography, EXAFS and photoluminescence. Needle electron tomography surprisingly shows a heterogeneous distribution of Er content in the silicon thin pores that until now couldn\\'t be revealed by the sole use of scanning electron microscopy compositional mapping. Besides, while showing that pore filling leads to enhanced photoluminescence emission, we demonstrate that the latter is originated from both erbium oxide and silicate. These results give a much deeper understanding of the photoluminescence origin down to nanoscale and could lead to novel approaches focused on noteworthy enhancement of Er-related photoluminescence in porous silicon.

Doping porous silicon with erbium: pores filling as a method to limit the Er-clustering effects and increasing its light emission

KAUST Repository

Mula, Guido; Printemps, Tony; Licitra, Christophe; Sogne, Elisa; D’ Acapito, Francesco; Gambacorti, Narciso; Sestu, Nicola; Saba, Michele; Pinna, Elisa; Chiriu, Daniele; Ricci, Pier Carlo; Casu, Alberto; Quochi, Francesco; Mura, Andrea; Bongiovanni, Giovanni; Falqui, Andrea

2017-01-01

Er clustering plays a major role in hindering sufficient optical gain in Er-doped Si materials. For porous Si, the long-standing failure to govern the clustering has been attributed to insufficient knowledge of the several, concomitant and complex processes occurring during the electrochemical Er-doping. We propose here an alternative road to solve the issue: instead of looking for an equilibrium between Er content and light emission using 1-2% Er, we propose to significantly increase the electrochemical doping level to reach the filling the porous silicon pores with luminescent Er-rich material. To better understand the intricate and superposing phenomena of this process, we exploit an original approach based on needle electron tomography, EXAFS and photoluminescence. Needle electron tomography surprisingly shows a heterogeneous distribution of Er content in the silicon thin pores that until now couldn't be revealed by the sole use of scanning electron microscopy compositional mapping. Besides, while showing that pore filling leads to enhanced photoluminescence emission, we demonstrate that the latter is originated from both erbium oxide and silicate. These results give a much deeper understanding of the photoluminescence origin down to nanoscale and could lead to novel approaches focused on noteworthy enhancement of Er-related photoluminescence in porous silicon.

Plasma processing of microcrystalline silicon films : filling in the gaps

NARCIS (Netherlands)

Bronneberg, A.C.

2012-01-01

Hydrogenated microcrystalline silicon (µc-Si:H) is a mixed-phase material consisting of crystalline silicon grains, hydrogenated amorphous silicon (a-Si:H) tissue, and voids. Microcrystalline silicon is extensively used as absorber layer in thin-film tandem solar cells, combining the advantages of a

Electron beam crosslinked gels-Preparation, characterization and their effect on the mechanical, dynamic mechanical and rheological properties of rubbers

Energy Technology Data Exchange (ETDEWEB)

Mitra, Suman; Chattopadhyay, Santanu [Rubber Technology Centre, Indian Institute of Technology, Kharagpur 721302 (India); Sabharwal, Sunil [Radiation Technology Development Section, Bhabha Atomic Research Center, Trombay, Mumbai 400085 (India); Bhowmick, Anil K., E-mail: anilkb@rtc.iitkgp.ernet.i [Rubber Technology Centre, Indian Institute of Technology, Kharagpur 721302 (India)

2010-03-15

Electron beam (EB) crosslinked natural rubber (NR) gels were prepared by curing NR latex with EB irradiation over a range of doses from 2.5 to 20 kGy using butyl acrylate as sensitizer. The NR gels were systematically characterized by solvent swelling, dynamic light scattering, mechanical and dynamic mechanical properties. These gels were introduced in virgin NR and styrene butadiene rubber (SBR) matrices at 2, 4, 8 and 16 phr concentration. Addition of the gels improved the mechanical and dynamic mechanical properties of NR and SBR considerably. For example, 16 phr of 20 kGy EB-irradiated gel-filled NR showed a tensile strength of 3.53 MPa compared to 1.85 MPa of virgin NR. Introduction of gels in NR shifted the glass transition temperature to a higher temperature. A similar effect was observed in the case of NR gel-filled SBR systems. Morphology of the gel-filled systems was studied with atomic force microscopy. The NR gels also improved the processability of the virgin rubbers greatly. Both the shear viscosity and the die swell values of EB-irradiated gel-filled NR and SBR were lower than their virgin counterparts as investigated by capillary rheometer.

Electron beam crosslinked gels-Preparation, characterization and their effect on the mechanical, dynamic mechanical and rheological properties of rubbers

International Nuclear Information System (INIS)

Mitra, Suman; Chattopadhyay, Santanu; Sabharwal, Sunil; Bhowmick, Anil K.

2010-01-01

Electron beam (EB) crosslinked natural rubber (NR) gels were prepared by curing NR latex with EB irradiation over a range of doses from 2.5 to 20 kGy using butyl acrylate as sensitizer. The NR gels were systematically characterized by solvent swelling, dynamic light scattering, mechanical and dynamic mechanical properties. These gels were introduced in virgin NR and styrene butadiene rubber (SBR) matrices at 2, 4, 8 and 16 phr concentration. Addition of the gels improved the mechanical and dynamic mechanical properties of NR and SBR considerably. For example, 16 phr of 20 kGy EB-irradiated gel-filled NR showed a tensile strength of 3.53 MPa compared to 1.85 MPa of virgin NR. Introduction of gels in NR shifted the glass transition temperature to a higher temperature. A similar effect was observed in the case of NR gel-filled SBR systems. Morphology of the gel-filled systems was studied with atomic force microscopy. The NR gels also improved the processability of the virgin rubbers greatly. Both the shear viscosity and the die swell values of EB-irradiated gel-filled NR and SBR were lower than their virgin counterparts as investigated by capillary rheometer.

Effect of gamma irradiation on properties of ultrafine rubbers as toughening filler in polybenzoxazine

Science.gov (United States)

Taewattana, Rapiphan; Jubsilp, Chanchira; Suwanmala, Phiriyatorn; Rimdusit, Sarawut

2018-04-01

Three types of ultrafine fully vulcanized powdered rubbers (UFRs), i.e. natural rubber (NR), carboxylated nitrile-butadiene rubber (XNBR), and carboxylated styrene-butadiene rubber (XSBR) were prepared by combined technology between gamma irradiation for crosslinking and spray drying. The effects of doses in a range of 0-250 kGy on swelling ratio, crosslink density, and thermal stability of UFRs were investigated. Smaller particle size of UFRs was obtained at higher dose. A decrease in the swelling ratio and an increase in crosslink density were well corresponded to crosslinking effect related with absorbed dose. The increase in dose was also found to improve thermal performance of URFs. The influence of irradiated UFRs on impact resistance and glass transition temperature (Tg) of polybenzoxazine composites was also evaluated. The highest impact resistance of the composites belonged to the composite filled with irradiated UFXNBR at 200 kGy. While the significantly enhanced Tg of the composite was obtained by an addition of irradiated UFRs with higher doses, i.e. Tg = 173 °C for the composite filled with irradiated UFXNBR at 250 kGy. As a consequence, the UFRs can be used to effectively modify thermal and mechanical properties, especially impact resistance of polybenzoxazine composites.

New rubber qualification for the igniter adapter

Science.gov (United States)

Humpherys, Mark A.

1994-01-01

Kirkhill Rubber Company (KRC) has informed Thiokol Corporation that two raw materials used in the asbestos and silica filled acrylonitrile butadience rubber (NBR) formulation per STW 2621 are no longer available from their vendors. Agerite White (Di-beta-naphthyl-paraphenylene diamine), manufactured by B. F. Goodrich, is an antioxidant used in NBR. This raw material makes up roughly 1-2 percent of the finished product. KRC proposed that this raw material be replaced by Agerite Stalite S (mixture of octylated diphenylamines) distributed by R. T. Vanderbilt Co. Protox-166 zinc oxide, manufactured by Zinc Corporation of America, is an activator currently used in NBR. This material also makes up about 1-2 percent of the finished material. Protox-166 is an American process grade zinc oxide. It is proposed by KRC to replace Protox-166 with Kadox-930C, a French process grade zinc oxide. American process grades have an ASTM minimum purity of 99.0 percent; the French process grades have a minimum purity of 99.5 percent. Previous testing per WTP-0270 has demonstrated that the mechanical and thermal properties of the rubber with the new ingredients are comparable to the 'old' rubber. The test results are reported in TWR-61790. One igniter adapter, Part no. 7U77562-02 serial no. 2 was insulated per ETP-1206 using the new rubber formulation and a modified lay up and cure method to demonstrate that there is no impact on this process. The results of this demonstration are reported.

Novel in situ coordinated cerium salt/acrylonitrile-butadiene rubber composite

Energy Technology Data Exchange (ETDEWEB)

Han, Jianjun [Key Laboratory of Special Functional Aggregated Materials, Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China); Lu, Haifeng, E-mail: lhf@sdu.edu.cn [Key Laboratory of Special Functional Aggregated Materials, Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China); Zhang, Jie [Key Laboratory of Special Functional Aggregated Materials, Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China); Feng, Shengyu, E-mail: fsy@sdu.edu.cn [Key Laboratory of Special Functional Aggregated Materials, Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China)

2012-09-14

A novel rubber composite of acrylonitrile-butadiene rubber (NBR) filled with cerium salt particles was vulcanized via in situ coordination for the first time. The resulting materials exhibit good mechanical properties. Curing characteristics analysis, differential scanning calorimetry, X-ray photoelectron spectroscopy, tensile testing, and an equilibrium swelling method were used for the characterization of the composite. The results in this paper indicate that the composite is a kind of elastomer based on the in situ coordination crosslinking interactions between the nitrile groups (-CN) of NBR and cerium ions. The mechanical properties of vulcanized cerium salt/ NBR rubber are altered when changing the sorts of cerium salt. Moreover, these materials show good irradiation resistance because of the introduction of the cerium salt. -- Highlights: Black-Right-Pointing-Pointer Cerium salts were firstly used to vulcanize the acrylonitrile-butadiene rubber. Black-Right-Pointing-Pointer Cerium salts act as not only crosslink agents but also reinforcing fillers in the matrix. Black-Right-Pointing-Pointer These materials show good irradiation resistance and mechanical properties at same time.

Nano-lignin filled natural rubber composites: Preparation and characterization

Directory of Open Access Journals (Sweden)

C. Jiang

2013-05-01

Full Text Available This paper presents a novel strategy to prepare nano-lignin and its composites with natural rubber. The nanolignin was ontained by fabricating colloidal lignin-Poly (diallyldimethylammonium chloride (PDADMAC complexes (LPCs via self-assembly technology. The characteristics of LPCs were investigated by zeta potential, dynamic light scattering (DLS, transmission electron microscopy (TEM, Fourier transform infrared spectroscopy (FTIR and ultraviolet – visible (UV-vis absorption measurements. The results indicated that PDADMAC intensively interacted with lignin by cation-π and π-π interactions, and lignin particles were stable in aqueous solution with an average particle size less than 100 nm. LPCs accelerated the vulcanization of NR/LPCs nanocomposites. Morphological studies and Dynamic mechanical analysis (DMA showed the homogeneous dispersion of LPCs in the NR matrix and the strong interfacial adhesion between them. The nanoscale dispersion of LPCs significantly enhanced the thermal stability and mechanical properties of NR/LPCs nanocomposites.

