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Sample records for chloride-epoxidized natural rubber

  1. Mechanical and morphological studies of silica filled polyvinyl chloride-epoxidized natural rubber nanocomposite by sol-gel technique

    International Nuclear Information System (INIS)

    Polyvinyl chloride-epoxidized natural rubber (PVC-ENR50) nanocomposites with different amounts of silica were prepared by sol-gel technique. Tetraethoxysilane (TEOS) was used as a precursor for silica in this technique. Si-O-Si and Si-O-C bonding occurred in the nanocomposites are confirmed by Fourier-transform infrared spectroscopy. The silica content of the in situ silica-filled from the thermogravimetric analysis (TGA), shows increases as the TEOS loading added. The maximum tensile strength of PVCENR50 nanocomposite was 25.3 MPa at 30% TEOS. Scanning electron microscopy (SEM) micrographs demonstrated the existence of silica frameworks dispersed in the matrix. Transmission electron microscopy (TEM) micrograph revealed that the silica particles, uniformly distributed over the matrix, are of nanometer scale. (Author)

  2. Electron beam irradiation of poly(vinyl chloride)/epoxidized natural rubber blend in the presence of additives

    International Nuclear Information System (INIS)

    The effect of irradiation on 50/50 poly(vinyl chloride)/epoxidized natural rubber blend (PVC/ENR) was studied with particular attention to irradiation-induced crosslinking. The influence of several additives such as A, Irganox1010, and tribasic lead sulfate on the irradiation-induced crosslinking of the blend was investigated. The blends were characterized for gel fraction, morphology, Fourier Transform Infra Red Spectroscopy (FTIR) and dynamic mechanical properties. Results revealed that A is efficient in accelerating irradiation-induced crosslinking. On the other hand the addition of Irganox1010 and tribasic lead sulfate were found to inhibit the irradiation-induced reaction in the blend to a considerable extent. (Author)

  3. Effect of irradiation on poly(vinyl chloride)/epoxidized natural rubber blend in the presence of additives: FTIR analysis

    International Nuclear Information System (INIS)

    The effect of irradiation on the structure of 50/50 poly(vinyl chloride)/epoxidized natural rubber blend (PVC/ENR) was studied using the Fourier Transform Spectroscopy (FTIR). The 50/50 PVC/ENR blend was irradiated by using 3.0 MeV electron beam machine at 0 and 200 kGy irradiation doses. The influence of several additives such as TMPTA, Irganox 1010, and tribasic lead sulfate on the irradiation induced changes of the blend was investigated. It was found that upon irradiation, ring opening of the epoxide groups, oxidation as well crosslinking at residual double bonds occurred, leading to decreases in the intensities of the epoxide and cis double bond bands and an increases in ether and furan bands. The addition of Irganox 1010 and tribasic lead sulfate were found to inhibit the irradiation-induced reaction in the blend to a considerable extent. The importance of TMPTA in preventing the intramolecular ring opening side chain reaction was also discussed. However, studies did not reveal the exact nature of the irradiation-induced reactions involved in the blend. (Author)

  4. Studies on physical properties and fractography of electron beam irradiated poly(vinyl chloride)/epoxidized natural rubber blend in the presence of trimethylolpropane triacrylate

    International Nuclear Information System (INIS)

    The effect of irradiation on the 50/50 poly(vinyl chloride)/epoxidized natural rubber blend was studied in the presence of 3 phr trimethylolpropane triacrylate (TMPTA). The blend was irradiated by using a 3.0 MeV electron beam machine at doses ranging from 20 to 200 kGy in air and room temperature. The tensile properties, resilience and gel fractions of the blends were measured. Electron beam irradiation of the blend in the presence of the TMPTA were found to cause crosslinking which in effect caused an enhancement in modulus and gel fraction together with a concomitant decline in ultimate elongation. The irradiation has resulted in a less hysteretic poly(vinyl chloride)/epoxidized natural rubber blend, with increased rebound resilience. The tensile strength of the blend reached a maximum at 60 kGy followed by a slight decrease at higher doses, implying embrittlement due to the excessive crosslinking. The scanning electron micrographs of the fracture surfaces of the irradiated blends show evidence consistent with the above contention. (Author)

  5. Natural rubber: leather composites

    OpenAIRE

    Ravichandran, K.; N. Natchimuthu

    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 ...

  6. 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.

  7. Water Swollen Natural Rubber

    Directory of Open Access Journals (Sweden)

    Sureurg KHONGTONG

    2008-01-01

    Full Text Available Modification of natural rubber by grafting of maleic anhydride yielded a water absorbable substrate. It was found that water contact angles of treated samples declined as the concentrations of maleic anhydride increased reflecting higher water compatibility in grafted samples. Submergence in water of these samples caused dramatic swelling with the water content up to about 60 wt %.

  8. Water Swollen Natural Rubber

    OpenAIRE

    Sureurg KHONGTONG; Narong FUNGCHONLAJIT

    2008-01-01

    Modification of natural rubber by grafting of maleic anhydride yielded a water absorbable substrate. It was found that water contact angles of treated samples declined as the concentrations of maleic anhydride increased reflecting higher water compatibility in grafted samples. Submergence in water of these samples caused dramatic swelling with the water content up to about 60 wt %.

  9. The Cyclization of natural rubber

    International Nuclear Information System (INIS)

    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 (SnCl4). Iodo metric titration show, with 8% SnCl4 (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

  10. Electrospinning of PVC with natural rubber

    International Nuclear Information System (INIS)

    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

  11. Microbial Degradation of Natural Rubber Vulcanizates

    OpenAIRE

    Tsuchii, Akio; Suzuki, Tomoo; Takeda, Kiyoshi

    1985-01-01

    An actinomycete, Nocardia sp. strain 835A, grows well on unvulcanized natural rubber and synthetic isoprene rubber, but not on other types of synthetic rubber. Not only unvulcanized but also various kinds of vulcanized natural rubber products were more or less utilized by the organism as the sole source of carbon and energy. The thin film from a latex glove was rapidly degraded, and the weight loss reached 75% after a 2-week cultivation period. Oligomers with molecular weights from 104 to 103...

  12. Morphology, Tensile Strength and Oil Resistance of Gum Rubber Sheets Prepared from Lignin Modified Natural Rubber

    OpenAIRE

    Asrul M.; Othman M.; Zakaria M; Ahmad-Nazir K.

    2014-01-01

    The paper describes the preparation of lignin filled natural rubber latex composite and its subsequent use to obtain lignin modified rubber. Two types of lignin i.e.: rubber wood and commercial alkali lignin were used as rubber filler. Gum rubber sheets were prepared from the lignin modified rubber and their properties were compared to Standard Malaysian Rubber (SMR 20) and a type of rubber obtained from the coagulation of high ammonia latex. Rubber morphology was investigated using Scanning ...

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

    OpenAIRE

    Velu CHANDRAN; Thomas MANVEL RAJ; Thangavelu LAKSHMANAN

    2016-01-01

    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 t...

  14. Radiation curing of natural rubber latex

    International Nuclear Information System (INIS)

    Natural rubber latex (60% solids) was irradiated with Cobalt-60 gamma radiation upto 30 megarads. It was observed that 90% of the rubber was cross-linked at a cumulative dose of 2 megarads to 12 megarads. In case of the coagulated latex 74% of the rubber was cross-linked at the same dose. Thereafter the percentage cross-linked polymer decreased continuously upto 16 megarads in both the cases but increased again. (auth.)

  15. Thermal properties of hydrogenated liquid natural rubber

    Science.gov (United States)

    Jamaluddin, Naharullah; Abdullah, Ibrahim; Yusoff, Siti Fairus M.

    2015-09-01

    Natural rubber (NR) was modified to form liquid natural rubber (LNR) via photooxidative degradation. Hydrogenated liquid natural rubber (HLNR) was synthesized by using diimide as source of hydrogen which the diimide is produced by thermolysis of p-toluenesulfonyl hydrazide (TSH). The structure of HLNR was characterized by determining the changes of main peaks in Fourier Transform infrared and nuclear magnetic resonance spectra after hydrogenation. Thermogravimetric analysis showed that the HLNR had higher decomposition temperature compared to LNR and the decomposition temperature is directly proportional to the percentage of conversion.

  16. Thermal properties of hydrogenated liquid natural rubber

    International Nuclear Information System (INIS)

    Natural rubber (NR) was modified to form liquid natural rubber (LNR) via photooxidative degradation. Hydrogenated liquid natural rubber (HLNR) was synthesized by using diimide as source of hydrogen which the diimide is produced by thermolysis of p-toluenesulfonyl hydrazide (TSH). The structure of HLNR was characterized by determining the changes of main peaks in Fourier Transform infrared and nuclear magnetic resonance spectra after hydrogenation. Thermogravimetric analysis showed that the HLNR had higher decomposition temperature compared to LNR and the decomposition temperature is directly proportional to the percentage of conversion

  17. Thermal properties of hydrogenated liquid natural rubber

    Energy Technology Data Exchange (ETDEWEB)

    Jamaluddin, Naharullah; Abdullah, Ibrahim; Yusoff, Siti Fairus M. [School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia)

    2015-09-25

    Natural rubber (NR) was modified to form liquid natural rubber (LNR) via photooxidative degradation. Hydrogenated liquid natural rubber (HLNR) was synthesized by using diimide as source of hydrogen which the diimide is produced by thermolysis of p-toluenesulfonyl hydrazide (TSH). The structure of HLNR was characterized by determining the changes of main peaks in Fourier Transform infrared and nuclear magnetic resonance spectra after hydrogenation. Thermogravimetric analysis showed that the HLNR had higher decomposition temperature compared to LNR and the decomposition temperature is directly proportional to the percentage of conversion.

  18. Screening of Natural Rubber-Degrading Microorganisms from Rubber Processing Factory Waste in Vietnam

    OpenAIRE

    Nguyen Lan Huong; To Kim Anh; Phan Trung Nghia; Dao Viet Linh; Bui Thi Trang; Masao Fukuda

    2013-01-01

    Natural rubber-degrading microorganisms were isolated from waste of rubber processing factory in Cam Thuy of Vietnam. Four of them belong to Streptomyces sp. that showed the higher abilities for natural rubber degradation than the others. They are able to use both deproteinised natural rubber (DPNR) and synthetic rubber cis-1,4-polyisoprene (SR) as a sole source of carbon. Gel permeation chromatography (GPC) analysis revealed that these strains degraded DPNR and SR to low-molecular-weight pro...

  19. Irradiation crosslinking of poly(vinylchloride)/ epoxidized natural rubber blend

    International Nuclear Information System (INIS)

    Irradiation crosslinking of 50/50 poly(vinyl chloride)/ epoxidized natural rubber (PVC/ ENR) was studied with particular attention to blending parameters, addition of a crosslinking agent (TMPTA) and addition of an antioxidant (Irganox 1010). The 50/ 50 PVC/ ENR blend was prepared with a Brabender Plasticoder. The blend was irradiated by using a 3 MeV electron beam accelerator with doses ranging from 0-200 kGy. Changes in tensile properties, hardness, gel fraction, dynamic mechanical and morphological properties of the blends with irradiation doses were investigated. Evidences from DMA, FTIR, Foz Model, Charlesby-Pineer equation and crosslink density results were also employed to characterize the occurrence of irradiation-induced crosslinking. The possible mechanism of crosslinking induced by the irradiation between PVC and ENR was also proposed. It was observed that the mixing parameters such as temperature and time studied in this work are important in enhancement of irradiation induced crosslinking in PVC/ ENR blend. Results revealed that a readily compatible blend prepared at 150 degree Celsius, 50 rpm and 10 minutes of minimum mixing time enjoy maximum benefit from irradiation. However, irradiation was found to impart compatibility to the partially compatible PVC/ ENR blends prepared at 140 degree Celsius, 50 rpm and 10 minutes due to the irradiation-induced crosslinking. Electron beam initiated crosslinking of PVC/ ENR, containing trimethylolpropane triacrylate (TMPTA), has been carried out over a range of irradiation doses (20-200 kGy) and concentrations of TMPTA (1 to 5 phr). Blends containing 3-4 phr TMPTA were found to achieve optimum crosslinking, which in effect causes a maximum in tensile strength at 70 kGy. It was evident from FTIR spectra that the irradiation-induced reaction in PVC/ ENR blend involves the ring opening of the epoxy group to form ether bonds. Upon irradiation, the fractured surface topography changes from ductile to brittle as results

  20. Improvements of natural rubber for flame resistance

    Directory of Open Access Journals (Sweden)

    Orasa Patarapaiboolchai

    2010-07-01

    Full Text Available The present invention provides a process for treating natural rubber to increase its flame retardant capability. Theprocess comprises a mixture of a natural rubber with, (a halogenated free flame retardant agent (zinc hydroxystannate;STORFLAM ZHS and (b halogenated flame retardant agent (decabromodiphenyl; Great Lake DE-83R and chlorinatedparaffins; Plastoil 152 and another material like antimony trioxide and aluminium hydroxide in appropriate amount, with ratio of halogenated flame retardant agent: antimony trioxide 3:1. In the resulting product with halogen flame retardant showed a more efficient flame retardant property than halogen free flame retardant, i.e. brominated flame retardant provide higher efficiency than chlorinated and ZHS, respectively. The minimum requirement ratio for being flame retardant of antimonytrioxide: brominated or chlorinated agent is 7:21 or 10:30 phr while aluminium hydroxide: ZHS is 10: 150 phr. It was found thatburning rate was zero for brominated and chlorinated agent used but not for zinc hydroxyl stannate system. Average time of burning (ATB was 135, 118 and 41 second for brominated, chlorinated and ZHS flame retardant, respectively. Average extent of burning (AEB was 24, 19 and 14 millimeters, respectively. An advantage of this invention is that chemicals (antimony trioxide and either brominated or chlorinated agent added to natural rubber have the effect of rendering the natural rubber flame-resistant like synthetic rubbers, chloroprene.

  1. Anomalous crack propagation in reinforced natural rubber

    Science.gov (United States)

    Sotta, Paul; Gabrielle, Brice; Long, Didier; Vanel, Loic; Albouy, Pierre-Antoine; Peditto, Francesca

    2009-03-01

    In reinforced natural rubber, crack propagation in mode I exhibits rotation of the tear in a direction perpendicular to the usual one. Our objective is, first, to understand the impact of this phenomenon on fracture toughness of the material, and, secondly, to understand how this phenomenon is related to the specific properties of reinforced natural rubber. To this aim, we combine measurements of ultimate properties, measurements of the number and length of tear rotations as a function of loading velocity and temperature, and investigation of material heterogeneities at sub-micrometric scales, originating both from fillers and strain-induced crystallites (strain-induced crystallinity is measured up to failure by X ray diffraction), in natural rubber samples reinforced by nanometric aggregates. Observations suggest that tear rotation is related both to the mechanical anisotropy induced by strain-induced crystallinity and to the dissipative properties of the material at high strain.

  2. Morphology, Tensile Strength and Oil Resistance of Gum Rubber Sheets Prepared from Lignin Modified Natural Rubber

    Directory of Open Access Journals (Sweden)

    Asrul M.

    2014-07-01

    Full Text Available The paper describes the preparation of lignin filled natural rubber latex composite and its subsequent use to obtain lignin modified rubber. Two types of lignin i.e.: rubber wood and commercial alkali lignin were used as rubber filler. Gum rubber sheets were prepared from the lignin modified rubber and their properties were compared to Standard Malaysian Rubber (SMR 20 and a type of rubber obtained from the coagulation of high ammonia latex. Rubber morphology was investigated using Scanning Electron Microscope on the cross-sectional area of cryo-fractured samples. Oil resistance of the rubber sheets was determined by measuring the mass change before and after ASTM IRM 903 oil immersion, while the tensile strengths were determined according to ASTM D412 standard. Low values of tensile strength obtained for the commercial alkali lignin modified rubber sheet relative to the rest of the rubber samples was attributed to poor lignin dispersion. This occurrence was substantiated by the SEM analysis of cryo-fractured samples where crazes and inhomogeneity was observed. Nonetheless, both lignin modified rubbers exhibited higher level of oil resistance compared to SMR 20. This is due to the nature of lignin as a hydrophilic component and its presence in the rubber matrix complicates the oil diffusion process into rubber.

  3. FTIR investigation into Degradation of Natural Rubber

    Science.gov (United States)

    Rich, Ryan; Waldek Zerda, T.

    2006-10-01

    The aging of tires is of the highest concerns to the automotive industry, due to its implications in fuel economy and automobile safety. Previously, the high absorption rate of carbon black filled polymers has hindered the use of Fourier Transform Infrared Spectroscopy (FTIR) in studying this occurrence. However, recent developments in attenuated total reflection (ATR) techniques have provided a means for spectroscopically monitoring the composition changes induced in rubber blends by heat, exposure to ultra-violet radiation, and mechanical strain. The ATR apparatus, employing a germanium crystal, collected high quality infrared spectra at a reduced penetration depth of less than one micron. This research analyzed natural polymer blends with varied aggregate size and concentration of carbon black. The samples were analyzed as a function of exposure time to 70 C heat and UV radiation, as well elongation by mechanical strain. In these spectra, growth of the 1740cm-1 peak is assigned to increase populations of the C=O band. Carbon black filler rubber is shown to slow the rate of oxidation in pure natural rubber. Crystallization of rubber composites under strain is characterized by changes in the shapes of the CH stretch bands.

  4. Reinforcement of graphene in natural rubber nanocomposite

    Science.gov (United States)

    Azira, A. A.; Kamal, M. M.; Rusop, M.

    2016-07-01

    In the present work, we report the use of graphene as multi-functional nanofiller for natural rubber (NR). Dispersion of reduced graphene into natural rubber (NR) was found to enhance the mechanical and electrical properties of NR. Through a facile approach rubber molecules are successfully grafted onto the surface of graphene. Stable graphene suspension with NR afforded a weblike morphology consisting of platelet networks between the rubber particles, while internal mixer processing broke down this structure, yielding a homogeneous and improved dispersion. The resulting graphene can be dispersed in NR via dry mixing. It is found that graphene is prominent in improving the mechanical properties of NR at low filler loading. The percolation point of graphene in the nanocomposites takes place at a content of less than 0.1 wt%. With incorporation of as low as 0.1 wt% of graphene, an increase in the tensile strength and improvement in the tensile modulus achieved. The improvement in the mechanical properties of NR nanocomposites at such low filler loading is attributed to the strong interfacial interaction and the molecular-level dispersion of graphene in the NR matrix. .

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

    Directory of Open Access Journals (Sweden)

    Velu CHANDRAN

    2016-05-01

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

  6. Performance Study of the Natural Rubber Composite with Clay Minerals

    International Nuclear Information System (INIS)

    The preparation, characterization and some applications of natural rubber clay composite have been studied. This study investigated the possibility of natural rubber latex to replace some part of natural clays. In formulation of rubber clay composite from natural rubber latex and various clay minerals, three main steps were involved (i) preparation of latex cream (ii) prevulcanization of latex cream (iii) mixing vulcanized latex compound, with other ingredients. In each step, several parameters have been carefully investigated to optimize the performance of natural rubber clay composite production. The composite products were of better quality and can be considered to be more cost effective.

  7. Sizing solar-assisted natural rubber dryers

    Energy Technology Data Exchange (ETDEWEB)

    Pratoto, A.; Daguenet, M. [Universite de Perpignan (France). Laboratoire de Thermodynamique et Energetique; Zeghmati, B. [IUT Belfort-Montbeliard (France). Laboratoire de Metrologie des Interfaces Techniques

    1997-10-01

    Due to the lack of firewood, the use of solar energy in drying of natural rubber has been envisaged and it has been the subject of several works. The present work is concerned with the design of solar-assisted natural rubber dryers. The system performance is estimated using the average day method. The possibility of heat dumping and the configuration of the collector array are taken into account. To facilitate the user in making a rapid estimation on the collector area required, a simplified sizing method is developed. To this end, an empirical relation is performed by correlating the results of short-cut simulation to design parameters which are easily determined. (author)

  8. Commercial irradiation of natural rubber latex

    International Nuclear Information System (INIS)

    Cost of irradiation is one of the important factor to expand industrial application of radiation vulcanized natural rubber latex (RVNRL). The irradiation cost was studied under the RCA project, RAS/8/061/1109, and reasonable cost was reported by use of single purpose latex irradiation facility of 1500 ton/year. For a market development of RVNRL, irradiation of latex of the order of 100 ton/year may be required. Construction of the single purpose pilot plant of this scale is not commercially feasible. In this stage use of contract irradiation facilities which are familiar world wide gives a solution. Radia Industry Co., Ltd. have two irradiation facilities with 1.4 MCi of Co-60 and irradiate natural rubber latex for Okamoto Industries, Inc. with use of the incremental dose irradiator which is commonly used for sterilization of medical supplies. Natural rubber latex filled in standard 20 liter plastic bags are loaded on the hanger of trolley conveyer, and irradiated without agitation. The dose uniformity was around 2, and properties of the RVNRL was reported satisfactory. The dose uniformity can be improved if special container is applied. In future it is expected to construct a larger single purpose irradiation plant to provide low cost irradiation for multi-client, or import RVNRL from RCA countries provided transportation test is successful. We have interest in electron beam valcanization. Radia Industry Co., Ltd. put an order 5 MeV, 150 kW electron beam machine and it will be operational in 1990. High penetration of 5 MeV electron beam is useful for radiation processing in the condensed media like natural rubber latex. (author)

  9. Innovative Neutron Shielding Material Composing of Natural Rubber-Styrene Butadiene Rubber Blends Diboron Trioxide

    International Nuclear Information System (INIS)

    The optimized flexible and lightweight neutron shielding materials were designed using the Monte Carlo N-Particle (MCNP) code. The neutron shielding materials thickness for 10 mm and 100 mm were considered for the neutron shielding performance. Results indicated that 10 mm shielding material of rubber compound between natural rubber (NR) and styrene butadiene rubber (SBR) blend (1:1) compose with diboron trioxide 60 phr and 100 mm shielding material for 4 layers structure of rubber compound between natural rubber (NR) and styrene butadiene rubber (SBR) blend compose with diboron trioxide 10 phr and rubber compound with iron oxide 100 phr offered advantages on neutron shielding compared to other designs. Experimental for these shielding material results verified the correctness of the optimal design and fabrication. The designed shielding materials are highly suitable for applications in nuclear science and technology.

  10. Radiation vulcanization of Philippine natural rubber latex

    International Nuclear Information System (INIS)

    The response of Philippine natural rubber latex to irradiation vulcanization and the stability of the irradiated natural rubber latex (INRL) upon storage and aging were investigated. Commercially available high ammonia (HA) concentrated latices obtained from various rubber plantations in Mindanao island were treated with 5 phr of n-butyl acrylate (nBA), and gamma-irradiated at the PNRI 60Co irradiation facility at a dose rate of 2.57 kGy/hr. Unirradiated cast latex films gave different green strengths which varied from 2-11 MPa. Cast films from INRL exhibited maximum tensile strengths were obtained from cast films with low Mg and high nitrogen contents. Thermal analysis using thermogravimetry (TG) revealed one major decomposition product at 374o-377oC. Its rate of decomposition decreased to a minimum at 15 kGy, then increased as radiation dose was increased. This trend correlated well with the tensile strength measurements. The stability of the INRL upon storage and aging is an essential parameter to the rubbe latex industry. For storage studies, INRL was stored for various periods of time. It was found that the pH and total solids content of the stored INRL did not change significantly after 12 months of storage; the MST values remained at above 1000 seconds, and the viscosity decreased with time. The cast films exhibited a decline in tensile strength, modulus300%, and crosslinking density upon storage. While there were observed changes in the physical properties of the INRL during the storage period, the data indicate that these properties were within values acceptable to the latex industry. Tests on the aging properties of INRL films were undertaken. It was shown that among the chemical antioxidants presently used by the latex industry, TNPP demonstrated the highest antioxidant property, followed by Antage DAHQ and Vulcanox BKF. Our data indicate that the natural rubber latex produced and processed in the Philippines is suited for radiation vulcanization

  11. Radiation vulcanization of Philippine natural rubber latex

    International Nuclear Information System (INIS)

    The response of Philippine natural rubber latex to radiation vulcanization and the stability of the irradiated natural rubber latex (INRL) upon storage and aging were investigated. Commercially available high ammonia (HA) concentrated lattices obtained from various rubber plantations in Mindanao Island were treated with 5 phr of n-butyl acrylate (nBA), and gamma-irradiated at the PNRI sup 60 Co irradiation facility at dose rate of 2.57 KGy/hr. Unirradiated cast latex films gave different green strength which varied from 2 - 11 MPa. Cast films from INRL exhibited maximum tensile strengths of 25 - 32 MPa at a radiation dose of 15 kGy. Higher tensile strengths were obtained from cast films with low Mg and high nitrogen contents. Thermal analysis using thermogravimetry (TG) revealed one major decomposition product at 374 degree C - 377 degree C. Its rate of decomposition decreased to a minimum at 15 kGy, then increased as radiation dose increased. This trend correlated well with the tensile strength measurements. The stability of the INRL upon storage and aging is an essential parameter to the rubber latex industry. For storage studies, INRL was stored for various periods of time. It was found that the pH and total solids content of the stored INRL did not change significantly after 12 months of storage; the MST values remained at above 100 seconds, and the viscosity decreased with time. The cast films exhibited a decline in tensile strength, modulus 300% and crosslinking density upon storage. While there were observed changes in the physical properties of the IRNL during the storage period, the data indicate that these properties were within values acceptable to the latex industry. Tests on the aging properties of INRL film were undertaken. It was shown that among the chemical antioxidants presently used by the latex industry. TNPP demonstrated the highest antioxidant property, followed by Antage DAHQ and Vulcanox BKF. Our data indicate that the natural rubber latex

  12. Radiation processing of natural rubber latex

    International Nuclear Information System (INIS)

    Significant progress has been made in the last 5 years in developing new rubber material using radiation technology that holds important benefits for industries in Southeast Asia and the Pacific. A driving force behind its development has been co-ordinated research through an international programme of the IAEA and United Nations Development Programme (UNDP) known as the Regional Co-operative Agreement (RCA). The technology is called radiation vulcanization of natural rubber latex, or RVNRL. It uses high-energy gamma radiation (it also can use electron beams) to initiate vulcanization, a process that chemically bonds molecules to produce rubber elasticity and strength. As with other radiation industrial processes, products are not radioactive. In the RVNRL process, radiation energy replaces the use of a sulphur-based process and produces a material that retains all properties of the conventional product. However, it has some additional remarkable qualities: the absence of carcinogenic nitrosoamines; extremely low cytotoxicity; absence of sulphur and zinc oxide; and high transparency and softness. Rubber products for medical and hygienic uses are obviously the most promising applications of RVNRL technology because of the absence of carcinogenic and toxic products. These essential requirements are easily met by the radiation technology, and at the moment, by no other alternative. Within the technology development programme, test production of various products such as condoms, gloves, nipples, pacifiers, and toy balloons are now being carried out at different centers participating in the programme. Pilot production of condoms and gloves for medical examinations is done in Indonesia. Products are tested extensively in various field locations. Low-cost irradiators have been specifically designed for vulcanization applications, and the main parameters for estimating production costs and for conducting feasibility studies have been developed

  13. Optical Characterization of Semiconducting Natural Rubber Nanoparticles and its Composites

    Science.gov (United States)

    Neena, P.; Mathew, Anisha Mary

    2011-10-01

    The present work explains optical properties of semiconducting natural rubber nanoparticles from pristine natural rubber by doping. The studies give evidence that the SbCl5 is an efficient dopant for natural rubber. The mechanism of conduction predominantly involves the formation of conjugated sequence of unsaturated double bond in the polymer backbone. Examination of the UV/Vis study reveals the formation of charge transfer complexes in the polymer back bone. Particle filled elastomeric composites have become attractive owing to their low cost and widespread industrial applications. The arrival of nanometer fillers to polymer materials is a promising channel for their property modification. Natural rubber composite is prepared by mixing the pristine natural rubber with semiconducting natural rubber powder.

  14. Radiation response of Philippine natural rubber latex

    International Nuclear Information System (INIS)

    Our earlier work has shown that the natural rubber latex (NRL) produced and processed in the Philippines is suited for radiation vulcanization. The cast films from NRL with 50% TSC exhibited maximum tensile strengths of 25-32 MPa at 15 kGy, which is the vulcanization dose or Dv. In the manufacture of dipped NRL products, certain specifications such as %TSC, protein content and tensile properties, must be met to ensure an acceptable product. For radiation vulcanization of natural rubber latex (RVNRL) to be accepted as an alternative process, it must also meet the requirements. Thus, this paper presents additional data on the radiation response of local NRL at different total solids contents (TSC), leachable proteins from NRL films as a function of dose, and the thermal activities of irradiated natural rubber latex (INRL). Different formulations of NRL showed varying tolerances to nBA. Data showed that as %TSC increases, the maximum concentration of nBA that can be added without affecting the stability of the latex decreases. The Dv increases as the %TSC increases and the nBA content decreases. This difference in response may be attributed to a lower concentration of nBA in formulations with higher %TSC. These data indicate that the parameters in the radiation treatment will be dictated by the intended applications of INRL. The thermogravimetric data showed greater stability of INRL to thermal oxidation relative to the unirradiated NRL, which correlates directly with the tensile properties of the INRL. A radiation dose of 10 kGy increased the amount of proteins leached from cast latex films. The amount of extractable proteins did not increase significantly at higher doses. The SDS PAGE analysis of the extractable proteins from unirradiated latex film showed distinct bands. An additional band at 60 Kda appeared at 10 kGy. All these bands became diffuse at higher doses, indicating the radiolysis of the proteins

  15. Radiation vulcanization of natural rubber latex

    International Nuclear Information System (INIS)

    This paper describes the experimental techniques and the results of radiation vulcanization of natural rubber latex carried out on several high ammonia latices available in the country. The efficiency of various sensitisers and stabilisers used were evaluated in terms of the gamma radiation dose required to produce the maximum tensile strengths. The extent of crosslinking of RVNRL sample films were estimated by equilibrium swelling ratio measurements. The stability of pre-irradiated and post-irradiated samples were monitored using viscosity measurements as the parameter

  16. The use of radiotracers in natural rubber research in Malaysia

    International Nuclear Information System (INIS)

    Five main areas where radiotracers have been used in research on natural rubber are on studies on the uptake of plant nutrients by Hevea brasiliensis using 32P, 86Rb and 45Ca as tracers; biosynthesis of Hevea rubber using 14C or 3H labelled intermediates; translocation and metabolism of 14C. Ethephon in Hevea brasiliensis; use of radiotracers as analytical tools and adsorption of labelled fatty acid soaps on natural rubber lattices. These studies are discussed to show the powerful tool that radiotracers provide in agricultural, biochemical and chemical research on natural rubber. (author)

  17. Influence of the incorporation process of clay as filler on the properties of natural rubber and epoxidized natural vulcanized rubber

    International Nuclear Information System (INIS)

    Vulcanizates of natural rubber and epoxidized natural rubber, having clay as filler were prepared by different process. The degree of exfoliation of the clay was evaluated by X-ray analysis and mechanical properties were determined by stress-strain. The crosslink density was evaluated by swelling measurements. It could be observed that the use of epoxidized rubber improves significantly the mechanical properties of the vulcanizates. (author)

  18. Curing of natural rubber and epoxy adhesive

    International Nuclear Information System (INIS)

    Low molecular weight epoxy resin based on diglycidyl ether of bisphenol A was synthesized and mixed at constant percentages with natural rubber. The rubber epoxy system was cured with various types of curing agents such as ethylene diamine, maleic anhydride as well as the prepared resole phenol formaldehyde. A study of the photo-induced crosslinking of the prepared elastic adhesives and film samples was carried out by exposure to ultraviolet lamp (300 w) for 2 weeks at 20 deg. C. Samples containing ethylene diamine were cured at 25 + - 1 deg. C. for 24 h while samples containing maleic anhydride or resole phenol formaldehyde resins were thermally cured at 150-170 deg. C. for 10 min. Cured adhesive compositions were tested mechanically and physically and evaluated as wood adhesives. While hardness, chemical resistance as well as heat stability of the prepared cured film sample were investigated. The obtained data indicate that the highest epoxy resin content and the presence of resole phenol formaldehyde resin in composition improve the tensile strength and adhesion properties on wood. While their cured film sample have the best hardness properties, chemical resistance and heat stability. (author)

  19. Functionalization of Liquid Natural Rubber via Oxidative Degradation of Natural Rubber

    Directory of Open Access Journals (Sweden)

    Suhawati Ibrahim

    2014-12-01

    Full Text Available Natural rubber (NR is a high molecular weight natural polymer and can be degraded to liquid natural rubber (LNR leaving certain functional groups at the end of chains. In this study, LNR samples prepared via oxidative degradation using H2O2 and NaNO2 as reagents were found to have different end groups depending on the pH of the reaction medium. In an acidic medium, LNR with hydroxyl terminal groups was formed as the degradation reaction was initiated by hydroxyl radicals produced from decomposition of peroxynitrite acid. In contrast, a redox reaction took place in an alkaline medium to yield LNR with carbonyl terminal groups. The mechanisms of reaction are discussed and proposed to explain the formation of different end groups when reaction carried out in acidic and alkaline media. Chain degradation in an acidic medium seems to be more effective than in an alkaline medium, and thus yields LNR with lower Mn.

  20. Development of radiation-curable resin based on natural rubber

    International Nuclear Information System (INIS)

    A new radiation curable resin based on natural rubber has been developed. The resin was based on the reaction between low molecular weight epoxidised natural rubber and acrylic acid. When formulated with reactive monomers and photoinitiator, it solidified upon irradiation with UV light. The resin may find applications in coating for cellulosic-based substrates and pressure-sensitive adhesive

  1. Effect of Nanoclay on Natural Rubber Microstructure

    Energy Technology Data Exchange (ETDEWEB)

    Carretero-Gonzalez,J.; Retsos, H.; Verdejo, R.; Toki, S.; Hsiao, B.; Giannelis, E.; Lopez-Manchado, M.

    2008-01-01

    The inclusion of highly anisotropic clay nanoparticles (nanoclays) in cross-linked natural rubber (NR) provides a more homogeneous distributed network structure and induces an early onset as well as enhancement of crystallization under uniaxial deformation. The molecular structure of the polymer network and its morphological changes during deformation were characterized by using broadband dielectric spectroscopy and in situ synchrotron wide-angle X-ray diffraction, respectively. It was found that the presence of nanoclay introduces a dual crystallization mechanism due to the alignment of nanoparticles during stretching. The improved properties in NR-nanoclay nanocomposites can be attributed to both microstructural and morphological changes induced by nanoclay as well as to the nanoclay mobility in the NR matrix during crystallization. The interplay of these factors during deformation contributes to the formation of a supernetwork structure containing cross-linked chemical chains, nanofiller, and crystallizable networks with similar length scales.

  2. Radiation vulcanization of natural rubber latex sensitized with commercial gases

    International Nuclear Information System (INIS)

    The industrial activities using natural rubber latex are fully compatible with rural areas in Amazon and other places in Brazil, as well as in other tropical countries. However the classical sulfur vulcanization presents many occupational problems for the workers in rural areas. Radiation vulcanization of natural rubber latex is a much more friendly process as sulfur compounds are not needed for crosslinking, although chemicals as acrylate monomers, particularly multifunctional acrylates are still used as sensitizers for radiation processes. Two commercial gases, acetylene and butadiene, were selected as sensitizers for the radiation vulcanization of natural rubber latex instead of acrylates. These gases accelerate the crosslinking rates of the cure process and lower the radiation dose required to achieve vulcanization of natural rubber latex and improve the mechanical properties to reduce the tackiness of rubber goods. (author)

  3. Production of liquid epoxidised natural rubber (ENR) by photochemical technique

    International Nuclear Information System (INIS)

    Controlled reduction of molecular weight of solid-form epoxidised natural rubber (ENR) by a 17 photochemical technique has been studied. The product would be used for preparing rubber-based resin for radiation curing. The technique studied the effects of hydrogen peroxide on the rate of molecular weight reduction of the solid rubber as well as its combination with reducing agent such as sodium nitrite. Analysis by IR spectroscopic technique suggests the formation of hydroxyl and carbonyl groups as a result of the ring-opening of the epoxy groups of rubber. NMR as well as IR spectra show the possible formation of furan-like species. (Author)

  4. Natural Rubber Quantification in Sunflower Using an Automated Solvent Extractor

    Science.gov (United States)

    Leaves of sunflower (Helianthus annuus) produce a small amount of low molecular weight natural rubber (NR) and this species has potential as a rubber-producing crop plant. Quantifying NR in plant tissue has traditionally been accomplished using Soxhlet or gravimetric methodologies. Accelerated solve...

  5. Sugarcane bagasse ash: new filler to natural rubber composite

    Directory of Open Access Journals (Sweden)

    Renivaldo José dos Santos

    2014-12-01

    Full Text Available Waste recycling has been the subject of numerous scientific researches regarding the environmental care. This paper reports the redirecting of sugarcane bagasse ash (SBA as new filler to natural rubber (NR/SBA. The NR/SBA composites were prepared using an opened cylinder mixer to incorporate the vulcanization agents and different proportions of residue (SBA. The ash contains about 70-90% of inorganic compounds, with silica (SiO2 being the main compound. The SBA incorporation improved the mechanical properties of the vulcanized rubber. Based on these results, a new use is proposed for the agro-industry organic waste to be implemented in the rubber vulcanization process, aimed at improving the rubber physical properties as well as decreasing the prices of natural rubber composites.

  6. Interfacial interaction between the epoxidized natural rubber and silica in natural rubber/silica composites

    International Nuclear Information System (INIS)

    Highlights: • Substantiate the ring open reaction between Si-OH of silica and epoxy groups of ENR. • ENR can act as a bridge between NR and silica to enhance the interfacial interaction. • As a modifier, ENR gets the potential to be used in the tread of green tire for improving the wet skid resistance apparently. - Abstract: The epoxidized natural rubber (ENR) as an interfacial modifier was used to improve the mechanical and dynamical mechanical properties of NR/silica composites. In order to reveal the interaction mechanism between ENR and silica, the ENR/Silica model compound was prepared by using an open mill and the interfacial interaction of ENR with silica was investigated by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), X-ray diffraction (XRD) and stress–strain testing. The results indicated that the ring-opening reaction occurs between the epoxy groups of ENR chains and Si-OH groups on the silica surfaces and the covalent bonds are formed between two phases, which can improve the dispersion of silica in the rubber matrix and enhance the interfacial combination between rubber and silica. The ring-opening reaction occurs not only in vulcanization process but also in mixing process, meanwhile, the latter seems to be more important due to the simultaneous effects of mechanical force and temperature

  7. Interfacial interaction between the epoxidized natural rubber and silica in natural rubber/silica composites

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Tiwen [College of Materials Science and Engineering, South China University of Technology, Guangzhou 510640 (China); Jia, Zhixin, E-mail: zxjia@scut.edu.cn [College of Materials Science and Engineering, South China University of Technology, Guangzhou 510640 (China); Luo, Yuanfang; Jia, Demin [College of Materials Science and Engineering, South China University of Technology, Guangzhou 510640 (China); Peng, Zheng [Agricultural Product Processing Research Institute, Chinese Academy of Tropical Agriculture Sciences, Zhanjiang 524001 (China)

    2015-02-15

    Highlights: • Substantiate the ring open reaction between Si-OH of silica and epoxy groups of ENR. • ENR can act as a bridge between NR and silica to enhance the interfacial interaction. • As a modifier, ENR gets the potential to be used in the tread of green tire for improving the wet skid resistance apparently. - Abstract: The epoxidized natural rubber (ENR) as an interfacial modifier was used to improve the mechanical and dynamical mechanical properties of NR/silica composites. In order to reveal the interaction mechanism between ENR and silica, the ENR/Silica model compound was prepared by using an open mill and the interfacial interaction of ENR with silica was investigated by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), X-ray diffraction (XRD) and stress–strain testing. The results indicated that the ring-opening reaction occurs between the epoxy groups of ENR chains and Si-OH groups on the silica surfaces and the covalent bonds are formed between two phases, which can improve the dispersion of silica in the rubber matrix and enhance the interfacial combination between rubber and silica. The ring-opening reaction occurs not only in vulcanization process but also in mixing process, meanwhile, the latter seems to be more important due to the simultaneous effects of mechanical force and temperature.

  8. Maillard Reaction in Natural Rubber Latex: Characterization and Physical Properties of Solid Natural Rubber

    OpenAIRE

    Montha, S.; P. Suwandittakul; A. Poonsrisawat; Oungeun, P.; Kongkaew, C.

    2016-01-01

    Maillard reaction in Natural Rubber (NR) latex was investigated by treating fresh NR latex with glutaraldehyde (C5H8O2) in amounts of 0, 50, 100, and 200 mmol/kg of latex. Protein cross-linking in fresh NR latex and solid NR was confirmed by using sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE) and attenuated total reflection infrared (ATR-IR) spectroscopy, respectively. It was found that degree of protein cross-linking in NR increased with increasing C5H8O2 concentration....

  9. Preparation, thermal and flow properties of epoxidised natural rubber

    OpenAIRE

    Nakason, C.; Sainumsai, W.; Kaesaman, A.; Klinpituksa, P.

    2001-01-01

    Epoxidised natural rubber (ENR) was prepared using high ammonia concentrated latex, performic acid and non-ionic surfactant (Emulwin W). The presence and quantity of epoxide groups in the natural rubber molecules were analysed using infrared spectroscopy. The characteristic peaks of epoxide groups at the wave numbers 870 and 1140 cm-1 were observed. The quantities of epoxide groups were found to depend on reaction temperature and reaction time. Glass transition temperature (Tg) of epoxidised ...

  10. Time series analysis of the behavior of brazilian natural rubber

    Directory of Open Access Journals (Sweden)

    Antônio Donizette de Oliveira

    2009-03-01

    Full Text Available The natural rubber is a non-wood product obtained of the coagulation of some lattices of forest species, being Hevea brasiliensis the main one. Native from the Amazon Region, this species was already known by the Indians before the discovery of America. The natural rubber became a product globally valued due to its multiple applications in the economy, being its almost perfect substitute the synthetic rubber derived from the petroleum. Similarly to what happens with other countless products the forecast of future prices of the natural rubber has been object of many studies. The use of models of forecast of univariate timeseries stands out as the more accurate and useful to reduce the uncertainty in the economic decision making process. This studyanalyzed the historical series of prices of the Brazilian natural rubber (R$/kg, in the Jan/99 - Jun/2006 period, in order tocharacterize the rubber price behavior in the domestic market; estimated a model for the time series of monthly natural rubberprices; and foresaw the domestic prices of the natural rubber, in the Jul/2006 - Jun/2007 period, based on the estimated models.The studied models were the ones belonging to the ARIMA family. The main results were: the domestic market of the natural rubberis expanding due to the growth of the world economy; among the adjusted models, the ARIMA (1,1,1 model provided the bestadjustment of the time series of prices of the natural rubber (R$/kg; the prognosis accomplished for the series supplied statistically adequate fittings.

  11. 21 CFR 801.437 - User labeling for devices that contain natural rubber.

    Science.gov (United States)

    2010-04-01

    ... rubber, and synthetic latex or synthetic rubber that contains natural rubber in its formulation. (1) The... displayed in conformance with section 502(c) of the Federal Food, Drug, and Cosmetic Act (the act) (21...

  12. Rubber recovery from centrifuged natural rubber latex residue using sulfuric acid

    Directory of Open Access Journals (Sweden)

    Wirach Taweepreda

    2013-04-01

    Full Text Available Waste latex sludge from centrifuged residue, which is a null by-product of concentrated latex manufacturing, wasdigested to retrieve the rubber by using sulfuric acid. It was found that the acid concentration and digestion time have aneffect on the amount and purity of the retrieved rubber. Sulfuric acid at concentrations of more than 10% by weight with adigestion time of 48 hours completely digested waste latex sludge and gave rubber 10% by weight. The quality of the retrievedrubber was examined for Mooney viscosity (MV, plasticity retention index, nitrogen content, and ash content. The averagemolecular weight of the retrieved rubber, using gel permeation chromatography, was lower than that of normal natural rubber(NR which corresponds with the MV and initial plasticity (Po. The molecular structure from Fourier transform infraredspectroscopy (FT-IR indicated that the retrieved rubber surface is wet composed with hydroxyl functional ended group.The residue solution was evaporated and crystallized. The structure of crystals was determined using power X-ray diffractometer.

  13. Characteristics of natural rubber latex from Indonesia

    International Nuclear Information System (INIS)

    Five field latexes from different clones have been characterized. The total solid content increases and the protein content decreases with increasing the age of rubber trees. The average particle size is between 190 and 234 nm. The number average molecular weight varies from 160,000 to 700,000 while the weight average molecular weight varies from 1,000,000 to 500,000. Negligivle difference was observed in the physical properties of rubber films prepared from the irradiated field latexes. (author)

  14. Maillard Reaction in Natural Rubber Latex: Characterization and Physical Properties of Solid Natural Rubber

    Directory of Open Access Journals (Sweden)

    S. Montha

    2016-01-01

    Full Text Available Maillard reaction in Natural Rubber (NR latex was investigated by treating fresh NR latex with glutaraldehyde (C5H8O2 in amounts of 0, 50, 100, and 200 mmol/kg of latex. Protein cross-linking in fresh NR latex and solid NR was confirmed by using sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE and attenuated total reflection infrared (ATR-IR spectroscopy, respectively. It was found that degree of protein cross-linking in NR increased with increasing C5H8O2 concentration. Physical properties of untreated and treated NR substances in terms of gel content, initial Wallace plasticity (P0, plasticity retention index (PRI, Mooney viscosity, and tensile strength were carefully explored. Results clearly showed that the Maillard cross-linking of proteins had remarkable effect on bulk NR properties, that is, solvent resistance, hardness, resistance to oxidation, rheological behavior, and resistance to stretching out.

  15. Agronomic and Natural Rubber Characteristics of Sunflower as a Rubber-Producing Plant

    Science.gov (United States)

    Sunflower (Helianthus annuus L., Asteraceae) is a genus native to North American and is a potential natural rubber (NR) producing crop. The objectives of the study were to: 1) evaluate commercial sunflower cultivars to determine biomass production and how they partition biomass into leaves, stems, ...

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

    International Nuclear Information System (INIS)

    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 60Co 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

  17. Radiation processing of natural rubber and its applications

    International Nuclear Information System (INIS)

    Research in natural rubber (NR) is still offering good and exciting opportunities especially in making NR into superior products and as a source for new chemicals by modification of its structure. As in the case of liquid epoxidised natural rubber acrylic (LENRA), it has been shown that it has the ability to induce the interfacial interaction between NR and polyolefin i.e. High-density polyethylene (HDPE) as demonstrated by Transmission Electron Microscopy (TEM) and small angle neutron scattering (SANS) techniques. For NR/HDPE blend, without deuteration technique, SANS was also to induce some scattering data leading to fruitful information on the interfacial interaction between the blend compositions. (author)

  18. Recent developments in radiation vulcanisation of natural rubber latex

    International Nuclear Information System (INIS)

    Natural rubber latex, an important industrial raw material, is cross linked using energy of gamma radiation. To reduce the energy of radiation, sensitizers like n-butyl acrylate are used. The product so obtained is called radiation vulcanized natural rubber latex (RVNRL). This product is found to have many superior properties in comparison to the conventionally cross linked latexes. Because of the very low levels of cytotoxicity and nitrosamines in RVNRL, it is expected to be the future raw material for producing products like nipples, catheters, balloons and gloves. (author)

  19. Enhancement of Adhesion between EPDM and Polyester Fabric by Using Natural Rubber Modified by Maleic Anhydride

    Directory of Open Access Journals (Sweden)

    A. A. El-Wakil

    2011-01-01

    Full Text Available This study presents a new method for improving adhesion between ethylene propylene diene monomer (EPDM rubber and polyester fabric. In this work, natural rubber was modified by maleic anhydride in order to improve the adhesion force between ethylene propylene diene monomer rubber and polyester fabric. The effect of thermal aging and ionizing radiation on the stability of the rubber mix as well as on the peel strength of the rubber-coated fabric was investigated. It was observed that the natural rubber modified by maleic anhydride improved the peel strength of the EPDM rubber-coated polyester fabric.

  20. Rheological behavior of raw natural rubber coagulated by microorganisms

    Directory of Open Access Journals (Sweden)

    Zhifen Wang

    2014-01-01

    Full Text Available Tests of the strain sweep, frequency sweep and stress relaxation for raw natural rubber coagulated by microorganisms (NR-m and raw natural rubber coagulated by acid (NR-a were carried out with the use of a rubber process analyzer (RPA. The results showed that the storage torque, complex viscosity of NR-m were higher than those of NR-a while the loss factor was lower. The effect of temperature on viscosity of raw NR was studied following the Arrhenious-Frenkel-Eyring model. The viscous flow behavior of NR-m was poorer than those of NR-a. Furthermore, stress relaxation measurements of raw NR showed a longer period of relaxation for NR-m.

  1. Accelerated Thermal Aging Studies on Natural Rubber in Seismic Isolation Bearings

    International Nuclear Information System (INIS)

    Most rubbers harden and eventually become brittle owing to the aging process. The thermal aging is known to be the most significant factor in the deterioration of rubber materials. The ambient temperature substantially increases the stiffness and damping of the rubber bearings, even at room temperature. Under low temperature, a long duration of exposure increases both quantities. High temperatures have a significant effect on the mechanical properties of rubber bearings. This study focuses on the aging behavior of natural rubber material used in seismic isolation bearings by accelerated heat exposure tests. Accelerated thermal aging tests were carried out for a natural rubber material, and its lifetime was predicted. The deterioration of the rubber material is more significant at high ambient temperature. In addition, the deterioration of rubber influences the adhesion between the rubber and the steel plates. Dynamic properties of the rubber will be a critical factor for defining the service time of seismic isolation bearings

  2. Studies on Microbial Degradation of Natural Rubber Using Dilute Solution Viscosity Measurement and Weight Loss Techniques

    OpenAIRE

    G. N. Onyeagoro; E. G. Ohaeri; U. J. Timothy

    2012-01-01

    Reduction of molecular weight of rubber polymers for easy absorption of compounding ingredients is critical in every rubber compounding operation. Yet, rubber mastication which is the current practice of achieving this is expensive, requiring high energy and equipment cost. To address this problem, microbial degradation of natural rubber (NR) and waste rubber tire (WRT) by Nocardia sp. strain 385A was studied using dilute solution viscosity measurement and weight loss methods. Solutions of NR...

  3. Enhancement of Adhesion between EPDM and Polyester Fabric by Using Natural Rubber Modified by Maleic Anhydride

    OpenAIRE

    A. A. El-Wakil

    2011-01-01

    This study presents a new method for improving adhesion between ethylene propylene diene monomer (EPDM) rubber and polyester fabric. In this work, natural rubber was modified by maleic anhydride in order to improve the adhesion force between ethylene propylene diene monomer rubber and polyester fabric. The effect of thermal aging and ionizing radiation on the stability of the rubber mix as well as on the peel strength of the rubber-coated fabric was investigated. It was observed that the natu...

  4. Radiation Copolymerization of Styrene Monomer Onto Natural Rubber Film

    International Nuclear Information System (INIS)

    Studies on the effect of radiation copolymerization of styrene monomer onto natural rubber film on physical and chemical properties of natural rubber-polystyrene copolymer (NPC) have been done. Natural rubber film firstly immersed in styrene monomer in certain time, then it was wrapped with Mylar film, and then it was irradiated with gamma rays in various doses from 10,25, 50 up to 100 kGy. The styrene monomer content was also varying from 25, 50 and 100 phr (part per hundred part of rubber). Using tensile tester and hardness tester carried out physical characterization of NPC such as modulus-30G, modulus-600, elongation at break, permanent set and hardness. While chemical characterization was carried out by extraction method. The solvent used was acetone and tetrahydrofuran. The experimental results showed that by increasing the styrene monomer at the same irradiation dose, the molecule crosslinked fraction of NPC decreased, while the molecule grafted fraction was increased. But at the saine styrene monomer content, increasing irradiation dose was increasing the molecule crosslinked fraction and decreasing the molecule grafted fraction of NPC. The increasing of molecule crosslinked fraction was effected on the increasing of tensile strength, modulus, hardness, and decreasing of elongation at break of NPC. The tensile strength, modulus, aJId baldness ofNPC were achieved 195 kg/cm2, 108 kg/cm2 and 63 shore respectively at monomer content I00 phr and irradiation dose was 100 kGy

  5. Preparation and properties of natural nanocomposites based on natural rubber and naturally occurring halloysite nanotubes

    International Nuclear Information System (INIS)

    A 'green' composite based on natural halloysite nanotubes (HNTs) and natural rubber (NR) was prepared by mechanical mixing. A silane coupling agent, bis (triethoxysilylpropyl)-tetrasulphide, was utilized to enhance the properties of these composites. It was observed that the reinforcing activity of HNTs was superior to commercial silica coupled with the same amount of silane coupling agent. Moreover the on-set thermal degradation decomposition temperature was improved by ∼64 oC with the addition of 10 parts HNTs per hundred of rubber. Transmission electron microscopic images confirmed the good dispersion of the HNTs in the rubber matrix, whereas X-ray diffraction studies showed a little change in interlayer spacing between the two silicate layers of HNTs.

  6. Natural rubber latex: past, present and future in Latin America

    International Nuclear Information System (INIS)

    The origin of the Hevea braziliensis tree was the Amazonian region in South America, particularly the Brazilian jungle. The rubber expansion at the end of 9th century brought prosperity and determined the borders of Amazonian countries. In spite of that, the Brazilian government has failed in establishing a successful policy for improving the NR production in the jungle. However, rubber plantations were successfully introduced recently near marginal areas of the humid forest in the Amazon due to the absence of the fungus Microcyclos ulei. Both, extraction of wild rubber and plantation have a key role in the maintenance of the forest health. The market for dipping products is small but is growing very fast and is expected to follow this pattern as the sanitary conditions are improved by the health authority. The history of the Brazilian NR products industry is contemporary and is based on the policy of market protection and on the lack of investments due to extremely high interest rates. As a result, the industry was not competitive. It was concluded that, in order to cope with the future challenge, the industry is required to invest in very modern technologies to produce first class goods with international acceptance. Latin America would follow the world trend for nitrosamine and protein free products. The radiation vulcanization of natural rubber latex could prove itself as a profitable solution and not only a quality solution. It was also concluded that both wild rubber and rubber plantations in Brazil have their future coupled with the future of a regional dipping industry. Moreover, the buildup of the dipping industry will be beneficial to the protection of the humid forest and the recovery of degraded areas

  7. Situation of wastewater treatment of natural rubber latex processing in the Southeastern region, Vietnam

    OpenAIRE

    Nguyen, Nhu Hien; Luong, Thanh Thao

    2012-01-01

    Rubber tree is one of the main plants which play an important role in the economy of Southeastern region, Vietnam. Approximately 90% of Vietnamese natural rubber latex is exported as raw products. The preliminary process of natural rubber latex discharges a large amount of wastewater to the environment. In Vietnam, there are many available technologies set up and operated for treatment wastewater of rubber latex processing. However, the effluent quality is still poor and the concentration of ...

  8. The influence of temperature and reaction time in the degradation of natural rubber latex

    International Nuclear Information System (INIS)

    Liquid natural rubber (LNR /LENR) should be considered as a new material instead of a new type of rubber though they have the same configuration as the rubber used. In this work, thermal degradation of natural rubber latex was carried out to obtain LNR/LENR by varying the reaction time at different temperatures. The degraded polymers were characterized structurally using FTIR and NMR spectroscopies and the average molecular weights were determined by membrane-osmometry and viscometry. (author)

  9. Natural Rubber - Layered Silicates Nanocomposites: Mechanical Properties, Structure & Dynamics

    Science.gov (United States)

    Retsos, Haris

    2008-03-01

    Natural Rubber (NR) is one of the most industrially relevant elastomers due to unique elastic properties. Recently we have been developed NR composites with incorporated natural or synthetic clays. We present structural, dynamical and mechanical properties to justify the influence of different parameters, like silicate dispersion, cross-linking density and strength of polymer/silicate interface, on the reinforcement phenomena of those composites. To understand the improvement of the mechanical properties we have investigated the possibility of any bound rubber formation on the outer surface of fillers like in carbon black or silica composites. Evidence from a rather similar situation have been found in silicate nanocomposites by dielectric spectroscopy and the existence of a possible relaxation mode suggests a strong adhesion with the fillers (interfacially adsorbed polymer IA) that corresponds to a glass transition around 100 C higher than the bulk glass transition.

  10. Borracha natural e nanocompósitos com argila Natural rubber and nanocomposites with clay

    Directory of Open Access Journals (Sweden)

    Márcia Maria Rippel

    2009-01-01

    Full Text Available The natural rubber is a strategic material which can not be replaced by synthetic rubber in many technological applications. Brazil is a rubber importer, but new techniques of cultivation, breeding and diversification of producing species can reverse this situation. One of the best ways to add value to this commodity is nanotechnology. The production of nanocomposites is already a reality and shows that the sustainable use of this natural resource can lead to new products and boost the national agribusiness setting labor-qualified in the field.

  11. Extractable proteins from irradiated field natural rubber latex

    Energy Technology Data Exchange (ETDEWEB)

    Rogero, S.O.; Lugao, A.B.; Yoshii, Fumio; Makuuchi, Keizo

    2003-06-01

    In this study field natural rubber latex was irradiated with different doses near a {sup 60}Co gamma source to reduce the water-soluble protein content in the final product. The protein content of the films obtained by casting method was extracted with phosphate buffer solution, pH 7 and was measured using Micro BCA Protein Assay kit. Also was measured protein in the serum samples of field NRL. The concentration of extractable proteins increased with increasing radiation dose.

  12. Extractable proteins from irradiated field natural rubber latex

    International Nuclear Information System (INIS)

    In this study field natural rubber latex was irradiated with different doses near a 60Co gamma source to reduce the water-soluble protein content in the final product. The protein content of the films obtained by casting method was extracted with phosphate buffer solution, pH 7 and was measured using Micro BCA Protein Assay kit. Also was measured protein in the serum samples of field NRL. The concentration of extractable proteins increased with increasing radiation dose

  13. Extractable proteins from irradiated field natural rubber latex

    Science.gov (United States)

    Rogero, Sizue O.; Lugão, Ademar B.; Yoshii, Fumio; Makuuchi, Keizo

    2003-06-01

    In this study field natural rubber latex was irradiated with different doses near a 60Co gamma source to reduce the water-soluble protein content in the final product. The protein content of the films obtained by casting method was extracted with phosphate buffer solution, pH 7 and was measured using Micro BCA Protein Assay kit. Also was measured protein in the serum samples of field NRL. The concentration of extractable proteins increased with increasing radiation dose.

  14. Radiation vulcanised natural rubber latex (RVNRL) market and challenges

    International Nuclear Information System (INIS)

    RVNRL has the required properties and proven useful for the manufacturing of examination gloves, balloons and finger cots at industrial scale. To date only RVNRL finger cots are available in the market. Problems and challenges for the market of other products are identified. Further success in the on going research activities will be the reference for more applications of RVNRL in the relevant industry to produce natural rubber latex products of more competitive values

  15. Modifikasi Aspal Dengan Menggunakan Karet Alam Siklik (Cyclic Natural Rubber)

    OpenAIRE

    Ritonga, Winsyahputra

    2015-01-01

    The research has been done about using of Cyclic Natural Rubber as asphalt modifier material. Besides addition CNR, acrylate acid and BPO are added to strengthen the forces of asphalt and CNR. Modified of asphalt designed by mixing asphalt, CNR, acrylate acid and BPO for further testing physical regulation of asphalt according to SNI. After met physical requlation of asphalt, modified asphalt mixed with aggregate and than Marshall testing. The result of physical regulation o...

  16. Radiation vulcanized natural rubber latex is not cytotoxic

    International Nuclear Information System (INIS)

    It has been reported that urethritis and/or urethral strictures caused by urinary catheters relates to cytotoxicities of their materials, and that natural rubber latex (NRL) materials often show the strong cytotoxicities. This paper reports the cytotoxicity testing method using chinese hamster V79 cultured cells, clarifies that the toxicities of NRLs vulcanized by the conventional processes are due mainly to the contents of zinc dialkyldithiocarbamates in the materials, and that the cytotoxicity of radiation vulcanized NRL (RVNRL) is very weak. (author)

  17. Nano-lignin filled natural rubber composites: Preparation and characterization

    OpenAIRE

    Jiang, C.; He, H.; Jiang, H.; Ma, L.; D. M. Jia

    2013-01-01

    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 measuremen...

  18. Application of radiation vulcanized natural rubber latex in Indonesia

    International Nuclear Information System (INIS)

    The center has carried out R and D of Radiation Vulcanization Natural Rubber Latex (RVNRL) technology and introduced it to the industries since the inauguration and operation of the latex pilot plant in 1983. After years of experiences and the environmental consideration, n-butylacrylate (n-BA) has replaced CCI, as the sensitizer. Until now the introduction program shows that radiation vulcanized latex is more suitable for home industries than large industries. The obstacle of the program is the marketing of the dipped products. In spite of these problems, the introduction of this technology to the people in some undeveloped area of Java has supported the national program to improve their living standard. The problems of nitrosamine and protein allergic have turn up RVNRL to be the substitute of sulfur vulcanized latex in the future. The cooperation with a national condom manufacturer (PT Mitra Banjaran) has applied RVNRL for condom production in the large scale. Soft condoms with less probability of pinhole are obtained, but the technical problem is stickiness after pilling. Supply to a baby teat and a rubber thread manufacturer offers great advantages by not using any chemicals. In spite of the advantages, the problem of latex viscosity for dipping and the low modulus of elasticity of the threads arise. Through those input CAIR-BATAN is conducting the research and development in improving the crosslinking among the rubber particles that are supposed to be the reason of the stickiness and low modulus of elasticity. This effort is expected to be able to broaden the application of RVNRL, and it will be achieved only by the involvement of rubber chemist, rubber technologist, and radiation chemist

  19. Modification of (DGEBA epoxy resin with maleated depolymerised natural rubber

    Directory of Open Access Journals (Sweden)

    2008-04-01

    Full Text Available In this work, diglycidyl ether of bisphenol A (DEGBA type epoxy resin has been modified with maleated depolymerised natural rubber (MDPR. MDPR was prepared by grafting maleic anhydride onto depolymerised natural rubber. MDPR has been characterized by Fourier transform infrared (FT-IR spectroscopy and nuclear magnetic resonance spectroscopy. MDPR was blended with epoxy resin at three different ratios (97/3, 98/2 and 99/1, by keeping the epoxy resin component as the major phase and maleated depolymerised natural rubber component as the minor phase. The reaction between the two blend components took place between the acid/anhydride group in the MDPR and the epoxide group of the epoxy resin. The proposed reaction schemes were supported by the FT-IR spectrum of the uncured Epoxy/MDPR blends. The neat epoxy resin and Epoxy/MDPR blends were cured by methylene dianiline (DDM at 100°C for three hours. Thermal, morphological and mechanical properties of the neat epoxy and the blends were investigated. Free volume studies of the cured, neat epoxy and Epoxy/MDPR blends were correlated with the morphological and mechanical properties of the same systems using Positron Annihilation Lifetime Studies.

  20. Effect of antioxidants on radiated vulcanization natural rubber latex

    International Nuclear Information System (INIS)

    The effect of antioxidants on the radiated vulcanization of natural rubber latex by radiation was chosen for this studies. Irradiation with gamma ray at 8 kGy of a mixture of natural rubber latex, 0.5.phr of η-butyl acrylate (η-BA), and 0.1 phr of tert.-butyl hydroperoxide (sensitizer), yielded a radiated vulcanization natural rubber latex (RVNRL). It was found that the viscosity of this product decreased but tensile strength of its films increased with the storage time of the P,VNRL. Various kinds of antioxidants were added to RVNRL, it revealed that the physical properties of the films after aging was improved, including the tensile strength which depended on the time of leaching (0-60 minutes). Vulcanox KB was the best effective antioxidant that gave the maximum tensile strength at low concentration and with a short time for leaching. One example is medical gloves prepared from RVNRL, in the presence of 0.5 phr of Vulcanox KB. After being leached with water at 50OC for 3 min., the resulting products showed different tensile strength of 21 MPa and 20 MPa before and after aging condition respectively

  1. Progress in radiation vulcanization of natural rubber latex

    International Nuclear Information System (INIS)

    Vulcanization dose defined as the radiation dose at which cross-linked natural rubber in latex has the maximum tensile strength can be reduced by adding carbon tetrachloride as a reaction accelerator. The radiation vulcanization of natural rubber latex was selected as one of regional projects of IAEA in 1989 and a pilot plant was built in Jakarta. The products from it were evaluated during 1983-1985, followed by IAEA decision to support the continued R and D study at Takasaki, JAERI. Various factors to improve the properties of the products have been studied. Several advantages of the process over conventional method, such as absence of N-nitrosoamines, low cytotoxicity, decomposability in the environment, transparency and softness, were confirmed. The technology has been transferred toward commercial application in Thailand, and pilot plants being set up in Indonesia, India, Malaysia and Thailand. Moreover, the process was found to be effective in reducing protein remaining in natural rubber latex products and the initial investment and irradiation cost was found to be greatly reduced by employing low energy electron accelerator. This paper reviews such progress. (S. Ohno)

  2. Extractable proteins from field radiation vulcanized natural rubber latex

    International Nuclear Information System (INIS)

    The type I allergy associated with the use of natural rubber latex (NRL) products is caused by the NRL proteins leached by the sweat or other body fluids. Makuuchi's group proposed for the first time the proteins removal by the addition of water-soluble polymers (WSP) on radiation vulcanization of natural rubber latex (RVNRL) that is a promising process under development in many countries. In this study, Brazilian field natural rubber was irradiated with a 60Co gamma source to reduce the content of WSP in the final product. WSP was used as additive to improve the extraction of protein. After irradiation the RVNRL was centrifuged to extract the WSP and proteins. The analytical methodology for protein content was based on the modified Lowry method according to ASTM D5712. Protein determination was carried out in serum of latex and in the extracts of the gloves. The concentration of extractable water-soluble proteins in serum of irradiated field NRL (NRL1), not irradiated one (NRL2); of twice centrifuged sample with polymer additive NRL (NRL3) and of the glove manufactured (NRLG) are compared with commercial glove (CG). The irradiation process increases the extractable water-soluble proteins, EP, as reported in the literature. In this study the use of polymeric additive on the bi-centrifugation process to remove protein was successful and the EP of the glove obtained in NRL3 was at around 40% of the commercial glove

  3. Dynamically vulcanized biobased polylactide/natural rubber blend material with continuous cross-linked rubber phase.

    Science.gov (United States)

    Chen, Yukun; Yuan, Daosheng; Xu, Chuanhui

    2014-03-26

    We prepared a biobased material, dynamically vulcanized polylactide (PLA)/natural rubber (NR) blend in which the cross-linked NR phase owned a continuous network-like dispersion. This finding breaks the traditional concept of a sea-island morphology formed after dynamic vulcanization of the blends. The scan electron microscopy and dissolution/swell experiments provided the direct proof of the continuous cross-linked NR phase. This new biobased PLA/NR blend material with the novel structure is reported for the first time in the field of dynamic vulcanization and shows promise for development for various functional applications. PMID:24621374

  4. The immobilisation of trypsin onto irradiated, oxidised natural rubber converted to the natural rubber-g.co-HEMA system

    International Nuclear Information System (INIS)

    Natural rubber has been grafted with 2-HEMA to relatively high levels by pre-irradiating the natural rubber in a continuous medium containing H2O2 prior to exposure to the monomer. The extent of grafting increased with increase in the hydrogen peroxide concentration up to a concentration of approx 7.0 M. The series of oxidised graft copolymers, so produced, successfully immobilised trypsin when cyanuric chloride was used as the coupling agent. p-Benzoquinone and p-toluene sulphonyl chloride were less successful. Partial hydrolysis of the grafted MEMA branches produced a copolymer that was more efficient in immobilising trypsin. Thus, 3-5 mg of active enzyme/g of copolymer were immobilised. The character of this immobilised species was compared with that of the free enzyme both with respect to pH and to KM. The immobilised system possesses good retention of activity over extended periods. (author)

  5. Alternative vulcanization process of natural rubber latex induced by ionizing radiation

    International Nuclear Information System (INIS)

    The natural rubber latex was vulcanized by two different process: a) thermal process in the presence of sulfur; b) alternative process using radiation (gamma rays and electrons beam). The comparative study of rubber goods quality (surgical gloves and balloons) was carried out by physical and chemical properties of pre vulcanized latex and physical and mechanics properties of rubber goods for two process. (author)

  6. [Residual chemicals in natural rubber products for food contact use].

    Science.gov (United States)

    Kawamura, Y; Nakajima, A; Yamada, T

    2001-06-01

    The residues of additives and other chemicals were investigated by GC/MS in natural rubber products for food contact, which included nipples, packing, gloves and a net for ham. The packings and gloves contained 980-6,570 micrograms/g of vulcanization accelerators, such as zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate (EZ), zinc di-n-buthyldithiocarbamate (BZ) and 2-mercaptobenzothiazole. Some samples contained BHT, Irganox 1076 and Yoshinox 2246R as antioxidants; dibutyl phthalate and di(2-ethylhexyl) phthalate as plasticizers; and palmitic acid, stearic acid, palmitamide, stearamide and hydrocarbons as lubricants. Two unknown peaks were identified as stigmasterol and beta-sitosterol, and others were estimated to be fucosterol, oryzanol and alpha-sitosterol. These sterols are widely distributed in plants, so their origin was presumed to be the rubber plants. The sterols were detected at a level of 340-2,940 micrograms/g in all natural rubber samples. A migration test was carried out for some samples. No chemicals were released into water, 4% acetic acid or 20% ethanol at 60 degrees C for 30 min, though BHT, Yoshinox 2246R, EZ, BZ and sterols were released into n-heptane at 25 degrees C for 60 min. PMID:11577390

  7. Extractable proteins from irradiated field natural rubber latex

    International Nuclear Information System (INIS)

    Complete text of publication follows. Natural rubber latex (NRL) is extracted from Hevea brasiliensis tree and is used to produce different kinds of rubber goods like gloves, condoms, balloons and some part of medical and dental equipments, but it is predominantly used in the production of surgical and examination gloves. The allergy caused by latex products has become a serious problem; the sweat can remove proteins and allow contact with skin causing sensitization or allergic reactions. Some methods have been suggested to reduce the extractable protein content in latex gloves, as using low protein latex; proper leaching during the process of production etc. In this study field natural rubber latex was irradiated in different doses in a 60Co to reduce the water-soluble protein content in the final product. The protein content of the films obtained by casting method was extracted with phosphate buffer solution, pH 7 and was measured using Micro BCA Protein Assay kit. Also was measured protein in the serum samples of field NRL. The concentration of extractable proteins increased with increasing radiation dose

  8. Cure and physical properties of natural rubber and epoxidized natural rubber compounds using various types of accelerators

    Directory of Open Access Journals (Sweden)

    Klinpituksa, P.

    2003-01-01

    Full Text Available Cure characteristics and tear properties of epoxidized natural rubber (ENR-33 and natural rubber were studied. Three types of accelerators, namely 2-mercaptobenzothiazole (MBT, 2-morpholinothiobenzothiazole (MBS and N-tert-butyl-2-benzothiazyl sulphenamide (TBBS were used in this work. The conventional valcanization (CV system was used. Cure characteristics were determined using a Monsanto Oscillating Disk Rheometer (ODR 2000 at 150ºC. Also, a systematic study of tear strength was carried out before and after ageing at 70ºC for 72 h. A Hounsfield tensometer (Model H10KS operating at 500 mm/min was used to determine the tear strength using standard angle test pieces. The results indicated that scorch time and cure time of natural rubber are greater than those of ENR-33 compounds. However, the contrary was observed for the minimum and maximum torques and the torque differences. The observation is attributed to the activation of a double bond by the adjacent epoxide group in ENR-33. Furthermore, we found that the change in tear strength of aged ENR sample was greater than that of NR vulcanizates.