Pavement system with rubber tire chips in subgrade

Energy Technology Data Exchange (ETDEWEB)

Ashtakala, B.; Hoque, A.K.M.M. [Concordia Univ., Montreal, PQ (Canada). Dept. of Civil Engineering

1995-12-31

A pavement design method was developed in which shredded rubber tire chips mixed with sand were used as a material for pavement subgrade. Rubber tire chips are highly compressible and produce both elastic and plastic deformations under the application of loads. Sand was added to fill the void between the tire chips and make the mixture a strong material. The design method considered the vertical compressive strain produced by the design life traffic load 18k (80 KN) repetitions. The equivalent thicknesses of the layers above the subgrade corresponding to this vertical compressive strain were determined using contour charts. From this equivalent thickness, the thicknesses for asphalt pavement, base, and sub-base were determined by Odemark`s method. 3 refs., 1 tab., 3 figs.

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

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.

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

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

Location of a Dexamethasone Implant at the Macula after Intravitreal Injection in a Silicone Oil-Filled Eye

Directory of Open Access Journals (Sweden)

Cenap Mahmut Esenulku

2016-01-01

Full Text Available Here, we report a case with cystoid macular edema (CME due to central retinal vein occlusion (CRVO presented with a dexamethasone implant (Ozurdex trapped at the macula in her silicone oil- (SO- filled eye after injection. No additional complications such as intraocular pressure (IOP rise or retinal damage were observed. The CME was resolved during the follow-up period. At the last visit, 3 months following the injection, Ozurdex implant was found to be mostly dissolved without any additional ocular complications.

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.

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

Silicon deposition in nanopores using a liquid precursor

Science.gov (United States)

Masuda, Takashi; Tatsuda, Narihito; Yano, Kazuhisa; Shimoda, Tatsuya

2016-11-01

Techniques for depositing silicon into nanosized spaces are vital for the further scaling down of next-generation devices in the semiconductor industry. In this study, we filled silicon into 3.5-nm-diameter nanopores with an aspect ratio of 70 by exploiting thermodynamic behaviour based on the van der Waals energy of vaporized cyclopentasilane (CPS). We originally synthesized CPS as a liquid precursor for semiconducting silicon. Here we used CPS as a gas source in thermal chemical vapour deposition under atmospheric pressure because vaporized CPS can fill nanopores spontaneously. Our estimation of the free energy of CPS based on Lifshitz van der Waals theory clarified the filling mechanism, where CPS vapour in the nanopores readily undergoes capillary condensation because of its large molar volume compared to those of other vapours such as water, toluene, silane, and disilane. Consequently, a liquid-specific feature was observed during the deposition process; specifically, condensed CPS penetrated into the nanopores spontaneously via capillary force. The CPS that filled the nanopores was then transformed into solid silicon by thermal decomposition at 400 °C. The developed method is expected to be used as a nanoscale silicon filling technology, which is critical for the fabrication of future quantum scale silicon devices.

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

Crumb Rubber-Concrete Panels Under Blast Loads

Science.gov (United States)

2010-05-01

and the samples were labeled. Samples were picked up with an overhead crane and a form spreader connected to two points on the sample, each outside...uniform loading. Shortly after test started 8 to 9 cracks developed within quarter points and 2 cracks developed through pick points where form spreader ...dynamic behaviour of recycled tyre rubber-filled concrete.” Cem. Concr. Res., 32, 1587–1596. Huang, B., Li, G., Pang, S. S., and Eggers, J. (2004

Microwave pre-heating of natural rubber using a rectangular wave guide (MODE: TE10

Directory of Open Access Journals (Sweden)

Doo-ngam, N.

2007-11-01

Full Text Available This paper presents an application of microwave radiation for pre-heating of natural rubbercompounding with various sulphur contents. The natural rubber-compounding was pre-heated by microwave radiation using a rectangular wave guide system (MODE: TE10 operating at frequency of 2.45 GHz in which the power can vary from 0 to 1500 W. In the present work, the influence of power input, sample thickness, and sulphur content were examined after applying microwave radiation to the rubber samples. Results are discussed regarding the thermal properties, 3-D network, dielectric properties and chemical structures. From the result, firstly, it was found that microwave radiation can be applied to pre-heating natural rubber-compounding before the vulcanization process. Secondly, microwave radiation was very useful for pre-heating natural rubber-compounding that has a thickness greater than 5mm. Thirdly, crosslinking in natural rubber-compounding may occurs after pre-heating by microwave radiation though Fourier Transform Infrared Spectroscopy(FTIR. Finally, there a little effect of sulphur content on temperature profiles after applying microwave radiation to the natural rubber-compounding. Moreover, natural rubber-compounding without carbon black showed a lower heat absorption compared with natural rubbercompounding filled carbon black. This is due to the difference in dielectric loss factor. This preliminary result will be useful information in terms of microwave radiation for pre-heating natural rubber-compounding and rubber processing in industry.

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.

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.

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.

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).

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.

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.

The role of carbon nanotubes in promoting the properties of carbon black-filled natural rubber/butadiene rubber composites

Directory of Open Access Journals (Sweden)

Jiangshan Gao

Full Text Available 80/20 natural rubber (NR/butadiene rubber (BR blends in which the carbon black (CB was replaced partially by multi-walled carbon nanotubes (MWCNTs according to the ratios m (CNTs: m (decreasing amount of CB = 1: X (X was varied from 1 to 6, was prepared by blending of internal mixer and the two-roll mill at the mill opening of 0.5 mm for 10 times. SEM and TEM were used to investigate the filler networks and the good dispersion of fillers. The compounds containing 5 phr CNTs/27.5 phr CB exhibited the best abrasion resistance which was increased by 12.69% compared that without CNTs. 3D morphology images of wear surfaces and tensile fracture surfaces being similar to the layered map of the geography, which match the abrasion resistance and tensile properties, were observed by 3D measuring laser microscope. The uncured blend with 5 phr CNTs/35 phr CB showed the shortest cure time, the highest modulus and level of crosslink density. Significant improvement in mechanical properties were achieved by incorporating 5 phr CNTs and 35 phr CB, and the tear strength, 100% and 300% modulus of the vulcanizate were enhanced by 36.36%, 61.29% and 31.63% compared with the composite with 0 phr CNTs/40 phr CB, respectively. Additionally, compared with the composite without CNTs, the thermal conductivity of the composites with 5 phr CNTs/35 phr CB is increased by an average of 6.15% at three different temperatures. These considerable reinforcements resulted from the synergistic effect of CNTs and CB. Keywords: Synergistic effect, Carbon nanotubes, DIN abrasion, Mechanical properties, Thermal conductivity, 3D measuring laser microscope

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.)

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.

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.

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.

Enhancing mechanical and thermal properties of styrene-butadiene rubber/carboxylated acrylonitrile butadiene rubber blend by the usage of graphene oxide with diverse oxidation degrees

Science.gov (United States)

Xue, Xiaodong; Yin, Qing; Jia, Hongbing; Zhang, Xuming; Wen, Yanwei; Ji, Qingmin; Xu, Zhaodong

2017-11-01

Graphene oxide (GO) with various oxidation degrees were prepared through a modified Hummer's method by varying the dosage of oxidizing agent. Styrene-butadiene rubber (SBR)/carboxylated acrylonitrile butadiene rubber (XNBR)/GO nanocomposites were fabricated by aqueous-phase mixing of GO colloidal dispersion with SBR latex and a small loading of XNBR latex, followed by co-coagulation. Effects of GO oxidation degree on the morphology, structure, mechanical and thermal properties of nanocomposites were thoroughly investigated. The results showed that the mechanical strength of nanocomposites were enhanced with the increase of oxidation degree of GO. Especially, when the weight ratio of KMnO4 to graphite was 15/5, the tensile strength, tear strength and thermal conductivity of SBR/XNBR/GO filled with 3 phr (parts per hundred rubber) GO increased by 255.3%, 141.5% and 22.8%, respectively, compared to those of neat SBR/XNBR blend. In addition, the thermal stability and the solvent resistance of the nanocomposites were also improved significantly. This work suggested that GO with higher oxidation degree could effectively improve the properties of SBR/XNBR blend.

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.

Droplets on posterior surface of intraocular lens in silicone oil filled eye.

Directory of Open Access Journals (Sweden)

Sharma Y

2003-01-01

Full Text Available Silicone oil adherence to silicone IOLs after silicone oil removal is a known complication in pseudophakic patients. Droplet removal is difficult and may require IOL exchange. We describe two cases in which silicone oil droplets were observed early in the postoperative period in PMMA pseudophakic eyes and disappeared during silicone oil-fluid exchange--a phenomenon that has not been reported earlier in human PMMA pseudophakic eyes.

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.

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...

Nitrile rubber and carboxylated nitrile rubber resistance to soybean biodiesel

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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.

Analysis of a metal filling and liner formation mechanism of the blind via with nano-Ag particles for TSV (through silicon via) interconnection

International Nuclear Information System (INIS)

Ham, Y-H; Kim, D-P; Baek, K-H; Park, K-S; Do, L-M; Kwon, K-H

2012-01-01

We investigated a metal filling and liner formation mechanism with a nano-Ag particle for the blind Si via, which is used in the via first process of through silicon via (TSV) interconnection. Using the deep reactive ion etching process, we produced the blind Si via (which is called the blind via hole or via) with a nearly vertical profile. The diameter and depth of the blind Si via were about 10 and 71 µm, respectively. The blind via holes were filled with a nano-Ag particle solution to form a metal plug or a metal liner. At this time, the Ag filling properties were monitored as a function of the volatilization rate of the Ag particle solution in the evacuating chamber. In the fast volatilization of the nano-Ag particle solution, an Ag liner formed on the inner wall of via holes. Meanwhile, both an Ag liner at the sidewall and the Ag plug at the bottom were obtained by the slow volatilization process. Finally, blind via holes fully filled with nano-Ag particles were obtained using four repetitions of the slow volatilization filling process. The proposed TSV filling process can fill large-diameter via holes over 100 µm without a seed layer and chemical mechanical planarization for TSV interconnection at low temperature. This is a simple and cost-effective TSV filling process. (paper)

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

Quantification of radiation induced crosslinking in a commercial, toughened silicone rubber, TR-55, by 1H MQ-NMR

Energy Technology Data Exchange (ETDEWEB)

Maxwell, R; Chinn, S; Alviso, C; Harvey, C A; Giuliani, J; Wilson, T; Cohenour, R

2008-11-10

Radiation induced degradation in a commercial, filled silicone composite has been studied by SPME/GC-MS, DMA, DSC, swelling, and Multiple Quantum NMR. Analysis of volatile and semivolatile species indicates degradation via decomposition of the peroxide curing catalyst and radiation induced backbiting reactions. DMA, swelling, and spin-echo NMR analysis indicate a increase in crosslink density of near 100% upon exposure to a cumulative dose of 250 kGray. Analysis of the sol-fraction via Charlseby-Pinner analysis indicates a ratio of chain scission to crosslinking yields of 0.38, consistent with the dominance of the crosslinking observed by DMA, swelling and spin-echo NMR and the chain scissioning reactions observed by MS analysis. Multiple Quantum NMR has revealed a bimodal distribution of residual dipolar couplings near 1 krad/sec and 5 krad/sec in an approximately 90:10 ratio, consistent with bulk network chains and chains associated with the filler surface. Upon exposure to radiation, the mean {Omega}{sub d} for both domains and the width of both domains both increased. The MQ NMR analysis provided increase insight into the effects of ionizing radiation on the network structure of silicone polymers.