  9. Shape memory alloy wire-based smart natural rubber bearing

    International Nuclear Information System (INIS)

    In this study, two types of smart elastomeric bearings are presented using shape memory alloy (SMA) wires. Due to the unique characteristics of SMAs, such as the superelastic effect and the recentering capability, the residual deformation in SMA-based natural rubber bearings (SMA-NRBs) is significantly reduced whereas the energy dissipation capacity is increased. Two different configurations of SMA wires incorporated in elastomeric bearings are considered. The effect of several parameters, including the shear strain amplitude, the type of SMA, the aspect ratio of the base isolator, the thickness of SMA wire, and the amount of pre-strain in the wires on the performance of SMA-NRBs is investigated. Rubber bearings are composed of natural rubber layers bonded to steel shims as reinforcement. Results show that ferrous SMA wire, FeNiCuAlTaB, with 13.5% superelastic strain and a very low austenite finish temperature (−62 °C), is the best candidate to be used in SMA-NRBs subjected to high shear strain amplitudes. In terms of the lateral flexibility and wire strain level, the smart rubber bearing with a cross configuration of SMA wires is more efficient. Moreover, the cross configuration can be implemented in high-aspect-ratio elastomeric bearings since the strain induced in the wire does not exceed the superelastic range. When cross SMA wires with 2% pre-strain are used in a smart NRB, the dissipated energy is increased by 74% and the residual deformation is decreased by 15%. (paper)

  10. INDONESIAN NATURAL RUBBER: AN ECONOMETRIC ANALYSIS OF ITS EXPORT SUPPLY AND FOREIGN IMPORT DEMAND

    OpenAIRE

    Soependi, Ida Yunia

    1993-01-01

    This study is concerned with a quantitative examination of the Indonesian natural rubber. The main objective of the study is to analyze the nature of the supply of and demand for Indonesian natural rubber. To meet the above objective a simultaneous equation model was developed consisting of fifteen behavioral equations and six definitional identities which are hypothesized to describe the annual structure of the Indonesian natural rubber and its place in the world market for the period 1970 t...

  11. Thermomechanical analysis of Natural Rubber behaviour stressed at room temperature.

    Directory of Open Access Journals (Sweden)

    Chrysochoos A.

    2010-06-01

    Full Text Available Owing to their high molecular mobility, stressed rubber chains can easily change their conformations and get orientated. This phenomena leads to so high reversible draw ratio that this behaviour is called rubber elasticity [1-3]. The analogy with ideal gases leads to an internal energy independent of elongation, the stress being attributed to a so-called configuration entropy. However, this analysis cannot take thermal expansion into account and moreover prohibits predicting standard thermo-elastic effect noticed at small elongations and the thermoelastic inversion effects [4]. This paper aims at : observing and quantifying dissipative and coupling effects associated with deformation energy, generated when Natural Rubber is stretched. re-examine the thermomechanical behaviour model of rubberlike materials, under the generalised standard material concept. From an experimental viewpoint, energy balance is created using infrared and quantitative imaging techniques. Digital Image Correlation (DIC provides in-the-plane displacement fields and, after derivation, strain and strain-rate fields. We have used those techniques to evidence the thermoelastic inversion effect as shown on Figure 1 where different weights have been fixed to warmed specimen and we monitored the sample deformation while it recovers room temperature. But we have also used those techniques to perform energy balance : analysis of the mechanical equilibrium allows estimates of the stress pattern and computation of deformation energy rates under a plane stress hypothesis [5]. Infrared Thermography (IRT gives the surface temperature of the sample. To estimate the distribution of heat sources, image processing with a local heat equation and a minimal set of approximation functions (image filtering was used. The time courses of deformation energy and heat associated with cyclic process are plotted in Figure 2. The time derivatives of both forms of energy are approximately similar. This

  12. Preparation of Natural Rubber (NR) Based Nano-Sized Materials Using Sol-Gel Technique

    International Nuclear Information System (INIS)

    The objectives of this project are to prepare nano-sized natural rubber-based hybrid coating material by sol-gel technique; to explore the possibility of producing ENR-Si (epoxidized natural rubber-silica) cramer with toughening effects; and to use it in radiation curing of surface coating. Since early 1960s Malaysia has introduced various forms of value-added natural rubber such as Standard Malaysian Rubber (SMR), methylmethacrylate-grafted natural rubber (MG rubber), followed by liquid natural rubber and epoxidized natural rubber (ENR). Products such as liquid epoxidized natural rubber acrylate (LENRA) and thermoplastic natural rubber (TPNR) are still on-going research projects in Nuclear Malaysia. The former has strong possibility to be used as radiation-sensitive comparabilities in TPNR blends, besides its original purpose for example in radiation curing of surface coating. But earlier findings indicated that, to make it (as for surface coating) more effective, reinforcement system is needed to be introduced. Strong candidate is silica by sol-gel technique, since common reinforcement filler for example carbon black has drawbacks in this particular case. This technique was introduced in late 1960s to produce metal oxides such as silica and titanium oxides in solution. (author)

  13. Reinforcement of natural rubber/high density polyethylene blends with electron beam irradiated liquid natural rubber-coated rice husk

    Energy Technology Data Exchange (ETDEWEB)

    Chong, E.L.; Ahmad, Ishak [Polymer Research Center (PORCE), School of Chemical Science and Food Technology, Universiti Kebangsaan Malaysia 4, 43600 UKM Bangi, Selangor Darul Ehsan (Malaysia); Dahlan, H.M. [Radiation Processing Technology Division, Malaysian Nuclear Agency (Nuclear Malaysia), Bangi, 43000 Kajang, Selangor Darul Ehsan (Malaysia); Abdullah, Ibrahim, E-mail: dia@ukm.m [Polymer Research Center (PORCE), School of Chemical Science and Food Technology, Universiti Kebangsaan Malaysia 4, 43600 UKM Bangi, Selangor Darul Ehsan (Malaysia)

    2010-08-15

    Coating of rice husk (RH) surface with liquid natural rubber (LNR) and exposure to electron beam irradiation in air were studied. FTIR analysis on the LNR-coated RH (RHR) exposed to electron beam (EB) showed a decrease in the double bonds and an increase in hydroxyl and hydrogen bonded carbonyl groups arising from the chemical interaction between the active groups on RH surface with LNR. The scanning electron micrograph showed that the LNR formed a coating on the RH particles which transformed to a fine and clear fibrous layer at 20 kGy irradiation. The LNR film appeared as patches at 50 kGy irradiation due to degradation of rubber. Composites of natural rubber (NR)/high density polyethylene (HDPE)/RHR showed an optimum at 20-30 kGy dosage with the maximum stress, tensile modulus and impact strength of 6.5, 79 and 13.2 kJ/m{sup 2}, respectively. The interfacial interaction between the modified RH and TPNR matrix had improved on exposure of RHR to e-beam at 20-30 kGy dosage.

  14. Reinforcement of natural rubber/high density polyethylene blends with electron beam irradiated liquid natural rubber-coated rice husk

    International Nuclear Information System (INIS)

    Coating of rice husk (RH) surface with liquid natural rubber (LNR) and exposure to electron beam irradiation in air were studied. FTIR analysis on the LNR-coated RH (RHR) exposed to electron beam (EB) showed a decrease in the double bonds and an increase in hydroxyl and hydrogen bonded carbonyl groups arising from the chemical interaction between the active groups on RH surface with LNR. The scanning electron micrograph showed that the LNR formed a coating on the RH particles which transformed to a fine and clear fibrous layer at 20 kGy irradiation. The LNR film appeared as patches at 50 kGy irradiation due to degradation of rubber. Composites of natural rubber (NR)/high density polyethylene (HDPE)/RHR showed an optimum at 20-30 kGy dosage with the maximum stress, tensile modulus and impact strength of 6.5, 79 and 13.2 kJ/m2, respectively. The interfacial interaction between the modified RH and TPNR matrix had improved on exposure of RHR to e-beam at 20-30 kGy dosage.

  15. Reinforcing effect of plasma modified halloysite nanotubes in a carbon black filled natural rubber-butadien rubber matrix

    OpenAIRE

    Poikelispaa, Minna; Das, Amit; Dierkes, Wilma; 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. A successful application of such composites depends mainly on the degree of dispersion of the nano-sized fillers. Recently, a naturally occurring clay mineral, halloysite nanotubes (HNTs), is inve...

  16. Development of surgical gloves from radiation vulcanized natural rubber latex

    International Nuclear Information System (INIS)

    Natural rubber latex (55% DRC) containing 3 phr of CCl4 was irradiation γ-rays from Co-60 source at a dose rate of 7.5 kGy/h. Specifications of irradiated latex and mechanical properties of the radiation vulcanized latex were studied. The maximum tensile strength which was obtained at 25 kGy was 240 kg/cm2. The viscosity of the irradiated latex kept constant value under 30 kGy. The G value for crosslinking calculated from swelling is 17.0. Chlorine contents measured with activation analysis increased with increasing irradiation dose. 400 kg of latex was vulcanized at 25 kGy and used for production of rubber gloves in an existing factory with coagulant dipping process. The physical properties of the rubber gloves were as follows: tensile strength; 220-250 kg/cm2, elongation at break; 950%, permanent set; 5-10%, aging residual tensile strength after at 70degC for 72 hours; 70-80%. The gloves were accepted for domestic use as surgical and examination gloves. (author)

  17. Genetic and biochemical evaluation of natural rubber from Eastern Washington prickly lettuce (Lactuca serriola L.).

    Science.gov (United States)

    Bell, Jared L; Burke, Ian C; Neff, Michael M

    2015-01-21

    Alternative sources of natural rubber are of importance due to economic, biological, and political threats that could diminish supplies of this resource. Prickly lettuce (Lactuca serriola L.) synthesizes long-chain natural rubber and was studied to determine underlying genetic and phenotypic characteristics of rubber biosynthesis. Genotypic and phenotypic analysis of an F2 segregating population using EST-SSR markers led to the discovery of genetic regions linked to natural rubber production. Interval mapping (IM) and multiple QTL mapping (MQM) identified several QTL in the mapping population that had significance based on LOD score thresholds. The discovered QTL and the corresponding local markers are genetic resources for understanding rubber biosynthesis in prickly lettuce and could be used in marker-assisted selection (MAS) breeding. Prickly lettuce is an excellent candidate for elucidating the rubber synthesis mechanism and has potential as a crop plant for rubber production. PMID:25513853

  18. Study on grafting of different types of acrylic monomers onto natural rubber by {gamma}-rays

    Energy Technology Data Exchange (ETDEWEB)

    Dafader, N.C. [Nuclear and Radiation Chemistry Division, Institute of Nuclear Science and Technology, Bangladesh Atomic Energy Commission, P.O. Box 3787, Dhaka (Bangladesh)]. E-mail: nrcd@instaere.com; Haque, M.E. [Nuclear and Radiation Chemistry Division, Institute of Nuclear Science and Technology, Bangladesh Atomic Energy Commission, P.O. Box 3787, Dhaka (Bangladesh)]. E-mail: nrcd@instaere.com; Akhtar, F. [Nuclear and Radiation Chemistry Division, Institute of Nuclear Science and Technology, Bangladesh Atomic Energy Commission, P.O. Box 3787, Dhaka (Bangladesh)]. E-mail: nrcd@instaere.com; Ahmad, M.U. [Department of Chemistry, Jahangirnagar University, Savar, Dhaka (Bangladesh)]. E-mail: mesbah_ahmad@hotmail.com

    2006-01-15

    A comparative study of various acrylic monomers for grafting onto natural rubber was done. The stability of natural rubber latex (NRL) against coagulum with monomer, mechanical properties of grafted rubbers and percent of grafting were investigated. The NRL with monomers, methylacrylate (MA), ethylacrylate (EA) and n-butylacrylate (n-BA), is unstable but it is stable with methyl methacrylate (MMA), n-butyl methacrylate (BMA) and cyclohexyl methacrylate (CHMA). The mechanical properties and degree of grafting attained a maximum at a total radiation dose of 4 kGy. The values of tensile properties of MMA and CHMA grafted rubbers are almost similar, and higher than those of BMA grafted rubbers. On the other hand, the degree of grafting for CHMA is higher than those of MMA and BMA grafted rubbers. The infrared (IR) spectra of monomer grafted natural rubber were also studied.

  19. Silver nanoparticles delivery system based on natural rubber latex membranes

    International Nuclear Information System (INIS)

    The search for new materials for biomedical applications is extremely important. Here, we present results on the performance of a silver nanoparticles delivery system using natural rubber latex (NRL) as the polymeric matrix. Our aim was to obtain an optimized wound dressing by combining materials with potential healing action. The synthesis of silver nanoparticles and their characterization by UV–Vis spectroscopy, transmission electron microscopy, zeta potential, dynamic light scattering, and Fourier transform infrared spectroscopy (FTIR) are depicted. The NRL membranes are good matrix for silver nanoparticles and allow for their gradual release. The release of 30 nm silver nanoparticles by the NRL membranes depends on their mass percentage in NRL membranes. The total concentration of AgNP released by the NRL membranes was calculated. The AgNP attached to the cis-isoprene molecules in the NRL matrix remain attached to the membrane (∼0.1 % w/w). So, only the AgNP bound to the non-rubber molecules are released. FTIR spectra suggest that non-rubber molecules, like aminoacids and proteins, associated with the serum fraction of the NRL may be attached to the surfaces of the released nanoparticles, thereby increasing the release of such molecules. The released silver nanoparticles are sterically stabilized, more stable and well dispersed. Because the serum fraction of the NRL is responsible for the angiogenic properties of the matrix, the silver nanoparticles could increment the angiogenic properties of NRL. This biomaterial has desirable properties for the fabrication of a wound dressing with potential healing action, since it combines the angiogenic and antibacterial properties of the silver nanoparticles with the increased angiogenic properties of the NRL.Graphical AbstractThe AgNP attached to the cis-isoprene molecules remain in the NRL matrix and only the AgNP bound to the non-rubber molecules (NRL serum fraction) are released. The released AgNP are sterically

  20. About the cure kinetics in natural rubber/styrene Butadiene rubber blends at 433 K

    Energy Technology Data Exchange (ETDEWEB)

    Mansilla, M.A., E-mail: mmansilla@df.uba.ar [Laboratorio de Polimeros y Materiales Compuestos, Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellon 1, C1428EGA Buenos Aires (Argentina); Marzocca, A.J. [Laboratorio de Polimeros y Materiales Compuestos, Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellon 1, C1428EGA Buenos Aires (Argentina)

    2012-08-15

    Vulcanized blends of elastomers are employed in several goods mainly to improve physical properties and reduce costs. One of the most used blends of this kind is that composed by natural rubber (NR) and styrene butadiene rubber (SBR). The cure kinetic of these blends depends mainly on the compound formulation and the cure temperature and time. The preparation method of the blends can influence the mechanical properties of the vulcanized compounds. In this work the cure kinetic at 433 K of NR/SBR blends vulcanized with the system sulfur/TBBS (N-t-butyl-2-benzothiazole sulfenamide) is analyzed in samples prepared by mechanical mixing and solution blending. The two methods produce elastomer domains of NR and SBR, which present different microstructure due to the cure level attained during vulcanization. The cure kinetics is studied by means of rheometer tests and the model proposed by Kamal and Sourour. The analysis of the cure rate is presented and is related to the structure obtained during the vulcanization process.

  1. STUDY ON THE PROPERTIES OF BLEND OF NATURAL RUBBER LATEX/METHYL METHACRYLATE GRAFTED RUBBER LATEX BY GAMMA RADIATION

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Natural rubber latex (NRL) and methyl methacrylate (MMA) grafted rubber latex were blended in different ratios and irradiated at various absorbed doses by gamma rays from Co-60 source at room temperature.The tensile properties,swelling ratio and permanent set were measured.The maximum tensile strength and modulus at 500% elongation were obtained at an absorbed dose of 8 kGy.Modulus increases from 6.99 Mpa to 9.87 Mpa for an increase in proportion of MMA grafted rubber from 40% to 60% in the blend at similar absorbed dose.Elongation at break and swelling ratio decrease with increasing absorbed dose as well as the MMA grafted rubber content in the blends.The decreasing trend of permanent set is high up to 5 kGy absorbed dose, and beyond that dose,it becomes almost flat.

  2. Radiation dose required for the vulcanization of natural rubber latex

    International Nuclear Information System (INIS)

    The radiation dose required for the vulcanization of natural rubber latex was optimized. To enhance the crosslinking, several sensitizers were used. Among the sensitizers, n-butyl acrylate (n-BA) alone was found to be the best one. The effects of concentration of n-BA, mixing and standing time of latex with n-BA on the tensile properties of latex film were investigated. 12 kGy radiation dose, 5 phr n-BA and 30-40 min of mixing time were found to be the optimum conditions for irradiation. (author)

  3. Toughening Effect of Strain-Induced Crystallites in Natural Rubber

    Science.gov (United States)

    Zhang, H. P.; Niemczura, J.; Dennis, G.; Ravi-Chandar, K.; Marder, M.

    2009-06-01

    We study fracture propagation in stretched natural rubber sheets. Experimental results in specimens stretched less than 3.8 times show a monotonic increase in the crack speed with stretch and can be explained by a numerical model based on neo-Hookean theory and Kelvin dissipation. In specimens stretched more than 3.8 times, strain-induced crystallites act as reinforcing and toughening fillers and significantly increase fracture resistance, like nanostructures in other polymeric or biological materials. Consequently, as we increase the amount of stretch, fractures travel slower and slower, and eventually halt altogether.

  4. Preparation of highly stabilised natural rubber latex for radiation vulcanisation

    International Nuclear Information System (INIS)

    There is a bright future for radiation vulcanised natural rubber latex (RVNRL) but there are problems in manufacturing it as the centrifuged latex to be used for radiation has to be kept for at least a month or sometimes even three to six months before adding the sensitisers and even then the latex sometimes coagulates on adding the sensitisers. This paper describes a process by which the latex can be stabilised by addition of an anionic soap before centrifuging so that it has a high mechanical stability and hence can be used even within one week of the manufacture of the centrifuged latex

  5. Properties of Natural Rubber-Based Composites Containing Fullerene

    Directory of Open Access Journals (Sweden)

    Omar A. Al-Hartomy

    2012-01-01

    Full Text Available In this study the influence of fullerenes in concentrations from 0.5 to 1.5 phr on both the vulcanization characteristics of the compounds and physicomechanical, dynamic, and dielectric properties and thermal aging resistance of nanocomposites on the basis of natural rubber has been investigated. The effect of the filler dispersion in the elastomeric matrix has been also investigated. Neat fullerene and the composites comprising it have been studied and characterized by scanning electron microscopy (SEM and transmission electron microscopy (TEM.

  6. Radiation vulcanization of natural rubber latex with low energy accelerator

    International Nuclear Information System (INIS)

    The radiation vulcanization of natural rubber latex (RVNRL) with the recently installed electron beam (EB) pilot plant at Takasaki Radiation Chemistry Research Establishment, Takasaki, Japan has been discussed. The accelerating voltage and beam current of the plant are 250 kV and 10 mA respectively. The plant has a reaction vessel with the capacity of 18 liters latex to irradiate at a time. In order to obtain a suitable setting of experimental for RVNRL under EB of the plant the parameters such as irradiation time, defoamer concentration, volume of latex, beam current etc. are being optimized by varying the individual parameter at a constant set of the other variables. (author)

  7. Study on radiation vulcanization of natural rubber latex

    Institute of Scientific and Technical Information of China (English)

    ZhuNan-Kang; MakuuchiK; 等

    1997-01-01

    The effect of dose rate of 60Co γ-ray on radiation vulacnization of natural rubber latex is studied using Malysian latex with 0.002 mass fraction KOH and 0.05 mass fraction n-BA.Results show that,when radiation doses are 20 and 15kGy,only that the dose rates are greater than 0.49 and 1.6 kGY/h,respectively can make the tensile strength of latex film meet the related standard;besides,storage time of radiation vulcanization latex has no effect on physical properties of the film.

  8. Compatibilization of natural rubber (NR and chlorosulfonated polyethylene (CSM blends with zinc salts of sulfonated natural rubber

    Directory of Open Access Journals (Sweden)

    Kwanruethai Boonsong

    2008-07-01

    Full Text Available A rubbery ionomer of zinc salt of sulfonated natural rubbers (Zn-SNR was synthesized and used as a new compatibilizerfor the blends of natural rubber (NR and chlorosulfonated polyethylene (CSM. Epoxidized natural rubber (ENRwas also used for the preparation of NR/CSM blends. The effect of ionomer concentration on melt viscosity of the 50/50(%wt/wt NR/CSM blends at different constant shear rates was characterized. It was found that the incorporation of ionomerincreased shear viscosity of the blends, indicating an increase in interfacial interaction between the NR and CSM. Themaximum shear viscosity was observed when the ionomer of 10% by weight of NR was added into the blends. The tensile,tear, oil resistant properties and morphology of the various 20/80 NR/CSM blends with and without the Zn-SNR and ENR atthe 10% wt of NR were examined. The 100% modulus, tensile strength, tear strength and oil resistance of the compatibilizedblends improved over those of the uncompatibilized blends. The blends compatibilized with the Zn-SNR showed higher levelsof improvement in modulus, tensile and tear strength than those of ENR. The tensile strength of 20/80 blends with the Zn-SNRand ENR compatibilizers increased by 38 and 30% over the corresponding neat blends. Furthermore, the addition of ionomerand ENR resulted in decreased domain of dispersed NR phase size and improved interfacial adhesion between the NR andCSM, indicating enhanced blend compatibility. These results suggest that the Zn-SNR is a new effective compatibilizer forNR and CSM blends.

  9. Effect of Spray Drying on Protein Content of Natural Rubber Serum (NRS)

    OpenAIRE

    I. Aimi Izyana and M.N. Zairossani

    2011-01-01

    Natural rubber latex comprises approximately 70% natural rubber serum (NRS) which is the aqueous part of the latex. The NRS is made up of mainly water and non-rubber components; sugar, protein and other lipids. The protein component of the NRS is separated using membrane separation and spray dried whereby the amino acid and protein content was monitored during the process. The optimum drying temperatures were first determined to obtain the maximum recovery of the protein powder, whereby the a...

  10. Curing characteristics of chlorosulphonated polyethylene and natural rubber blends

    Directory of Open Access Journals (Sweden)

    M. MARINOVIC-CINCOVIC

    2005-05-01

    Full Text Available The dependence of the Mooney scorch time and cure index on the blend ratio of chlorosulphonated polyethylene/natural rubber (CSM/SMR 20 CV and chlorosulphonated polyethylene/chlorinated natural rubber (CSM/Pergut S 40 blends were determined in the temperature range from 120 oC to 160 oC using a Monsanto Mooney viscometer. Semi-efficient vulcanization systems were used for the study. The morphology of the fracture surface of the crosslinked systems was determined by Scanning Electron Microscopy (SEM. The results showed that the scorch time decreased with increasing SMR 20 CV and Pergut S 40 contents. This observation is attributed to the increasing solubility of sulfur, as the content of SMR 20 CV and Pergut S 40 in the composition increased. For temperatures greater than 140 oC, the dependence of the scorch time on blend ratios diminishes, as enough thermal energy is available to overcome the activation energy of vulcanization. The differing curing characteristics of the two blends is explained by the compatibility factor of the respective blend. Morphological analysis of the blends shows a very satisfactory agreement.

  11. Naturally occurring amino acid: Novel curatives for chloroprene rubber

    NARCIS (Netherlands)

    Das, A.; Naskar, N.; Datta, R.N.; Bose, P.P.; Debnath, S.C.

    2006-01-01

    Polychloroprene is a diene rubber, but unlike other diene rubbers, its compounding with various additives and curing mechanisms is different. A derivative of thiourea, ethylene thiourea (ETU), is widely used to vulcanize chloroprene rubber (CR), and the vulcanizates thus obtained exhibit excellent m

  12. 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. PMID:27337545

  13. Flow properties of natural rubber composites filled with defatted soy flour

    Science.gov (United States)

    The linear and nonlinear viscoelastic properties of natural rubber composites reinforced with defatted soy flour were studied. Defatted soy flour is an abundant, renewable commodity, and its rigid nature makes it suitable as a reinforcement phase in rubber composites. At small strain, the elastic ...

  14. Toughening mystery of natural rubber deciphered by double network incorporating hierarchical structures

    Science.gov (United States)

    Zhou, Weiming; Li, Xiangyang; Lu, Jie; Huang, Ningdong; Chen, Liang; Qi, Zeming; Li, Liangbin; Liang, Haiyi

    2014-12-01

    As an indispensible material for modern society, natural rubber possesses peerless mechanical properties such as strength and toughness over its artificial analogues, which remains a mystery. Intensive experimental and theoretical investigations have revealed the self-enhancement of natural rubber due to strain-induced crystallization. However a rigorous model on the self-enhancement, elucidating natural rubber's extraordinary mechanical properties, is obscured by deficient understanding of the local hierarchical structure under strain. With spatially resolved synchrotron radiation micro-beam scanning X-ray diffraction we discover weak oscillation in distributions of strain-induced crystallinity around crack tip for stretched natural rubber film, demonstrating a soft-hard double network structure. The fracture energy enhancement factor obtained by utilizing the double network model indicates an enhancement of toughness by 3 orders. It's proposed that upon stretching spontaneously developed double network structures integrating hierarchy at multi length-scale in natural rubber play an essential role in its remarkable mechanical performance.

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

    OpenAIRE

    Bryan B. Pajarito; Christia Angeline de Torres; Marienne Maningding

    2014-01-01

    Surface migration kinetics of chemical additives in vulcanized natural rubber compounds were studied as function of ingredient loading. Rubber sheets were compounded according to a 212-8 fractional factorial design of experiment, where ingredients were treated as factors varied at two levels of loading. Amount of migrated additives in surface of rubber sheets was monitored through time at ambient conditions. The maximum amount and estimated rate of additive migration were determined from weig...

  16. Reinforcement of natural rubber by precipitated silica: the influence of processing temperature

    OpenAIRE

    Sarkawi, S.S.; Dierkes, W.K.; Noordermeer, J.W.M.

    2012-01-01

    The thermal history and in particular the mixing dump temperature is a parameter of paramount importance in mixing rubber and silica with a silane coupling agent in order to achieve proper silanization of silica and to avoid premature scorch reactions. In this work, the influence of mixing dump temperature on the performance of silica reinforced Natural Rubber (NR) is investigated. The investigation also includes the effect of non-rubber constituents, primarily proteins in NR, by using deprot...

  17. A natural rubber drainage tube with antithrombogenic lumen surface.

    Science.gov (United States)

    Klöcking, H P; Schunk, W; Merkmann, G; Giessmann, C; Knoll, H; Borgmann, S

    1993-12-15

    A drainage tube was made by radiation vulcanization of a high polymeric substance based on natural rubber elastomers. Pentosan polysulphate sodium bound to a carrier substance (synthetic type 4A or 13X zeolite) was incorporated in the drainage tube which was then tested for its anticoagulant properties during perfusion with Tris buffer solution, citrated plasma, and blood, resp. The amount of pentosan polysulphate sodium released from the tube walls during perfusion with human citrated plasma in an open circulatory system was sufficient to exert an anticoagulant effect on the streaming plasma. This effect was corroborated by prolonged thrombin times and by unclottability in case of recalcified plasma samples in thrombelastographic studies. The antithrombogenicity test according to Chandler in a closed circulatory system revealed thrombus formation times (TFT) of more than 24 h (control: TFT = 1-3 min in native blood). PMID:7510427

  18. Extractable protein content of radiation vulcanized natural rubber latex films

    International Nuclear Information System (INIS)

    The effects of processing conditions on extractable protein content of coagulant dipped radiation vulcanized natural rubber latex films have been investigated. Drying of wet-gel of radiation vulcanized latex films even at a relatively low temperature of 70 degree C resulted in increases of extractable protein content of the films. The extractable protein content is dependent upon both the temperature and time of drying of wet-gel deposit. Wet-gel leaching of film alone is not adequate to reduce the extractable protein content of films to low levels. Combination of wet-gel leaching, post-leaching, a dip in corn starch slurry, followed by drying at a low temperature of 70 degree C reduces the extractable protein content of films to very low levels

  19. Investigative methods for natural rubber latex allergy in the UK.

    Science.gov (United States)

    Lowe, J G; Green, C M; Nasser, S M

    2005-01-01

    Allergy to natural rubber latex (NRL) has become an important health issue in recent years, but little is known about how this condition is investigated by physicians in the UK. This postal questionnaire of British dermatology and allergy specialists shows substantial variation in diagnostic practice, most notably with regard to the utilization and choice of starting dose of commercial latex prick test dilutions, reliance on allergen-specific immunoglobulin E measurement, investigation of associated fruit allergy and provision of resuscitation equipment/method of consent when challenge testing. 17% of responding physicians who investigate for NRL allergy do not perform prick test or glove challenge because of the potential risk of anaphylaxis or lack of resuscitation facilities. 87% of allergy clinic specialists report no reduction in the number of patients presenting as new referrals with suspected NRL allergy. These findings suggest a need for robust guidance to achieve more consistent investigative practice by those dealing with this condition. PMID:15701123

  20. Stabilization of radiation vulcanized natural rubber latex film

    International Nuclear Information System (INIS)

    Radiation vulcanized natural rubber latex (RVNRL) film has poor aging characteristics especially after it has been subject to leaching. The effect of the addition of antioxidants on the aging properties of RVNRL obtained using carbon tetrachloride and n-butyl acrylate (n-BA) as sensitizers respectively were evaluated. Antioxidant 2'2'-methylene-bis-(4-methyl-6-tert-butylphenol) containing 0.8 phr was found to be the most effective for RVNRL produced by using CCl4 as sensitizer and antioxidant 2,4-Bis[(octylthio)methyl]-o-cresol containing 1.0 phr for RVNRL produced by using n-BA as sensitizer. Antioxidant 2-mercaptobenzimidazole showed slightly less effective but gave less tendency for discolouration compared to 2.4-Bis[(octylthio)methyl]-o-cresol when used in the n-BA system. (author)

  1. 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.

  2. Investigation of Swelling and Dissolution Process of Natural Rubber in Aromatic Oil

    Institute of Scientific and Technical Information of China (English)

    Wang Feng; Kuang Minming; Li Guanlong; Zhou Xiaolong; Li Chenglie

    2015-01-01

    Aromatic oil has been used to promote the properties of crumb rubber modiifed asphalt which is an ideal method to deal with the resource utilization of waste rubber tires and by-product of reifnery. Furfural extract oil (FEO) was sepa-rated into the light fraction and the heavy fraction. Swelling and dissolution process of natural rubber sheet in these three oil samples was investigated to shed light on the interaction mechanism. Crumb rubber also interacted on FEO and asphalt respectively. Energy dispersive spectrometer (EDS), thermo-gravimetric analysis (TGA) and scanning electron microscope (SEM) were used to characterize the chemical and structural properties of processed rubber. The chemical composition of processed oils and asphalt was investigated by using the hydrocarbon group analysis (SARA) and gel permeation chroma-tography. The results revealed that the swelling rate and mass loss of rubber in oils were much higher than those in asphalt and rose with an increasing processing temperature. The heavy fraction of FEO had more diffusion and dissolving capabil-ity than the light fraction, whilst compatibility was observed between the heavy fraction and the light fraction. Selective ab-sorption was not observed in the study and detachment of dissolved rubber was disseminated from the outside to the inside. The cross-linking degree of the residue rubber was unchanged with the processing time, and sulfur predominantly remained in the undissolved rubber. Dissolution of crumbed rubber in oils was attributed to devulcanization, while that in the asphalt was mainly attributed to depolymerization.

  3. Occupational asthma and rhinoconjunctivitis induced by natural rubber latex exposure.

    Science.gov (United States)

    Fish, James E

    2002-08-01

    A number of reports indicate that occupational exposure to natural rubber latex (NRL) in health care workers can elicit symptoms of rhinoconjunctivitis with or without asthma in selected individuals who are sensitized. The prevalence or risk of NRL-induced asthma in relation to rhinoconjunctivitis is small in comparison with other forms of occupational allergic respiratory disease. The lower risk of NRL-induced asthma appears to be related to poor penetration of the allergen into the lower respiratory tract because of the relatively large particle size of allergen-bearing cornstarch particles. Because of a lack of large prospective studies, little is know about the incidence and natural history of latex-induced respiratory disease. Because of heightened awareness of NRL allergy and changing patterns in glove manufacturing and glove use, it is likely that the occurrence of NRL-induced occupational respiratory disease will decline and its natural history will change. Nevertheless, because large number of individuals are exposed to NRL in various occupations, the incidence, prevalence, and natural history of NRL allergy merit further monitoring. PMID:12170247

  4. Influence of protein hydrolysis on the mechanical properties of natural rubber composites reinforced with soy protein particles

    Science.gov (United States)

    For natural rubber applications, the reinforcing fillers are used to improve the mechanical properties of the rubber. Soy protein particles have been shown to reinforce natural rubber. The hydrolysis conditions of soy protein are studied to understand its effect on the particle size and size distrib...

  5. From certification outcomes to certification processes: Demand, supply and adoption of eco certification along the natural rubber supply chain

    OpenAIRE

    Kennedy, Sean F.

    2014-01-01

    In recent years, issues associated with natural rubber production have gained visibility and a number of industry stakeholders across a range of rubber submarkets have started to adopt forms of eco-certification and labeling in response to a growing market for certified rubber products. While encouraging, the disparate nature of rubber certification efforts across an already highly fragmented industry makes it difficult to determine the alignment between claims to address environmental and so...