Safely re-integrating silicone breast implants into the plastic surgery practice.

Science.gov (United States)

Gladfelter, Joanne

2006-01-01

In the early 1990s, it was reported that silicone breast implants were possibly responsible for serious damage to women's health. In January 1992, the Food and Drug Administration issued a voluntary breast implant moratorium and, in April, issued a ban on the use of silicone gel-filled implants for cosmetic breast augmentation. Since that time, silicone gel-filled breast implants have been available to women only for select cases: women seeking breast reconstruction or revision of an existing breast implant, women who have had breast cancer surgery, a severe injury to the breast, a birth defect that affects the breast, or a medical condition causing a severe breast deformity. Since the ban on the use of silicone gel-filled breast implants for cosmetic breast augmentation, numerous scientific studies have been conducted. To ensure patient safety, the American Board of Plastic Surgery believes that these scientific studies and the Food and Drug Administration's scrutiny of silicone gel-filled breast implants have been appropriate and necessary.

Gamma radiation effects on polydimethylsiloxane rubber foams under different radiation conditions

Science.gov (United States)

Sui, H. L.; Liu, X. Y.; Zhong, F. C.; Li, X. Y.; Wang, L.; Ju, X.

2013-07-01

Polydimethylsiloxane rubber foams were irradiated by gamma ray under different radiation conditions designed by orthogonal design method. Compression set measurement, infrared attenuated total reflectance spectroscopy (ATR) and X-ray induced photoelectron spectroscopy (XPS) were used. Three aging factors' influence effects on the mechanical property and chemical structure were studied. It was found that among the three factors and the chosen levels, both properties were affected most by radiation dose, while radiation dose rate had no obvious influence on both properties. The stiffening of the rubber foams was caused by cross-linking reactions in the Si-CH3. At the same radiation dose, the rigidity of the foams irradiated in air was lower than that in nitrogen. When polydimethylsiloxane was irradiated at a high dose in sealed nitrogen atmosphere, carbon element distribution would be changed. Hydrocarbons produced by gamma ray in the sealed tube would make the carbon content in the skin-deep higher than that in the middle, which indicated that polydimethylsiloxane rubber foams storing in a sealed atmosphere filled with enough hydrocarbons should be helpful to extend the service life.

Gamma radiation effects on polydimethylsiloxane rubber foams under different radiation conditions

Energy Technology Data Exchange (ETDEWEB)

Sui, H.L. [Department of Physics, University of Science and Technology Beijing, Beijing 100083 (China); Institute of Chemical Materials, CAEP, Mianyang 621900 (China); Liu, X.Y.; Zhong, F.C. [Institute of Chemical Materials, CAEP, Mianyang 621900 (China); Li, X.Y. [Institute of Nuclear Physics and Chemistry, CAEP, Mianyang 621900 (China); Wang, L. [Institute of Chemical Materials, CAEP, Mianyang 621900 (China); Ju, X., E-mail: jux@ustb.edu.cn [Department of Physics, University of Science and Technology Beijing, Beijing 100083 (China)

2013-07-15

Polydimethylsiloxane rubber foams were irradiated by gamma ray under different radiation conditions designed by orthogonal design method. Compression set measurement, infrared attenuated total reflectance spectroscopy (ATR) and X-ray induced photoelectron spectroscopy (XPS) were used. Three aging factors’ influence effects on the mechanical property and chemical structure were studied. It was found that among the three factors and the chosen levels, both properties were affected most by radiation dose, while radiation dose rate had no obvious influence on both properties. The stiffening of the rubber foams was caused by cross-linking reactions in the Si–CH{sub 3}. At the same radiation dose, the rigidity of the foams irradiated in air was lower than that in nitrogen. When polydimethylsiloxane was irradiated at a high dose in sealed nitrogen atmosphere, carbon element distribution would be changed. Hydrocarbons produced by gamma ray in the sealed tube would make the carbon content in the skin-deep higher than that in the middle, which indicated that polydimethylsiloxane rubber foams storing in a sealed atmosphere filled with enough hydrocarbons should be helpful to extend the service life.

The demonstration of nonlinear analytic model for the strain field induced by thermal copper filled TSVs (through silicon via

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M. H. Liao

2013-08-01

Full Text Available The thermo-elastic strain is induced by through silicon vias (TSV due to the difference of thermal expansion coefficients between the copper (∼18 ppm/ °C and silicon (∼2.8 ppm/ °C when the structure is exposed to a thermal ramp budget in the three dimensional integrated circuit (3DIC process. These thermal expansion stresses are high enough to introduce the delamination on the interfaces between the copper, silicon, and isolated dielectric. A compact analytic model for the strain field induced by different layouts of thermal copper filled TSVs with the linear superposition principle is found to have large errors due to the strong stress interaction between TSVs. In this work, a nonlinear stress analytic model with different TSV layouts is demonstrated by the finite element method and the analysis of the Mohr's circle. The characteristics of stress are also measured by the atomic force microscope-raman technique with nanometer level space resolution. The change of the electron mobility with the consideration of this nonlinear stress model for the strong interactions between TSVs is ∼2–6% smaller in comparison with those from the consideration of the linear stress superposition principle only.

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.

Clinical study of secondary glaucoma after silicone oil tamponade

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Xiao-Chun Chen

2013-12-01

Full Text Available AIM: To evaluate the related risk factors and treatment method of secondary glaucoma after pars plana vitrectomy and silicone oil tamponade.METHODS: The retrospective study analyzed 114 patients(118 eyeswho were treated with pars plana vitrectomy combined with silicone oil tamponade. Lenses were reserved in 78 eyes and were taken away in 40 eyes among which intraocular lens were implanted in 17 eyes. There were 39 eyes in which the filling time of silicone was no more than 6 months while 79 eyes in which the filling time was more than 6 months. The follow-up time was(16.2±4.9months. Primary and secondary glaucoma were excluded before the vitrectomy. Silicone oil glaucoma(SOGwas diagnosed when intraocular pressure(IOPwas measured higher than 21mmHg(1mmHg=0.133kPathree times in succession at least 1 month after silicone oil tamponade and inflammation and neovascular glaucoma should be excluded. Anti-glaucoma drugs were administrated once SOG was diagnosed. If the IOP was not controlled after 2 weeks, the silicone oil was taken away. If the IOP was still high, the anti-glaucoma surgery was operated. The data was analyzed by the SPSS 16.0 software using a binary logistic regression analysis. RESULTS: Among the 32 eyes of SOG, lenses were removed in 16 eyes(50%. The filling time of silicone oil was more than 6 months in 27 eyes(84.4%and silicone oil emulsion happened in 20 eyes(62.5%. IOP returned normal in 17 eyes after administrating anti-glaucoma medication within 2 weeks. Silicone oils were taken away in 15 eyes. However, 4 eyes still had high IOP after surgery; one of them was given anti-glaucoma drugs once more; two of them underwent trabeculectomy and one of them underwent cyclophotocoagulation. The lens conditions(whether it was taken away or not, P=0.024, the silicone oil filling time(whether the time was more than 6 months, P=0.014, and the status of the silicone oil(whether emulsification occurred or not, P=0.000were all found to be

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.

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

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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.

Photoluminescence studies on porous silicon/polymer heterostructure

International Nuclear Information System (INIS)

Mishra, J.K.; Bhunia, S.; Banerjee, S.; Banerji, P.

2008-01-01

Hybrid devices formed by filling porous silicon with MEH-PPV or poly [2-methoxy-5(2-ethylhexyloxy-p-phenylenevinylene)] have been investigated in this work. Analyses of the structures by scanning electron microscopy (SEM) demonstrated that the porous silicon layer was filled by the polymer with no significant change of the structures except that the polymer was infiltrated in the pores. The photoluminescence (PL) of the structures at 300 K showed that the emission intensity was very high as compared with that of the MEH-PPV films on different substrates such as crystalline silicon (c-Si) and indium tin oxide (ITO). The PL peak in the MEH-PPV/porous silicon composite structure is found to be shifted towards higher energy in comparison with porous silicon PL. A number of possibilities are discussed to explain the observations

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

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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.

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.

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.)

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.)

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

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

ODC-Free Solvent Implementation Issues for Vulcanized Rubber and Bond Systems

Science.gov (United States)

Hodgson, James R.; McCool, Alex (Technical Monitor)

2001-01-01

Thiokol Propulsion has worked extensively to replace 1,1,1-trichloroethane (TCA) with ozone depleting chemicals (ODC)-free solvents for use in the manufacture of the Reusable Solid Rocket Motor (RSRM) for the Space Shuttle Program. As Thiokol has transitioned from sub-scale to full-scale testing and implementation of these new solvents, issues have been discovered which have required special attention. The original intent of Thiokol's solvent replacement strategy was to replace TCA with a single drop-in solvent for all equivalent applications. We have learned that a single candidate does not exist for replacing TCA. Solvent incompatibility with process materials has caused us to seek for niche solvents and/or processing changes that provide an ODC-free solution for special applications. This paper addresses some of the solvent incompatibilities, which have lead to processes changes and possible niche solvent usage. These incompatibilities were discovered during full-scale testing of ODC-free solvents and relate to vulcanized rubber and bond systems in the RSRM. Specifically, the following items are presented: (1) Cure effects of d-limonene based solvents on Silica Filled Ethylene Propylene Diene Monomer (SF-EPDM) rubber. During full-scale test operations, Thiokol discovered that d-limonene (terpene) based solvents inhibit the cure of EPDM rubber. Subsequent testing showed the same issue with Nitrile Butadiene Rubber (NBR). Also discussed are efforts to minimize uncured rubber exposure to solvents; and (2) Cured bond system sensitivity to ODC-free solvents. During full scale testing it was discovered that a natural rubber to steel vulcanized bond could degrade after prolonged exposure to ODC-free solvents. Follow on testing showed that low vapor pressure and residence time seemed to be most likely cause for failure.