  6. Synthesis, characterization and degradation behavior of admicelled polyacrylate-natural rubber

    International Nuclear Information System (INIS)

    In order to improve weatherability of the cured natural rubber, the novel introduction of good ozone resistant polymers such as polyacrylates (poly(methyl acrylate) (PMA) or poly(methyl methacrylate) (PMMA)) into natural rubber (NR) by admicellar polymerization was investigated in this work. The admicellar polymerization to synthesize polyacrylate layer over the surface of NR latex particles was performed with varying monomer type (PMA and PMMA) and content (50 and 100 mM). The admicelled PMMA showed higher molecular weight than PMA. Fourier transform infrared spectra of the admicellar synthesized natural rubbers exhibited characteristic peaks of those polyacrylates. Micrographs from transmission electron and field emission scanning electron microscopes (FE-SEM) revealed the coatings of PMA and PMMA over the rubber particles, suggesting a core-shell structure. Thermogravimetric analysis revealed that the admicelled rubbers not only showed an improvement in heat stability but also a single decomposition temperature. After vulcanization, FE-SEM results showed the cured admicelled rubbers had phase transformation from core-shell to phase separation (aggregate domains of polyacrylate-rich phase) with smooth interface. This agreed well to their one glass transition temperature (∼−48 °C) which indicated good miscibility between NR and each polyacrylate. The cracks generated after exposure to ozone found in the admicelled rubbers were smaller than those in NR, suggesting better ozone resistance was achieved. Increasing monomer concentration led to less cracks or much better ozone resistance. Furthermore, changes in mechanical properties after ozone exposure of the admicelled PMA-NR were less than those of the admicelled PMMA-NR (having the same shell content) and the NR, respectively. - Highlights: • We use admicellar technique to add polyacrylates to NR in form of core-shell rubber. • This core-shell structure was physically formed as seen by the phase

  7. Synthesis, characterization and degradation behavior of admicelled polyacrylate-natural rubber

    Energy Technology Data Exchange (ETDEWEB)

    Pongpilaipruet, Angkana; Magaraphan, Rathanawan, E-mail: rathanawan.k@chula.ac.th

    2015-06-15

    In order to improve weatherability of the cured natural rubber, the novel introduction of good ozone resistant polymers such as polyacrylates (poly(methyl acrylate) (PMA) or poly(methyl methacrylate) (PMMA)) into natural rubber (NR) by admicellar polymerization was investigated in this work. The admicellar polymerization to synthesize polyacrylate layer over the surface of NR latex particles was performed with varying monomer type (PMA and PMMA) and content (50 and 100 mM). The admicelled PMMA showed higher molecular weight than PMA. Fourier transform infrared spectra of the admicellar synthesized natural rubbers exhibited characteristic peaks of those polyacrylates. Micrographs from transmission electron and field emission scanning electron microscopes (FE-SEM) revealed the coatings of PMA and PMMA over the rubber particles, suggesting a core-shell structure. Thermogravimetric analysis revealed that the admicelled rubbers not only showed an improvement in heat stability but also a single decomposition temperature. After vulcanization, FE-SEM results showed the cured admicelled rubbers had phase transformation from core-shell to phase separation (aggregate domains of polyacrylate-rich phase) with smooth interface. This agreed well to their one glass transition temperature (∼−48 °C) which indicated good miscibility between NR and each polyacrylate. The cracks generated after exposure to ozone found in the admicelled rubbers were smaller than those in NR, suggesting better ozone resistance was achieved. Increasing monomer concentration led to less cracks or much better ozone resistance. Furthermore, changes in mechanical properties after ozone exposure of the admicelled PMA-NR were less than those of the admicelled PMMA-NR (having the same shell content) and the NR, respectively. - Highlights: • We use admicellar technique to add polyacrylates to NR in form of core-shell rubber. • This core-shell structure was physically formed as seen by the phase

  8. Hydrogenation of liquid natural rubber via diimide reduction in hydrazine hydrate/hydrogen peroxide system

    International Nuclear Information System (INIS)

    Liquid natural rubber (LNR) with molecular weight of lower than 105 and shorter polymeric chain than natural rubber was prepared. LNR was then hydrogenated via diimide reduction by oxidation of hydrazine hydrate with hydrogen peroxide. The unsaturated units of the rubber were converted into saturated hydrocarbon to strengthen the backbone of the polymer so it was able to resist thermal degradation. The results indicated that hydrogenation degree of the product (HLNR) could be extended to 91.2% conversion under appropriate conditions. The hydrogenated LNR (HLNR) was characterized using Fourier-Transform Infrared (FTIR) and Nuclear Magnetic Resonance (NMR) spectroscopy. The physical characteristics of HLNR were analyzed with Termogravimetric Analysis (TGA)

  9. Hydrogenation of liquid natural rubber via diimide reduction in hydrazine hydrate/hydrogen peroxide system

    Energy Technology Data Exchange (ETDEWEB)

    Yusof, Muhammad Jefri Mohd; Jamaluddin, Naharullah; Abdullah, Ibrahim; Yusoff, Siti Fairus M. [School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia)

    2015-09-25

    Liquid natural rubber (LNR) with molecular weight of lower than 10{sup 5} and shorter polymeric chain than natural rubber was prepared. LNR was then hydrogenated via diimide reduction by oxidation of hydrazine hydrate with hydrogen peroxide. The unsaturated units of the rubber were converted into saturated hydrocarbon to strengthen the backbone of the polymer so it was able to resist thermal degradation. The results indicated that hydrogenation degree of the product (HLNR) could be extended to 91.2% conversion under appropriate conditions. The hydrogenated LNR (HLNR) was characterized using Fourier-Transform Infrared (FTIR) and Nuclear Magnetic Resonance (NMR) spectroscopy. The physical characteristics of HLNR were analyzed with Termogravimetric Analysis (TGA)

  10. Technology development of natural rubber latex products by radiation

    International Nuclear Information System (INIS)

    Development of radiation vulcanized natural rubber latex (RVNRL) was conducted to produce 2-3 tons of RVNRL per batch. The sensitizer used was 5 phr of 2 ethylhexyl acrylate and 1 phr of CCl4 which required vulcanization dose of 15 kGy. Irradiation vessel was thin stainless steel box of 15 cm width with capacity of 180 l. Two boxes could fill into one carrier of gamma irradiator at Thai irradiation Center (TIC). Once thorough irradiation could produce 3200 l of RVNRL per batch. Average dose rate, determined by nylon thin film at 21 points in the tank was 0.83 kGy/hr with over dose ratio of 1.4. The RVNRL was successfully made to exam gloves at a glove manufacturing factory by coagulant dipping. Optimum condition of the dipping were: TSC 50-52%, partial dry at 900C after dipping of dwell time 50 seconds, dried after beading at 700C and heated to full vulcanized at 1100C. The RVNRL was also successfully made to thick wall products such as baby nipple by heat sensitive dipping using 1.8% of polyvinyl methyl ether in the latex

  11. Natural rubber latex allergy after 12 years: recommendations and perspectives.

    Science.gov (United States)

    Charous, B Lauren; Blanco, Carlos; Tarlo, Susan; Hamilton, Robert G; Baur, Xaver; Beezhold, Donald; Sussman, Gordon; Yunginger, John W

    2002-01-01

    Natural rubber latex (NRL) allergy is a "new" illness whose prevalence reached epidemic proportions in highly exposed populations during the last decade. In children with spina bifida and in patients exposed to NRL during radiologic procedures, institution of prophylactic safety measures has had demonstrable effects in preventing allergic reactions. The risk of NRL allergy appears to be largely linked to occupational exposure, and NRL-associated occupational asthma is due almost solely to powdered latex glove use. Prevalence of NRL-allergic sensitization in the general population is quite low; several studies of young adults demonstrate rates of positive skin test results that are less than 1%. After occupational exposure, rates of sensitization and NRL-induced asthma rise dramatically in individuals using powdered NRL gloves but not in individuals using powder-free gloves. Airborne NRL is dependent on the use of powdered NRL gloves; conversion to non-NRL or nonpowdered NRL substitutes results in predictable rapid disappearance of detectable levels of aeroallergen. For these reasons, adoption of the following institutional policies designed to prevent new cases of NRL allergy and maximize safety is recommended: (1) NRL gloves should be used only as mandated by accepted Standard Precautions; (2) only nonpowdered, nonsterile NRL gloves should be used; and (3) nonpowdered, sterile NRL gloves are preferred for use. Low-protein powdered, sterile gloves may be used, but only in conjunction with an ongoing assessment for development of allergic reactions. PMID:11799362

  12. On the release of metronidazole from natural rubber latex membranes

    International Nuclear Information System (INIS)

    The controlled release of drugs can be efficient if a suitable encapsulation procedure is developed, which requires biocompatible materials to hold and release the drug. In this study, a natural rubber latex (NRL) membrane is used to deliver metronidazole (MET), a powerful antiprotozoal agent. MET was found to be adsorbed on the NRL membrane, with little or no incorporation into the membrane bulk, according to energy dispersive X-ray spectroscopy. X-ray diffraction and FTIR spectroscopy data indicated that MET retained its structural and spectroscopic properties upon encapsulation in the NRL membrane, with no molecular-level interaction that could alter the antibacterial activity of MET. More importantly, the release time of MET in a NRL membrane in vitro was increased from the typical 6-8 h for oral tablets or injections to ca. 100 h. The kinetics of the drug release could be fitted with a double exponential function, with two characteristic times of 3.6 and 29.9 h. This is a demonstration that the induced angiogenesis known to be provided by NRL membranes can be combined with a controlled release of drugs, whose kinetics can be tailored by modifying experimental conditions of membrane fabrication for specific applications.

  13. Natural Rubber Based Fuel Rich Propellant for Ramjet Rocket

    Directory of Open Access Journals (Sweden)

    Solomon Thomas

    1992-07-01

    Full Text Available Development of fuel rich propellants for air-breathing propulsion is one of the frontier areas of research. This carries less oxidiser than the normal propellants, uses ram air for complete combustion and is heavily metallised. Studies were conducted at VSSC for the development of hydroxyl-terminated natural rubber (HTNR-based Mg and Mg-Al alloy-filled polyurethane systems. The HTNR prepolymer was modified to make it free of acid functionality so as to avoid reaction with the metals and was then reacted with calculated amount of propylene oxide in the presence of tertiary amine catalyst at room temperature. Various levels of Mg and Mg-Al alloy were used in different compositions and the effect on propellant characteristics was studied. TMP and butane diol were used for higher crosslinking, chain extension, etc and their effects were evaluated. Propellant compositions using 30-35 per cent by weight of Mg/Mg-Al alloy with the modified prepolymer have been developed. They exhibit good processibility and mechanical properties. The feasibility of room temperature curing was attempted. Motors weighing 2 kg with 100 mm OD and 200 mm length were successfully static-tested in the primary mode for performance evaluation.

  14. The Rheological Behavior of Natural Rubber Modified by Admicellar Polymerization Technique of Styrene

    Science.gov (United States)

    Isahoh, Saman; Magaraphan, Rathanawan

    2007-03-01

    The combination with appropriate polymer component is the one way to improve the mechanical properties and processability of polymer according to gain the industrial importance. The admicellar polymerization is a fine-coating technique to form the ultrathin polymer films on charged surface of another polymer that could be possible to improve its mechanical properties^1. In this work, the thin polystyrene films are used to coat on natural rubber particles to improve its modulus and impact strength. The study of optimum condition regarding types of surfactant and initiator and amount ratio of monomer/initiator was completed. The thermal analysis, physical properties and rheological behavior of natural rubber modified with 50-mM, 100-mM, 200-mM and 300-mM styrene were also investigated. It was found that the higher contents of polystyrene modified in natural rubber show natural rubber with more plastic.

  15. Evaluation of natural rubber from IAC series clones by solid state 13C NMR

    International Nuclear Information System (INIS)

    Agronomic Institute (IAC) and EMBRAPA Agricultural Instrumentation (EMBRAPA/CNPDIA) have been studied Hevea species in order to increase the production of the natural rubber and to develop new clones more appropriated to Brazil's soil and climate. Structural characterization of natural rubber [Hevea brasiliensis (Willd. ex Adr. de Juss.) Muell. - Arg.] from new clones of the IAC series (IAC 300, 301, 302, 303, 35, 40, and 56) and from RRIM 600 clone has been studied by high-resolution solid-state 13C NMR and by single pulse technique. The results have shown that the application of solid-state 13C NMR using the single pulse technique is a powerful tool to study natural rubber. The spectra obtained through this technique confirmed that natural rubber from all clones studied are cis-1,4-polyisoprene (author) form.(author)

  16. Study on preparation of new antioxidants for radiation vulcanized natural rubber latex product. Antioxidant from keratin

    International Nuclear Information System (INIS)

    The thermo-oxidative aging resistance of radiation vulcanization of natural rubber latex (RVNRL) products should be adequately by using suitable antioxidants or new kind of effective antioxidant. This work presents the results of preparation of natural antioxidant from hair keratin. Characteristics and effectiveness of resultant antioxidant are also presented. The results obtained indicates that antioxidant made from hair keratin is safe and effective for rubber products from RVNRL. (author)

  17. Studies on Microbial Degradation of Natural Rubber Using Dilute Solution Viscosity Measurement and Weight Loss Techniques

    Directory of Open Access Journals (Sweden)

    G. N. Onyeagoro

    2012-10-01

    Full Text Available Reduction of molecular weight of rubber polymers for easy absorption of compounding ingredients is critical in every rubber compounding operation. Yet, rubber mastication which is the current practice of achieving this is expensive, requiring high energy and equipment cost. To address this problem, microbial degradation of natural rubber (NR and waste rubber tire (WRT by Nocardia sp. strain 385A was studied using dilute solution viscosity measurement and weight loss methods. Solutions of NR and WRT in toluene were inoculated with the microbes (Nocardia sp. strain 385A and kept in incubator. Incubation period varied between 0 to 10 weeks. The results obtained show that NR and WRT were mineralized and degraded by the microbes. Intrinsic viscosity values of both NR and WRT decreased with increasing period of incubation, indicating that degradation increases with increase in the incubation period. For the incubation periods investigated, WRT produced higher intrinsic viscosity values than NR due to the inhibitory effect of additives present in WRT to microbial degradation. Equivalent reduction in molecular weight obtained by rubber mastication technique was achieved by microbial degradation after 10 weeks incubation period. Rubber degrading bacteria can be useful for the disposal of discarded rubber products.

  18. Development of condom and gloves from radiation vulcanized natural rubber latex

    International Nuclear Information System (INIS)

    Study on radiation vulcanisation of natural rubber (NR) had been carried out since early of 1970. The positive result guided it to the establishment of a latex irradiator in 1983. This installation was designed for studying the economic aspect of radiation vulcanised of natural rubber latex (RVNRL), as well as for training and demonstration. After years of experiences in using that installation, it appeared that a lot of improvement should be done before transfering that technology to industry. Further development being done and a significant success has been achieved: characteristic of NR latex, antioxidant for RVNRL, new sensitizer, and cost analysis of RVNRL. A combination of n-BA and CCl4 or n-BA alone showing a promising new sensitizer, which will be able in reducing the irradiation cost of NR latex. In order to introduce this technology to rubber gloves industry, a study of producing rubber gloves from RVNRL, a survey of the consumption of rubber gloves by the Hospital in Indonesia, and personal contact with rubber gloves industries have been done. The physical properties of rubber gloves prepared from RVNRL was reported to meet the Indonesian Standard of Industry. A comparison study with conventional sulfur vulcanisation has been done using the same of NR latex. According to the survey, the consumption of rubber gloves in the Hospital throughout Indonesia was about 3.5 million pairs, in with each pair was used for several times. A number of new rubber gloves companies which was established in this year (1989) was directed to meet the world consumption of examination rubber gloves. The total estimated capacity was about 1000 million/year. Several of those companies having a formal co-operation with BATAN in the development of the application of RVNRL. (author)

  19. Thermal analysis and microstructure of hexaperrite based magnet composite with natural rubber matrix

    International Nuclear Information System (INIS)

    Thermal and microstructure analyse of hexa ferrite based on composite magnets with natural rubber matrix have been done to investigate their performance. Such magnets play an important role in the toy and house-hold industries because of their suitable magnetic properties, low cost, lightness and flexibility. The composite magnets were synthesized by blending the ferrite powder and natural rubber at composition 30%-70% rubber volume. The microstructure and thermal behaviour of the composite were examined by using SEM and OTA/TGA. The result show that the natural rubber swelling is optimally at 181,17 oC, which is the recommended top condition for blending. The performance magnet composite is limited by the change of natural rubber properties which decompose at temperature around 400 oC. In the decomposition process, the natural rubber molecule trapped in a composite system based on BaM is more difficult are more compared to the composite system based on SrM because the BaM system particle microstructure and its distribution more homogeneous

  20. 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.

  1. Fatigue effect of elastocaloric properties in natural rubber.

    Science.gov (United States)

    Sebald, Gael; Xie, Zhongjian; Guyomar, Daniel

    2016-08-13

    In the framework of elastocaloric (eC) refrigeration, the fatigue effect on the eC effect of natural rubber (NR) is investigated. Repetitive deformation cycles at engineering strain regime from 1 to 6 results in a rapid rupture (approx. 800 cycles). Degradation of properties and fatigue life are then investigated at three different strain regimes with the same strain amplitude: before onset strain of strain-induced crystallization (SIC) (strain regime of 0-3), onset strain of melting (strain regime of 2-5) and high strain of SIC (strain regime of 4-7). Strain of 0-3 leads to a low eC effect and cracking after 2000 cycles. Strain of 2-5 and 4-7 results in an excellent crack growth resistance and much higher eC effect with adiabatic temperature changes of 3.5 K and 4.2 K, respectively, thanks to the effect of SIC. The eC stress coefficient index γ (ratio between eC temperature change and applied stress) for strains of 2-5 and 4-7 are γ2-5=4.4 K MPa(-1) and γ4-7=1.6 K MPa(-1), respectively, demonstrating the advantage of the strain regime 2-5. Finally, a high-cycle test up to 1.7×10(5) cycles is successfully applied to the NR sample with very little degradation of eC properties, constituting an important step towards cooling applications.This article is part of the themed issue 'Taking the temperature of phase transitions in cool materials'. PMID:27402933

  2. Degradation of non-vulcanized natural rubber - renewable resource for fine chemicals used in polymer synthesis

    Directory of Open Access Journals (Sweden)

    Alexander Fainleib

    2013-01-01

    Full Text Available In the current scenario, there is growing interest in the products of degradation of rubber (natural and synthetic for specific applications in different industry sectors, whose benefits in replacing conventionally used products are mainly related to sustainability. Since the degradation products of rubber can be used in different areas, several research groups may have the interest aroused by these products, but are not familiar with the aspects related to the chemical behavior of rubber. This review aims to bring together the key information in the published literature on the degradation of natural rubber, emphasizing metatheses reactions, oxidative damage and splitting of the double bond, in order to serve as a reference source for researchers from different fields interested in obtaining such kind of products. The structures and properties as well as additional chemical transformations resulting in oligomers of isoprene, functionalised oligomers and polymers based on both are also described.

  3. Effect of urea addition on the radiation vulcanisation of natural rubber latex

    International Nuclear Information System (INIS)

    Acrylate monomers have been in recent years to reduce the radiation dose required to vulcanise natural rubber latex, originally 300 kGy to 15 kGy. However, there is still a need to further reduce the dose requirement without increasing the sensitiser concentration. In the present study, the synergistic effect of addition of urea along with the sensitiser n-butyl acrylate (n-BA) on the crosslinking density and mechanical properties of radiation vulcanised natural rubber (RVNRL) film has been investigated. The results show that by addition of 0.2 part hundred rubber (phr) urea to the latex before irradiation, the crosslinking density and tensile strength increases by about 15% and 47% respectively. This increase has been attributed to the higher concentration of the sensitiser n-butyl acrylate in the rubber phase in presence of urea. The effects of urea addition on the ageing properties of the latex are being investigated. (author). 6 refs., 3 figs., 1 tab

  4. Thermal behaviour of radiation crosslinked natural rubber films grafted with methyl methacrylate

    International Nuclear Information System (INIS)

    Thermal behaviour of radiation crosslinked as well as methyl methacrylate (MMA) grafted natural rubber latex films has been investigated. The results show that crosslinking and grafting have little effect on the thermo-oxidative stability of the rubber films, although thermal stability increases on crosslinking. The thermo-mechanical analysis results show that dimensional stability as well as elasticity are considerably improved on grafting of MMA. (author). 3 refs., 3 figs., 1 tab

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

    OpenAIRE

    Bokobza, L.

    2012-01-01

    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 unia...

  6. Blends of natural rubber and polyurethane lattices studied by solid-state NMR

    International Nuclear Information System (INIS)

    Molecular mixing in films formed from a mixture of a polyurethane and natural rubber lattices has been studied using 1H and 13C solid-state NMR. The techniques employed include 1H relaxation measurements, and 13C cross-polarisation and direct excitation methods. The spectra of the blends were essentially a weighted superposition of the spectra of the individual components, indicating that the polyurethane and rubber remained phase-separated in large domains. (author)

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

    Directory of Open Access Journals (Sweden)

    Bryan B. Pajarito

    2014-12-01

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

  8. Investigation of Mechanical Properties of Magneto-Rheological Ethylene Propylene Diene Monomer and Natural Rubber Type Synthetic Rubbers for Both Isotropic and Anisotropic Situations

    Directory of Open Access Journals (Sweden)

    Uğur Mazlum

    2015-12-01

    Full Text Available Magneto-rheological (MR materials are in a smart material class that has the rheological properties to be quickly and reversibly controlled with the external magnetic field applications. Considering the technological developments the rubber-like smart materials has had a more functional usage area with magneto- rheological effect. This study investigates the axial mechanical properties of magneto-rheological Ethylene Propylene Diene Monomer (EPDM and Natural Rubber (NR type synthetic rubbers for isotropic and anisotropic situations. Also, these composite materials were built by means of hot press systems as either isotropic or anisotropic using magnetic field application after addition of ferromagnetic powders. The influence of magnetic field was investigated. In this study, NR rubber was found to be more susceptible in terms of smart material properties unlike EPDM synthetic rubber.

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

    International Nuclear Information System (INIS)

    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), TiO2 titanium dioxide and clay; the reinforcing ability of these fillers was found to follow the order: Hisil > HAF carbon black > Clay > TiO2The 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.

  10. Application of gamma irradiation for incorporation of rubber powder in the formulations of EPDM and natural rubber; Aplicacao da radiacao gama para incorporacao do po de borracha em formulacoes de borracha natural e EPDM

    Energy Technology Data Exchange (ETDEWEB)

    Kiyan, Ludmila Y.P.; Parra, Duclerc Fernandes; Lugao, Ademar Benevolo, E-mail: ludmilapozzo@gmail.com [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP/CQMA), Sao Paulo, SP (Brazil). Centro de Quimica e Meio Ambiente

    2013-07-01

    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 {sup 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.

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

    NARCIS (Netherlands)

    Poikelispaa, Minna; Das, Amit; Dierkes, Wilma; 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.

  12. Study on the structure-properties relationship of natural rubber/SiO2 composites modified by a novel multi-functional rubber agent

    OpenAIRE

    Yang, S Y; Liu, L; Z. X. Jia; W. W. Fu; D. M. Jia; Y. F. Luo

    2014-01-01

    Vulcanization property and structure-properties relationship of natural rubber (NR)/silica (SiO2) composites modified by a novel multi-functional rubber agent, N-phenyl- N'-(γ-triethoxysilane)-propyl thiourea (STU), are investigated in detail. Results from the infrared spectroscopy (IR) and X-ray photoelectron spectroscopy (XPS) show that STU can graft to the surface of SiO2 under heating, resulting in a fine-dispersed structure in the rubber matrix without the connectivity of SiO2 particles ...

  13. Silica-reinforced natural rubber for low rolling resistance, energy-saving tires: aspects of mixing, formulation and compatibilization

    OpenAIRE

    Kaewsakul, W.

    2013-01-01

    Natural rubber (NR) is a renewable material, which combines excellent mechanical and dynamic properties. It has been and still is in use in a variety of applications, mostly in the form of filled vulcanizates. Silica filler technology used for rubber is relatively new, since silica can reinforce rubber and gives high performance of articles, particularly in tires. The major problem of this combination is that silica has a relatively high polarity by nature and can not easily be mixed with NR ...

  14. Implant doping in radiation vulcanized natural rubber latex using N+ ions

    International Nuclear Information System (INIS)

    Recently, we have demonstrated that implant doping can create an insulator-semiconductor transition in Natural Rubber (cis 1,4 polyisoprene), a member of the well-known butadiene family, in the unvulcanized state using N+ ion. Here we report, for the first time, the ion beam bombardment in Radiation Vulcanized Natural Rubber Latex using N+ ion with energy 60 KeV in the fluence range of 1014 to 1016 ions/cm2. The electrical conductivity shows about 10 orders of magnitude compared to the virgin state and is found to be increase with increasing fluence rate. Besides the UV/Vis and FTIR spectroscopic studies indicate the presence of new peaks with increase of fluence suggests the formation of an ion beam induced conjugation in the Natural Rubber backbone. A dramatic reduction in the optical band gap with the ion fluence, as deduced from the absorption spectra, revealed the resulting substrate to be conducting. (author)

  15. New Green Polymeric Composites Based on Hemp and Natural Rubber Processed by Electron Beam Irradiation

    Directory of Open Access Journals (Sweden)

    Maria-Daniela Stelescu

    2014-01-01

    Full Text Available A new polymeric composite based on natural rubber reinforced with hemp has been processed by electron beam irradiation and characterized by several methods. The mechanical characteristics: gel fraction, crosslink density, water uptake, swelling parameters, and FTIR of natural rubber/hemp fiber composites have been investigated as a function of the hemp content and absorbed dose. Physical and mechanical properties present a significant improvement as a result of adding hemp fibres in blends. Our experiments showed that the hemp fibers have a reinforcing effect on natural rubber similar to mineral fillers (chalk, carbon black, silica. The crosslinking rates of samples, measured using the Flory-Rehner equation, increase as a result of the amount of hemp in blends and the electron beam irradiation dose increasing. The swelling parameters of samples significantly depend on the amount of hemp in blends, because the latter have hydrophilic characteristics.

  16. Rapid determination of dry rubber content in natural rubber latex by low-resolution pulsed NMR technique

    International Nuclear Information System (INIS)

    The dry rubber content (DRC) of rubber latex varies considerably depending upon genetic and environmental conditions. To facilitate speedy evaluation of yield of experimental trees and quick payment to latex tappers on the basis of rubber content, there is need of a rapid and accurate method of determination of DRC in rubber latex. In the present paper a rapid, reliable and easy method for DRC determination using proton low resolution NMR is reported. 6 refs., 1 tab

  17. High performance natural rubber composites with a hierarchical reinforcement structure of carbon nanotube modified natural fibers

    International Nuclear Information System (INIS)

    A simple and facile method for depositing multiwall carbon nanotubes (MWCNTs) onto the surface of naturally occurring short jute fibers (JFs) is reported. Hierarchical multi-scale structures were formed with CNT-networks uniformly distributed and fully covering the JFs (JF–CNT), as depicted by the scanning electron microscopy (SEM) micrographs. The impact of these hybrid fillers on the mechanical properties of a natural rubber (NR) matrix was systematically investigated. Pristine JFs were cut initially to an average length of 2.0 mm and exposed to an alkali treatment (a-JFs) to remove impurities existing in the raw jute. MWCNTs were treated under mild acidic conditions to generate carboxylic acid moieties. Afterward, MWCNTs were dispersed in an aqueous media and short a-JFs were allowed to react with them. Raman spectroscopy confirmed the chemical interaction between CNTs and JFs. The JF–CNT exposed quite hydrophobic behavior as revealed by the water contact angle measurements, improving the wettability of the non-polar NR. Consequently, the composite interfacial adhesion strength was significantly enhanced while a micro-scale “mechanical interlocking” mechanism was observed from the interphase-section transmission electron microscopy (TEM) images. SEM analysis of the composite fracture surfaces demonstrated the interfacial strength of NR/a-JF and NR/JF–CNT composites, at different fiber loadings. It can be presumed that the CNT-coating effectively compatibillized the composite structure acting as a macromolecular coupling agent. A detailed analysis of stress-strain and dynamic mechanical spectra confirmed the high mechanical performance of the hierarchical composites, consisting mainly of materials arising from natural resources. - Highlights: • Natural rubber (NR) composites reinforced with CNT-modified short jute fibers. • MWCNTs deposited to the surface of jute fibers via non-covalent interactions. • Hierarchical reinforcement structure with

  18. Quality parameters of some natural rubber (NR) clones indigenous to Nigeria. II. Ionic content, stability and degradation resistance of natural rubber

    International Nuclear Information System (INIS)

    The degradation resistance, protein content and the ionic analysis of the lattices of two local natural rubber (NR) clones (NNRL-Ilawe Ekiti) and (NNRG-Igede) and an international natural rubber clone (TJI-Malaysia) have been studied. The international clone (TJI) was observed to be more resistant to oxidative degradation than the local clones. The resistance of NR to oxidative breakdown was improved by oxalic and phosphoric acid additives and was found to be related to absolute temperature by an arrhenius type of equation thereby allowing for the evaluation of the activation energy which is taken to be a measure of the degradation resistance of NR. The lattice of the international clone (TJI) appears superior to the lattices of the local clones examined, being of higher protein content, stability and degradation resistance. (author)

  19. Measurement of crystallinity of thermoplastic natural rubber (TPNR) using x-ray diffraction and thermal methods

    International Nuclear Information System (INIS)

    The measurement of crystallinity of thermoplastic natural rubber (TPNR) of NR:HDPE blends have been made at various compositions of liquid natural rubber (LNR) using x-ray and thermal analysis methods. The results show that the crystallinity of the blends increase significantly with the addition of LNR into the blends. The data indicates a good agreement between the two methods. The tensile properties, stress and strain of the blend improved significantly with addition of LNR. SEM micrographs of the samples also indicates an increase in homogeneity of the blends with addition of LNR. (Author)

  20. The Effect of Novel Binary Accelerator System on Properties of Vulcanized Natural Rubber

    Directory of Open Access Journals (Sweden)

    Moez Kamoun

    2009-01-01

    Full Text Available The mechanical properties, curing characteristics, and swelling behaviour of vulcanized natural rubber with a novel binary accelerator system are investigated. Results indicate that the mechanical properties were improved. Crosslinking density of vulcanized natural rubber was measured by equilibrium swelling method. As a result, the new binary accelerator was found to be able to improve both cure rate and crosslinking density. Using the numerical analysis of test interaction between binary accelerator and operational modelling of vulcanization-factors experiments, it can be concluded that the interaction (Cystine, N-cyclohexyl-2-benzothiazyl sulfenamide was significant and the optimum value of binary accelerator was suggested, respectively, at levels 0 and +1.

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

    International Nuclear Information System (INIS)

    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)

  2. Gamma irradiator design concepts for radiation vulcanisation of natural rubber latex

    International Nuclear Information System (INIS)

    Radiation vulcanisation of natural rubber latex (NRL) is a new and yet unproven technology and one which involves undefined problems of consumer acceptance and high degree of radiation risk. Therefore, the designer should take care that the initial capital cost of the plant is as low as possible to keep the unit processing cost low during the initial lean period of the product requirement by the market. Three irradiators to process natural rubber latex have been designed as per capacity requirement of the user. Their salient features are described. (author). 2 tabs., 24 figs

  3. 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)

  4. Pilot Scale Production of Irradiated Natural Rubber Latex and its Dipping Products

    Directory of Open Access Journals (Sweden)

    M. Utama

    2005-07-01

    Full Text Available One hundred and fifty kg natural rubber latex (NRL before and after concentration were added with 3 phr (part hundred ratio of rubber normal butyl acrylate, then the mixture were irradiated at 25 kGy by gamma rays of 60Co in pilot scale. The irradiated natural rubber latex (INRL were then being to use for producing rubber products such as condom, surgical gloves, and spygmomanometer in factory scale. The quality of INRL and rubber products such as : total solid content (TSC, dry rubber content (DRC, KOH, VFA and MST number, tensile strength, modulus, elongation at break, extractable protein content, and response against Type I allergy etc. were evaluated. The economic aspect for producing INRL by means of Gamma Irradiator (GI and Electron Beam Machine (EBM such as payback period (PP, net present value (NPV and internal rate return (IRR were calculated. The results showed that the latex properties of INRL such as DRC, TSC, KOH, VFA, and MST number are not only found to the requirement of the ISO 2004 standard but also the latex has low protein, lipid, and carbohydrate content. The physical and mechanical properties (tensile strength, modulus, and elongation at break of rubber dipping products such as condom, gloves, and sphygmomanometer are not only found to the requirement of ISO 4074, ISO 10282, and ANSI/AAMI SP-1994 standards, but also the allergic response tested clinical latex-sensitive protein allergen by ELISA test on gloves, and by SPT test on condom are found to be negative. It indicates that production of INRL or PVNRL or RVNRL by EBM 250 keV/10 mA, was more cheap than by using gamma γ irradiator 200 kCi, or sulfur vulcanization. The value of PBP (payback period was 2,1 years, NPV (net present value was 4,250 US $, PI (profitability index 1,06 and IRR (internal rate of returns was 25,0%.

  5. Pilot Scale Production of Irradiated Natural Rubber Latex and Its Dipping Products

    International Nuclear Information System (INIS)

    One hundred and fifty kg natural rubber latex (NRL) before and after concentration were added with 3 phr (part hundred ratio of rubber) normal butyl acrylate, then the mixture were irradiated at 25 kGy by gamma rays of 60Co in pilot scale. The irradiated natural rubber latex (INRL) were then being to use for producing rubber products such as condom, surgical gloves, and sphygmomanometer in factory scale. The quality of INRL and rubber products such as : total solid content (TSC), dry rubber content (DRC), KOH, VFA and MST number, tensile strength, modulus, elongation at break, extractable protein content, and response against Type I allergy etc. were evaluated. The economic aspect for producing INRL by means of Gamma Irradiator (GI) and Electron Beam Machine (EBM) such as payback period (PP), net present value (NPV) and internal rate return (IRR) were calculated. The results showed that the latex properties of INRL such as DRC, TSC, KOH, VFA, and MST number are not only found to the requirement of the ISO 2004 standard but also the latex has low protein, lipid, and carbohydrate content. The physical and mechanical properties (tensile strength, modulus, and elongation at break) of rubber dipping products such as condom, gloves, and sphygmomanometer are not only found to the requirement of ISO 4074, ISO 10282, and ANSI/AAMI SP-1994 standards, but also the allergic response tested clinical latex-sensitive protein allergen by ELISA test on gloves, and by SPT test on condom are found to be negative. It indicates that production of INRL or PVNRL or RVNRL by EBM 250 keV/10 mA, was more cheap than by using gamma γ irradiation 200 kCi, or sulfur vulcanization. The value of PBP (payback period) was 2.1 years, NPV (net present value) was 4,250 US $, PI (profitability index) 1.06 and IRR (internal rate of returns) was 25.0%. (author)

  6. Processing researches on radiation vulcanization of natural rubber latex with low energy electron beam machine

    International Nuclear Information System (INIS)

    Processing researches on radiation vulcanization of natural rubber latex (RVNRL) was carried out with low energy electron beam machine, and explored the impact of RVNRL in a variety of factors. The results showed: It was beneficial to manufacture with increasing the dry rubber content of latex and increasing beam current. It was important to increase strength of RVNRL film using natural latex with higher green strength. Added to 0.5-1.5 phr (parts per hundreds of rubber) of PVA (polyvinyl alcohol) in radiation vulcanized latex, then the centrifugal method can greatly remove the water-soluble proteins, so that the residual water-soluble proteins in films or products can be reduced to acceptable levels. (authors)

  7. The effect of proteins on the aging properties of radiation vulcanized natural rubber latex

    International Nuclear Information System (INIS)

    The effect of natural rubber latex (NRL) proteins on the aging properties of NRL films was investigated. SDS-PAGE electrophoresis of the rubber proteins in NRL (Sri-Lanka) indicated a total of 18 proteins. A sharp decrease in tensile strength was observed after aging when NRL films were leached in 1% NH4OH. However, when these films were soaked in ethanol prior to leaching, the aging properties approximated those of the unleashed samples. Electrophoretic analysis of the proteins present in the NH3 extracts of leached RVNRL films showed a high concentration of the protein herein. This protein was not found in the NH3 extracts of ethanol soaked films. NRL proteins were shown to decelerate the aging process of Radiation Vulcanized Natural Rubber Latex (RVNRL) films. Among the proteins, herein exhibited good anti-aging properties. The hydrolyzates from NR proteins also enhanced considerably the aging properties of RVNRL. (auth.). 8 refs.; 40 figs.; 30 tabs

  8. Effects of Liquid Natural Rubber (LNR) on the Mechanical Properties of LNR Toughened Epoxy Composite

    International Nuclear Information System (INIS)

    The effects of liquid natural rubber (LNR) on the morphology and mechanical properties of rubber modified epoxy were investigated. Epoxy composites were prepared in four different compositions of LNR (3, 5, 7 and 9 phr) by using twin screw extruder. The samples for tensile, fracture toughness and impact tests were prepared according to ASTM D 638, D 5045 and D 256. The elastomeric nature of rubber can act as energy dissipating centre to cause the ductile fracture for the rubber modified epoxy. They was an obvious increment of fracture toughness where maximum value was observed with 3 phr LNR. A clear increment of impact strength at 3 phr LNR was observed, followed by a small increment at 5 phr and no further increment at 7 and 9 phr LNR. The tensile strength showed a similar trend with impact strength and Young's modulus. SEM micrographs showed an increment of rubber particle size when the amount of LNR was increased and caused the mechanical properties to drop. (author)

  9. Natural rubber latex: determination and interpretation of flow curves

    Directory of Open Access Journals (Sweden)

    Harrison Lourenço Corrêa

    2015-08-01

    Full Text Available AbstractAs consumers become more demanding, the importance grows of guaranteeing the quality of products. The employment of reliable testing techniques that assure the origin and characteristics of the inputs used by industry is a key factor in this respect. In the rubber processing industry, the most commonly used characterization tests include determination of the total solids and dry rubber content, mechanical stability, odor, color and presence of volatile compounds, among others. For the most part, these tests are sufficient for the latex transformation industry. However, in situations where there is a need to know the behavior of latex in reaction to the mechanical forces of machines (mixers, pumps, etc., other tests must be used. Rheological tests to determine viscoelastic data by means of plotting flow curves combined with the application of theoretical models can provide important details for characterization of different types of latex. This article presents the protocol employed by the Rheology and Image Laboratory of Rio de Janeiro State University (UERJ for the rheological study of Brazilian latex. The samples analyzed came from the state of São Paulo.