A new mechanism for selective adsorption of rubber on carbon black surface caused by nano-confinement in SBR/NBR solution

Science.gov (United States)

Kawazoe, Masayuki

A novel mechanism of selective adsorption of rubber molecules onto carbon black surface in a binary immiscible rubber blend solution has been proposed in this dissertation. The phenomenon leads to uneven distribution of carbon black to the specific polymer in the blend and the obtained electrically conductive composite showed drastic reduction of percolation threshold concentration (PTC). The mechanism and the feature of conductive network formation have much potential concerning both fundamental understanding and industrial application to improve conductive polymer composites. In chapter I, carbon black filled conductive polymer composites are briefly reviewed. Then, in chapter II, a mechanism of rubber molecular confinement into carbon black aggregate structure is introduced to explain the selective adsorption of a specific rubber onto carbon black surface in an immiscible rubber solution blend (styrene butadiene rubber (SBR) and acrylonitrile butadiene rubber (NBR) with toluene or chloroform). Next, in chapters III and IV, polymers with various radius of gyration (Rg) and carbon blacks with various aggregate structure are examined to verify the selective adsorption mechanism. Finally, in chapter V, the novel mechanism was applied to create unique meso-/micro-unit conductive network in carbon black dispersed SBR/NBR composites.

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 ...

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...

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.

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.

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.

A nonlinear auxetic structural vibration damper with metal rubber particles

International Nuclear Information System (INIS)

Ma, Yanhong; Zhang, Dayi; Zhu, Bin; Chen, Lulu; Hong, Jie; Scarpa, Fabrizio

2013-01-01

The work describes the mechanical performance of a metal rubber particles (MRP) damper design based on an auxetic (negative Poisson’s ratio) cellular configuration. The auxetic damper configuration is constituted by an anti-tetrachiral honeycomb, where the cylinders are filled with the MRP material. The MRP samples have been subjected to quasi-static loading to measure the stiffness and loss factor from the static hysteresis curve. A parametric experimental analysis has been carried out to investigate the effect of relative density and filling percentage on the static performance of the MRP, and to identify design guidelines for best use of MRP devices. An experimental assessment of the integrated auxetic-MRP damper concept has been provided through static and dynamic force response techniques. (paper)

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 ...

The influence of nano silica particles on gamma-irradiation ageing of elastomers based on chlorosulphonated polyethylene and acrylonitrile butadiene rubber

Science.gov (United States)

Marković, G.; Marinović-Cincović, M.; Tanasić, Lj.; Jovanović, V.; Samaržija-Jovanović, S.; Vukić, N.; Budinski-Simendić, J.

2011-12-01

The goal of this work was to study gamma irradiation ageing of rubber blends based on acrylonitrile butadiene rubber (NBR) and chlorosulphonated polyethylene rubber (CSM) reinforced by silica nano particles. The NBR/CSM compounds (50: 50, w/w) filled with different content of filler (0-100 phr) were crosslinked by sulfur. The vulcanization characteristics were assessed using the rheometer with an oscillating disk. The vulcanizates were prepared in a hydraulic press. The obtained materials were exposed to the different irradiation doses (100, 200, 300 and 400 kGy). The mechanical properties (hardness, modulus at 100% elongation, tensile strength and elongation at break) and swelling numbers were assessed before and after gamma irradiation ageing.

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....

Effect of elevated temperature on the properties of silica fume and recycled rubber-filled high strength concretes (RHSC

Directory of Open Access Journals (Sweden)

Magda I. Mousa

2017-04-01

The results obtained show high resistance to fire with increasing SF content up to 20% replacement of cement. Additional improvement was obtained with using dolomite and 3% of recycled rubber (2 mm, 5 mm.

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.

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...

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)

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…

Mechanical and tribological properties of acrylonitrile–butadiene rubber filled with graphite and carbon black

International Nuclear Information System (INIS)

Wang, Lei Lei; Zhang, Li Qun; Tian, Ming

2012-01-01

Highlights: ► Graphite/carbon black/rubber micro- and nano-composites were prepared. ► Nanocomposites showed better mechanical properties and wear resistance. ► The effect of load and sliding speed on friction and wear is significant. ► Graphite lubricant film can reduce friction coefficient and wear rate. -- Abstract: In this work, acrylonitrile–butadiene rubber (NBR)/expanded graphite (EG)/carbon black (CB) micro- and nanocomposites were prepared by two different methods, and the resulting mechanical and tribological properties were compared with those of NBR/CB composites. Meanwhile, the effects of graphite dispersion and loading content, as well as the applied load and sliding velocity on the tribological behavior of the above composites under dry friction condition were also evaluated. The worn surfaces were analyzed by scanning electron microscopy (SEM) to disclose wear mechanism. As expected, the better the dispersion of graphite, the more remarkable enhancement on tensile and dynamic mechanical properties, and the greater reduction in the coefficient of friction (COF) and specific wear rate (W s ). It was found that a small amount of EG could effectively decrease COF and W s of NBR/CB composites because of the formation of graphite lubricant films. The COF and W s of NBR/CB/EG composites show a decreasing trend with a rise in applied load and sliding velocity. NBR/CB/EG nanocomposite always shows a stable wearing process with relatively low COF and W s . It is thought that well-dispersed graphite nano-sheets were beneficial to the formation of a fine and durable lubricant film.

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...

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

The partial replacement of palm kernel shell by carbon black and halloysite nanotubes as fillers in natural rubber composites

Science.gov (United States)

Daud, Shuhairiah; Ismail, Hanafi; Bakar, Azhar Abu

2017-07-01

The effect of partial replacement of palm kernel shell powder by carbon black (CB) and halloysite nanotube (HNT) on the tensile properties, rubber-filler interaction, thermal properties and morphological studies of natural rubber (NR) composites were investigated. Four different compositions of NR/PKS/CB and NR/PKS/HNT composites i.e 20/0, 15/5, 10/10,5/15 and 0/20 parts per hundred rubber (phr) were prepared on a two roll mill. The results showed that the tensile strength and modulus at 100% elongation (M100) and 300% elongation (M300) were higher for NR/PKS/CB compared to NR/PKS/HNT composites. NR/PKS/CB composites had the lowest elongation at break (Eb). The effect of commercial fillers in NR/PKS composites on tensile properties was confirmed by the rubber-filler interaction and scanning electron microscopy (SEM) study. The thermal stability of PKS filled NR composites with partially replaced by commercial fillers also determined by Thermo gravimetric Analysis (TGA).

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.

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.

Physical and magnetic properties, microstructure of bonded magnet NdFeB prepared by using synthesis rubber

International Nuclear Information System (INIS)

Suprapedi; Sardjono, P.; Muljadi

2016-01-01

The magnet permanent has been made by using NdFeB (NQP-B) powder with purity 99.90% and polymer rubber with purity 90%. This research was done to determine the effect of the polymer (rubber) composition as binder in the manufacture of bonded magnet NdFeB on physical properties, microstructure and magnetic properties. Bonded magnets are magnet material made from a mixture of magnetic powder as a filler and the polymer as a matrix material or as binder to bind the magnetic particles. The NdFeB (NQP-B) powder fractions of bonded magnets NdFeB investigated were as follows: a) 97 wt.% of NdFeB (NQP-B) and 3 wt.% of rubber,b) 95wt.% of NdFeB (NQP-B) and 5 wt.% of rubber, c) 93 wt.% of NdFeB (NQP-B) and 7 wt.% of rubber, d) 91 wt.% of NdFeB (NQP-B) and 9 wt.% of rubber. Both raw materials were mixed by using mixer until homogen with total weight about 16 g for each sample, then added 0.3 ml of catalyst and mixed again and put in dies mould and compacted at pressure 30 MPa, then dried for 2 hours at room temperature. The dried samples was characterized such as: bulk density measurement and magnetic properties by using BH-curve permeagraph. The bulk density values of the sample bonded NdFeB magnets using the binder 3% wt. and 5% wt. rubber are respectively 4,70 g/cm 3 and 4.88 g/cm 3 . The result from BH- curve shows that the highest value of remanence (Br = 5.12 kGauss) is at sample with 3% wt. of rubber, but sample with 5% wt. of rubber has lowest value of remanance (Br = 4.40 kGauss). Based on the observation of the SEM photograph shown that the rubber material has been successfully covered the whole surface of the grain and fill some of the voids that are in the grain boundary. (paper)

Physical and magnetic properties, microstructure of bonded magnet NdFeB prepared by using synthesis rubber

Science.gov (United States)

Suprapedi; Sardjono, P.; Muljadi

2016-11-01

The magnet permanent has been made by using NdFeB (NQP-B) powder with purity 99.90% and polymer rubber with purity 90%. This research was done to determine the effect of the polymer (rubber) composition as binder in the manufacture of bonded magnet NdFeB on physical properties, microstructure and magnetic properties. Bonded magnets are magnet material made from a mixture of magnetic powder as a filler and the polymer as a matrix material or as binder to bind the magnetic particles. The NdFeB (NQP-B) powder fractions of bonded magnets NdFeB investigated were as follows: a) 97 wt.% of NdFeB (NQP-B) and 3 wt.% of rubber,b) 95wt.% of NdFeB (NQP-B) and 5 wt.% of rubber, c) 93 wt.% of NdFeB (NQP-B) and 7 wt.% of rubber, d) 91 wt.% of NdFeB (NQP-B) and 9 wt.% of rubber. Both raw materials were mixed by using mixer until homogen with total weight about 16 g for each sample, then added 0.3 ml of catalyst and mixed again and put in dies mould and compacted at pressure 30 MPa, then dried for 2 hours at room temperature. The dried samples was characterized such as: bulk density measurement and magnetic properties by using BH-curve permeagraph. The bulk density values of the sample bonded NdFeB magnets using the binder 3% wt. and 5% wt. rubber are respectively 4,70 g/cm3 and 4.88 g/cm3. The result from BH- curve shows that the highest value of remanence (Br = 5.12 kGauss) is at sample with 3% wt. of rubber, but sample with 5% wt. of rubber has lowest value of remanance (Br = 4.40 kGauss). Based on the observation of the SEM photograph shown that the rubber material has been successfully covered the whole surface of the grain and fill some of the voids that are in the grain boundary.

Structural and Magnetic Properties of Type-M Barium Ferrite - Thermoplastic Natural Rubber Nano composites

International Nuclear Information System (INIS)

Nurhidayaty Mokhtar

2012-01-01

Structural and magnetic properties of type-M barium ferrite (BaFe 12 O 19 ) nanoparticles (∼ 20 nm) embedded in non-magnetic thermoplastic natural rubber (TPNR) matrices were investigated. The TPNR matrices were prepared from high density polyethylene (HDPE) and natural rubber (NR) in the weight ratios of 80:20 and 60:40, respectively, with 10 wt % of NR in the form of liquid natural rubber (LNR) which act as a comparabilities. BaFe 12 O 19 - filled nano composites with 2 - 12 wt % BaFe 12 O 19 ferrite were prepared using a melt- blending technique. Magnetic hysteresis was measured using a vibrating sample magnetometer (VSM) in a maximum field of 10 kOe at room temperature (25 degree Celsius). The saturation magnetisation (MS), remanence (MR) and coercivity (Hc) were derived from the hysteresis loops. The results show that the structural and magnetic properties of nano composites depend on both the ferrite content and the composition of the natural rubber or plastic in the nano composites. All the nano composites exhibit an exchange bias-like phenomenon resulting from the exchange coupling of spins at the interface between the core ferrimagnetic region and the disordered surface region of the nanoparticles. (author)

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

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.