  10. Extractable protein of radiation vulcanized natural rubber latex

    International Nuclear Information System (INIS)

    Protein remained in the latex products are reported to cause serious allergy. A new method to reduce the protein level in the latex products by irradiation is reported. Water soluble protein (WSP) solution (10%) was added into radiation vulcanized NR latex (RVNRL) in three different processes. The amount of WSP was 3 phr. It was only added to RVNRL (standard), added to re-centrifuged RVNRL (pre-centrifugation), and added to RVNRL followed by centrifugation (post-centrifugation). The protein content was determined by enhanced BCA method, and identified by SDS-PAGE. Extractable protein (EP) from the rubber has been reduced up to the minimum protein detection by combining WSP addition and centrifugation. Short leaching time (20-30 min.) can be achieved after the combine treatment, and SDS-PAGE confirms the reduction of soluble protein in the serum phase, and disappearance of protein bands in the rubber extract. Protein-WSP interaction produces water soluble complex, and removed by centrifugation. The efficiency of protein removal by WSP depends on its molecular weight of WSP which relates to its water solubility. (author)

  11. Effect of Spray Drying on Protein Content of Natural Rubber Serum (NRS

    Directory of Open Access Journals (Sweden)

    I. Aimi Izyana and M.N. Zairossani

    2011-12-01

    Full Text Available Natural rubber latex comprises approximately 70% natural rubber serum (NRS which is the aqueous part of the latex. The NRS is made up of mainly water and non-rubber components; sugar, protein and other lipids. The protein component of the NRS is separated using membrane separation and spray dried whereby the amino acid and protein content was monitored during the process. The optimum drying temperatures were first determined to obtain the maximum recovery of the protein powder, whereby the amino acid content was approximately 40 times that of the feed. The production of protein powder from NRS increases the rubber industry's competitiveness through value addition to the previously discarded NRS but also to the processing industry. NRS protein powder has a great opportunity to be developed as an alternative protein source.ABSTRAK: Susu getah asli mengandungi lebih kurang 70% serum getah asli (natural rubber serum (NRS iaitu bahagian susu getah yang berair. NRS sebahagian besarnya merupakan air dan komponen bukan getah; gula, protein dan lipid-lipid lain. Komponen protein NRS dipisahkan dengan menggunakan membran pemisah dan kaedah kering semburan dimana asid amino dan kandungan protein dipantau semasa proses tersebut. Pada mulanya, suhu pengeringan optimum ditentukan untuk mendapatkan hasil maksima serbuk protein, dimana kandungan asid amino adalah lebih kurang 40 kali suapan. Penghasilan serbuk protein daripada NRS meningkatkan daya saing industri getah dan industri pemprosesan menerusi pertambahan nilai terhadap NRS yang sebelum ini hanya dibuang. Serbuk protein NRS mempunyai peluang besar untuk dimajukan sebagai sumber protein alternatif.KEY WORDS:  protein, spray dry, natural rubber serum.

  12. Extractable protein of radiation vulcanized natural rubber latex

    Energy Technology Data Exchange (ETDEWEB)

    Soebianto, Y.S. [Center for Research and Development of Isotopes and Radiation Technology, BATAN, Jakarta (Indonesia); Upul, R.M. [Rubber Research Institute of Sri Lanka, Ratmalana (Sri Lanka); Makuuchi, K.; Yoshii, F.; Kume, T. [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2000-03-01

    A new method to reduce the protein level in the latex products by irradiation is reported. Water soluble protein (WSP) solution (10%) was added into radiation vulcanized NR latex (RVNRL) as much as 3 phr in three different processes: added to RVNRL, added to re-centrifuged RVNRL, and added to RVNRL followed by centrifugation. The protein content was determined by enhanced BCA method, and identified by SDS-PAGE analysis. Addition of WSP followed by centrifugation reduces EP up to the minimum protein detection, and shortens the leaching time to 20-30 min. SDS-PAGE analysis confirms the reduction of soluble protein in the serum phase, and disappearance of protein bands in the rubber extract. Protein-WSP interaction produces water soluble complex, and removed by centrifugation. The molecular weight of WSP dictates the efficiency of protein removal. (author)

  13. Extractable protein of radiation vulcanized natural rubber latex

    International Nuclear Information System (INIS)

    A new method to reduce the protein level in the latex products by irradiation is reported. Water soluble protein (WSP) solution (10%) was added into radiation vulcanized NR latex (RVNRL) as much as 3 phr in three different processes: added to RVNRL, added to re-centrifuged RVNRL, and added to RVNRL followed by centrifugation. The protein content was determined by enhanced BCA method, and identified by SDS-PAGE analysis. Addition of WSP followed by centrifugation reduces EP up to the minimum protein detection, and shortens the leaching time to 20-30 min. SDS-PAGE analysis confirms the reduction of soluble protein in the serum phase, and disappearance of protein bands in the rubber extract. Protein-WSP interaction produces water soluble complex, and removed by centrifugation. The molecular weight of WSP dictates the efficiency of protein removal. (author)

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

    International Nuclear Information System (INIS)

    Structural and magnetic properties of type-M barium ferrite (BaFe12O19) 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. BaFe12O19 - filled nano composites with 2 - 12 wt % BaFe12O19 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)

  15. Radiation vulcanization of natural rubber latex using i-octyl acrylate

    International Nuclear Information System (INIS)

    Powdered natural rubber can be prepared by using gamma-rays vulcanization and special drying method from natural rubber latex (NRL). This kind of powdered natural rubber would be expected to toughen plastics as an impact modifier and the property of natural rubber depends on its crosslinking degree. Therefore, it is necessary to study the crosslinking behavior of NRL under gamma irradiation. In the paper, the NRL was vulcanized with i-octyl acrylate (OA) as a crosslinking sensitizer under gamma irradiation. The influences of absorbed dose, dose rate and crosslinking concentration were discussed. The radiation vulcanization of NRL depends significantly on absorbed dose and crosslinking sensitizer content. The gel fraction of NR increased with absorbed dose and OA content, and it increased slightly above 10 kGy. With increasing dose rate, the gel fraction decreased slightly. The highest gel fraction (about 90%) reached at dose of 25 kGy with 5% OA. In the system, the radiation crosslinking behavior of NRL with OA as a crosslinking sensitizer could be described well with Charlesby-Pinner equation and G(x) was calculated to be about 3.8. (authors)

  16. Properties of organo-clay/natural rubber nanocomposites: effects of organophilic modifiers

    Czech Academy of Sciences Publication Activity Database

    Hrachová, J.; Komadel, P.; Jochec-Mošková, D.; Krajči, J.; Janigová, I.; Šlouf, Miroslav; Chodák, I.

    2013-01-01

    Roč. 127, č. 5 (2013), s. 3447-3455. ISSN 0021-8995 R&D Projects: GA ČR GAP205/10/0348 Institutional research plan: CEZ:AV0Z40500505 Keywords : nanocomposites * natural rubber * morphology Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.640, year: 2013

  17. Decrease in the rate of sensitization and clinical allergy to natural rubber latex

    DEFF Research Database (Denmark)

    Blaabjerg, Michelle S B; Andersen, Klaus E; Bindslev-Jensen, Carsten;

    2015-01-01

    BACKGROUND: In the 1980s, a striking increase in natural rubber latex (NRL) allergy was seen. Since then, many measures have been taken to prevent NRL allergy. OBJECTIVES: To investigate changes in the prevalence of NRL sensitization/clinical NRL allergy over time from 2002 to 2013. METHODS: All...

  18. Positron Annihilation Study on Nickel and Iron Nano-Particles in Natural Rubber Composites

    Directory of Open Access Journals (Sweden)

    Emad H. Aly

    2011-01-01

    Full Text Available Problem statement: The effect of Ni and Fe nano-particles as a filler on the free volume properties Of Natural Rubber (NR was studied using Positron Annihilation Lifetime Spectroscopy (PALS. Approach: The PAL measurements revealed that the free volume properties are strongly affected by the amount and type of filler. Results: Particularly speaking, the free volume fraction dramatically decreased by increasing the filler content. Besides, the addition of nano-prticles created new positron trapping sites at filler-rubber interfaces. Furthermore, correlations were made between the free volume hole sizes (Vh and each of the mechanical and electrical properties successively. A negative correlation was observed between Vh and hardness in the Ni-rubber composites while a positive counterpart was found in the case of Fe-rubber composites. Finally, the polarity of the fillers, being higher than that of the rubber itself, leads to an increase in electrical parameters and an inhibition of o-Ps formation. Conclusion: These results indicate that the investigated composites are considered to be insulating materials as their conductivity values are in the order of an insulator range.

  19. Identification of emitted air pollutants from natural rubber processing via thermal desorbed-gas chromatography

    International Nuclear Information System (INIS)

    Natural rubber processing has been identified as one of the major sources of organic pollution in Malaysia. Emissions of malodorous vapors which mainly consist of volatile organic compounds (VOC) resulted from the breakdown of non-rubber constituent during drying of block rubbers has contributed to air pollution. The malodour pollution is currently being controlled by treatment using water scrubber systems as adopted by most rubber processing factories. Performance of water scrubbers is monitored by analyzing vapors before and after treatment using a dynamic olfactometer in a form of odor concentration unit. Most water scrubbers installed are able achieve 75-80 % removal of malodour. However, previous research carried out in identifying and quantifying air pollutants using gas chromatographic technique with calibration against limited volatile fatty acids (VFAs) revealed that 90 % removal of VFAs which is not in agreement with the olfactometric results. This paper describes a new technique to characterize air pollutants using a combination of thermal desorbed and gas chromatography. This set up broadens detection of VFAs and also mercaptans. Present results showed more VFAs and some mercaptans were being detected in the emission as compared to the previous technique using a regular gas chromatography. It was shown that the malodour was contributed by more VOC as reflected from the olfactometric results. The new characterization technique provides new technical information to develop more efficient treatment systems to treat malodour pollution from the rubber processing industry. (author)

  20. Preparation and evaluation of some investigated natural and acrylonitrile rubber vulcanizations for physiotherapeutic purposes

    International Nuclear Information System (INIS)

    A trial was made to design and prepare rubber article that can be used to reactivate, strengthen and reinforce the hand muscles and fingers which had suffered from trouble movement.The investigated rubber article was prepared from natural and acrylonitrile rubber formulations. These formulations were processed in the form of compounds which contain significant quantities of fillers as Hisil, CaCO3 and TiO2.The rheological characteristics and physicochemical properties of the vulcanizations were determined according to standard tests. It was found that it is possible to prepare the designated rubber article for the desired purpose. The test results show that the prepared rubber article has a good chemical resistant against acid, alkali, and salt. Also it possesses high resistance to deterioration and deformation. The prepared article has an ability to retain its elastic property after the action of compressive forces at 70 degree C for 24 hours.This was conformed with applied commercial hand exercise therapeutic article

  1. Properties of halloysite nanotubes-filled natural rubber prepared using different mixing methods

    International Nuclear Information System (INIS)

    Highlights: • Filler dispersion in rubber matrix influences the properties of rubber nanocomposites. • Mixing method is the factor that affects filler dispersion in rubber nanocomposites. • Solution mixing method able to show better filler dispersion in rubber matrix. • Better filler dispersion in HNTs/NR nanocomposites is proven by SEM images. - Abstract: Two different mixing methods, i.e., mechanical and solution mixing were used in preparation of halloysite nanotubes/natural rubber (HNTs/NR) nanocomposites with various loading of HNTs. The result showed that the addition of HNTs caused increment in scorch time, cure time and maximum torque for both mixing methods. However, longer scorch and cure time of nanocomposites prepared via solution mixing method than nanocomposites prepared via mechanical mixing method was observed. Nanocomposites prepared by solution mixing method showed higher tensile strength, tensile modulus, fatigue life and decomposition temperature at lower percentage of weight loss than mechanical mixing method. Scanning electron microscope (SEM) images showed better dispersion of HNTs in nanocomposites prepared via solution mixing method than mechanical mixing method

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

    International Nuclear Information System (INIS)

    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

  3. Antioxidant and sensitizer effect on the stability of natural rubber latex vulcanized by gamma rays

    International Nuclear Information System (INIS)

    The natural rubber latex was vulcanized by gamma rays and electrons beam, in the presence and absence of sensitizer at room temperature. The sensitizers were the following; n-butyl acrylate (n-BA) / t-butyl hydroperoxide (t-B H) / KOH, C Cl4 / potassium laurate and n-BA / KOH. The studied antioxidants, Irganox 1520, Vulcanox SP and Vulcanox BKF, were added to the latex after irradiation. Among the studied antioxidants in function of tensile strength (TS) after the aging of rubber plates, the Irganox was the best efficient on the gamma vulcanization in the presence of n-BA/t-B H/KOH, because only 0,20 p hr is enough to obtain the greatest increase of TS, that was 34%, 12 MPa to 16 MPa. The formulating method of latex with the sensitizer constituted the 3,0 p hr of n-BA/ 0,1 p hr of t-B H and 0,2 p hr of KOH, was evaluated respecting the TS of rubber plates. The electrons beam vulcanization produces the greatest reversible perturbance in the colloidal stability of latex after irradiation caused by radiolytic species absorption that promotes the increase of particle size. The antioxidant also contributes to reversible destabilization of gamma irradiated latex, because it is also adsorbed by particles surface. The relation between the latex viscosity and the TS of respective rubber plates is reverse, showing the latex stability affects the quality of rubber goods. (author)

  4. Cross-border forest disturbance and the role of natural rubber in mainland Southeast Asia using annual Landsat time series

    DEFF Research Database (Denmark)

    Grogan, Kenneth; Pflugmacher, Dirk; Hostert, Patrick;

    2015-01-01

    The recent rise in global demand for natural rubber (Hevea brasiliensis) has led to expansive areas of natural forest being transformed into monoculture plantations. This paper explores the utility of annual Landsat time series for monitoring forest disturbance and the role of natural rubber in...... cross border differences in frontier and non-frontier forest disturbance rates between Cambodia and Vietnam, 3) what proportion of disturbances in frontier and non-frontier forests can be accounted for by the impact of rubber plantations, and 4) is there a relationship between global market prices for...... disturbance rates related to rubber plantation expansion and price fluctuations of natural rubber. This suggests links between localized land cover/use change and international market forces, irrespective of differing political and socioeconomic backgrounds. Our study underlines the value of using dense...

  5. NANOMECHANICAL MAPPING OF CARBON BLACK REINFORCED NATURAL RUBBER BY ATOMIC FORCE MICROSCOPY

    Institute of Scientific and Technical Information of China (English)

    Toshio Nishi; Hideyuki Nukaga; So Fujinami; Ken Nakajima

    2007-01-01

    Atomic force microscopy (AFM) has the advantage of obtaining mechanical properties as well as topographic information at the same time. By analyzing force-distance curves measured over two-dimensional area using Hertzian contact mechanics, Young's modulus mapping was obtained with nanometer-scale resolution. Furthermore, the sample deformation by the force exerted was also estimated from the force-distance curve analyses. We could thus reconstruct a real topographic image by incorporating apparent topographic image with deformation image. We applied this method to carbon black reinforced natural rubber to obtain Young's modulus distribution image together with reconstructed real topographic image.Then we were able to recognize three regions; rubber matrix, carbon black (or bound rubber) and intermediate regions.Though the existence of these regions had been investigated by pulsed nuclear magnetic resonance, this paper would be the first to report on the quantitative evaluation of the interfacial region in real space.

  6. Proceedings of the international symposium on radiation vulcanization of natural rubber latex

    International Nuclear Information System (INIS)

    The First International Symposium on Radiation Vulcanization of Natural Rubber Latex (RVNRL) was held from 26 to 28 July 1989 at Tokyo and Takasaki. In these proceedings, thirty six papers presented at the Symposium are compiled. Main topics are commercial application of RVNRL, characterization of NR latex and vulcanization, properties of radiation vulcanized NR latex, development of sensitizers, mechanism of RVNRL, RVNRL with electron beams, and new Co-60 irradiator for RVNRL. Absence of nitrosamines and low cytotoxicity of radiation vulcanized NR latex are recognized as the remarkable advantages of RVNRL. The radiation vulcanization process for the production of protective rubber gloves for radioactive contamination was presented as the first commercial success in RVNRL. It was reported that various kinds of rubber articles for medical uses have being developed in West Germany. A sensitizer system consisting of n-butyl acrylate and t-butyl hydroperoxide was found to reduce the vulcanization dose to 8 kGy. (author)

  7. Development of an efficient process for radiation vulcanization of natural rubber latex using hydroperoxide with sensitizers

    International Nuclear Information System (INIS)

    An attempt was made to reduce radiation dose for radiation vulcanization of natural rubber latex. One of the best methods found was to co-vulcanize the latex using partial radiation vulcanization at 4 kGy with 5 phr n-butyl acrylate as sensitizer and 0.1 phr t-butyl hydroperoxide (BHPO) as co-sensitizer followed by redox vulcanization using either 4 phr fructose at temperature of 60 degree C for 3 hours or 0.2 phr BHPO and 0.4 phr tetra-ethylene pentamine (TEPA) at room temperature for I hour. The rubber film obtained had tensile strength of about 25 MPa, modules 300% of 0. 9 MPa and cross link density of about 1. 5 x 10 sup 19 crosslink/cm sup 3. It was noted that the crosslink density of rubber films from the co-vulcanization was the average value of the values obtained by radiation vulcanization and redox vulcanization

  8. 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.

  9. Incorporation of nano-sized mesoporous MCM-41 material used as fillers in natural rubber composite

    International Nuclear Information System (INIS)

    Research highlights: → Mesoporous MCM-41 as reinforcing filler to polymers was used in our previous study. → Few paper has mentioned this kind of filler in rubber. → Modification of MCM-41 as reinforcing filler in natural rubber was studied. → The reinforcing effect was remarkable. - Abstract: The nano-sized mesoporous MCM-41 (without template), and the modification of MCM-41 (without template) were used to prepare natural rubber (NR) composites. The effects of coupling agents γ-aminopropyltriethoxysilane (KH-550), γ-methacryloxypropyltrimethoxysilane (KH-570), bis-(γ-triethoxysilylpropyl)-tetrasulfide (Si-69), isopropyl tri-(dioctylpyrophosphate)titanate (NDZ-201) on the mechanical properties of the composites were also investigated. The results showed that the tensile properties of Natural rubber/mesoporous MCM-41 nanocomposite were improved as compared with those of NR compound. KH-570 had good effect on enhancing the overall properties of the composites. Scanning electron microscopy (SEM) observations revealed that the modified nano-sized MCM-41 material was well dispersed in the polymer matrix and the enhancement of the interface between the matrix and fillers was obtained.

  10. SUSTAINABILITY OF NATURAL RUBBER-PRODUCING CROPS IN THE UNITED STATES: APPLIED BIOTECHNOLOGY LESSONS 2000-2010

    Science.gov (United States)

    Natural rubber (NR) is a critical and strategic raw material for industrial manufacturing and national defense. Development of a US-based supply of NR is recognized in the Critical Agricultural Materials Act, Public Law 95–592. Domestic rubber-producing crops have been introduced in the US during ti...

  11. 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; 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.

  12. Energy efficiency enhancement of natural rubber smoking process by flow improvement using a CFD technique

    Energy Technology Data Exchange (ETDEWEB)

    Tekasakul, Perapong [Energy Technology Research Center and Department of Mechanical Engineering, Faculty of Engineering, Prince of Songkla University, Hat Yai, Songkhla 90112 (Thailand)], E-mail: perapong.t@psu.ac.th; Promtong, Machimontorn [Division of Mechanical Engineering, School of Engineering and Resources, Walailak University, Nakhon Si Thammarat 80160 (Thailand)

    2008-09-15

    A non-uniform flow and large temperature variation in a natural rubber smoking-room cause an inefficient use of energy. Flow uniformity and temperature variation can be improved by using a computational fluid dynamics (CFD) simulation. The effects of the size, position and number of gas supply ducts and ventilating lids which were at the inlets and the outlets of the smoking-room were investigated. The optimal rubber smoking-room of size 2.6 m x 6.2 m x 3.6 m contains 154 50 mm-diameter hot gas supply ducts, and four 0.25 x 0.25 m and four 0.25 x 0.20 m ventilating lids. The velocity distribution of this model in the rubber-hanging area was rather uniform. The average monitoring temperature of 54 positions was 62.1 deg. C. This model could reduce the temperature variation by a factor of three from the original room model, i.e., from 15 to 5.5 deg. C. In a further study, the heat input of an appropriate room model was finely adjusted to obtain a suitable temperature (60 deg. C) for the smoking process. It was found that an appropriate heat supply at this temperature is 11 kW. At this rate, the temperature variation is 5.3 deg. C. This improved model should help the rubber smoking cooperatives to achieve at least a 31.25% saving in energy.

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

    International Nuclear Information System (INIS)

    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

  14. How Do “Renewable Products” Impact Biodiversity and Ecosystem Services – The Example of Natural Rubber in China

    Directory of Open Access Journals (Sweden)

    Marc Cotter

    2009-04-01

    Full Text Available This paper aims to present the implications brought by the expansion of “renewable products” plantation systems in the tropics with cultivation of rubber (Hevea brasiliensis as a main focus. Throughout South East Asia, natural forest is being replaced by rubber or oil palm (Elaeis guineensis plantations, with severe consequences for the local flora and fauna. Main aspects of this review are: i The provision of an overview over renewable resources in general and rubber in particular, with eco-physiological and agronomical information concerning rubber cultivation. ii The effect of rubber plantations on biodiversity and species composition under different rubber farming approaches. In addition we debate the possible influences of such large scale land cover transformations on ecosystem services. iii The conversion of natural forests into rubber plantations releases considerable amounts of carbon dioxide into the atmosphere. We estimated these values for different land cover types in southern China and assessed the carbon sequestration potential of local rubber plantations.

  15. Mechanical property test of natural rubber bearing for the evaluation of uncertainty value of seismic isolation devices

    International Nuclear Information System (INIS)

    Seismic safety of NPP is one of the most important issues in a nuclear field after great east Japan earthquake in 2011. For the improvement of seismic safety of nuclear power plant, seismic isolation is the easiest solution for increasing the seismic safety. Otherwise, the application of seismic isolation devices for nuclear power plants doesn't make the seismic risk of NPP increases always. The rubber bearing have many uncertainties of material properties and large displacement should absorb according to the application of isolation devices. In this study, for the evaluation of uncertainty of the material properties of rubber bearing, material tests for rubber and mechanical properties test for natural rubber bearing were performed. For the evaluation of effect of hardness of rubber, 4 kinds of rubber hardness for material property tests and 2 kinds of rubber hardness for mechanical property test were considered. As a result, the variation of material properties is higher than that of mechanical properties of natural rubber bearings

  16. INFLUENCE OF THE VOLATILE FATTY ACID CONTENT TO RADIATION VULCANIZED NATURAL RUBBER LATEX (RVNRL

    Directory of Open Access Journals (Sweden)

    CHIRINOS, Hugo David

    2012-01-01

    Full Text Available Natural rubber latex is a dispersion of natural rubber particles in water. These particles are coated with aprotein layer which will stabilize the dispersion in water by forming an electric charge in the layer. Any differentcondition affecting this layer disturbs the stability of dispersion. Microorganism attack disturbs the protein layerand consequently the stability of the dispersion. By adding 1.2% by weight of NH3, the stability of the dispersioncan be improved. The fresh latex was irradiated by Co-60 with irradiation dose of 10, 20, 30, 40 and 100 kGy.The results showed a relationship between the volatile fatty acid content (VFA, product from microorganismattack on carbohydrate and the green strength or the physical properties of vulcanized film. Low VFA numbershowing a higher physical strength of the film either un-vulcanized or vulcanized. It appeared that the structurewas responsible in yielding a good physical property of the film.

  17. Effect of epoxidation on 30% poly(methyl methacrylate)-grafted natural rubber polymer electrolytes

    International Nuclear Information System (INIS)

    Epoxidized 30% poly(methyl methacrylate)-grafted natural rubber (EMG 30) as a polymer host in solid polymer electrolytes (SPEs) has been investigated. EMG30 was synthesized via performicepoxidation method onto 30% poly(methyl methacrylate)-grafted natural rubber (MG30) and the formations of epoxy group were discussed. The EMG30 were characterized by proton nuclear magnetic resonance (1HNMR) to investigate their chemical structure and differential scanning calorimeter to determine their crystallinity. A new peak in 1HNMR spectra (2.71 ppm) confirmed the appearance of epoxy group. SPE based on EMG30 doped with 40 wt% LiCF3SO3 show the highest conductivity. The complexation between EMG30 and LiCF3SO3 were confirmed by attenuated total reflection Fourier transform infrared (ATR-FTIR)

  18. Enhanced microactuation with magnetic field curing of magnetorheological elastomers based on iron–natural rubber nanocomposites

    Indian Academy of Sciences (India)

    M P Vasudevan; P M Sudeep; I A Al-Omari; Philip Kurian; P M Ajayan; T N Narayanan; M R Anantharaman

    2015-06-01

    The incorporation of nanoparticles of iron in a natural rubber matrix leads to flexible magnetorheological (MR) materials. Rod-shaped MR elastomers based on natural rubber and nanosized iron have been moulded both with and without the application of an external magnetic field during curing. These MR elastomer rods and filler material were characterized by X-ray powder diffraction, scanning electron microscopy and transmission electron microscopy. Magnetic properties were investigated by using vibrating sample magnetometry. Microactuation studies were carried ou t by employing a laser Doppler vibrometer. It is seen that microactuation of field cured samples have been enhanced by two times when compared with that of zero field cured samples. The effect of alignment of magnetic particles during field-assisted curing was also studied by using a dynamic mechanical analyzer. A plausible model is put forwarded to explain the observed enhancement of actuation for field cured samples.

  19. The sensitizing effect of acrylates on radiation vulcanization of natural rubber latex

    International Nuclear Information System (INIS)

    The sensitizing effect of acrylates on radiation vulcanization of natural rubber latex was studied. The results indicate that Gc value of crosslinking (Gc) will be higher at the same radiation dose when a sensitizer exists, and Gc value decreases with the increase of radiation dose (D) conforming to the formula Gc KD-α, where K and α are constants depending on sensitizers. The more sensitizers added, the greater the Gc value. However, the viscosity of the natural rubber latex also increases rapidly along with the increase of sensitizers added. Some sensitizers, such as TMPTA, can decrease the optimum dose from about 200 kGy to approximately 20 kGy according to our experiment. The tensile strength of the film can reach round 20 MPa. Other physical properties are comparable to those of unsensitized. (author)

  20. Epoxidized natural rubber toughened aqueous resole type liquefied EFB resin: Physical and chemical characterization

    Science.gov (United States)

    Amran, Umar Adli; Zakaria, Sarani; Chia, Chin Hua

    2013-11-01

    A preliminary study on the reaction between aqueous resole type resinified liquefied palm oil empty fruit bunches fibres (RLEFB) with epoxidized natural rubber (ENR). Liquefaction of empty fruit bunches (EFB) is carried out at different ratio of phenol to EFB (P:EFB). Resole type phenolic resin is prepared using sodium hydroxide (NaOH) as the catalyst with the ratio of liquefied EFB (LEFB) to formaldehyde (LEFB:F) of 1:1.8. 50% epoxidation of epoxidized natural rubber (ENR-50) is used to react with resole resin by mixing with ENR with aqueous resole resin. The cured resin is characterized with FT-IR and SEM. Aqueous system have been found to be unsuitable medium in the reaction between resin and ENR. This system produced a highly porous product when RLEFB/ENR resin is cured.

  1. Dental surgeons with natural rubber latex allergy: a report of 20 cases.

    Science.gov (United States)

    Field, E A

    1999-02-01

    Latex allergy is becoming a major occupational health issue and dental surgeons are at risk from becoming sensitized to natural rubber latex. A study was conducted to investigate risk factors and glove-related symptoms reported by dentists with natural rubber latex allergy. Twenty dentists, who had undergone serological or dermatological testing for a Type I allergy to latex, were identified from a questionnaire survey. Risk factors investigated were: gender, years in clinical practice, exposure to latex gloves, atopic history and food allergy. The majority of dentists (75%) gave an atopic history. Glove-related adverse reactions ranged from cutaneous to systemic manifestations. All twenty dentists reported itching of the hands in response to latex gloves. One respondent was unable to continue in dental practice because of her glove-related allergies; nineteen dentists were able to continue by using synthetic, non-latex gloves. PMID:10436562

  2. Effect of epoxidation on 30% poly(methyl methacrylate)-grafted natural rubber polymer electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Nazir, Khuzaimah; Aziz, Ahmad Fairoz [Faculty of Applied Sciences, Universiti Teknologi MARA, 40450 Shah Alam, Selangor (Malaysia); Adam, Nurul Ilham [Faculty of Applied Sciences, Universiti Teknologi MARA, KampusTapah, 35400 Tapah Road, Tapah, Perak (Malaysia); Yahya, Muhd Zu Azhan [Faculty of Defence Sciences and Technology, Universiti Pertahanan Nasional Malaysia, Kem Sungai Besi, 57000 Kuala Lumpur (Malaysia); Ali, Ab Malik Marwan [Institute of Science, Universiti Teknologi MARA, 40450 Shah Alam, Selangor (Malaysia)

    2015-08-28

    Epoxidized 30% poly(methyl methacrylate)-grafted natural rubber (EMG 30) as a polymer host in solid polymer electrolytes (SPEs) has been investigated. EMG30 was synthesized via performicepoxidation method onto 30% poly(methyl methacrylate)-grafted natural rubber (MG30) and the formations of epoxy group were discussed. The EMG30 were characterized by proton nuclear magnetic resonance ({sup 1}HNMR) to investigate their chemical structure and differential scanning calorimeter to determine their crystallinity. A new peak in {sup 1}HNMR spectra (2.71 ppm) confirmed the appearance of epoxy group. SPE based on EMG30 doped with 40 wt% LiCF{sub 3}SO{sub 3} show the highest conductivity. The complexation between EMG30 and LiCF{sub 3}SO{sub 3} were confirmed by attenuated total reflection Fourier transform infrared (ATR-FTIR)

  3. Migration of BTEX and phthalates from natural rubber latex balloons obtained from the Sri Lankan market

    OpenAIRE

    Jayawardena, Imanda; Godakumbura, Pahan I.; Prashantha, M. A. B.

    2016-01-01

    The current study evaluates the migration of benzene, toluene, ethylbenzene, xylene (BTEX) and phthalates into artificial saliva from natural rubber latex (NRL) balloons available for sale in Sri Lanka. It was discovered that at least one BTEX compound migrated from almost all the brands. The migration of four phthalates; diethyl phthalate, dibutyl phthalate, di-isobutyl phthalate and butyl benzyl phthalate were also observed. Migratory levels of BTEX and phthalates in most of the balloon bra...

  4. Analysis of Toxicity of Ceramic Nanoparticles and Functional Nanocomposites Based on Vulcanized Natural Rubber

    OpenAIRE

    Bellucci Felipe Silva; Fukushima Jeferson Camargo; de Moraes Josué; Lima Nobre Marcos Augusto; Paschoalini Amarildo Tabone; Job Aldo Eloizo

    2015-01-01

    Nanocomposites are multiphase materials of which, at least one of the phases, has a dimension smaller than 100 nm. These materials have attracted technological and scientific interest due to their multifunctional characteristics and potential, which allow them to combine unique properties which are not found in traditional commercial materials, such as natural rubber alone. The objective of this work is to analyse the toxicity of nanoparticles and nanocomposites when applied to mammal cells i...

  5. A Micro-Mechanically Based Continuum Model for Strain-Induced Crystallization in Natural Rubber

    Science.gov (United States)

    Mistry, Sunny Jigger

    Recent experimental results show that strain-induced crystallization can substantially improve the crack growth resistance of natural rubber. While this might suggest superior designs of tires or other industrial applications where elastomers are used, a more thorough understanding of the underlying physics of strain-induced crystallization in natural rubber has to be developed before any design process can be started. The objective of this work is to develop a computationally-accessible micro-mechanically based continuum model, which is able to predict the macroscopic behavior of strain crystallizing natural rubber. While several researchers have developed micro-mechanical models of partially crystallized polymer chains, their results mainly give qualitative agreement with experimental data due to a lack of good micro-macro transition theories or the lack of computational power. However, recent developments in multiscale modeling in polymers provide new tools to continue this early work. In this thesis, a new model is proposed to model strain-induced crystallization in natural rubber. To this end, a micro-mechanical model of a constrained partially crystallized polymer chain with an extended-chain crystal is derived and connected to the macroscopic level using the non-affine micro-sphere model. On the macroscopic level, a thermodynamically consistent framework for strain-crystallizing materials is developed, and a description of the crystallization kinetics is introduced. For that matter, an evolution law for crystallization based on the gradient of the macroscopic Helmholtz free energy function (chemical potential) in combination with a simple threshold function is used. A numerical implementation of the model is proposed and its predictive performance assessed using published data.

  6. Physical-biopolymer characterization of polyhydroxybutyrate-co-hydroxyvalerate (PHBV) blended with natural rubber latex

    International Nuclear Information System (INIS)

    A biopolymer of polyhydroxybutyrate-co-hydroxyvalerate (PHBV) is blended with bio-based materials, natural rubber latex, to improve their microstructures. The various ratios between PHBV and natural rubber latex are examined to develop their mechanical properties. In general, physical properties of PHBV are hard, brittle and low flexible while natural rubber (NR) is presented itself as high elastic materials. Concentrations of the PHBV solution are constituted at 1%, 2% and 3% (w/v). The mixtures of their PHBV solutions to natural rubber latex are produced the blended films in three different ratios of 4:6, 5:5 and 6:4, respectively. They are characterized by appearance analyses which are the scanning electron microscope (SEM), universal testing machine (UTM) and differential scanning calorimetry (DSC). The SEM photomicrographs of the blended films and the controlled PHBV can provide the void distribution in the range of 12-14% and 19-21%, respectively. For mechanical properties of the blended films, the various elastic moduli of 1%, 2% and 3% (w/v) PHBV are the average of 773, 956 and 1,007 kPa, respectively. The tensile strengths of the blends increase with the increased concentrations of PHBV, similarly trend to the elastic modulus. The crystallization and melting behavior of unmixed PHBV and the blends are determined by DSC. Melting transition temperatures (Tm) of the unmixed PHBV are stated two melting peak at 154°C and 173°C. Besides, the melting peaks of the blends alter in the range of 152-156°C and 168-171°C, respectively. According to morphology of the blends, the void distribution decreases twice compared to the unmixed PHBV. The results of mechanical properties and thermal analysis indicate that the blended PHBV can be developed their properties by more resilient and wide range of temperature than usual

  7. Trial Production of Surgical Gloves from Irradiated Natural Rubber Latex on Factory Scale

    OpenAIRE

    Utama, M.; Herwinarni; M. Sumarti; Siswanto; Suharyanto; S. Ruslim

    2005-01-01

    Trial production of surgical gloves from irradiated natural rubber latex at the PT. Laxindo Utama Serang Banten glove factory has been carried out. The variation of heating temperature and leaching time during processing were evaluated. The physical and mechanical properties and the protein allergen respond of surgical gloves using ELISA method were measured. The results showed that the physical and mechanical of surgical gloves such as tensile strength, modulus, and elongation at break arefo...

  8. Preparation and Properties of Biocomposite Based on Natural Rubber and Bagasse Nanocellulose

    OpenAIRE

    Jarnthong Methakarn; Wang Fei; Wei Xiao Yi; Wang Rui; Li Ji Hua

    2015-01-01

    Biocomposite based on natural rubber (NR) and bagasse nanocellulose (BNC) was prepared in latex state. The mechanical, morphological and thermal properties of NR/BNC biocomposite were investigated. It was found that the addition of 3 wt% of BNC in NR film caused significant increase in modulus at 100% and 300% elongations and improved thermal stability of NR/BNC biocomposite. However, the strength at break and elongation at break of the biocomposite were not enhanced correlating to the morpho...

  9. Physical-biopolymer characterization of polyhydroxybutyrate-co-hydroxyvalerate (PHBV) blended with natural rubber latex

    Science.gov (United States)

    Kuntanoo, K.; Promkotra, S.; Kaewkannetra, P.