Limitations of using Raman microscopy for the analysis of high-content-carbon-filled ethylene propylene diene monomer rubber

DEFF Research Database (Denmark)

Ghanbari-Siahkali, A.; Almdal, K.; Kingshott, P.

2003-01-01

The effects of laser irradiation on changes to the surface chemistry and structure of a commercially available ethylene propylene diene monomer (EPDM) rubber sample after Raman microscopy analysis was investigated. The Raman measurements were carried out with different levels of laser power...... on the sample, ranging from 4.55 mW to 0.09 mW. The surface of the EPDM was analyzed before and after laser exposure using X-ray photoelectron spectroscopy (XPS) and attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. The techniques have surface probe depths of approximately less...... than or equal to10 nm and 1 mum, respectively. Both sets of analysis show that ingredients of the blended EPDM rubber "bloom" to the surface as a result of local heating that takes place due to the absorption of laser by carbon black during the Raman analysis. Scanning electron microscopy (SEM...

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.

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.

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.

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

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.

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.

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.

Curing kinetics and mechanical behavior of natural rubber reinforced with pretreated carbon nanotubes

International Nuclear Information System (INIS)

Sui, G.; Zhong, W.H.; Yang, X.P.; Yu, Y.H.

2008-01-01

To significantly improve the performance of rubber materials, fundamental studies on rubber nanocomposites are necessary. The curing kinetics and vulcanizate properties of carbon nanotubes (CNTs)/natural rubber (NR) nanocomposites were analyzed in this paper. The pretreatment of CNTs was carried out by acid bath followed by ball milling with HRH bonding systems in experiments. The CNT/NR nanocomposites were prepared through solvent mixing on the basis of pretreatment of CNTs. The surface characteristic of CNTs and physical interaction between CNTs and NR macromolecules were analyzed by Fourier transform infrared spectroscopy (FT-IR). The vulcanization kinetics of CNT/NR nanocomposites were studied contrasting with the neat NR. The quality of the NR vulcanizates was assessed through static and dynamic mechanical property tests and scanning electron microscope (SEM). Curing kinetic parameters of the neat NR and CNT/NR nanocomposites were obtained from experiments; the results indicated that the presence of CNTs affects the curing process of the NR, and additional heating is required to cure CNT/NR nanocomposites due to its higher active energy. The dispersion of pretreated CNTs in the rubber matrix and interfacial adhesion between them were obviously improved. The physical and mechanical properties of the CNT/NR nanocomposites showed considerable increases by incorporation of the pretreated CNTs compared to the neat NR and untreated CNTs-filled NR nanocomposites

Curing kinetics and mechanical behavior of natural rubber reinforced with pretreated carbon nanotubes

Energy Technology Data Exchange (ETDEWEB)

Sui, G. [Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, Beijing 100029 (China); Department of Mechanical Engineering and Applied Mechanics, North Dakota State University, Fargo, ND 58105 (United States); Zhong, W.H. [Department of Mechanical Engineering and Applied Mechanics, North Dakota State University, Fargo, ND 58105 (United States)], E-mail: Katie.Zhong@ndsu.edu; Yang, X.P.; Yu, Y.H. [Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, Beijing 100029 (China)

2008-06-25

To significantly improve the performance of rubber materials, fundamental studies on rubber nanocomposites are necessary. The curing kinetics and vulcanizate properties of carbon nanotubes (CNTs)/natural rubber (NR) nanocomposites were analyzed in this paper. The pretreatment of CNTs was carried out by acid bath followed by ball milling with HRH bonding systems in experiments. The CNT/NR nanocomposites were prepared through solvent mixing on the basis of pretreatment of CNTs. The surface characteristic of CNTs and physical interaction between CNTs and NR macromolecules were analyzed by Fourier transform infrared spectroscopy (FT-IR). The vulcanization kinetics of CNT/NR nanocomposites were studied contrasting with the neat NR. The quality of the NR vulcanizates was assessed through static and dynamic mechanical property tests and scanning electron microscope (SEM). Curing kinetic parameters of the neat NR and CNT/NR nanocomposites were obtained from experiments; the results indicated that the presence of CNTs affects the curing process of the NR, and additional heating is required to cure CNT/NR nanocomposites due to its higher active energy. The dispersion of pretreated CNTs in the rubber matrix and interfacial adhesion between them were obviously improved. The physical and mechanical properties of the CNT/NR nanocomposites showed considerable increases by incorporation of the pretreated CNTs compared to the neat NR and untreated CNTs-filled NR nanocomposites.

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.

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.

Conformal deposition of an insulator layer and Ag nano paste filling of a through silicon via for a 3D interconnection

Energy Technology Data Exchange (ETDEWEB)

Baek, Kyu-Ha; Kim, Dong-Pyo; Park, Kun-Sik; Ham, Yong-Hyun; Do, Lee-Mi [Electronics and Telecommunications Research Institute, Daejeon (Korea, Republic of); Lee, Ki-Jun [Chungnam National University, Daejeon (Korea, Republic of); Kim, Kyung-Seob [Yeoju Institute of Technology, Yeoju (Korea, Republic of)

2011-09-15

In this study, we reported the feasibility of filling a high-aspect-ratio through silicon via (HARTSV) with Ag nano paste for a 3D interconnection. TSVs with aspect ratios of 8:1 {approx} 10:1 were fabricated in a deep reactive etching system by using the Bosch process. Then, SiO{sub 2} insulators were deposited by using various chemical vapor deposition (CVD) processes, including plasma enhanced CVD oxides, of which precursors were silane (PECVD Oxide) and tetraethoxysilane (PECVDTEOS), and sub-atmospheric CVD oxide (SACVD oxide). We succeeded in obtaining a SiO{sub 2} layer with good step coverage over 80% for all via CD sizes by using SACVD oxidation process. The thickness of SiO{sub 2} for the via top and the via bottom were in the range 158.8 {approx} 161.5 nm and 162.6 {approx} 170.7 nm, respectively. The HAR-TSVs were filled with Ag nano paste by using vacuum assisted paste printing. Then, the samples were cured on a hotplate at 80 .deg. C for 2 min. The temperature was increased to 180 .deg. C at a rate of 25 .deg. C/min and the samples were re-annealed for 2 min. We investigated the effects for the time of evacuation/purge process and of the vacuum drying on the filling properties. A field emission scanning electron microscope (FE-SEM), X-ray microscope and focused ion beam (FIB) microscope were used to investigate the filling profile of the TSV with Ag nano pastes. By increasing the evacuation/purge time and the vacuum drying time, we could fully fill the TSV was full filled with Ag nano paste and then form a metal plug.

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

Temporal sealing material of tritium-contaminated stainless steel

International Nuclear Information System (INIS)

Wen Wei; Dan Guiping; Zhang Dong; Qiu Yongmei; Zhang Li

2010-01-01

Tritium can be released from the exterior of tritium-contaminated stainless steel by slight stirring while decontaminating and disassembling. In order to avoid secondary tritium contamination to environment and operators, it is necessary to cover with an effective coating to tritium on the exterior of tritium-contaminated stainless steel and fill an effective substance to tritium inside. The results of tritium sealed experiments show that sealing efficiency of neutral silicone rubber is more than 85% for condition of static state and more than 99% for foam concrete condition of dynamic state. Neutral silicone rubber and foam concrete which have finer sealing efficiency can be used as temporal sealed material for the decontamination and disassembly of tritium-contaminated stainless steel. (authors)

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)

Carbon nanotubes as reinforcement of styrene-butadiene rubber

International Nuclear Information System (INIS)

De Falco, Alejandro; Goyanes, Silvia; Rubiolo, Gerardo H.; Mondragon, Inaki; Marzocca, Angel

2007-01-01

This study reports an easy technique to produce cured styrene-butadiene rubber (SBR)/multi-walled carbon nanotubes (MWCNT) composites with a sulphur/accelerator system at 150 deg. C. Significant improvement in Young's modulus and tensile strength were achieved by incorporating 0.66 wt% of filler without sacrificing SBR elastomer high elongation at break. A comparison with carbon black filled SBR was also made. Field emission scanning electron microscopy was used to investigate dispersion and fracture surfaces. Results indicated that the homogeneous dispersion of MWCNT throughout SBR matrix and strong interfacial adhesion between oxidized MWCNT and the matrix are responsible for the considerable enhancement of mechanical properties of the composite

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 -.

Methods To Determine the Silicone Oil Layer Thickness in Sprayed-On Siliconized Syringes.

Science.gov (United States)

Loosli, Viviane; Germershaus, Oliver; Steinberg, Henrik; Dreher, Sascha; Grauschopf, Ulla; Funke, Stefanie

2018-01-01

The silicone lubricant layer in prefilled syringes has been investigated with regards to siliconization process performance, prefilled syringe functionality, and drug product attributes, such as subvisible particle levels, in several studies in the past. However, adequate methods to characterize the silicone oil layer thickness and distribution are limited, and systematic evaluation is missing. In this study, white light interferometry was evaluated to close this gap in method understanding. White light interferometry demonstrated a good accuracy of 93-99% for MgF 2 coated, curved standards covering a thickness range of 115-473 nm. Thickness measurements for sprayed-on siliconized prefilled syringes with different representative silicone oil distribution patterns (homogeneous, pronounced siliconization at flange or needle side, respectively) showed high instrument (0.5%) and analyst precision (4.1%). Different white light interferometry instrument parameters (autofocus, protective shield, syringe barrel dimensions input, type of non-siliconized syringe used as base reference) had no significant impact on the measured average layer thickness. The obtained values from white light interferometry applying a fully developed method (12 radial lines, 50 mm measurement distance, 50 measurements points) were in agreement with orthogonal results from combined white and laser interferometry and 3D-laser scanning microscopy. The investigated syringe batches (lot A and B) exhibited comparable longitudinal silicone oil layer thicknesses ranging from 170-190 nm to 90-100 nm from flange to tip and homogeneously distributed silicone layers over the syringe barrel circumference (110- 135 nm). Empty break-loose (4-4.5 N) and gliding forces (2-2.5 N) were comparably low for both analyzed syringe lots. A silicone oil layer thickness of 100-200 nm was thus sufficient for adequate functionality in this particular study. Filling the syringe with a surrogate solution including short

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

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)

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.