    2015-03-01

    A biopolymer of polyhydroxybutyrate-co-hydroxyvalerate (PHBV) is blended with bio-based materials, natural rubber latex, to improve their microstructures. The various ratios between PHBV and natural rubber latex are examined to develop their mechanical properties. In general, physical properties of PHBV are hard, brittle and low flexible while natural rubber (NR) is presented itself as high elastic materials. Concentrations of the PHBV solution are constituted at 1%, 2% and 3% (w/v). The mixtures of their PHBV solutions to natural rubber latex are produced the blended films in three different ratios of 4:6, 5:5 and 6:4, respectively. They are characterized by appearance analyses which are the scanning electron microscope (SEM), universal testing machine (UTM) and differential scanning calorimetry (DSC). The SEM photomicrographs of the blended films and the controlled PHBV can provide the void distribution in the range of 12-14% and 19-21%, respectively. For mechanical properties of the blended films, the various elastic moduli of 1%, 2% and 3% (w/v) PHBV are the average of 773, 956 and 1,007 kPa, respectively. The tensile strengths of the blends increase with the increased concentrations of PHBV, similarly trend to the elastic modulus. The crystallization and melting behavior of unmixed PHBV and the blends are determined by DSC. Melting transition temperatures (Tm) of the unmixed PHBV are stated two melting peak at 154°C and 173°C. Besides, the melting peaks of the blends alter in the range of 152-156°C and 168-171°C, respectively. According to morphology of the blends, the void distribution decreases twice compared to the unmixed PHBV. The results of mechanical properties and thermal analysis indicate that the blended PHBV can be developed their properties by more resilient and wide range of temperature than usual.

  10. Physical-biopolymer characterization of polyhydroxybutyrate-co-hydroxyvalerate (PHBV) blended with natural rubber latex

    Energy Technology Data Exchange (ETDEWEB)

    Kuntanoo, K., E-mail: thip-kk@hotmail.com [Graduate School of Khon Kaen University, Khon Kaen, 40002 Thailand (Thailand); Promkotra, S., E-mail: sarunya@kku.ac.th [Department of Geotechnology, Faculty of Technology, Khon Kaen University, Khon Kaen 40002 Thailand (Thailand); Kaewkannetra, P., E-mail: paknar@kku.ac.th [Department of Biotechnology, Faculty of Technology, Khon Kaen University, Khon Kaen 40002 Thailand (Thailand)

    2015-03-30

    A biopolymer of polyhydroxybutyrate-co-hydroxyvalerate (PHBV) is blended with bio-based materials, natural rubber latex, to improve their microstructures. The various ratios between PHBV and natural rubber latex are examined to develop their mechanical properties. In general, physical properties of PHBV are hard, brittle and low flexible while natural rubber (NR) is presented itself as high elastic materials. Concentrations of the PHBV solution are constituted at 1%, 2% and 3% (w/v). The mixtures of their PHBV solutions to natural rubber latex are produced the blended films in three different ratios of 4:6, 5:5 and 6:4, respectively. They are characterized by appearance analyses which are the scanning electron microscope (SEM), universal testing machine (UTM) and differential scanning calorimetry (DSC). The SEM photomicrographs of the blended films and the controlled PHBV can provide the void distribution in the range of 12-14% and 19-21%, respectively. For mechanical properties of the blended films, the various elastic moduli of 1%, 2% and 3% (w/v) PHBV are the average of 773, 956 and 1,007 kPa, respectively. The tensile strengths of the blends increase with the increased concentrations of PHBV, similarly trend to the elastic modulus. The crystallization and melting behavior of unmixed PHBV and the blends are determined by DSC. Melting transition temperatures (T{sub m}) of the unmixed PHBV are stated two melting peak at 154°C and 173°C. Besides, the melting peaks of the blends alter in the range of 152-156°C and 168-171°C, respectively. According to morphology of the blends, the void distribution decreases twice compared to the unmixed PHBV. The results of mechanical properties and thermal analysis indicate that the blended PHBV can be developed their properties by more resilient and wide range of temperature than usual.

  11. Safety Evaluation Test on Human for Radiation Pre vulcanised Natural Rubber Latex (RVNRL)

    International Nuclear Information System (INIS)

    This paper discussed about clinical test conducted to determine safety evaluations on human for latex examination gloves and latex films made from Radiation Vulcanized Natural Rubber Latex (RVNRL). Two types of test were being adopted which are i) Modified Draize-95 test and ii) Patch Test on Sensitized Individuals. Modified Draize-95 test was conducted on 200 non-sensitized human subjects and Patch Test on Sensitized Individuals was conducted on 25 individuals who are allergic to the defined major chemical sensitizer presents in natural rubber product. It was found that Modified Draize-95 test has prove that there is no clinical evidence on the presence of residual chemical additives at the level that may induce Type IV allergy in the un sensitized general user population in the RVNRL gloves. Meanwhile Patch Test on Sensitized Individuals has proved that the patch test conducted using the test article on 25 individuals who are allergic to the defined major chemical sensitizers present in natural rubber products, thiuram, carbamates or thiazoles produced a negative response, meeting the pre requirement for the claim of reduced reaction-inducing potential. (author)

  12. Surface modification of Natural Rubber by ion implantation: Evidence for implant doping

    International Nuclear Information System (INIS)

    Ion implantation is one of the most powerful and well-known technique for surface modification in polymers. Thin films of Natural Rubber were modified by the implantation of 60 keV N+ ions to the fluences of 1011-1015 cm-2. The electrical conductivity measurements of irradiated sample show 10 orders of magnitude compared to pristine state. Along with conductivity change there was a noticeable change in color to a dense shiny black for the most highly conducting films. The analysis of temperature dependence of dc electrical conductivity data reveals a three-dimensional variable range hopping mechanism. The microstructural evolution of the virgin and ion-beam modified samples was investigated by spectroscopic analysis such as UV/Vis and FTIR. These spectral studies gave evidence for the production of conjugate double bonds, which is a clear cut indication of implant doping. This is an important result since ion implantation usually does not produce doping in polymeric materials and only a few reports about the possibility of implant doping in polymers are available. The significant aspect of this study is that this confirms, the Natural Rubber's potential to be used as a microelectronic device material. Also an attempt has been made to compare the conductivity enhancement in Natural Rubber by chemical and implant doping

  13. Natural Rubber Latex Hypersensitivity with Skin Prick Test in Operating Room Personnel

    Directory of Open Access Journals (Sweden)

    Seyed Hessamedin Nabavizadeh

    2009-12-01

    Full Text Available Hypersensitivity reactions to natural rubber latex have increased recently, especially among people with high exposure to latex allergens. Hypersensitivity reactions to latex are related to many conditions like occupational asthma. Our study was performed to determine the prevalence of hypersensitivity to natural rubber latex and potential food cross reactions in operation room personnel in Shiraz hospitals. In this cross-sectional, descriptive study, 580 operation room personnel filled out our questionnaire which included data about their personal history, symptoms of latex hypersensitivity, and other related allergies such as food hypersensitivity. An informed consent was obtained and skin prick tests were performed for natural rubber latex and potential food cross reactions (kiwi, banana, and potato. The obtained data were analyzed by SPSS and Chi-square test.Results: 104 (17.9% of the operating room personnel showed positive latex skin tests. We revealed a significant correlation between those with positive skin tests to latex with atopia, urthicaria, and food hypersensitivity. The prevalence did not vary by sex, age, education, surgical and non-surgical gloves users, or history of contact dermatitis. Latex hypersensitivity is common among operation room personnel. Evaluation of symptoms and prediction of future diseases necessitate screening tests in individuals at risk.

  14. Graft Copolymerization of Methyl Methacrylate Monomer onto Starch and Natural Rubber Latex Initiated by Gamma Irradiation

    Directory of Open Access Journals (Sweden)

    S. Iskandar

    2011-04-01

    Full Text Available To obtain the degradable plastic, the graft copolymerization of methyl methacrylate onto starch and natural rubber latex was conducted by a simultaneous irradiation technique. Gamma-ray from cobalt-60 source was used as the initiator. The grafted copolymer of starch-polymethyl methacrylate and the grafted copolymer of natural rubber-polymethyl methacrylate were mixed in the blender, and dried it in the oven. The dried grafted copolymer mixture was then molded using hydraulic press machine. The effect of irradiation dose, composition of the grafted copolymer mixture, film forming condition and recycle effect was evaluated. The parameters observed were tensile strength, gel fraction and soil burial degradability of grafted copolymer mixture. It was found that the tensile strength of grafted copolymer mixture increased by -ray irradiation. Increasing of the grafted copolymer of natural rubber-polymethyl methacrylate content, the gel fraction and tensile strength of the grafted copolymer mixture increased. The tensile strength of the grafted copolymer mixture was increased from 18 MPa to 23 MPa after recycled (film forming reprocessed 3 times. The grafted copolymer mixture was degraded completely after soil buried for 6 months

  15. Mechanical and Magnetic Properties of Thermoplastic Natural Rubber Nanocomposites Filled with Barium Ferrit

    Science.gov (United States)

    Milad, Mohamed M. M.; Ahmad, Sahrim Hj.; Yahya, S. Y.; Tarawneh, Mou'ad. A.

    2009-06-01

    This study was undertaken to investigate the mechanical and magnetic properties of thermoplastic natural rubber (TPNR) filled with barium ferrite BaFe12O19 nanoparticle. The nanocompasites were prepared via melt blending method using the Haake 600 p internal mixer. The content of the filler is varied from 2-10% by volume fraction. TPNR is a blend of polypropylene (PP), liquid natural rubber (LNR) and natural rubber (NR) at the percentage of volume ratio 70:10:20. The nanocomposites were prepared at 180° C with mixing speed 110 and 13 min mixing time. Tensile properties of the samples were measured using a universal machine, Tensometric 500. The results show that TPNR nanocomposites with only 4% nanoparticles exhibited good mechanical properties. The improvements were about 23.7% for tensile strength 20.1% for Young's modulus and 11.16% for strain respectively. The magnetic properties of TPNR filled nanoparticles was studied using vibrating sample magnetometer (VSM) at room temperature and it was found that magnetization (Ms), and remanent magnetization (Mr) increased with increasing ferrite content.

  16. Wood Sawdust/Natural Rubber Ecocomposites Cross-Linked by Electron Beam Irradiation

    Directory of Open Access Journals (Sweden)

    Elena Manaila

    2016-06-01

    Full Text Available The obtaining and characterization of some polymeric eco-composites based on wood sawdust and natural rubber is presented. The natural rubber was cross-linked using the electron beam irradiation. The irradiation doses were of 75, 150, 300 and 600 kGy and the concentrations of wood sawdust were of 10 and 20 phr, respectively. As a result of wood sawdust adding, the physical and mechanical properties such as hardness, modulus at 100% elongation and tensile strength, showed significant improvements. The presence of wood sawdust fibers has a reinforcing effect on natural rubber, similar or better than of mineral fillers. An increase in the irradiation dose leads to the increasing of cross-link density, which is reflected in the improvement of hardness, modulus at 100% elongation and tensile strength of blends. The cross-linking rates, appreciated using the Flory-Rehner equation, have increased with the amount of wood sawdust in blends and with the irradiation dose. Even if the gel fraction values have varied irregularly with the amount of wood sawdust and irradiation dose it was over 90% for all blends, except for the samples without wood sawdust irradiated with 75 kGy. The water uptake increased with increasing of fiber content and decreased with the irradiation dose.

  17. Sensitisation to natural rubber latex: an epidemiological study of workers exposed during tapping and glove manufacture in Thailand

    OpenAIRE

    CHAIEAR, N.; Sadhra, S; Jones, M.; Cullinan, P.; Foulds, I.; BURGE, P

    2001-01-01

    OBJECTIVES—To estimate the prevalence of sensitisation to natural rubber latex in latex tappers and latex glove factory workers, and to relate this to airborne exposure to latex.
METHODS—Five hundred workers employed in three latex glove factories, 314 tappers, and 144 college students (control group) were studied. The workers in the glove factories were classified into three exposure groups; high, moderate, and low. Personal exposures to natural rubber latex aeroallergens were measured by im...

  18. Sensitizers for the Radiation-Induced Vulcanization of Natural Rubber and Other Hydrocarbon Polymers

    International Nuclear Information System (INIS)

    A considerable volume of work has been directed towards the radiation-induced vulcanization of natural and synthetic rubbers, principally with a view to finding a novel application of radiation in the processing and manufacture of rubber products. It is clear that the cost of such processing is high and the mechanical properties of the radiation-vulcanized product are inferior when compared to its sulphur-cured competitor; only in a limited number of properties, e.g. heat aging, is there any improvement. The present work describes a laboratory study of sensitizers which enable the dose for a satisfactory cure to be reduced from 40-50 Mrad to 2-5 Mrad or even lower doses if conditions are carefully controlled. The mechanism of the reaction is described and it is shown that as the radiation-induced cross-linking reaction in the presence of these sensitizers is a chain process, the reaction becomes dose rate dependent and, therefore, it is favoured by the use of isotope sources giving a low dose rate. The physical properties of the cross-linked rubbers are compared with those made by peroxide and sulphur-curing techniques and the differences are explained in terms of the nature of the new type of cross link. Isotope-labelled sensitizers have been used to determine independently the concentration of cross-links produced by irradiation. (author)

  19. Swelling behaviour of isora/natural rubber composites in oils used in automobiles

    Indian Academy of Sciences (India)

    Lovely Mathew; K U Joseph; Rani Joseph

    2006-02-01

    Natural rubber/isora fibre composites were cured at various temperatures. The solvent swelling characteristics of natural rubber composites containing both untreated and alkali treated fibres were investigated in aromatic and aliphatic solvents like toluene, and -hexane. The diffusion experiments were conducted by the sorption gravimetric method. The restrictions on elastomer swelling exerted by isora fibre as well as the anisotropy of swelling of the composite have been confirmed by this study. Composite cured at 100°C shows the lowest percentage swelling. The uptake of aromatic solvent is higher than that of aliphatic solvent for the composites cured at all temperatures. The effect of fibre loading on the swelling behaviour of the composite was also investigated in oils like petrol, diesel, lubricating oil etc. The % swelling index and swelling coefficient of the composite were found to decrease with increase in fibre loading. This is due to the increased hindrance exerted by the fibres at higher fibre loadings and also due to the good fibre–rubber interactions. Maximum uptake of solvent was observed with petrol followed by diesel and then lubricating oil. The presence of bonding agent in the composites restrict the swelling considerably due to the strong interfacial adhesion. At a fixed fibre loading, the alkali treated fibre composite showed lower percentage swelling compared to the untreated one.

  20. Novel sustained-release of Stryphnodendron obovatum leaves extract using natural rubber latex as carrier

    Directory of Open Access Journals (Sweden)

    Felipe Azevedo Borges

    2016-07-01

    Full Text Available Natural rubber latex biomembranes (NRL, obtained from rubber tree Hevea brasiliensis (Willd. ex A. Juss. Mull. Arg., have been used as sustained drug release of drugs and plant extracts with medicinal properties. The Stryphnodendron obovatum Bench (Fabaceae, popularly known as “barbatimão” has anti-inflammatory and healing properties already described in literature. Thus, the aim of this work were to study the release behavior of the hydroethanolic extract from the leaves of S. obovatum loaded in the NRL by ultraviolet–visible spectroscopy (UV-VIS. The release followed a bi- exponential pattern and the mechanism of release was Super Case II (n > 1. FTIR analyses did not show reaction between NRL and extract, only intermolecular interaction. From SEM was possible to observe the extract at the surface, responsible for the initial fast release, which the concentrations at 5.0 mg/mL released 2.4% and at 0.1 mg/mL released 96.8%; both reached the plateau in 7 days.Keywords: Stryphnodendron obovatum. Hevea brasiliensis. Sustained release. Barbatimão. Tannin. Natural rubber latex.  

  1. Attenuation of foot pressure during running on four different surfaces: asphalt, concrete, rubber, and natural grass.

    Science.gov (United States)

    Tessutti, Vitor; Ribeiro, Ana Paula; Trombini-Souza, Francis; Sacco, Isabel C N

    2012-01-01

    The practice of running has consistently increased worldwide, and with it, related lower limb injuries. The type of running surface has been associated with running injury etiology, in addition other factors, such as the relationship between the amount and intensity of training. There is still controversy in the literature regarding the biomechanical effects of different types of running surfaces on foot-floor interaction. The aim of this study was to investigate the influence of running on asphalt, concrete, natural grass, and rubber on in-shoe pressure patterns in adult recreational runners. Forty-seven adult recreational runners ran twice for 40 m on all four different surfaces at 12 ± 5% km · h(-1). Peak pressure, pressure-time integral, and contact time were recorded by Pedar X insoles. Asphalt and concrete were similar for all plantar variables and pressure zones. Running on grass produced peak pressures 9.3% to 16.6% lower (P rubber was greater than on concrete for the rearfoot and midfoot. The behaviour of rubber was similar to that obtained for the rigid surfaces - concrete and asphalt - possibly because of its time of usage (five years). Running on natural grass attenuates in-shoe plantar pressures in recreational runners. If a runner controls the amount and intensity of practice, running on grass may reduce the total stress on the musculoskeletal system compared with the total musculoskeletal stress when running on more rigid surfaces, such as asphalt and concrete. PMID:22897427

  2. Novel Slide-Ring Material/Natural Rubber Composites with High Damping Property

    Science.gov (United States)

    Wang, Wencai; Zhao, Detao; Yang, Jingna; Nishi, Toshio; Ito, Kohzo; Zhao, Xiuying; Zhang, Liqun

    2016-03-01

    A novel class of polymers called “slide-ring” (SR) materials with slideable junctions were used for high damping composites for the first time. The SR acts as the high damping phase dispersed in the natural rubber (NR) matrix, and epoxidized natural rubber (ENR) acts as the compatibilizer. The morphological, structural, and mechanical properties of the composites were investigated by atomic force microscope (AFM), transmission electron microscope (TEM), dynamic mechanical thermal analyzer (DMTA), rubber processing analyzer (RPA), and tensile tester. AFM and TEM results showed that the SR phase was uniformly dispersed in the composites, in a small size that is a function of ENR. DMTA and RPA results showed that the damping factor of the composites is much higher than that of NR, especially at room temperatures. Stretch hysteresis was used to study the energy dissipation of the composites at large strains. The results showed that SR and ENR can significantly improve the dissipation efficiency at strains lower than 200% strain. Wide-angle X-ray diffraction was used to study the strain-induced crystallization of the composites. The results indicated that the impact of the SR on the crystallization of NR is mitigated by the insulating effect of ENR.

  3. Molecular Structures and Mechanical Properties of Microbe Rapid Coagulation Natural Rubber

    Institute of Scientific and Technical Information of China (English)

    LIANG Yue; HUANG Mao-Fang; ZENG Zong-Qiang

    2011-01-01

    In this work,molecular structures,dynamic mechanical properties and glass transition temperatures of microbe coagulated natural rubber(NR) samples were analyzed by using pyrolysis gas chromatography-mass spectrometry(py-GC/MS),rubber process analyzer(RPA) and dynamic mechanical thermal analysis(DMA).And the cross-linked network structures and mechanical properties of the corresponding NR vulcanizates were further determined by using nuclear magnetic resonance(NMR) crosslink density spectrometer(XLDS-15) and universal testing machines.The results show that NR raw rubber produced by rapidly coagulated with microorganism exhibits a simple molecular structure composition and good dynamic mechanical properties,and the corresponding NR vulcanizates possess the aggregation structure of high cross-linked density,a high glass transition temperature of-61.5 ℃ and high mechanical properties(tensile strength reaches 25.2 MPa),as compared with that coagulated with acetic acid.

  4. Effect of radiation dose on the properties of natural rubber nanocomposite

    International Nuclear Information System (INIS)

    Effect of radiation dose and carbon nanotubes (CNT) on the mechanical properties of standard Malaysian rubber (SMR) was investigated in this study. SMR nanocomposites containing 1-7 phr CNT were prepared using the solvent casting method and the nanocomposites were radiated at doses of 50-200 kGy. The change in mechanical properties, especially, tensile strength (Ts), elongation at break (Eb), hardness and tensile modulus at 100% elongation (M100) were studied as a function of radiation dose. The structure and morphology of reinforced natural rubber was investigated by FESEM, TEM and AFM in order to gain further evidence on the radiation-induced crosslinking. It was found that the Ts, M100 and the hardness of the SMR/CNT nanocomposites significantly increased with radiation dose; the elongation at break exhibited an increase up to 100 kGy, and a downward trend thereafter. Results on gel fraction further confirmed the crosslinking of SMR/CNT nanocomposites upon radiation.

  5. Monitoring Network and Interfacial Healing Processes by Broadband Dielectric Spectroscopy: A Case Study on Natural Rubber.

    Science.gov (United States)

    Hernández, M; Grande, A M; van der Zwaag, S; García, S J

    2016-04-27

    Broadband dielectric spectroscopy (BDS) is introduced as a new and powerful technique to monitor network and macroscale damage healing in an elastomer. For the proof of concept, a partially cured sulfur-cured natural rubber (NR) containing reversible disulfides as the healing moiety was employed. The forms of damage healed and monitored were an invisible damage in the rubber network due to multiple straining and an imposed macroscopic crack. The relaxation times of pristine, damaged, and healed samples were determined and fitted to the Havriliak-Negami equation to obtain the characteristic polymer parameters. It is shown that seemingly full mechanical healing occurred regardless the type of damage, while BDS demonstrates that the polymer architecture in the healed material differs from that in the original one. These results represent a step forward in the understanding of damage and healing processes in intrinsic self-healing polymer systems with prospective applications such as coatings, tires, seals, and gaskets. PMID:27057588

  6. Radiation vulcanization of natural rubber latex with 3 MeV electron beams, 1

    International Nuclear Information System (INIS)

    The sensitized radiation vulcanization of natural rubber latex has been carried out with a 3 MeV, 25 mA Dynamitron electron accelerator. Latex was irradiated over a range of dose rate from 0.3 to 60 kGy/sec in the presence of sensitizers such as n-butyl acrylate, 2-ethylhexyl acrylate, and 1,6-hexanediol diacrylate. The sensitized vulcanization of NR latex with electron beams is greatly affected by dose rate. The vulcanization dose increases with increasing dose rate. The maximum tensile strength of rubber films from the irradiated latex decreases slightly with increasing dose rate. There is negligible effect of dose rate on the viscosity of the irradiated latex. (author)

  7. Improved dynamic properties of natural rubber filled with irradiation-modified carbon black

    Science.gov (United States)

    Wu, Yongpeng; Wen, Shipeng; Shen, Jing; Jiang, Jian; Hu, Shui; Zhang, Liqun; Liu, Li

    2015-06-01

    In this work, carbon black particles (CBs) were modified by high-energy electron beam (EB) irradiation at different doses. The influence of EB irradiation on the surface and particle size of CBs was investigated. Then, the CBs were compounded with natural rubber (NR), and the mechanical properties and dynamic properties of CBs/NR composite were further researched. The results showed that the irradiated CBs had more oxygen-containing groups and smaller particle sizes than original CBs. After irradiation, the content of bound rubber around the irradiated CBs increased, and the mechanical properties of CBs/NR composite were improved. Most importantly, NR filled with irradiated CBs has lower abrasion, higher wet skid resistance, and lower rolling resistance than NR filled with untreated CBs.

  8. Extractable proteins from electron beam (EB) irradiated natural rubber (NR) latex

    International Nuclear Information System (INIS)

    The protein assay of natural rubber latex (NRL) vulcanized by low energy electron beam (EB, 300 keV, 30 mA) has been carried out using Bicinchoninic acid (BCA) reagent. Extractable protein in irradiated latex film was determined by measuring the absorption of colored solution at 562 nm using UV spectrometer. The effect of various radiation doses on the extractable protein content of NRL was investigated. It was ,found that the quantities of extractable protein increases with radiation dose. When compared with ,gamma-ray irradiated samples the same trend was observed. Electron beam irradiated latex films are leached in 1% (ammonia water for various lengths of time. From the results it was established that within 2 hours of leaching in ammonia water most of the extractable protein (96%) were removed from rubber film

  9. Radiation vulcanization of natural rubber latex using irradiation n-butyl acrylate aqueous emulsion as sensitizer

    International Nuclear Information System (INIS)

    Natural rubber latex was vulcanized by gamma radiation with n-butyl acrylate aqueous emulsion irradiated at dose of 1.5 kGy as sensitizer. The total solid content of latex increases on the irradiation dose. The viscosity of latex on the standing time was investigated and became stable after one month of storage. The gel content of latex films increasing with irradiation dose and attained more than 94% at dose of 10 kGy. Tensile strength of films reached the values of 31MPa; 30 Mpa and 25 Mpa at vulcanization doses of 20 kGy, 15 kGy and 8 kGy for the concentrations of sensitizer 7 phr, 9 phr and 13 phr respectively. Elongation at break decreases as increasing dose. Tear strength of rubber films was from 30-40 N/mm. The tackiness of latex films decreases and smell of vulcanized latex is almost negligible. (author)

  10. Nanocelluloses from jute fibers and their nanocomposites with natural rubber: Preparation and characterization.

    Science.gov (United States)

    Thomas, Martin George; Abraham, Eldho; Jyotishkumar, P; Maria, Hanna J; Pothen, Laly A; Thomas, Sabu

    2015-11-01

    Nanocellulose fibers having an average diameter of 50nm were isolated from raw jute fibers by steam explosion process. The isolation of nanocellulose from jute fibers by this extraction process is proved by SEM, XRD, FTIR, birefringence and TEM characterizations. This nanocellulose was used as the reinforcing agent in natural rubber (NR) latex along with crosslinking agents to prepare crosslinked nanocomposite films. The effects of nanocellulose loading on the morphology and mechanics of the nanocomposites have been carefully analyzed. Significant improvements in the Young's modulus and tensile strength of the nanocomposite were observed because of the reinforcing ability of the nanocellulose in the rubber matrix. A mechanism is suggested for the formation of the Zn-cellulose complex. The three-dimensional network of cellulose nanofibers (cellulose/cellulose network and Zn/cellulose network) in the NR matrix plays a major role in improving the properties of the crosslinked nanocomposites. PMID:26318667

  11. Extraction and comparison of proteins from natural rubber latex by conventional and ionizing radiation methods

    International Nuclear Information System (INIS)

    Several proteins in natural rubber latex (NRL) have been assigned to be significant allergens. It is known that proteins submitted to ionizing radiation suffer denaturation and immunochemical modification resulting in low antigenic reactivity. The aim of this study was to extract and compare water extractable proteins from NRL films vulcanized by conventional and by ionizing radiation methods. SDS-polyacrylamide gel electrophoresis (SDS--PAGE) and high pressure liquid chromatography (HPLC) showed a diffuse protein band of about 14 KDa, which we believe is rubber elongation factor (REF), in both eluates, but smaller in latex film vulcanized by ionizing radiation. REF has been suggested to be a major latex allergen. These data suggest that ionizing radiation vulcanization could be an useful method for the production of NRL goods with low antigenicity. (author). 8 refs., 2 figs., 1 tab

  12. The door leaf design for X-rays room basically on the composite of natural rubber lead oxide

    International Nuclear Information System (INIS)

    The door leaf design for X-rays room basically on the composite of natural rubber lead oxide have been carried out. Aim these design is to mastery in manufacture technology and optimalization of fabrication proses of the composite. The design involve the absorption strength in which basically on the composition of lead oxide in the composite and thickness of the door leaf for X-ray in that 100 keV energy is application. Result of this calculation show that X-ray door leaf in 2 mm thickness can be change by the composite natural rubber lead oxide in that 75 - 150 part per one hundred rubber composition and 3.5 - 2 cm thick. At the time that door leaf in which has 3 mm thick can be change by the composite in which have 100 - 175 part per one hundred rubber composition and 4 - 2.5 cm thickness. (author)

  13. Development of human tissue simulator from natural rubber latex vulcanized by gamma rays

    International Nuclear Information System (INIS)

    In this study, a tissue simulator as 'bolus' was developed from natural rubber latex vulcanized by gamma rays from 60Co source (10 kGy, [An-B] 3 phr, [KOH] = 0.2 phr), placed directly onto the skin in order to raise the dose for radiotherapy treatment lesions close to skin surface. The latex formulation, either in the first step of radiovulcanization or in filler addition (n-butyl acrylate, An-B, 0-14 phr and titanium dioxide, TiO2, 0-16 phr) was calculated in accordance with total solid contents (61.6%) and dried rubber (60.4%) contents. The natural rubber slabs were obtained by casting method. Then they were characterized by the specific mass, effective atomic number (Z-bar) and the absorbed dose curve which were compared with those from water, assumed as the standard material for human tissue, besides to evaluating the irritability of the skin surface. The Z-bar values were calculated by two different methodologies. In the 'weight analysis' the Equation Z-bar = ΣiαiZi was considered, where m is a constant (White, m = 0.82, Bichsel m = 0.25), αi and Zi are the electron number and the atomic number of the i element, respectively. The second method was 'stopping power' (dE/dx) and it was used the following Equation Z-bar = ΣZ-i(dE/dx)iαi/Σ(dE/dx)iαi i and the parameters were obtained from the adsorbed dose curve. Weight fraction of each element was determined by elemental analysis and by X-rays spectrometry fluorescence. The weight method values were higher than (m = 0.82) or equal (m = 0.25) from that obtained by 'stopping power'. The An-B filler (14 phr) neither modifies significantly the specific gravity nor Z-bar but when 12.0 phr of TiO2 was added the rubber specific gravity increases from 0.9166 g/mL to 1.004 g/mL and Z-bar from 4.26 to 4.78 (Dwater = 1 g/mL, Z-barpolyethylene = 6.6). The depth dose absorbed measurements irradiated with 6 MeV electron beams, expressed in ionization percentage, showed that the addition of 12 phr of TiO2 in the natural

  14. The curing behaviors of the epoxy/dicyanamide system modified with epoxidized natural rubber

    International Nuclear Information System (INIS)

    The effects of epoxidized natural rubber (ENR) on the curing behaviors and adhesive strengths of an epoxy (diglycidyl ether of bisphenol-A) and dicyandiamide/2-methyl imidazole system are studied with differential thermal calorimetry (DSC), scanning electron microscopy (SEM), and Instron tensile testing instrument. From DSC analyses of specimens prepared with unsealed aluminum pans, it is obtained that the reaction exotherm, the time to maximal curing rate, the glass transition temperature, the rate constant, and the reaction order of the epoxy system change with respect to the content of ENR added because of the reaction of ENR with the epoxy system. The results obtained from SEM micrographs indicate that the particle size of the rubber phase increases with increasing the curing temperature and the ENR content. The volume fraction of the separated rubber phase also follows the similar trend except at the high curing temperature which implying that the dissolution of epoxy resin in the ENR phase also depends on the curing temperature and the amount of ENR present. The lap shear strengths of specimens prepared with etched aluminum substrates increase with increasing the curing temperature because of a better cure at a higher temperature, but decrease with increasing the ENR content resulting from an adverse effect of ENR on the mechanical properties of the cured resins

  15. The curing behaviors of the epoxy/dicyanamide system modified with epoxidized natural rubber

    Energy Technology Data Exchange (ETDEWEB)

    Hong, S.-G.; Chan, C.-K

    2004-07-09

    The effects of epoxidized natural rubber (ENR) on the curing behaviors and adhesive strengths of an epoxy (diglycidyl ether of bisphenol-A) and dicyandiamide/2-methyl imidazole system are studied with differential thermal calorimetry (DSC), scanning electron microscopy (SEM), and Instron tensile testing instrument. From DSC analyses of specimens prepared with unsealed aluminum pans, it is obtained that the reaction exotherm, the time to maximal curing rate, the glass transition temperature, the rate constant, and the reaction order of the epoxy system change with respect to the content of ENR added because of the reaction of ENR with the epoxy system. The results obtained from SEM micrographs indicate that the particle size of the rubber phase increases with increasing the curing temperature and the ENR content. The volume fraction of the separated rubber phase also follows the similar trend except at the high curing temperature which implying that the dissolution of epoxy resin in the ENR phase also depends on the curing temperature and the amount of ENR present. The lap shear strengths of specimens prepared with etched aluminum substrates increase with increasing the curing temperature because of a better cure at a higher temperature, but decrease with increasing the ENR content resulting from an adverse effect of ENR on the mechanical properties of the cured resins.

  16. Solar-assisted smokehouse for the drying of natural rubber on small-scale Indonesian farms

    Energy Technology Data Exchange (ETDEWEB)

    Breymayer, M.; Pass, T.; Muehlbauer, W. (Hohenheim Univ., Stuttgart (Germany). Inst. for Agricultural Engineering in the Tropics and Subtropics); Amir, E.J.; Mulato, S. (Bogor Research Inst. for Estate Crops, Bogor (Indonesia))

    1993-11-01

    Natural rubber in Indonesia is mainly produced by smallholder farmers and-being the highest foreign currency generating agricultural commodity-is of great importance for the Indonesian economy. Nevertheless, due to the lack of appropriate dryers, more than 80% of the total production has to be sold as low-grade Standard Indonesian Rubber (SIR) for a relatively low price. In order to improve the product quality, a solar-heated rubber sheet dryer was developed. It consists of a flat-plate solar air heater connected to a drying chamber. Part-recirculation of the exhaust air leads to the desired drying air temperature of 45-60[sup o]C and results in a significant reduction of the drying time. To enable drying independent of weather conditions, a biomass furnace was incorporated underneath the drying chamber. The simple design of the solar-assisted smokehouse allows local production and after further improvements seems to be an economical alternative for farmer groups or nucleus estates. (Author)

  17. The Integration of Cleaner Production Indicators on the Environmental Performance Measurement System for the Indonesian Natural Rubber Industry

    Directory of Open Access Journals (Sweden)

    Sawarni Hasibuan

    2013-01-01

    Full Text Available This study aims to identify the priority of the cleaner production implementation and integrate it in the design of a comprehensive environmental performance measurement system for natural rubber industry in Indonesia. Prioritizing the cleaner production on the production process of natural rubber is based on the case of 10 Indonesian crumb rubber companies using the Analytical Hierarchy Process. The comprehensive environmental performance measurement system in natural rubber industry, i.e. in crumb rubber industry, starts from the selection of key environmental performance indicators (KEPI using the fuzzy independent preference evaluation method. The environmental performance measurement model is developed to assist users in evaluating the comprehensive environmental performance and condition of the key indicators. The weighting for each of the KEPI is performed by means of the expert choice software. The environmental performance measurement model is designed in the form of a environmental scorecard with traffic light facilities which can provide recommendations based on the performance achievement status of each KEPI. From the results of the model verification in the case of crumb rubber industry, several indicator statuses were found "not good", i.e. on the index of raw materials, solid waste load, water conservation, energy conservation, and environmental innovation indicators. The environmental performance ranking model is designed to evaluate the comprehensive environmental performance in different companies or at different assessment periods.

  18. 2,2,2-Trifluoroethyl methacrylate-graft-natural rubber: Synthesis and application as compatibilizer in natural rubber/fluoroelastomer blends

    International Nuclear Information System (INIS)

    The incompatibility and immiscibility of natural rubber (NR)/fluoroelastomers (FKM) blends were improved by incorporation of a graft copolymer synthesized from the free radical graft copolymerization of 2,2,2-trifluoroethyl methacrylate (TFEM) onto NR initiated by benzoyl peroxide via a melt-mixing process. The grafting properties were investigated as functions of the initiator and monomer concentrations, reaction temperature and time. At the optimal conditions, the obtained graft NR (GNR) purified by Soxhlet extraction contained a maximum grafting efficiency of 1.34% with 49.1% monomer conversion. The structure of the purified GNR was analyzed using attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and nuclear magnetic resonance spectroscopy (1H NMR and 19F NMR). The gross GNR was then applied as the compatibilizer for NR/FKM vulcanizates (20/80 (w/w)) cured by peroxide vulcanization. The addition of GNR at 15 parts per hundred of rubber (phr) gave a vulcanizate with the highest tensile strength (9.93 MPa), some 5.31-fold higher than that of the incompatibilized one (1.87 MPa). This is likely to be due to the higher degree of homogeneity of the constituent phases in the GNR-compatibilized blends, as observed by scanning electron microscopy (SEM). The GNR-compatibilized NR/FKM vulcanizates were also resistant to gasohol E85 (85% (w/w) of ethanol). Highlights: ► 2,2,2-Trifluoroethyl methacrylate could be grafted on NR via melt-mixing process. ► Effect of grafting parameters on grafting efficiency and gel content was observed. ► NR/FKM containing graft NR had higher tensile strength than uncompatibilized ones. ► The compatibilized NR/FKM vulcanizates had higher gasohol-swelling resistance

  19. 2,2,2-Trifluoroethyl methacrylate-graft-natural rubber: Synthesis and application as compatibilizer in natural rubber/fluoroelastomer blends

    Energy Technology Data Exchange (ETDEWEB)

    Hinchiranan, N., E-mail: nhn78@hotmail.com [Department of Chemical Technology, Faculty of Science, Chulalongkorn University, Bangkok 10330 (Thailand); Wannako, P. [Program in Petrochemistry and Polymer Science, Faculty of Science, Chulalongkorn University, Bangkok 10330 (Thailand); Paosawatyanyong, B. [Department of Physics, Faculty of Science, Chulalongkorn University, Bangkok 10330 (Thailand); Prasassarakich, P. [Department of Chemical Technology, Faculty of Science, Chulalongkorn University, Bangkok 10330 (Thailand)

    2013-05-15

    The incompatibility and immiscibility of natural rubber (NR)/fluoroelastomers (FKM) blends were improved by incorporation of a graft copolymer synthesized from the free radical graft copolymerization of 2,2,2-trifluoroethyl methacrylate (TFEM) onto NR initiated by benzoyl peroxide via a melt-mixing process. The grafting properties were investigated as functions of the initiator and monomer concentrations, reaction temperature and time. At the optimal conditions, the obtained graft NR (GNR) purified by Soxhlet extraction contained a maximum grafting efficiency of 1.34% with 49.1% monomer conversion. The structure of the purified GNR was analyzed using attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and nuclear magnetic resonance spectroscopy ({sup 1}H NMR and {sup 19}F NMR). The gross GNR was then applied as the compatibilizer for NR/FKM vulcanizates (20/80 (w/w)) cured by peroxide vulcanization. The addition of GNR at 15 parts per hundred of rubber (phr) gave a vulcanizate with the highest tensile strength (9.93 MPa), some 5.31-fold higher than that of the incompatibilized one (1.87 MPa). This is likely to be due to the higher degree of homogeneity of the constituent phases in the GNR-compatibilized blends, as observed by scanning electron microscopy (SEM). The GNR-compatibilized NR/FKM vulcanizates were also resistant to gasohol E85 (85% (w/w) of ethanol). Highlights: ► 2,2,2-Trifluoroethyl methacrylate could be grafted on NR via melt-mixing process. ► Effect of grafting parameters on grafting efficiency and gel content was observed. ► NR/FKM containing graft NR had higher tensile strength than uncompatibilized ones. ► The compatibilized NR/FKM vulcanizates had higher gasohol-swelling resistance.

  20. Magnetic and microwave absorbing properties of magnetite-thermoplastic natural rubber nanocomposites

    International Nuclear Information System (INIS)

    Magnetic and microwave absorbing properties of thermoplastic natural rubber (TPNR) filled magnetite (Fe3O4) nanocomposites were investigated. The TPNR matrix was prepared from polypropylene (PP), natural rubber (NR) and liquid natural rubber (LNR) in the ratio of 70:20:10 with the LNR as the compatibilizer. TPNR-Fe3O4 nanocomposites with 4-12 wt% Fe3O4 as filler were prepared via a Thermo Haake internal mixer using a melt-blending method. XRD reveals the presence of cubic spinel structure of Fe3O4 with the lattice parameter of a=8.395 A. TEM micrograph shows that the Fe3O4 nanoparticles are almost spherical with the size ranging 20-50 nm. The values of saturation magnetization (MS), remanence (MR), initial magnetic susceptibility (χi) and initial permeability (μi) increase, while the coercivity (HC) decreases with increasing filler content for all compositions. For nanocomposites, the values of the real (εr') and imaginary permittivity (εr'') and imaginary permeability (μr'') increase, while the value of real permeability (μr') decreases as the filler content increases. The absorption or minimum reflection loss (RL) continuously increases and the dip shifts to a lower frequency region with the increasing of both filler content in nanocomposites and the sample thickness. The RL is -25.51 dB at 12.65 GHz and the absorbing bandwidth in which the RL is less than -10 dB is 2.7 GHz when the filler content is 12 wt% at 9 mm sample thickness.

  1. Radiation induced grafting of monomers onto natural rubber : processes and applications

    International Nuclear Information System (INIS)

    Full text: Certain inherent mechanical properties of natural rubber (NR) can be modified by grafting vinyl monomers onto the polymer backbone. This paper described the gamma radiation induced graft copolymerization of methyl methacrylate (MMA), styrene and acrylonitrile (AN) onto NR. The graft copolymers can be crosslinked by sulphur and organic accelerators. The crosslinked graft copolymers show improved modulus and hardness in their films compared to NR. However the tensile strength of the films is reduced by grafting. The methods for preparing the graft copolymers, their properties and applications are briefly described

  2. Radiation Vulcanization of Natural Rubber Latex (RVNRL): A Potential Material for Nuclear Power Plant Gloves

    International Nuclear Information System (INIS)

    Radiation vulcanization of natural rubber latex has great potential for the production of nuclear power plant gloves due to its low ash and mineral content. And this is in-line with the role played by Malaysian Nuclear Agency as Technical Supporting Organization for Nuclear Power Program. This paper discussed the evaluation done to determine ash content in RVNRL and SVNRL films. Both samples were prepared using casting technique and the properties were compared. Films prepared from raw latex without any vulcanizing agent were regarded as a control. (author)

  3. Miscibility study of hexanoyl chitosan in blend with epoxidized natural rubber by viscometric analysis

    Science.gov (United States)

    Jamal, Asheila; Chan, C. H.; Muhammad, F. H.; Winie, Tan

    2015-08-01

    Miscibility of blends of hexanoyl chitosan and epoxidized natural rubber with 25 mol% epoxidation level (ENR25) was investigated by dilute solution viscometry (DSV). Experimental results obey the Huggins' equation in the concentration range under investigation. Intrinsic viscosities are found to vary linearly with blend composition. The difference between experimental and ideal Huggins coefficients, κ =K12-√{K1ṡK2 } is proposed to evaluate the miscibility behavior of the blends. Negative deviations from the ideal behavior indicated immiscibility between hexanoyl chitosan and ENR25.

  4. Trial Production of Surgical Gloves from Irradiated Natural Rubber Latex on Factory Scale

    Directory of Open Access Journals (Sweden)

    M. Utama

    2005-07-01

    Full Text Available Trial production of surgical gloves from irradiated natural rubber latex at the PT. Laxindo Utama Serang Banten glove factory has been carried out. The variation of heating temperature and leaching time during processing were evaluated. The physical and mechanical properties and the protein allergen respond of surgical gloves using ELISA method were measured. The results showed that the physical and mechanical of surgical gloves such as tensile strength, modulus, and elongation at break arefound to meet the requirements of the ISO or SNI standard for surgical gloves. While the allergic response through clinical tested latex-sensitive protein allergen known as ELISA test is found to be negative.

  5. Mechanical Properties of Thermoplastic Natural Rubber (TPNR) Reinforced with Different Types of Carbon Nano tube

    International Nuclear Information System (INIS)

    The effect of various multi-walled carbon nano tubes (MWNTs) on the tensile properties of thermoplastic natural rubber (TPNR) nano composite was investigated. The nano composite was prepared using melt blending method. MWNTs were added to improve the mechanical properties of MWNTs/TPNR composites in different compositions of 1, 3, 5, and 7 wt. %. The results showed that the mechanical properties of nano composites were affected significantly by the composition and the properties of MWNTs. SEM micrographs confirmed the homogenous dispersion of MWNTs in the TPNR matrix and promoted strong interfacial adhesion between MWNTs and the matrix which was improved mechanical properties significantly. (author)

  6. Commercial options for the alternative process of natural rubber latex vulcanization induce by gamma radiation

    International Nuclear Information System (INIS)

    This work discuss the economical aspects of the surgical gloves fabrication process from the natural rubber latex vulcanized with gamma radiation. A medium size surgical gloves plant has been considered, with a daily capacity of 11,000 pairs of gloves, working under a three shifts work regime. Fabrication costs of the alternative process are 15% lower than the conventional process. From the four considered commercial options, the installation of a vulcanization plant is the most attractive for an investor aiming the smallest time for capital return. However, if a three times higher profit is desired, the investments must be oriented for a surgical gloves plant with the irradiation system installed

  7. Surgical gloves fabrication using natural rubber latex vulcanized with gamma radiation

    International Nuclear Information System (INIS)

    Surgical gloves were manufactured by immersion coagulant method from vulcanized natural rubber latex by gamma rays at dose of 10 kGy in the air, at room temperature, using the following sensitizer vulcanization An-B 3 phr/KOH 0.2 phr. The influence of the parameter in the thickness of the surgical gloves manufacture, studied through fractional factorial designs technic, can be resumed by empirical linear correlation: y = 0.213 + 0.025 [Ca Cl2] + 0.019 t. (author). 49 refs., 13 figs., 31 tabs

  8. Trial Production of Surgical Gloves from Irradiated Natural Rubber Latex on Factory Scale

    International Nuclear Information System (INIS)

    Trial production of surgical gloves from irradiated natural rubber latex at the PT. Laxindo Utama Serang Banten glove factory has been carried out. The variation of heating temperature and leaching time during processing were evaluated. The physical and mechanical properties and the protein allergen respond of surgical gloves using ELISA method were measured. The result showed that the physical and mechanical of surgical gloves such as tensile strength, modulus, and elongation at break are found to meet the requirements of the ISO or SNI standard for surgical gloves. While the allergic response through clinical tested latex-sensitive protein allergen known as ELISA test is found to be negative. (author)

  9. Preparation and Properties of Biocomposite Based on Natural Rubber and Bagasse Nanocellulose

    Directory of Open Access Journals (Sweden)

    Jarnthong Methakarn

    2015-01-01

    Full Text Available Biocomposite based on natural rubber (NR and bagasse nanocellulose (BNC was prepared in latex state. The mechanical, morphological and thermal properties of NR/BNC biocomposite were investigated. It was found that the addition of 3 wt% of BNC in NR film caused significant increase in modulus at 100% and 300% elongations and improved thermal stability of NR/BNC biocomposite. However, the strength at break and elongation at break of the biocomposite were not enhanced correlating to the morphological result obtained from scanning electron microscope (SEM.

  10. Use of low energy accelerator for the radiation vulcanization of natural rubber latex and nitrile rubber. The battle for the sustainability and poverty alleviation

    International Nuclear Information System (INIS)

    The origin of the Hevea braziliensis tree was the Amazonian basin. The rubber expansion at the end of 19th century brought prosperity and determined the borders of Amazonian countries. In spite of that, the Brazilian government has failed in establishing a successful policy for improving the NR production in the jungle. This battle has been a continuous defeat against the environment as it was not possible to control the fungus Microcyclos ulei in its natural environment. The defeat was catastrophic for the population of Amazon region as they were not able to shift to other sustainable activity. As a consequence of the tack of economical options, the population had to explore all available natural resources. It has been also catastrophic for the Amazonian environment. Nevertheless, rubber plantations were successfully introduced in areas were Hevea braziliensis was not native, mainly in the southeast of Brazil. And recently, it was also introduced near marginal areas of the humid forest in the Amazon due to the absence of the fungus Microcyclos ulei. Both, extraction of wild rubber and plantation have a key role in the maintenance of the forest health as the seringueiros not only have a sustainable activity but can also play a role as soldiers of the jungle. Actually, rubber activities are not only associated to the environment but also with poverty because the activities are labor intensive, so it needs cheap labor. The poverty is unfortunately spread out in rural areas of Brazil and in the peripheral areas of the big cities. Regarding environment and poverty the dilemma is critical in the Amazonian region and is the following: the forest should be maintained healthy and protected from devastating projects and at the same time needs of the inhabitants should be considered. (author)

  11. Nanolipoprotein particles comprising a natural rubber biosynthetic enzyme complex and related products, methods and systems

    Energy Technology Data Exchange (ETDEWEB)

    Hoeprich, Paul D.; Whalen, Maureen

    2016-04-05

    Provided herein are nanolipoprotein particles that comprise a biosynthetic enzyme more particularly an enzyme capable of catalyzing rubber or other rubbers polymerization, and related assemblies, devices, methods and systems.

  12. Improvement of toughness and water resistance of bioplastic based on wheat gluten using epoxidized natural rubber

    Science.gov (United States)

    Hemsri, S.; Thongpin, C.; Somkid, P.; Sae-arma, S.; Paiykaew, A.

    2015-07-01

    Novel blends based on wheat gluten (WG) and epoxidized natural rubber (ENR) were fabricated with different ENR contents of 10, 20 and 30 wt% in an internal mixer. Sulfur vulcanization was used to crosslink the ENR phase in the blends. Comparatively, blends of WG and natural rubber (WG/NR) were prepared in the same condition as the WG/ENR blends. Tensile mechanical properties and impact strength of the WG/ENR blends were investigated and compared with the WG/NR blends as well as pure WG. Moreover, water absorption of pure WG and the WG/ENR blends was also tested. As investigated by scanning electron microscopy (SEM), the results revealed more compatibility between WG and ENR compared with NR. The elongation at break, impact strength and water resistance of the WG/ENR blends were found to remarkably increase with respect to the pure WG. Thus, incorporation of ENR into WG could improve toughness and water resistance of WG. Furthermore, the effect of adding glycerol acting as a plasticizer on the mechanical properties and impact strength of the WG/ENR blends was also studied. The blends with glycerol-plasticized WG (WG-Gly/ENR) showed more homogeneous morphologies and superior results in the mechanical properties and impact strength compared with the WG/ENR blends.

  13. Radiation prevulcanized natural rubber latex: Cytotoxicity and safety evaluation on animal

    International Nuclear Information System (INIS)

    Radiation prevulcanized natural rubber latex (RVNRL) was claimed to be more user friendly than natural rubber latex prevulcanized by sulphur curing system. The absence of Type IV allergy inducing chemicals in RVNRL make it a suitable material for manufacturing of many kinds of latex products, especially those come into direct contact with users. This paper reveals and discusses the findings of cytotoxicity test and safety evaluation on animal for RVNRL. The test was done on RVNRL films prepared by coagulant dipping method and RVNRL dipped products produced by latex dipped product manufacturers. Cytotocixity test was carried out on mammalian cell culture American Type Culture Collection CCL 81, Vero. Results indicated that no cytotoxic effect from RVNRL films and products was found on the cell culture. Two animal studies, namely dermal sensitization study and primary skin irritation study, were done on gloves made from RVNRL. Albino white guinea pigs were used as test subjects in dermal sensitization study and results showed no sensitization induced by the application of test material in the guinea pigs. Primary skin irritation study was done on New Zealand white rabbits and results showed that the product tested was not corrosive and was not a primary irritant

  14. Thermal Characterization of Modified Tacca Leontopetaloides Starch and Natural Rubber Based Thermoplastic Elastomer

    International Nuclear Information System (INIS)

    The purpose of this study is to identify the potential of Tacca leontopetaloides starch as bio-based thermoplastic elastomers, TPEs. Starch based polymer had been recognized to have highly potential in replace existing source of conventional elastomeric polymer. The modification process of blending starch with natural rubber, plasticizers, additives, and filler contribute to the enhancement and improvement for the properties of starch in order to produce biopolymers by approaching the properties of TPEs. Thermal properties of starch based thermoplastic was studied to evaluate the decomposition and degradation of the samples by using Thermogravimetric Analysis, TGA while the properties of endothermic reactions of the samples were thermally analyzed via Differential Scanning Calorimetry, DSC. From the analysis, it was found that the thermal properties of samples were revealed by recognizing GM-2 (green materials, GM) has high thermal resistance towards high temperature up to 480.06 degree Celsius with higher amount of residue which is 4.97 mg compared to other samples. This indicates GM-2 comprises of superior combination of ratio between natural rubbers and glycerol (plasticizer) in purpose of approaching the properties of Thermoplastic Elastomers, TPEs. (author)

  15. Analysis of Toxicity of Ceramic Nanoparticles and Functional Nanocomposites Based on Vulcanized Natural Rubber

    Directory of Open Access Journals (Sweden)

    Bellucci Felipe Silva

    2015-01-01

    Full Text Available Nanocomposites are multiphase materials of which, at least one of the phases, has a dimension smaller than 100 nm. These materials have attracted technological and scientific interest due to their multifunctional characteristics and potential, which allow them to combine unique properties which are not found in traditional commercial materials, such as natural rubber alone. The objective of this work is to analyse the toxicity of nanoparticles and nanocomposites when applied to mammal cells in order to obtain bioactive agents, as well as to evaluate the potential to be applied in biological systems. Ferroelectric ceramic nanoparticles of KSr2Nb5O15 (KSN and paramagnetic ceramic nanoparticles Ni0.5Zn0.5Fe2O4 (NZF were prepared and utilized to produce functional and multifunctional nanocomposites based on vulcanized natural rubber (NR/KSN and NR/NZF with different nanoparticle concentrations. For both kinds of nanoparticles and both classes of nanocomposites, independently of the nanoparticle concentration, it is not possible to observe any reduction of the cellular viability until the incubation time is finished. In this way, these results point to the possibility of using these nanoparticles and nanocomposites, from the toxicity point of view, as bioactivity agents in biological systems based on mammalian cells.

  16. Natural rubber latex: glove use, sensitization, and airborne and latent dust concentrations at a Denver hospital.

    Science.gov (United States)

    Page, E H; Esswein, E J; Petersen, M R; Lewis, D M; Bledsoe, T A

    2000-06-01

    Exposure to natural rubber latex may cause immediate hypersensitivity reactions. Published latex sensitization prevalence rates range from 2.9% to 22% among health care workers, and from 0.12% to about 20% of occupationally unexposed populations. In this study, self-administered questionnaires addressed job and personal characteristics, glove use, and symptoms in two groups of hospital workers: those who regularly used latex gloves and those who did not. Serum was tested for latex-specific immunoglobulin E. Air, surface, and air-filter dust samples for natural rubber latex were collected. The prevalence of latex sensitization was 6.3% in the non-users and 6.1% in the latex glove users (P = 0.9); 81.3% of sensitized workers were atopic compared with 59.5% of non-sensitized workers (P glove users (23.4%) than in the non-users (4.9%), as were rhino-conjunctivitis (16.3% and 7.9%, respectively, [P glove use was not a risk factor for sensitization. PMID:10874654

  17. Effect of Reagents Concentration and Ratio on Degradation of Natural Rubber Latex in Acidic Medium

    International Nuclear Information System (INIS)

    The molecular weight of natural rubber (NR) was reduced via degradation to liquid natural rubber (LNR) using hydrogen peroxide and sodium nitrite as reagents in latex solution. In this study, the reaction was carried out in an acidic medium at 70 degree Celsius at various ratio and concentration of reagents. Results showed that the properties of degraded product for example LNR depends on the concentration and ratio of the reagents added into reaction mixtures. Increasing the concentration of hydrogen peroxide and sodium nitrite as reagents at 1 to 1 ratio efficiently reduced the molecular weight of LNR, but the gel content increased when reagents were added more than 0.2 mol. Hydrogen peroxide was found to have greater effect on degradation reaction compared to sodium nitrite when excessive amount of hydrogen peroxide showed further reduction in molecular weight of LNR. The degradation reaction also resulted in the formation of certain functional groups such as hydroxyl and carbonyl as shown from spectroscopy microstructure analysis. (author)

  18. The improvement in functional characteristics of eco-friendly composites made of natural rubber and cellulose

    Energy Technology Data Exchange (ETDEWEB)

    Araki, Kunihiro; Kaneko, Shonosuke; Matsumoto, Koki; Tanaka, Tatsuya; Arao, Yoshihiko [Applied Materials Engineering Laboratory, Faculty of Engineering, Doshisha University, 1-3, Tatara Miyakodani, Kyotanabe, Kyoto, 610-0321 (Japan); Nagatani, Asahiro [Applied Materials Engineering Laboratory, Faculty of Engineering, Doshisha University, 1-3, Tatara Miyakodani, Kyotanabe, Kyoto, 610-0321 (Japan); Hyogo Prefectural Institute of Technology, 3-1-12, Yukihira-cho, Suma-ku, Kobe, Hyogo, 654-0037 (Japan)

    2015-05-22

    We investigated the efficient use of cellulose to resolve the problem of the depletion of fossil resources. In this study, as the biomass material, the green composite based on natural rubber (NR) and the flake-shaped cellulose particles (FSCP) was produced. In order to further improvement of functional characteristics, epoxidized natural rubber (ENR) was also used instead of NR. The FSCP were produced by mechanical milling in a planetary ball mill with a grinding aid as a cellulose aggregation inhibitor. Moreover, talc and mica particles were used to compare with FSCP. NR and ENR was mixed with vulcanizing agents and then each filler was added to NR compound in an internal mixer. The vulcanizing agents are as follows: stearic acid, zinc oxide, sulfur, and vulcanization accelerator. The functionalities of the composites were evaluated by a vibration-damping experiment and a gas permeability experiment. As a result, we found that FSCP filler has effects similar to (or more than) inorganic filler in vibration-damping and O{sub 2} barrier properties. And then, vibration- damping and O{sub 2} barrier properties of the composite including FSCP was increased with use of ENR. In particular, we found that ENR-50 composite containing 50 phr FSCP has three times as high vibration-damping property as ENR-50 without FSCP.

  19. The improvement in functional characteristics of eco-friendly composites made of natural rubber and cellulose

    International Nuclear Information System (INIS)

    We investigated the efficient use of cellulose to resolve the problem of the depletion of fossil resources. In this study, as the biomass material, the green composite based on natural rubber (NR) and the flake-shaped cellulose particles (FSCP) was produced. In order to further improvement of functional characteristics, epoxidized natural rubber (ENR) was also used instead of NR. The FSCP were produced by mechanical milling in a planetary ball mill with a grinding aid as a cellulose aggregation inhibitor. Moreover, talc and mica particles were used to compare with FSCP. NR and ENR was mixed with vulcanizing agents and then each filler was added to NR compound in an internal mixer. The vulcanizing agents are as follows: stearic acid, zinc oxide, sulfur, and vulcanization accelerator. The functionalities of the composites were evaluated by a vibration-damping experiment and a gas permeability experiment. As a result, we found that FSCP filler has effects similar to (or more than) inorganic filler in vibration-damping and O2 barrier properties. And then, vibration- damping and O2 barrier properties of the composite including FSCP was increased with use of ENR. In particular, we found that ENR-50 composite containing 50 phr FSCP has three times as high vibration-damping property as ENR-50 without FSCP

  20. The influence of molybdenum disulfide nanoplatelets on the dispersion of nano silica in natural rubber composites

    Science.gov (United States)

    Weng, Peijin; Wei, Qiuyan; Tang, Zhenghai; Lin, Tengfei; Guo, Baochun

    2015-12-01

    The dispersion of nanofiller in polymer composites is critical in governing the ultimate performances. Present study aimed to improve the dispersion of silica in elastomeric materials based on natural rubber (NR) composites using the nanoplatelets of molybdenum disulfide (MoS2), a graphene-like layered inorganic. NR latex was co-coagulated with MoS2 suspension to form NR/MoS2 compounds (1∼5 phr). Then silica (30 phr) was incorporated into NR/MoS2 compounds, followed by curing with sulfur, to obtained NR/MoS2/silica composites. The dispersion state of silica in the composites was examined by TEM and the effects of MoS2 on the performance of the composites were investigated. It was found that a small amount of MoS2 nanoplatelets significantly improved the silica dispersion. Consequently, the static and dynamic mechanical properties of the crosslinked natural rubber materials were greatly enhanced. The improved dispersion of silica is associated with charge transfer interaction, giving rise to electrostatic repulsion among silica.

  1. Gentamicin sulfate-loaded porous natural rubber films for wound dressing.

    Science.gov (United States)

    Phaechamud, Thawatchai; Issarayungyuen, Pongsathorn; Pichayakorn, Wiwat

    2016-04-01

    Antimicrobial wound dressings have been developed for effectiveness of wound therapy. In this study, gentamicin sulfate was loaded into modified porous natural rubber films. The hydrophilic porous structure in natural rubber films was formed when the polar liquid such as glycerin or triethyl citrate and hydrophilic xanthan gum were blended. Film properties including morphology, drug release, water sorption and erosion, mechanical property, adhesive property, surface free energy, water vapor transmission rate, oxygen permeation, and antimicrobial activity were determined. The angiogenesis activity of films was investigated using chick chorio-allantoic membrane assay. For the system containing triethyl citrate, bi-layers comprising of a dense-top layer and a high porous-bottom layer were observed. Xanthan gum enhanced the water sorption capacity and modified to obtain the optimum rate of the drug release from the film. The developed film topography with dense-top layer induced the low adhesive property, water vapor and oxygen permeability whereas demonstrated good antimicrobial activities against Staphylococcus aureus and Pseudomonas aeruginosa with angiogenic activity. Therefore it had the potential use for medicated wound dressing. PMID:26776874

  2. Effect of Ultrasonic Treatment on The Tensile and Impact Properties of Thermoplastic Natural Rubber Nanocomposites Reinforced with Carbon Nanotubes

    International Nuclear Information System (INIS)

    This study investigates the effect of ultrasonic treatment on the mechanical properties of thermoplastic natural rubber (TPNR) nanocomposites reinforced with multi-walled nanotubes. The TPNR nanocomposites were prepared using melt blending method from polypropylene (PP), natural rubber (NR) and liquid natural rubber (LNR) as a compatibilizer, respectively, with 1% of Multi-wall nanotubes. The nanocomposite was prepared using the indirect technique (IDT) with the optimum processing parameters at 180 deg. C with 80 rpm mixing speed and 11 minutes processing time. The results have showed that the good dispersion on nanotubes was achieved by ultrasonic treatment. The optimization of ultrasonic time indicated that the maximum tensile and impact properties occurred with 1 h ultrasonic treatment. The Young's modulus, tensile strength, elongation at break and impact strength have increased by almost 11%, 21%, 43% and 50%, respectively. The results from our study indicate that nanotubes have as excellent reinforcement filler in TPNR matrix.

  3. Effect of Ultrasonic Treatment on The Tensile and Impact Properties of Thermoplastic Natural Rubber Nanocomposites Reinforced with Carbon Nanotubes

    Science.gov (United States)

    Tarawneh, Mou'ad A.; Ahmad, Sahrim Hj.; Yahya, S. Y.; Rasid, Rozaidi

    2009-06-01

    This study investigates the effect of ultrasonic treatment on the mechanical properties of thermoplastic natural rubber (TPNR) nanocomposites reinforced with multi-walled nanotubes. The TPNR nanocomposites were prepared using melt blending method from polypropylene (PP), natural rubber (NR) and liquid natural rubber (LNR) as a compatibilizer, respectively, with 1% of Multi-wall nanotubes. The nanocomposite was prepared using the indirect technique (IDT) with the optimum processing parameters at 180° C with 80 rpm mixing speed and 11 minutes processing time. The results have showed that the good dispersion on nanotubes was achieved by ultrasonic treatment. The optimization of ultrasonic time indicated that the maximum tensile and impact properties occurred with 1 h ultrasonic treatment. The Young's modulus, tensile strength, elongation at break and impact strength have increased by almost 11%, 21%, 43% and 50%, respectively. The results from our study indicate that nanotubes have as excellent reinforcement filler in TPNR matrix.

  4. 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.

  5. Study on the structure-properties relationship of natural rubber/SiO2 composites modified by a novel multi-functional rubber agent

    Directory of Open Access Journals (Sweden)

    S. Y. Yang

    2014-06-01

    Full Text Available Vulcanization property and structure-properties relationship of natural rubber (NR/silica (SiO2 composites modified by a novel multi-functional rubber agent, N-phenyl- N'-(γ-triethoxysilane-propyl thiourea (STU, are investigated in detail. Results from the infrared spectroscopy (IR and X-ray photoelectron spectroscopy (XPS show that STU can graft to the surface of SiO2 under heating, resulting in a fine-dispersed structure in the rubber matrix without the connectivity of SiO2 particles as revealed by transmission electron microscopy (TEM. This modification effect reduces the block vulcanization effect of SiO2 for NR/SiO2/STU compounds under vulcanization process evidently. The 400% modulus and tensile strength of NR/SiO2/STU composites are much higher than that of NR/SiO2/TU composites, although the crystal index at the stretching ratio of 4 and crosslinking densities of NR/SiO2 composites are almost the same at the same dosage of SiO2. Consequently, a structure-property relationship of NR/SiO2/STU composites is proposed that the silane chain of STU can entangle with NR molecular chains to form an interfacial region, which is in accordance with the experimental observations quite well.

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

    International Nuclear Information System (INIS)

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

  7. The effects of electron beam irradiation on the thermal properties, fatigue life and natural weathering of styrene butadiene rubber/recycled acrylonitrile-butadiene rubber blends

    International Nuclear Information System (INIS)

    Research highlights: → Addition of TMPTA helps to align polymer chains through crosslinking. → Improvement in fatigue life of irradiated blends due to formation of irradiation-induced crosslinks. → Excessive crosslinking caused reduction of tensile properties of irradiated SBR/NBRr blends. -- Abstract: The effects of electron beam (EB) irradiation on the thermal properties, fatigue life and natural weathering of styrene butadiene rubber/recycled acrylonitrile-butadiene rubber (SBR/NBRr) blends were investigated. The SBR/NBRr blends were prepared at 95/5, 85/15, 75/25, 65/35, or 50/50 blend ratios with and without the presence of a 3 part per hundred rubber (phr) of polyfunctional monomer, trimethylolpropane triacrylate (TMPTA). Results indicate that the crystallisation temperature (Tc) observed in polymeric blends is due to the alignment of polymer chains forming a semi-crystalline phase. Addition of TMPTA helps to align polymer chains through crosslinking. More crosslinking occurred between polymer blends with the help of TMPTA, upon irradiation. The improvement in fatigue life can also be associated with the stabilisation of SBR/NBRr blends upon irradiation and irradiation-induced crosslinking, which was accomplished with relatively low radiation-induced oxidative degradation in the presence of TMPTA. The tensile properties of both blends decreased over the periods of environmental exposure due to the effect of polymer degradation. After 6 months, the irradiated SBR/NBRr blends could not retain better retention [mainly with 25, 35 or 50 phr of recycled acrylonitrile-butadiene rubber (NBRr) particles] due to the samples becoming brittle over the long period of outdoor exposure.

  8. A novel use of bio-based natural fibers, polymers, and rubbers for composite materials

    Science.gov (United States)

    Modi, Sunny Jitendra

    The composites, materials, and packaging industries are searching for alternative materials to attain environmental sustainability. Bio-plastics are highly desired and current microbially-derived bio-plastics, such as PHA (poly-(hydroxy alkanoate)), PHB (poly-(hydroxybutyrate)), and PHBV (poly-(beta-hydroxy butyrate-co-valerate)) could be engineered to have similar properties to conventional thermoplastics. Poly-(hydroxybutyrate) (PHB) is a bio-degradable aliphatic polyester that is produced by a wide range of microorganisms. Basic PHB has relatively high glass transition and melting temperatures. To improve flexibility for potential packaging applications, PHB is synthesized with various co-polymers such as Poly-(3-hydroxyvalerate) (HV) to decrease the glass and melting temperatures and, since there is improved melt stability at lower processing temperatures, broaden the processing window. However, previous work has shown that this polymer is too brittle, temperature-sensitive, and hydrophilic to meet packaging material physical requirements. Therefore, the proposed work focuses on addressing the needs for bio-derived and bio-degradable materials by creating a range of composite materials using natural fibers as reinforcement agents in bio-polymers and bio- plastic-rubber matrices. The new materials should possess properties lacking in PHBV and broaden the processing capabilities, elasticity, and improve the mechanical properties. The first approach was to create novel composites using poly-(beta-hydroxy butyrate-co-valerate) (PHBV) combined with fibers from invasive plants such as common reed (Phragmites australis), reed canary grass (Phalaris arundinacea), and water celery ( Vallisneria americana). The composites were manufactured using traditional processing techniques of extrusion compounding followed by injection molding of ASTM type I parts. The effects of each bio-fiber at 2, 5, and 10% loading on the mechanical, morphological, rheological, and thermal

  9. Water absorption and mechanical properties of water-swellable natural rubber

    Directory of Open Access Journals (Sweden)

    Diew Saijun

    2009-11-01

    Full Text Available Water-swellable rubber (WSR was prepared by blending superabsorbent polymer (SAP of crosslinked poly(acrylamide-co-sodium acrylate with natural rubber in latex condition. The crosslinked poly(acrylamide-co-sodium acrylate was first prepared by inverse suspension polymerization from acrylamide and sodium acrylate monomers with potassiumpersulfate initiator and N,N-methylenebisacrylamide crosslinker. The reaction was carried out at 60oC for 40 mins. Water absorption properties, such as the degree of water absorption, water absorption rate, degree of weight loss, and mechanicalproperties of WSR were then investigated. It was found that the degree of water absorption, water absorption rate, and thedegree of weight loss increased, while tensile strength and elongation at break decreased with increasing quantity of SAP inthe blends. However, the degree of water absorption, degree of weight loss, and elongation at break decreased, but tensilestrength increased with increasing quantity of the N-tert-butyl-2-benzothiazyl sulphenamide (TBBS accelerator used in thecompounds formulation.

  10. Ultrasound Devulcanization of Natural Rubber, Studied by NMR Relaxation and Diffusion

    Science.gov (United States)

    von Meerwall, E.

    2005-03-01

    In support of recycling of industrial rubbers, we have studied the effect of intense ultrasound on unfilled natural rubber networks using proton and carbon transverse NMR relaxation and diffusion, sol extraction, and bulk characterization. At 70.5^o C the proton echo decay exhibits three components, due to entangled sol and crosslinked network; unentangled polymeric sol plus dangling chain ends; and oligomer remnants. Contrary to the 13C results which indicate backbone mobilities decreasing with sonication (hence with increasing sol fraction), all 1H component T2 values, hence intermolecular mobilities, increase by similar modest factors; the network component amplitude decreases strongly. Diffusion of unentangled sol is sharply bimodal, arising from intermediate fractions and unreactive oligomers. Both diffusion rates decrease slightly with sonication in spite of plasticization by sol, because degradation adds sol primarily of intermediate molecular weights. We compare these results with our earlier work in SBR. Although ultrasound devulcanization does not recover many properties of the virgin melt, recyclability is not compromised.

  11. Improved dynamic properties of natural rubber filled with irradiation-modified carbon black

    International Nuclear Information System (INIS)

    In this work, carbon black particles (CBs) were modified by high-energy electron beam (EB) irradiation at different doses. The influence of EB irradiation on the surface and particle size of CBs was investigated. Then, the CBs were compounded with natural rubber (NR), and the mechanical properties and dynamic properties of CBs/NR composite were further researched. The results showed that the irradiated CBs had more oxygen-containing groups and smaller particle sizes than original CBs. After irradiation, the content of bound rubber around the irradiated CBs increased, and the mechanical properties of CBs/NR composite were improved. Most importantly, NR filled with irradiated CBs has lower abrasion, higher wet skid resistance, and lower rolling resistance than NR filled with untreated CBs. - Highlights: • Irradiated CBs had more oxygen-containing groups than original CBs. • Irradiated CBs had smaller particle sizes than original CBs. • NR filled with irradiated CBs has lower abrasion than NR filled with untreated CBs. • NR filled with irradiated CBs has lower rolling resistance than NR filled with untreated CBs

  12. Adhesion property of epoxidized natural rubber (ENR-based adhesives containing calcium carbonate

    Directory of Open Access Journals (Sweden)

    2008-06-01

    Full Text Available The adhesion property (i.e. viscosity, loop tack and peel strength of epoxidized natural rubber (ENR 25 and ENR 50 grade-based pressure-sensitive adhesive was studied in the presence of calcium carbonate. The range of calcium carbonate loaded was from 10 to 50 parts per hundred parts of rubber (phr. Coumarone-indene resin was used as the tackifier and its concentration was fixed at 80 phr. Toluene was chosen as the solvent throughout the investigation. The substrates (PET film/paper were coated with the adhesive using a SHEEN hand coater at a coating thickness of 60 µm. Viscosity of the adhesive was measured by a HAAKE Rotary Viscometer whereas loop tack and peel strength were determined by a Llyod Adhesion Tester operating at 30 cm/min. Results show that viscosity of ENR-based adhesives increases gradually with increase in calcium carbonate loading due to the concentration effect of the filler. However, for loop tack and peel strength, it passes through a maximum at 30 phr calcium carbonate, an observation which is attributed to the optimum wettability of adhesive on the substrate at this adhesive composition. ENR 25-based adhesive consistently exhibits higher adhesion property than ENR 50 for all calcium carbonate loadings studied.