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

Effects of ageing conditions on degradation of acrylonitrile butadiene rubber filled with heat-treated ZnO star-shaped particles in rapeseed biodiesel

OpenAIRE

Akhlaghi, Shahin; Pourrahimi, A. M.; Christian, Sjöstedt; Martin, Bellander; Mikael S., Hedenqvist; Ulf W., Gedde

2017-01-01

The degradation of acrylonitrile butadiene rubber (NBR) after exposure to biodiesel at different oxygen partial pressures in an automated ageing equipment at 80 °C, and in a high-pressure autoclave at 150 °C was studied. The oxidation of biodiesel was promoted by an increase in oxygen concentration, resulting in a larger uptake of fuel in the rubber due to internal cavitation, a greater decrease in the strain-at-break of NBR due to the coalescence of cavity, and a faster increase in the cross...

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.

Amorphous silicon crystalline silicon heterojunction solar cells

CERN Document Server

Fahrner, Wolfgang Rainer

2013-01-01

Amorphous Silicon/Crystalline Silicon Solar Cells deals with some typical properties of heterojunction solar cells, such as their history, the properties and the challenges of the cells, some important measurement tools, some simulation programs and a brief survey of the state of the art, aiming to provide an initial framework in this field and serve as a ready reference for all those interested in the subject. This book helps to "fill in the blanks" on heterojunction solar cells. Readers will receive a comprehensive overview of the principles, structures, processing techniques and the current developmental states of the devices. Prof. Dr. Wolfgang R. Fahrner is a professor at the University of Hagen, Germany and Nanchang University, China.

Feasibility of using microencapsulated phase change materials as filler for improving low temperature performance of rubber sealing materials.

Science.gov (United States)

Tiwari, Avinash; Shubin, Sergey N; Alcock, Ben; Freidin, Alexander B; Thorkildsen, Brede; Echtermeyer, Andreas T

2017-11-01

The feasibility of a novel composite rubber sealing material to improve sealing under transient cooling (in a so-called blowdown scenario) is investigated here. A composite of hydrogenated nitrile butadiene rubber (HNBR) filled with Micro Encapsulated Phase Change Materials (MEPCM) is described. The fillers contain phase change materials that release heat during the phase transformation from liquid to solid while cooling. This exotherm locally heats the rubber and may improve the function of the seal during a blowdown event. A representative HNBR-MEPCM composite was made and the critical thermal and mechanical properties were obtained by simulating the temperature distribution during a blowdown event. Simulations predict that the MEPCM composites can delay the temperature decrease in a region of the seal during the transient blowdown. A sensitivity analysis of material properties is also presented which highlights possible avenues of improvement of the MEPCMs for sealing applications.

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

Retinal Layers Measurements following Silicone Oil Tamponade for Retinal Detachment Surgery.

Science.gov (United States)

Jurišić, Darija; Geber, Mia Zorić; Ćavar, Ivan; Utrobičić, Dobrila Karlica

2017-12-19

This study aimed to investigate the influence of silicone oil on the retinal nerve fiber layer (RNFL) thickness in patients with primary rhegmatogenous retinal detachment who underwent vitreoretinal surgery. The study included 47 patients (eyes), who underwent a pars plana vitrectomy with the silicone oil tamponade. The control group included unoperated eye of all participants. Spectral-domain optical coherence tomography (SD-OCT) was used for the measurements of peripapilar and macular RNFL thickness. The average peripapillary RNFL thickness was significantly higher in the silicone oil filled eyes during endotamponade and after its removal. The eyes with elevated IOP had less thickening of the RNFL in comparison to the eyes with normal IOP. Central macular thickness and macular volume were decreased in the silicone oil filled eyes in comparison to the control eyes. In conclusion, silicone oil caused peripapilar RNFL thickening in the vitrectomized eyes during endotamponade and after silicone oil removal.

Use of epoxidized natural rubber as a compatibilizer in silica-filled natural rubber tire tread compounds ; Verwendung von epoxydiertem Naturkautschuk als Verträglichkeitsvermittler in Zusammensetzungen aus kieselsäuregefülltem Naturkautschuk für Reifenlaufflächen

NARCIS (Netherlands)

Sengloyluan, K.; Sahakaro, Kannika; Noordermeer, Jacobus W.M.

2012-01-01

Silica-reinforced natural rubber (NR) tire tread compounds with epoxidized natural rubber (ENR) as a compatibilizer are investigated. ENR contents of 2.5-15.0 phr, with epoxide levels of 10, 38 and 51 mol%, are used. The addition of ENRs, especially ENR-38 and ENR-51, as compatibilizers decreases

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.

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.

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.

The use of plasticizing additives based on recycled raw materials in the petrochemical rubber mixtures

Directory of Open Access Journals (Sweden)

Z. S. Shashok

2016-01-01

Full Text Available At present, the development of alternative products for elastomers based on recycling petrochemical raw materials is a new trend of the rubber industry progress. Petrochemical raw materials include spent lubricants and motor oils are among such recycling products. In this context, the influence of the products of recycling waste engine oil (DVCH and RA in comparison with industrial oil (I-20 on the technological properties of filled elastomeric compositions was investigated. The elastomeric compositions were based on poly isoprene and divinyl rubbers. The plasticizing components were manufactured by IOOO “DVCH-Menedzhment”. They are mixture of hydro-carbons, C16–C20 and differ from each other in the content of linear and branched paraffin. Plastic-elastic properties of rubber compounds on the shear disk viscometer MV2000 in accordance with GOST 10722–76 was carried out. Kinetics of vulcanization on the rheometer ODR2000 according to GOST 12535–84 was defined. It is shown that the introduction of RA test plasticizing component provides a significant effect on Mooney viscosity, as compared to elastomeric compositions containing a plasticizer and I-20 and plasticizing additive DVCH. It revealed that the administration of all components in the studied plasticizing elastomer compositions based on a combination poly isoprene and divinyl rubbers has no significant effect on the rate of relaxation of stress of rubber compounds. It is found that elastomeric compositions containing as additives investigated processing waste oil products (DVCH and RA are characterized by a slightly smaller value of time to reach an optimal degree of vulcanization.

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

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...

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

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

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

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.

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

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)

Microstructure Evolution and Protrusion of Electroplated Cu-Filled Through-Silicon Vias Subjected to Thermal Cyclic Loading

Science.gov (United States)

Chen, Si; An, Tong; Qin, Fei; Chen, Pei

2017-10-01

Through-silicon vias (TSVs) have become an important technology for three-dimensional integrated circuit (3D IC) packaging. Protrusion of electroplated Cu-filled vias is a critical reliability issue for TSV technology. In this work, thermal cycling tests were carried out to identify how the microstructure affects protrusion during thermal cycling. Cu protrusion occurs when the loading temperature is higher than 149°C. During the first five thermal cycles, the grain size of Cu plays a dominant role in the protrusion behavior. Larger Cu grain size before thermal cycling results in greater Cu protrusion. With increasing thermal cycle number, the effect of the Cu grain size reduces and the microstrain begins to dominate the Cu protrusion behavior. Higher magnitude of microstrain within Cu results in greater protrusion increment during subsequent thermal cycles. When the thermal cycle number reaches 25, the protrusion rate of Cu slows down due to strain hardening. After 30 thermal cycles, the Cu protrusion stabilizes within the range of 1.92 μm to 2.09 μm.

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

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.

Reinforcement of Multiwalled Carbon Nanotube in Nitrile Rubber: In Comparison with Carbon Black, Conductive Carbon Black, and Precipitated Silica

Directory of Open Access Journals (Sweden)

Atip Boonbumrung

2016-01-01

Full Text Available The properties of nitrile rubber (NBR reinforced by multiwalled carbon nanotube (MWCNT, conductive carbon black (CCB, carbon black (CB, and precipitated silica (PSi were investigated via viscoelastic behavior, bound rubber content, electrical properties, cross-link density, and mechanical properties. The filler content was varied from 0 to 15 phr. MWCNT shows the greatest magnitude of reinforcement considered in terms of tensile strength, modulus, hardness, and abrasion resistance followed by CCB, CB, and PSi. The MWCNT filled system also exhibits extremely high levels of filler network and trapped rubber even at relatively low loading (5 phr leading to high electrical properties and poor dynamic mechanical properties. Although CCB possesses the highest specific surface area, it gives lower level of filler network than MWCNT and also gives the highest elongation at break among all fillers. Both CB and PSi show comparable degree of reinforcement which is considerably lower than CCB and MWCNT.

Zeolite-filled silicone rubber membranes : Part 1. Membrane preparation and pervaporation results

NARCIS (Netherlands)

te Hennepe, H.J.C.; Bargeman, D.; Mulder, M.H.V.; Smolders, C.A.

1987-01-01

Amongst the alternative fuels obtained from renewable resources alcohol from fermentation may become one of the most important. The combination of fermentation with pervaporation in a membrane bioreactor offers the advantage of continuous processing. In this membrane bioreactor alcohol-selective

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.

Electroplated contacts and porous silicon for silicon based solar cells applications

Energy Technology Data Exchange (ETDEWEB)

Kholostov, Konstantin, E-mail: kholostov@diet.uniroma1.it [Department of information engineering, electronics and telecommunications, University of Rome “La Sapienza”, Via Eudossiana 18, 00184 Rome (Italy); Serenelli, Luca; Izzi, Massimo; Tucci, Mario [Enea Casaccia Research Centre Rome, via Anguillarese 301, 00123 Rome (Italy); Balucani, Marco [Department of information engineering, electronics and telecommunications, University of Rome “La Sapienza”, Via Eudossiana 18, 00184 Rome (Italy); Rise Technology S.r.l., Lungomare Paolo Toscanelli 170, 00121 Rome (Italy)

2015-04-15

Highlights: • Uniformity of the Ni–Si interface is crucial for performance of Cu–Ni contacts on Si. • Uniformly filled PS is the key to obtain the best performance of Cu–Ni contacts on Si. • Optimization of anodization and electroplating allows complete filling of PS layer. • Highly adhesive and low contact resistance Cu–Ni contacts are obtained on Si. - Abstract: In this paper, a two-layer metallization for silicon based solar cells is presented. The metallization consists of thin nickel barrier and thick copper conductive layers, both obtained by electrodeposition technique suitable for phosphorus-doped 70–90 Ω/sq solar cell emitter formed on p-type silicon substrate. To ensure the adhesion between metal contact and emitter a very thin layer of mesoporous silicon is introduced on the emitter surface before metal deposition. This approach allows metal anchoring inside pores and improves silicon–nickel interface uniformity. Optimization of metal contact parameters is achieved varying the anodization and electrodeposition conditions. Characterization of contacts between metal and emitter is carried out by scanning electron microscopy, specific contact resistance and current–voltage measurements. Mechanical strength of nickel–copper contacts is evaluated by the peel test. Adhesion strength of more than 4.5 N/mm and contact resistance of 350 μΩ cm{sup 2} on 80 Ω/sq emitter are achieved.

Formation of nanosize poly(p-phenylene vinylene) in porous silicon substrate

International Nuclear Information System (INIS)

Le Rendu, P.; Nguyen, T.P.; Cheah, K.; Joubert, P.

2003-01-01

We report the results of optical investigations in porous silicon (PS)/poly(p-phenylene vinylene) (PPV) systems obtained by filling the pores of silicon wafers with polymer. By scanning electron microscopy (SEM), IR, and Raman spectroscopy, we observed that the porous silicon layer was thoroughly filled by the polymer with no significant change in the structure of the materials. This suggests that there is no interaction between the components. On the other hand, the photoluminescence (PL) spectra of the devices investigated at different temperatures (from 11 to 290 K) showed that both materials are active at low temperatures. Porous silicon has a band located at 398 nm while PPV has two bands at 528 and 570 nm. As the temperature increases, the PL intensity of porous silicon decreases and that PPV is blue shifted. A new band emerging at 473 nm may indicate an energy transfer from the porous silicon to PPV, involving short segments of the polymer. The band of PPV located at 515 nm becomes more dominant and indicates that the nanosize polymer films are formed in the pores of the silicon layer, in agreement with the results obtained by SEM, IR, and Raman analyses

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.

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

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.

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.

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

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.

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.

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

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)

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

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...

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.

Porous silicon-based direct hydrogen sulphide fuel cells.

Science.gov (United States)

Dzhafarov, T D; Yuksel, S Aydin

2011-10-01

In this paper, the use of Au/porous silicon/Silicon Schottky type structure, as a direct hydrogen sulphide fuel cell is demonstrated. The porous silicon filled with hydrochlorid acid was developed as a proton conduction membrane. The Au/Porous Silicon/Silicon cells were fabricated by first creating the porous silicon layer in single-crystalline Si using the anodic etching under illumination and then deposition Au catalyst layer onto the porous silicon. Using 80 mM H2S solution as fuel the open circuit voltage of 0.4 V was obtained and maximum power density of 30 W/m2 at room temperature was achieved. These results demonstrate that the Au/Porous Silicon/Silicon direct hydrogen sulphide fuel cell which uses H2S:dH2O solution as fuel and operates at room temperature can be considered as the most promising type of low cost fuel cell for small power-supply units.

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...

Selective growth of vertically aligned Fe-filled carbon nanotubes on oxidized silicon substrates

Energy Technology Data Exchange (ETDEWEB)

Moench, I; Kozhuharova-Koseva, R; Ruemmeli, M; Elefant, D; Gemming, T; Kaltofen, R; Leonhardt, A; Schaefer, T; Buechner, B [Leibniz Institute of Solid State and Materials Research Dresden (IFW Dresden), Helmholtzstr. 20, D-01069 Dresden (Germany)

2007-04-15

Vertically aligned Fe-filled multi-wall carbon nanotubes (MWNTs) have been grown selectively on the SiO{sub 2} surfaces of patterned amorphous carbon (a-C)/SiO{sub 2}/Si substrates. Their morphology, structure and magnetic properties have been studied. The a-C patterns were prepared using conventional lithography processes combined with a sputter-deposition of a-C (thickness of 100 nm). The aligned Fe-filled MWNTs were produced by pyrolysis of ferrocene in a CVD reactor with a two zone furnace system and have high filling yield. The encapsulated Fe nanowires grown on the SiO{sub 2} structures of the patterned a-C/SiO{sub 2}/Si substrates have diameters of 10-20 nm and can reach a few micrometers in length. The described method enables the preparation of complex architectures of Fe-filled MWNTs and may be used for future applications based on filled nanotubes.

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.

Broadband infrared photoluminescence in silicon nanowires with high density stacking faults.

Science.gov (United States)

Li, Yang; Liu, Zhihong; Lu, Xiaoxiang; Su, Zhihua; Wang, Yanan; Liu, Rui; Wang, Dunwei; Jian, Jie; Lee, Joon Hwan; Wang, Haiyan; Yu, Qingkai; Bao, Jiming

2015-02-07

Making silicon an efficient light-emitting material is an important goal of silicon photonics. Here we report the observation of broadband sub-bandgap photoluminescence in silicon nanowires with a high density of stacking faults. The photoluminescence becomes stronger and exhibits a blue shift under higher laser powers. The super-linear dependence on excitation intensity indicates a strong competition between radiative and defect-related non-radiative channels, and the spectral blue shift is ascribed to the band filling effect in the heterostructures of wurtzite silicon and cubic silicon created by stacking faults.

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)

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.

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.

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...

Parameter analysis on the ultrasonic TSV-filling process and electrochemical characters

Science.gov (United States)

Wang, Fuliang; Ren, Xinyu; Wang, Yan; Zeng, Peng; Zhou, Zhaohua; Xiao, Hongbin; Zhu, Wenhui

2017-10-01

As one of the key technologies in 3D packaging, through silicon via (TSV) interconnection technology has become a focus recently. In this paper, an electrodeposition method for TSV filling with the assistance of ultrasound and additives are introduced. Two important parameters i.e. current density and ultrasonic power are studied for TSV filling process and electrochemical properties. It is found that ultrasound can improve the quality of TSV-filling and change the TSV-filling mode. The experimental results also indicate that the filling rate enhances more significantly with decreasing current density under ultrasonic conditions than under silent conditions. In addition, according to the voltammetry curve, the increase of ultrasonic power can significantly increase the current density of cupric reduction, and decrease the thickness of diffusion layer. So that the reduction speed of copper ions is accelerated, resulting in a higher TSV-filling rate.

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)

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.

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.

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

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.

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)

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)

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

Hybrid waste filler filled bio-polymer foam composites for sound absorbent materials

Science.gov (United States)

Rus, Anika Zafiah M.; Azahari, M. Shafiq M.; Kormin, Shaharuddin; Soon, Leong Bong; Zaliran, M. Taufiq; Ahraz Sadrina M. F., L.

2017-09-01

Sound absorption materials are one of the major requirements in many industries with regards to the sound insulation developed should be efficient to reduce sound. This is also important to contribute in economically ways of producing sound absorbing materials which is cheaper and user friendly. Thus, in this research, the sound absorbent properties of bio-polymer foam filled with hybrid fillers of wood dust and waste tire rubber has been investigated. Waste cooking oil from crisp industries was converted into bio-monomer, filled with different proportion ratio of fillers and fabricated into bio-polymer foam composite. Two fabrication methods is applied which is the Close Mold Method (CMM) and Open Mold Method (OMM). A total of four bio-polymer foam composite samples were produce for each method used. The percentage of hybrid fillers; mixture of wood dust and waste tire rubber of 2.5 %, 5.0%, 7.5% and 10% weight to weight ration with bio-monomer. The sound absorption of the bio-polymer foam composites samples were tested by using the impedance tube test according to the ASTM E-1050 and Scanning Electron Microscope to determine the morphology and porosity of the samples. The sound absorption coefficient (α) at different frequency range revealed that the polymer foam of 10.0 % hybrid fillers shows highest α of 0.963. The highest hybrid filler loading contributing to smallest pore sizes but highest interconnected pores. This also revealed that when highly porous material is exposed to incident sound waves, the air molecules at the surface of the material and within the pores of the material are forced to vibrate and loses some of their original energy. This is concluded that the suitability of bio-polymer foam filled with hybrid fillers to be used in acoustic application of automotive components such as dashboards, door panels, cushion and etc.

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

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...

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.

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

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.

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.

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.

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.)

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

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

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)

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.

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.

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

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

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.

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

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.

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.

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 ...

Experimental Study of Silicon Oil Effect on Two-Phase Closed Thermosyphon

Energy Technology Data Exchange (ETDEWEB)

Jung, Jun Yeong; Jeong, Yong Hoon [KAIST, Daejeon (Korea, Republic of)

2015-05-15

Two-phase closed thermosyphon (TPCT) is vertically oriented wickless heat pipe that has working fluid in the interior. The TPCT transports a large amount of heat from evaporator to condenser by phase change of working fluid, and the working fluid passively returns to evaporator by gravity. Due to these advantages of the TPCT, the TPCT is considered as method of PRHR (Passive Residual Heat Removal) system in nuclear system. Parametric studies have done to investigate the heat transfer characteristics of the TPCT. Different working fluids such as water, ethanol, methanol and acetone were used at various filling ratios and at different operating temperatures to find maximum heat transport capabilities of TPCT. Effect of heat transfer rate, filling ratio and aspect ratio were investigated. Inclined angle effect was investigated at several filling ratios and working fluids. This study is interested in silicon oil effect on the TPCT. To carry out the experiment, experimental apparatus is designed and manufactured. In design process, the TPCT operation limit is considered This study is interested in silicon oil effect on the TPCT. Experiments were carried out at three oil weight percent with three input power. Effect of oil on the TPCT is evaluated by inner wall temperature distribution and thermal resistance. In this study, silicon oil effect on TPCT was investigated. The TPCT was operated with several oil weight percent and input power. From experiment, overall, the silicon oil reduced evaporator thermal performance, but enhanced condenser thermal performance. However, the TPCT total thermal performance was reduced by 100 c St silicon oil.

Experimental Study of Silicon Oil Effect on Two-Phase Closed Thermosyphon

International Nuclear Information System (INIS)

Jung, Jun Yeong; Jeong, Yong Hoon

2015-01-01

Two-phase closed thermosyphon (TPCT) is vertically oriented wickless heat pipe that has working fluid in the interior. The TPCT transports a large amount of heat from evaporator to condenser by phase change of working fluid, and the working fluid passively returns to evaporator by gravity. Due to these advantages of the TPCT, the TPCT is considered as method of PRHR (Passive Residual Heat Removal) system in nuclear system. Parametric studies have done to investigate the heat transfer characteristics of the TPCT. Different working fluids such as water, ethanol, methanol and acetone were used at various filling ratios and at different operating temperatures to find maximum heat transport capabilities of TPCT. Effect of heat transfer rate, filling ratio and aspect ratio were investigated. Inclined angle effect was investigated at several filling ratios and working fluids. This study is interested in silicon oil effect on the TPCT. To carry out the experiment, experimental apparatus is designed and manufactured. In design process, the TPCT operation limit is considered This study is interested in silicon oil effect on the TPCT. Experiments were carried out at three oil weight percent with three input power. Effect of oil on the TPCT is evaluated by inner wall temperature distribution and thermal resistance. In this study, silicon oil effect on TPCT was investigated. The TPCT was operated with several oil weight percent and input power. From experiment, overall, the silicon oil reduced evaporator thermal performance, but enhanced condenser thermal performance. However, the TPCT total thermal performance was reduced by 100 c St silicon oil

RF characterization and analytical modelling of through silicon vias and coplanar waveguides for 3D integration

NARCIS (Netherlands)

Lamy, Y.; Jinesh, K.B.; Roozeboom, F.; Gravesteijn, D.J.; Besling, W.F.A.

2010-01-01

High-aspect ratio (12.5) through silicon vias (TSV) made in a silicon interposer have been electrically characterized in the direct current (dc) and microwave regimes for 3D interconnect applications. The vias were micro-machined in silicon, insulated, and filled with copper employing a bottom-up

SD OCT Features of Macula and Silicon Oil–Retinal Interface in Eyes Status Post Vitrectomy for RRD

Directory of Open Access Journals (Sweden)

Manish Nagpal

2015-03-01

Full Text Available Aim: To objectively document findings at the Silicon oil-Retinal interface, macular status and tamponade effect in Silicon Oil (SO filled eyes using SD OCT. Methods: 104 eyes of 104 patients underwent SD OCT examination, horizontal and vertical macular scans, in silicone oil filled eyes which underwent silicone oil injection post vitrectomy for rhegmatogenous retinal detachment. Findings were divided into 3 Groups; Group A: Findings at silicon oil retinal interface, Group B: Macular pathology and Group C: Tamponade effect. Group C was further divided into two groups; Group 1: Complete tamponade and Group 2: Incomplete tamponade. Results: Group A: subsilicon epiretinal membranes N = 17 (16.3%, emulsified silicon oil N = 16 (15.4% Group B: foveal thickening N = 22 (21.2%, foveal thinning N = 6 (5.7%, subfoveal fluid N = 8 (7.6%, macular hole N = 2 (1.9%; Group C: Incomplete tamponade was noted in N = 12 (11.5%, complete tamponade N = 92 (88.5%.10 out of 104 eyes (9.6% had recurrent retinal detachment post silicon oil removal. 8 of these eyes had complete tamponade and 2 had incomplete tamponade. Conclusion: SD OCT is a useful tool to assess the SO–Retina interface, tamponade effect and macular pathology in SO filled eyes. There is lesser incidence of redetachment with incomplete tamponade in OCT.

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.

Rapid Prototyping of Nanofluidic Slits in a Silicone Bilayer

Science.gov (United States)

Kole, Thomas P.; Liao, Kuo-Tang; Schiffels, Daniel; Ilic, B. Robert; Strychalski, Elizabeth A.; Kralj, Jason G.; Liddle, J. Alexander; Dritschilo, Anatoly; Stavis, Samuel M.

2015-01-01

This article reports a process for rapidly prototyping nanofluidic devices, particularly those comprising slits with microscale widths and nanoscale depths, in silicone. This process consists of designing a nanofluidic device, fabricating a photomask, fabricating a device mold in epoxy photoresist, molding a device in silicone, cutting and punching a molded silicone device, bonding a silicone device to a glass substrate, and filling the device with aqueous solution. By using a bilayer of hard and soft silicone, we have formed and filled nanofluidic slits with depths of less than 400 nm and aspect ratios of width to depth exceeding 250 without collapse of the slits. An important attribute of this article is that the description of this rapid prototyping process is very comprehensive, presenting context and details which are highly relevant to the rational implementation and reliable repetition of the process. Moreover, this process makes use of equipment commonly found in nanofabrication facilities and research laboratories, facilitating the broad adaptation and application of the process. Therefore, while this article specifically informs users of the Center for Nanoscale Science and Technology (CNST) at the National Institute of Standards and Technology (NIST), we anticipate that this information will be generally useful for the nanofabrication and nanofluidics research communities at large, and particularly useful for neophyte nanofabricators and nanofluidicists. PMID:26958449

[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.

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

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.

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.

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.

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-...

Using heat-treated starch to modify the surface of biochar and improve the tensile properties of biochar-filled stryene-butadiene rubber composites

Science.gov (United States)

Heat-treated starch is a renewable material that can be used to modify the surface chemistry of small particles. In this work, heat-treated starch was used to coat hydrophilic biochar particles in order to make them more hydrophobic. Then when added as filler to hydrophobic styrene-butadiene rubber,...

Copper-assisted, anti-reflection etching of silicon surfaces

Science.gov (United States)

Toor, Fatima; Branz, Howard

2014-08-26

A method (300) for etching a silicon surface (116) to reduce reflectivity. The method (300) includes electroless deposition of copper nanoparticles about 20 nanometers in size on the silicon surface (116), with a particle-to-particle spacing of 3 to 8 nanometers. The method (300) includes positioning (310) the substrate (112) with a silicon surface (116) into a vessel (122). The vessel (122) is filled (340) with a volume of an etching solution (124) so as to cover the silicon surface (116). The etching solution (124) includes an oxidant-etchant solution (146), e.g., an aqueous solution of hydrofluoric acid and hydrogen peroxide. The silicon surface (116) is etched (350) by agitating the etching solution (124) with, for example, ultrasonic agitation, and the etching may include heating (360) the etching solution (124) and directing light (365) onto the silicon surface (116). During the etching, copper nanoparticles enhance or drive the etching process.

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...

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

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)

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

Effect of via depth on the TSV filling process for different current densities

Science.gov (United States)

Wang, Feng; Zhao, Zhipeng; Nie, Nantian; Wang, Fuliang; Zhu, Wenhui

2018-04-01

Through-silicon-via (TSV) filling with optimum electrodeposition parameters is still a challenge in the industry, especially for via with different depths. Herein, the effects of via depth on optimum current density and filling patterns were investigated. It was found that the deeper the via, the lower the optimum current density. At low current density (4 mA cm-2), the via depth only affects the size of the defect, but does not change the filling pattern. However, at medium current density (7 mA cm-2), the filling pattern changes from super-conformal filling to sub-conformal filling with the increase of via depth, the pinch-off position remaining constant at a depth of about 70 µm from the top surface. Simulations of the TSV filling process using COMSOL modeling software revealed that the local concentration of additives, which is affected by the via depth, determine the morphology of the electrodeposition, matching well the experimental results.

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.

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

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)

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

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...

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.

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.

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.

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.

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.

A Novel Instrumented Human Head Surrogate for the Impact Evaluation of Helmets

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Nicola Petrone

2018-02-01

Full Text Available A novel Human Head Surrogate was obtained from available MRI scans of a 50th percentile male human head. Addictive manufacturing was used to produce the skull, the brain and the skin. All original MRI geometries were partially smoothed and adjusted to provide the best biofidelity compatible with printing and molding technology. The skull was 3D-printed in ABS and ten pressure sensors were placed into it. The brain surrogate was cast from silicon rubber in the 3D-printed plastic molds. Nine tri-axial accelerometers (placed at the tops of the lobes, at the sides of the lobes, in the cerebellum and in the center of mass and a three-axis gyroscope (at the center of mass were inserted into the silicon brain during casting. The cranium, after assembly with brain, was filled with silicon oil mimicking the cerebral fluid. Silicon rubber was cast in additional 3D-printed molds to form the skin surrounding the cranium. The skull base was adapted to be compatible with the Hybrid-III neck and allow the exit of brain sensors cabling. Preliminary experiments were carried out proving the functionality of the surrogate. Results showed how multiple accelerometers and pressure sensors allowed a better comprehension of the head complex motion during impacts.

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)

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)

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

Optimal placement of water-lubricated rubber bearings for vibration reduction of flexible multistage rotor systems

Science.gov (United States)

Liu, Shibing; Yang, Bingen

2017-10-01

Flexible multistage rotor systems with water-lubricated rubber bearings (WLRBs) have a variety of engineering applications. Filling a technical gap in the literature, this effort proposes a method of optimal bearing placement that minimizes the vibration amplitude of a WLRB-supported flexible rotor system with a minimum number of bearings. In the development, a new model of WLRBs and a distributed transfer function formulation are used to define a mixed continuous-and-discrete optimization problem. To deal with the case of uncertain number of WLRBs in rotor design, a virtual bearing method is devised. Solution of the optimization problem by a real-coded genetic algorithm yields the locations and lengths of water-lubricated rubber bearings, by which the prescribed operational requirements for the rotor system are satisfied. The proposed method is applicable either to preliminary design of a new rotor system with the number of bearings unforeknown or to redesign of an existing rotor system with a given number of bearings. Numerical examples show that the proposed optimal bearing placement is efficient, accurate and versatile in different design cases.

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

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....

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.

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.

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.

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.

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%.

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…

Soft tissue expansion before vertical ridge augmentation: Inflatable silicone balloons or self-filling osmotic tissue expanders?

Directory of Open Access Journals (Sweden)

Prasad Vijayrao Dhadse

2014-01-01

Full Text Available Recent advances in periodontal plastic surgical procedures allow the clinician to reconstruct deficient alveolar ridges in more predictable ways than previously possible. Placement of implant/s in resorbed ridges poses numerous challenges to the clinician for successful esthetic and functional rehabilitation. The reconstruction frequently utilizes one or combination of periodontal plastic surgical procedures in conjunction with autogenous bone grafting, allogenic bone block grafting, ridge split techniques, distraction osteogenesis, or guided bone regeneration (GBR for most predictable outcomes. Current surgical modalities used in reconstruction of alveolar ridge (horizontal and/or vertical component often involve the need of flap transfer. Moreover, there is compromise in tissue integrity and color match owing to different surgical site and the tissue utilized is insufficient in quantity leading to post surgical graft exposition and/or loss of grafted bone. Soft tissue expansion (STE by implantation of inflatable silicone balloon or self filling osmotic tissue expanders before reconstructive surgery can overcome these disadvantages and certainly holds a promise for effective method for generation of soft tissue thereby achieving predictable augmentation of deficient alveolar ridges for the implant success. This article focuses and compares these distinct tissue expanders for their clinical efficacy of achieving excess tissue that predominantly seems to be prerequisite for ridge augmentation which can be reasonably followed by successful placement of endosseous fixtures.

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

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.

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.

Cytotoxic evaluation of hydroxyapatite-filled and silica/hydroxyapatite-filled acrylate-based restorative composite resins: An in vitro study.

Science.gov (United States)

Chadda, Harshita; Naveen, Sangeetha Vasudevaraj; Mohan, Saktiswaren; Satapathy, Bhabani K; Ray, Alok R; Kamarul, Tunku

2016-07-01

Although the physical and mechanical properties of hydroxyapatite-filled dental restorative composite resins have been examined, the biocompatibility of these materials has not been studied in detail. The purpose of this in vitro study was to analyze the toxicity of acrylate-based restorative composite resins filled with hydroxyapatite and a silica/hydroxyapatite combination. Five different restorative materials based on bisphenol A-glycidyl methacrylate (bis-GMA) and tri-ethylene glycol dimethacrylate (TEGDMA) were developed: unfilled (H0), hydroxyapatite-filled (H30, H50), and silica/hydroxyapatite-filled (SH30, SH50) composite resins. These were tested for in vitro cytotoxicity by using human bone marrow mesenchymal stromal cells. Surface morphology, elemental composition, and functional groups were determined by scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDX), and Fourier-transformed infrared spectroscopy (FTIR). The spectra normalization, baseline corrections, and peak integration were carried out by OPUS v4.0 software. Both in vitro cytotoxicity results and SEM analysis indicated that the composite resins developed were nontoxic and supported cell adherence. Elemental analysis with EDX revealed the presence of carbon, oxygen, calcium, silicon, and gold, while the presence of methacrylate, hydroxyl, and methylene functional groups was confirmed through FTIR analysis. The characterization and compatibility studies showed that these hydroxyapatite-filled and silica/hydroxyapatite-filled bis-GMA/TEGDMA-based restorative composite resins are nontoxic to human bone marrow mesenchymal stromal cells and show a favorable biologic response, making them potential biomaterials. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.