  13. PMMA-N,N,N-trimethyl chitosan nanoparticles for fabrication of antibacterial natural rubber latex gloves.

    Science.gov (United States)

    Arpornwichanop, Thanida; Polpanich, Duangporn; Thiramanas, Raweewan; Suteewong, Teeraporn; Tangboriboonrat, Pramuan

    2014-08-30

    This paper presents one-pot synthesis of N,N,N-trimethyl chitosan (TMC) stabilized poly(methyl methacrylate) (PMMA) latex particles via the miniemulsion polymerization technique. From (1)H NMR, synthesized TMC contains 52% degree of quaternization. Compared to native biopolymer chitosan, TMC possesses permanently positive charges as well as provides greater antibacterial activity. Combining properties of PMMA and TMC, PMMA-TMC latex nanoparticles (hydrodynamic size ≈282 nm) could be used in place of inorganic lubricating powder in fabrication of latex gloves at pH ≥ 7. After immersing sulphur prevulcanized natural rubber (SPNR) film into 3 wt% of PMMA-TMC latex at pH 7, significant amount of nanoparticles uniformly deposited onto SPNR film was observed under SEM. A number of nanoparticles present on film surface would increase surface roughness of the rubber film and potentially inhibit the bacterial (Escherichia coli and Staphylococcus aureus) growth, which would be useful for fabrication of special gloves with antibacterial property. PMID:24815393

  14. Thermal degradation of epoxidized natural rubber in presence of neodymium stearate

    Institute of Scientific and Technical Information of China (English)

    LUO Yongyue; YANG Changjin; CHEN Bangqian; XU Kui; ZHONG Jieping; PENG Zheng; L(U) Zhen

    2013-01-01

    The effect of neodymium stearate (NdSt) synthesized by saponification method on thermal degradation and thermo-oxida-tive degradation of expoxidized natural rubber with 25 mol.% epoxidation (ENR25) was investigated by thermogravimetric analysis (TGA),and the structure of ENR25 vulcanized with NdSt after thermo-oxidative decomposition was characterized using Fourier transform infared spectroscopy-attenuated total-reflectance (FTIR-ATR).The thermal degradation kinetic parameters of ENR25 with different loadings of NdSt were determined by Coats-Redfern method.The results showed that the thermal degradation of ENR25 in nitrogen was a one-step reaction regardless of NdSt content,whereas the thermo-oxidative degradation was a multiple-step reaction.The thermal and thermo-oxidative stability of the ENR25 vulcanizates with the addition of NdSt was higher than that of pure ENR25 vulcanizates.The ENR25 vulcanizates with the incorporation of 1 phr (per hundred parts of rubber) NdSt imparted the highest activation energy (E) of thermal and thermo-oxidative degradation.This could be attributed to the many unoccupied orbits in rare earth Nd,which could capture the free radicals and make the epoxide groups stable in the process of thermal and thermo-oxidative degradation for ENR25.

  15. Development of expanded graphite filled natural rubber vulcanizates in presence and absence of carbon black: Mechanical, thermal and morphological properties

    International Nuclear Information System (INIS)

    Highlights: ► Fabricate natural rubber based nanocomposites containing expanded graphite (EG). ► Study the effect of EG and modified EG on the properties of natural rubber. ► Comparison of the results of EG/MEG filled and (EG/CB)/(MEG/CB) filled NR vulcanizates. ► EG can reduce the dose of CB in tire application. ► MEG loaded NR vulcanizates in presence and absence of CB show superior properties. -- Abstract: As nanosized expanded graphite (EG) reveals a similar layered structure like organoclay and also it has a high expansion ratio so rubber chains can easily be intercalated into the gallery space. To improve the dispersion of EG in the rubber matrices, primarily the surface modification of the expanded graphite have been done and then the modified expanded graphite (MEG)/polar compatibilizer [epoxidized natural rubber (ENR)] master batch have been prepared by solution mixing method in the laboratory. After that the MEG/ENR master batch have been mixed with bulk natural rubber (NR) in presence and absence of carbon black (CB) in a laboratory scale open two roll mixing mill. Wide angle X-ray diffraction (WAXD) and high resolution transmission electron microscopic (HR-TEM) analysis of the nanocomposites revealed that MEG was intercalated and as well as delaminated in the NR matrix. Scanning electron microscope (SEM) images of the nanocomposites showed very rough surface than the pure NR matrix. In presence of expanded graphite the crack paths are channelized and coincide in one point suggesting the effect of plate like expanded graphite to acts as a barrier. We have got improved mechanical, thermal and dynamic mechanical properties for the MEG and MEG/CB loaded NR compounds compared to EG and EG/CB loaded NR compounds.

  16. Effect of natural rubber processing sludge on the degradation of crude oil hydrocarbons in soil

    International Nuclear Information System (INIS)

    Crude oil-polluted soil (five parts of weathered crude oil per 100 parts of soil; equivalent to 50,000 mg oil kg-1 soil) samples were slurried in deionised water (300% of the water retention capacity of the soil) and treated with various amounts of natural-rubber processing sludge (nitrogen content 62.15 mgkg-1 and phosphorus contents 8.75 mgkg-1) in a well-stirred, continuously-aerated tank at 29oC. Changes in the total hydrocarbon content of the soil sample were determined, using a spectrophotometric technique, as a function of time. The extent of crude oil degradation was markedly higher (by up to 100%) in the sludge-treated soil than in the untreated soil sample. The efficiency of biodegradation of the crude oil hydrocarbons using the slurry-phase technique was compared with that of solid-phase technique. (author)

  17. Production of Natural Rubber Grafted Styrene Copolymer Latex as Water Base Coatings

    Directory of Open Access Journals (Sweden)

    M Utama

    2006-07-01

    Full Text Available Twelve kinds formulation of natural rubber grafted copolymer styrene (NR-g-S prepared by gamma radiation co-polymerization technique has been carried out. The characteristic of NR-g-S and its water base coating such as molecular structure, particle size, and the properties of latex and its film were evaluated. The results showed that the NR-g-S latex as a water base coating has low viscosity, height strength, good grease resistance, good flexibility, good aging and corrosion resistance on concrete cement and metal. The average particle size is between 270-300 nm, and the bonding between poly-isoprene of NRL and styrene molecules were grafted copolymer

  18. Effect of electron beam-cross-linked gels on the rheological properties of raw natural rubber

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-05-15

    Electron beam (EB)-cross-linked natural rubber (NR) gels were prepared from latex and characterized by various techniques. The addition of a small amount of these gels to raw NR was found to reduce the apparent shear viscosity and die swell remarkably. This effect was further enhanced with the addition of butyl acrylate as a sensitizer. The apparent shear viscosity first decreased up to 8 phr of gel loading and then increased. However, the percent die swell value decreased steadily upon gel loading. These were explained by calculating principal normal stress difference, the activation energy of melt flow and characteristics of EB-cross-linked gels. These effects were also reflected in the changes of mechanical and dynamic mechanical properties of gel-filled raw NR. Tailoring of the above properties could be done with the help of these gels.

  19. Radiation vulcanization of natural rubber latex (NRL) using low energy electron beam accelerator

    International Nuclear Information System (INIS)

    The electron beam induced vulcanization of natural rubber latex has been studied using low energy Electron Beam (EB) accelerators of 300, 250 and 175 keV ne latex was irradiated in a special type stainless steel reaction reactor with a stirrer at the bottom of the reactor. From the results it was found that 300 and 250 keV accelerators could effectively vulcanize NRL. But accelerator of 175 keV is too low energy to vulcanize the latex. At the same time a drum type irradiator where thin layer of NRL was irradiated by accelerator, was used for vulcanization of NRL. This type of irradiator also showed good physical properties of vulcanized latex. The effects of beam current and stirrer speed on vulcanization were studied

  20. Solid polymer electrolyte 49 % poly(methyl methacrylate)-grafted natural rubber-lithium tetrafluoroborate)

    International Nuclear Information System (INIS)

    The potential of 49 % poly(methyl methacrylate) grafted natural rubber (MG49) as a solid polymer electrolyte film for application in electrochemical device system has been investigated. The MG49 films with LiBF4 as a doping salt were prepared by solution casting technique. The ionic conductivity investigated by electrochemical impedance spectroscopy showed the optimum ionic conductivity was given by 25 wt % of LiBF4 salt loading with ionic conductivity value, 1.49 x 10-9 S.cm-1 at room temperature. The observation on structural and morphology studies have been done by X-ray diffraction and scanning electron microscopy. Results showed that complexation and crystallization occurred in polymer electrolyte system. This gave low electrical conductivity value even though the addition of LiBF4 salt has reached the optimum level. (author)

  1. Grafting copolymerization of natural rubber with 2-hydroxyethyl methacrylate for plywood adhesion improvement

    Directory of Open Access Journals (Sweden)

    Yoopadee Promdum

    2009-10-01

    Full Text Available The graft copolymer of natural rubber (NR and 2-hydroxyethyl methacrylate (HEMA was prepared by seeded emulsion polymerization using cumene hydroperoxide (CHP and tetraethylene pentamine TEPA as an initiator system. The structures of the copolymers were characterized by FT-IR and 1H-NMR spectroscopy techniques. The adhesion properties of NR-g-HEMA were examined. The effects of monomer concentration, initiator concentration, reaction temperature,reaction time and the agitation speed on grafting and grafting efficiency were investigated. It was found that the optimumconditions for preparing NR-g-HEMA when 5 phr of HEMA with 0.15mol% of initiator was used were 60oC for 90 min under agitation speed of 50 rpm. Furthermore, the adhesion properties to plywood of the graft copolymers are higher than those of original NR.

  2. FTIR and morphology of liquid epoxidized natural rubber acrylate (LENRA)/silica hybrid composites

    International Nuclear Information System (INIS)

    Synthesis of organic-inorganic hybrid composites was carried out by combination of liquid epoxidized natural rubber acrylate (LENRA) and silica. Silica was introduce to the matrix by sol gel technique. The sol-gel technique was employed to prepare silica using tetraethyorthosilicate (TEOS) as precursor. HDDA and irga cure 184 were added to the formulations as reactive diluents and photosensitizer, respectively. The chemical modification was studied by Fourier Transform Infrared (FTIR) and energy dispersive X-ray analysis (EDAX). The morphological studies were conducted by the optical and scanning electron microscopes (SEM). It shows that silica was dispersed very well in the matrix for lower concentration of TEOS while agglomeration occurs at the higher concentration. The average particles size of silica were less than 100 nm. (Author)

  3. The role of proteins on the thermal oxidative aging of radiation vulcanized natural rubber latex

    International Nuclear Information System (INIS)

    The effect of Hevea latex proteins on the aging properties of radiation vulcanized natural rubber latex (RVNRL) was investigated. Unpurified RVNRL films exhibited better aging properties than the purified RVNRL films. A sharp decrease in tensile strength was observed after aging when RVNRL films were leached in 1% NH sub 4 OH. However, when these films were soaked in ethanol prior to leaching, the aging properties approximated those of the unleached samples. Kjeldahl and FT-IR analyses of the leached and unleached RVNRL films indicated a higher protein content for both the unleached and ethanol-soaked films than for leached films. Electrophoretic analysis of the proteins present in the NH, extracts of leached RVNRL films showed a high concentration of hevein. This protein was not found in the ATH, extracts of ethanol soaked films. Hevein was shown to improve the aging properties of RVNRL

  4. Comparison of direct and indirect measurement of the elastocaloric effect in natural rubber

    Science.gov (United States)

    Xie, Zhongjian; Sebald, Gael; Guyomar, Daniel

    2016-01-01

    The directly measured temperature change Δ T upon deformation (elastocaloric effect) of natural rubber was compared with indirect method, which is deduced from the Clausius-Clapeyron factor ( ∂ σ / ∂ T ) ɛ , where σ is the stress and ɛ is the strain. The factor ( ∂ σ / ∂ T ) ɛ can be measured by two different methods. One is to measure the stress vs. strain behavior at different static temperatures. It is found that the Δ T deduction is underestimated or even of opposite sign compared with the directly measured one. These behaviors are different from elastocaloric effect of shape memory alloys. An interpretation based on strain-induced crystallite is proposed. The other characterization is to measure the stress vs. temperature at constant strain. It results in a prediction, which is in good quantitative agreement with the directly measured one. The stress appears then to be a non-state variable, thus questioning the ergodicity of the material.

  5. Data for effects of lanthanum complex on the thermo-oxidative aging of natural rubber

    Directory of Open Access Journals (Sweden)

    Wei Zheng

    2015-12-01

    Full Text Available Novel mixed antioxidants composed of antioxidant IPPD and lanthanum (La complex were added as a filler to form natural rubber (NR composites. By mechanical testing, Fourier transform infrared spectroscopy with attenuated total reflectance (FTIR-ATR and thermogravimetric analysis (TGA, a string of data, including the mechanical properties, the variation of internal groups and the thermal and thermo-oxidative decompositions of NR, was presented in this data article. The data accompanying its research article [1] studied the thermo-oxidative aging properties of NR in detail. The density function theoretical (DFT calculations were also used as an assistant to study the thermo-oxidative aging mechanism of NR. The data revealed that this new rare-earth antioxidant could indeed enhance the thermo-oxidative aging resistance of NR, which is associated with its different function mechanism from that of the pure antioxidant IPPD.

  6. Comparison effects of lanthanum stearate and antioxidants in epoxidized natural rubber

    Institute of Scientific and Technical Information of China (English)

    杨昌金; 罗勇悦; 彭政; 许逵; 钟杰平

    2015-01-01

    This work studied possibilities of using lanthanum stearate (LaSt) as an antioxidant in epoxidized natural rubber containing 25 mol.%expoxidation (ENR25) compounds. For comparison purposes, two commercial antioxidant 4010NA and MB were also used. The influence of LaSt, antioxidant 4010NA and MB on cure characteristics, mechanical properties, crosslink density, hot air aging and thermo-oxidative degradation were studied. The results indicated that the incorporation of LaSt and antioxidants could ac-celerate the vulcanization of ENR. The ENR vulcanizates with antioxidant MB had better mechanical properties than 4010NA and LaSt. Compared with antioxidant 4010NA and MB, the ENR25 vulcanizates with the addition of LaSt exhibited the best hot air aging resistance and thermo-oxidative stability.

  7. Properties of natural rubber/attapulgite composites prepared by latex compounding method: Effect of filler loading

    International Nuclear Information System (INIS)

    This paper reports on the effect of filler loading on properties of natural rubber (NR)/attapulgite (ATP) composites. The NR/ATP composites were prepared by latex compounding method. It is called as masterbatch. The masterbatch was subsequently added to the NR through melt mixing process. The vulcanized NR/ATP composites were subjected to mechanical, swelling and morphological tests. All the results were compared with NR/ATP composites prepared by conventional system. The composites from masterbatch method showed better results compared to composites prepared by conventional method. They have higher tensile properties, elongation at break and tear strength. The images captured through scanning electron microscopy test revealed the improvement of tensile strength in masterbatch NR/ATP composites. It can be seen clearly that masterbatch NR/ATP have better filler dispersion compared to conventional method NR/ATP composites

  8. STRAIN-CONTROLLED BIAXIAL TENSION OF NATURAL RUBBER: NEW EXPERIMENTAL DATA

    KAUST Repository

    Pancheri, Francesco Q.

    2014-03-01

    We present a new experimental method and provide data showing the response of 40A natural rubber in uniaxial, pure shear, and biaxial tension. Real-time biaxial strain control allows for independent and automatic variation of the velocity of extension and retraction of each actuator to maintain the preselected deformation rate within the gage area of the specimen. Wealso focus on the Valanis-Landel hypothesis that is used to verify and validate the consistency of the data.Weuse a threeterm Ogden model to derive stress-stretch relations to validate the experimental data. The material model parameters are determined using the primary loading path in uniaxial and equibiaxial tension. Excellent agreement is found when the model is used to predict the response in biaxial tension for different maximum in-plane stretches. The application of the Valanis-Landel hypothesis also results in excellent agreement with the theoretical prediction.

  9. Properties of natural rubber/attapulgite composites prepared by latex compounding method: Effect of filler loading

    Energy Technology Data Exchange (ETDEWEB)

    Muttalib, Siti Nadzirah Abdul, E-mail: sitinadzirah.amn@gmail.com; Othman, Nadras, E-mail: srnadras@usm.my; Ismail, Hanafi, E-mail: ihanafi@usm.my [School of Materials and Mineral Resources Engineering, Engineering Campus, Universiti Sains Malaysia, Seri Ampangan, 14300 Nibong Tebal, Pulau Pinang (Malaysia)

    2015-07-22

    This paper reports on the effect of filler loading on properties of natural rubber (NR)/attapulgite (ATP) composites. The NR/ATP composites were prepared by latex compounding method. It is called as masterbatch. The masterbatch was subsequently added to the NR through melt mixing process. The vulcanized NR/ATP composites were subjected to mechanical, swelling and morphological tests. All the results were compared with NR/ATP composites prepared by conventional system. The composites from masterbatch method showed better results compared to composites prepared by conventional method. They have higher tensile properties, elongation at break and tear strength. The images captured through scanning electron microscopy test revealed the improvement of tensile strength in masterbatch NR/ATP composites. It can be seen clearly that masterbatch NR/ATP have better filler dispersion compared to conventional method NR/ATP composites.

  10. Effect of added silicon carbide nanowires and carbon nanotubes on mechanical properties of 0-3 natural rubber composites

    Science.gov (United States)

    Janyakunmongkol, Khantichai; Nhuapeng, Wim; Thamjaree, Wandee

    2016-01-01

    In this work, the mechanical properties of 0-3 nanocomposite materials containing silicon carbide nanowires (SiCNWs), carbon nanotubes (CNTs), and natural rubber were studied. The SiCNWs and CNTs were used as reinforcement fiber whereas natural rubber was used as the matrix phase. The chemical vapor depositions (CVD) was used for synthesizing the nanowire and nanotube phases. The volume fraction of reinforcement was varied from 0 to 10%. The nanophases were mixed in the natural rubber matrix and molded by the hand lay-up technique. The mechanical properties of the samples were examined and compared with those of neat natural rubber. From the results, it was found that the hardness and density of the samples increased with the quantities of nanophases. The nanocomposites with a volume fraction of 10% exhibited maximum hardness (50.5 SHORE A). The maximum tensile strength and extent of elongation at break of the samples were obtained from the 4% volume fraction sample, which were 16.13 MPa and 1,540%, respectively.

  11. A smart surface from natural rubber: the mechanism of entropic control at the surface monitored by contact angle measurement

    Directory of Open Access Journals (Sweden)

    Sureurg Khongtong

    2006-03-01

    Full Text Available Surface oxidation of crosslinked natural rubber provided a hydrophilic substrate (sticky surface that became more hydrophobic (less sticky when equilibrated against hot water. This unusual temperaturedependent surface reconstruction is interpreted as the result of recoiling of entropic unfavorable uncoiled chains induced when rubber surface was oxidized. Subsequent equilibration of these annealed samples against water at room temperature returned their original hydrophilicity. The degree of this surface reconstruction and its kinetics are also dependent on the amounts of crosslinking of the samples.

  12. Effect of short nylon-6 fibres on natural rubber-toughened polystyrene

    International Nuclear Information System (INIS)

    Highlights: ► Short nylon-6 fibres improved the mechanical properties of NR-toughened PS. ► RFL treated fibre composites show better mechanical properties than untreated ones. ► Storage modulus is also better for the RFL treated fibre composites. ► SEM analysis shows improved fibre–matrix adhesion for RFL treated fibre composites. -- Abstract: Composites based on polystyrene and natural rubber at a ratio of 85/15 were prepared by melt mixing with nylon-6 fibres using an internal mixer. The loading of short nylon-6 fibre, untreated and resorcinol formaldehyde latex (RFL)-treated, was varied from 0 to 3 wt.%. Tensile and flexural test samples were punched out from sheets and tested to study the variation of mechanical and dynamic mechanical properties. The tensile behaviour of the composite has been determined at three different strain rates (4.1 × 10−4 s−1, 2 × 10−3 s−1 and 2 × 10−2 s−1). Both the tensile strength and Young’s modulus of the composite increased with strain rate. The tensile strength, tensile modulus, flexural strength and flexural modulus increased with the increase in fibre content up to 1 wt.%, above which there was a significant deterioration in the properties. The RFL-treated fibre composites showed improved mechanical properties compared to the untreated one. Dynamic mechanical analysis (DMA) showed that the storage modulus of the composite with RFL-treated fibre was better compared to the untreated one. The fibre–matrix morphology of the tensile fractured specimens was studied by scanning electron microscopy (SEM). The results suggested that the RFL treatment of nylon fibre promoted adhesion to the natural rubber phase of the blend, thereby improving the mechanical properties of the composite.

  13. Reinforcement of Natural Rubber by “Expanded Clay” Adopting “Propping-Open Approach”

    OpenAIRE

    Rooj, Sandip

    2013-01-01

    During the last years rubber nanocomposites obtained by incorporating anisotropic clay nanoparticles within a rubber matrix to tailor material properties have attracted steadily growing interest. However, one main complication preventing rubber-clay nanocomposites from many potential applications is the difficulty to achieve a high degree of exfoliation particularly in case of melt mixing or compounding (using mixing equipment like internal mixer, two roll mills which can be up-scaled in ind...

  14. Study of the effect of ionizing radiation on the structure of natural rubber latex by positron annihilation technique

    International Nuclear Information System (INIS)

    At the present research, were studied the changes in natural rubber latex structure, due to electron beam by a 3 MeV, 25 m A Dynamitron electron accelerator. The natural rubber latex was irradiated at 30, 40 and 50 kGy/s dose rate, over a total dose range from 150 to 250 kGy, for each dose rate used. From natural rubber latex irradiated films were prepared by casting with 0.7 mm. thickness. In the main part, the study was made by positron annihilation lifetime (PAL), this technique is unique in the determination of free-volume properties due to the fact that positronium atom (Ps) is found to be preferentially localized in the free-volume region of polymeric materials. The positron lifetime measurements were performing using a gamma-gamma coincidence system. These results were analyzed by PATFIT-88 program computer into three components, the long-lived component for orthopositronium (o-Ps) with parameters lifetime (τ3) and formation intensity (I3), were plotted and analyzed for each dose rate and total dose used. Besides with τ3 were calculated the mean free-volume size based on the spherical model for the free-volume bubble, found that the free-volume decrease slightly with the total dose due to the crosslinking of natural rubber latex. Besides was studied the effect of dose rate on tensile strength, the tensile strength is increased with the total dose although there was not a clear effect due to the dose rate. Also the films were subjected to aging in order to determined the thermal stability of natural rubber latex irradiated, the results show that the films have good stability. Besides was used the infrared spectroscopy to determine the changes due to the crosslinking by variations in the characteristically absorption bands for cis 1,4-polyisoprene. (Author)

  15. In situ generated silica in natural rubber latex via the sol–gel technique and properties of the silica rubber composites

    International Nuclear Information System (INIS)

    Natural rubber (NR) composites reinforced by silica generated in situ within the NR matrix were prepared by the sol–gel process using tetraethoxysilane (TEOS) as the silica precursor. The effect of the TEOS content, water: TEOS mole ratio, reaction time and temperature on the in situ silica content formed in the NR latex were investigated. The results indicated that the suitable condition to produce a high silica content (54 parts by weight per hundred parts of rubber (phr)) in the rubbery matrix was the use of 200 phr TEOS and a water: TEOS mole ratio of 28.9:1 at room temperature for 24 h. The curing, mechanical, and thermal properties of the composite materials were also investigated. Increasing the in situ silica content increased the cure time and improved the mechanical properties of the composite. Compared to the NR vulcanizates filled with the commercial (ex situ formed) silica, the mechanical and thermal properties of the in situ silica composite material were significantly improved. Transmission electron microscopy revealed that the in situ formed silica particles were well distributed within the NR matrix, in contrast to the clumping of the ex situ formed commercial silica within the NR matrix. - Highlights: • High in situ silica content in NR latex was obtained up to 54 phr. • A good dispersion of in situ silica filling into the rubbery matrix. • Comparison of silica generated in the rubber matrix using solid, solution and latex NR substrates. • A good reinforcement effect of in situ silica was observed on the NR vulcanizate. • Sol–gel method is an alternative way to develop a novel composite material

  16. Effect of synthesized zinc stearate on the properties of natural rubber vulcanizates in the absence and presence of some fillers

    International Nuclear Information System (INIS)

    Research highlights: → The mechanical properties of NR were enhanced through partial and complete replacement of zinc stearate. → The effect of adding different concentrations of zinc stearate on the physic-mechanical and SEM properties has been investigated. → Zinc stearate was found to play dual role, it reinforces the matrix blow its melting point and higher temperature it plasticizers the system. → Zinc stearate can be used as activator for sulfur vulcanization process of rubber instead of ZnO and stearic acid; in absence and presence of fillers. -- Abstract: Zinc stearate was synthesized by precipitation method through two steps; neutralization of stearic acid by sodium hydroxide then double decomposition using zinc sulphate to precipitate zinc stearate. Mass balances of the two steps were calculated and the physical properties of the prepared zinc stearate were measured and compared to standard. It was characterized and incorporated it into natural rubber in the absence and presence of some filler through mixing process of rubber. The vulcanization process was carried out at 142 oC. The rheological properties of natural rubber mixes were measured using oscillating disc rheometer. The plysico-mechanical properties of the vulcanizates were determined using tensile testing machine. It was found that, partial and complete replacement of synthesized zinc stearate instead of the conventional zinc oxide and stearic acid; enhanced the physico-mechanical properties of natural rubber. The measured reinforcing parameter value αf can be arranged according to the type of filler as follows: HAF>Hisil>CaCO3>Ca3(PO4)2>BaSO4>Talc The highest value of αf represents the strength of filler and consequently the reinforcing effect of carbon black (HAF) filler while the lowest value of αf was observed for Talc which show moderate reinforcing effect of Talc. The scanning electron microscope study showed high surface homogenity and good dispersion of zinc stearate through

  17. Reinforcement of natural rubber latex with silica modified by cerium oxide:preparation and properties

    Institute of Scientific and Technical Information of China (English)

    张福全; 廖禄生; 王永周; 汪月琼; 黄红海; 李普旺; 彭政; 曾日中

    2016-01-01

    Variable masses of nano cerium oxide (CeO2) were added into nano silica (SiO2) to prepare the well-dispersed SiO2-CeO2 suspension (SiO2-CeO2), cetyltrimethyl ammonium bromide (CTAB) was used to adjust the compatibility of SiO2-CeO2 with rubber matrix, then SiO2-CeO2 modified by CTAB and curing formulas were mixed with fresh natural rubber (NR) latex to prepare NR/SiO2-CeO2 nanocomposites that contained 0–10 parts of CeO2 by a new emulsion compounding method. The morphologies, cure characteristics, mechanical properties and thermal-oxidative stability of NR/SiO2-CeO2 nanocomposites were investigated. The re-sults revealed that the presence of CeO2 in NR/SiO2-CeO2nanocomposites was favorable for enhancing the interaction between NR matrix and fillers, helped to get smaller SiO2-CeO2 particles with narrower particle size distribution, further improved the crosslink densities and mechanical properties of NR/SiO2-CeO2 nanocomposites vulcanizates. Meanwhile, the addition of CeO2 increased the active energy at least 4.66%, obviously improved the thermal-oxidative aging-inhibiting properties of NR/SiO2-CeO2 nanocomposites. Additionally, nanocomposites containing CeO2 promotedTg shift to high temperature direction, causing the nanocomposites featured higher tanδ at 0 ºC and lower tanδ at 60 ºC and exhibited comparable wet grip and lower rolling resistance when NR/SiO2-CeO2nano-composites were used in tire tread compound.

  18. Enhancing the thermal stability of natural rubber/recycled ethylene–propylene–diene rubber blends by means of introducing pre-vulcanised ethylene–propylene–diene rubber and electron beam irradiation

    International Nuclear Information System (INIS)

    Highlights: • New route of processing was introduced to optimise the thermal stability of NR/R-EPDM blends. • Pre-vulcanised EPDM and EB irradiation were introduced into NR/R-EPDM blends. • Thermal stability is obviously enhanced by applying these two techniques. • Applying new route of processing methods is clearly successful to NR/R-EPDM blends. - Abstract: Most rubber materials are subjected to oxidation. The rate of oxidation depends on the type of rubber, processing method, and end-use conditions. The oxidation of rubber can result in the loss of physical properties, such as tensile strength, elongation, and flexibility. Hence, the service life is determined by oxidation stability. Thermal properties are relevant to the potential use of polymeric materials in many consumer oriented applications. Thermo-oxidative ageing and thermogravimetric analysis (TGA) have been proven to be successful techniques in determining the thermal stability of polymers and polymer blends. In this article, preparation of a series of natural rubber/recycled ethylene–propylene–diene rubber (NR/R-EPDM) blends is described. Processing of the blends, by means of introducing pre-vulcanised EPDM and electron beam (EB) irradiation, was carried out. Two thermal analysis methods, namely thermo-oxidative ageing and thermogravimetric analysis, were conducted. The results indicated that pre-vulcanising EPDM for 1.45 min (ts − 2) is sufficient to gain the optimum retained tensile and elongation at break. It was simultaneously observed that the introduction of pre-vulcanised EPDM increased decomposition temperature and activation energy by showing optimum values at a pre-vulcanising time of 3.45 min (ts). In the latter study, the retained properties increased after EB irradiation. The results can be verified by the thermal decomposition temperature and their activation energy. The obtained TG profiles and the calculated kinetic parameters indicated that introducing EB irradiation

  19. Influence of the mechanical stress and the filler content on the hydrostatic compression behaviour of natural rubber

    International Nuclear Information System (INIS)

    The behaviour of natural rubber (NR) compounds under mechanical stress is often reported in literature. An important and widely discussed effect that occurs is the Mullins effect. During the first loading cycles in a tensile test for example, a stress-softening effect is observed. This and other effects on the mechanical behaviour are investigated for different rubber materials with and without different types of fillers and filler contents. Besides, the hydrostatic compression behaviour is affected by the type and content of filler as well, which is shown for an NR with and without waxes and different contents of carbon black (CB) in this contribution. In contrast to the Mullins effect, there is no dependence of the number of loading cycles on the volumetric behaviour determined in hydrostatic compression tests. Furthermore, the influence of the previous stress-softening due to mechanical stress on the compression behaviour is elaborated. Cyclic uniaxial tensile tests are performed to realize the stress-softening in the rubber materials. The subsequent compression tests are compared to compression tests without any pre-stretching to determine the influence of previous mechanical loading on the compression behaviour of natural rubber with different filler contents

  20. Mapping Rubber Plantations and Natural Forests in Xishuangbanna (Southwest China Using Multi-Spectral Phenological Metrics from MODIS Time Series

    Directory of Open Access Journals (Sweden)

    Sebastian van der Linden

    2013-05-01

    Full Text Available We developed and evaluated a new approach for mapping rubber plantations and natural forests in one of Southeast Asia’s biodiversity hot spots, Xishuangbanna in China. We used a one-year annual time series of Moderate Resolution Imaging Spectroradiometer (MODIS, Enhanced Vegetation Index (EVI and short-wave infrared (SWIR reflectance data to develop phenological metrics. These phenological metrics were used to classify rubber plantations and forests with the Random Forest classification algorithm. We evaluated which key phenological characteristics were important to discriminate rubber plantations and natural forests by estimating the influence of each metric on the classification accuracy. As a benchmark, we compared the best classification with a classification based on the full, fitted time series data. Overall classification accuracies derived from EVI and SWIR time series alone were 64.4% and 67.9%, respectively. Combining the phenological metrics from EVI and SWIR time series improved the accuracy to 73.5%. Using the full, smoothed time series data instead of metrics derived from the time series improved the overall accuracy only slightly (1.3%, indicating that the phenological metrics were sufficient to explain the seasonal changes captured by the MODIS time series. The results demonstrate a promising utility of phenological metrics for mapping and monitoring rubber expansion with MODIS.

  1. Effect of blend ratio on aging, oil and ozone resistance of silica-filled chloroprene rubber/natural rubber (CR/NR blends

    Directory of Open Access Journals (Sweden)

    2007-01-01

    Full Text Available The effect of blend ratio on properties of chloroprene rubber/natural rubber (CR/NR blends was investigated. In addition to the mechanical properties, attention was also given to the resistance to thermal aging, oil and ozone of the blends. Silica was selected as a reinforcing filler in this study due to its unique characteristic to interact with CR. The results reveal that, due to the better filler dispersion and the greater crosslink density, the silica-filled CR possesses lower compound viscosity and better mechanical properties, compared to the silica-filled NR. The aging properties, oil and ozone resistance of the silica-filled CR are also significantly better than those of the silica-filled NR. The mechanical properties and the resistance to degradation of the silica-filled CR/NR blends are mainly governed by the blend morphology. It is found that good mechanical properties in association with adequately high resistance to degradation from thermal aging and oil are obtained when CR remains the matrix in the blends. Even though the ozone cracks are found in all blends, a thorough look at the results reveals that considerable improvement in ozone resistance is achieved with increasing CR content.

  2. The Effect of Minarex B Oil and Gamma Irradiation on the Mechanical Properties of Vulcanized Natural Rubber-LDPE Mixture for Shoe Sole

    International Nuclear Information System (INIS)

    To obtain the optimum concentration of minarex B oil and gamma irradiation dose on natural rubber compound for shoe sole, study on the effect of minarex B oil and gamma radiation on the mechanical properties of vulcanized natural rubber-LDPE mixture has been done. Natural rubber was masticated and mixed with additive and filler using two-roll machine, at 120 oC of forward roll and 100 oC of backward roll, with rotation speed of 18 rpm. The additives added with irganox 1076, paraffin wax, stearic acid, and minarex B oil, while fillers used were polyethylene (LDPE) and calcium carbonate. Minarex B oil mixed was vary such as 5, 10 and 20 phr (part per hundred of rubber). The amount of filler and other additives mixed was not varied. The natural rubber film was obtained by pressing the mixture using hot and cold press machine at 135 oC and room temperature for about 3 minutes. The film then irradiated with gamma rays from cobalt-60 source, at the doses of 150, 300, and 500 kGy. The results show that the mechanical properties of natural rubber vulcanized decreases by increasing minarex B oil, and increases by increasing of irradiation dose. The concentration optimum of minarex B oil in the natural rubber compound for shoe sole and irradiation dose about 5 phr and 300 kGy were agree with SII 0944-84. (author)

  3. Electron beam processing of rubbers

    International Nuclear Information System (INIS)

    At present, the country producing natural rubber most is Malaysia, but the future share of natural rubber production of Malaysia is likely to decrease, while the share of Indonesia is expected to increase because the area of rubber plantation is increasing. Indonesia exports natural rubber as a raw material, and imports natural rubber products such as tires, belts and surgical gloves. Indonesia would obtain more foreign currency if it could export rubber products, and the future success in the export of rubber products is dependent on the development of new rubber technology. In this connection, two electron beam processings of rubbers are discussed in this paper, that is, tire production and the radiation vulcanization of natural rubber latex. Both processings are deeply related to the cross-linking of rubbers. The physical properties of natural rubber change by cross-linking, namely, the solvent resistance, tensile strength and hardness increase, and the elongation at breaking down decreases. About ten medium energy electron beam machines are used for tire production in Japan. The merits of radiation vulcanized natural rubber latex are shown. Its industrial application is explained. (K.I.)

  4. Numerical natural rubber curing simulation, obtaining a controlled gradient of the state of cure in a thick-section part

    Science.gov (United States)

    El Labban, A.; Mousseau, P.; Bailleul, J. L.; Deterre, R.

    2007-04-01

    Although numerical simulation has proved to be a useful tool to predict the rubber vulcanization process, few applications in the process control have been reported. Because the end-use rubber properties depend on the state of cure distribution in the parts thickness, the prediction of the optimal distribution remains a challenge for the rubber industry. The analysis of the vulcanization process requires the determination of the thermal behavior of the material and the cure kinetics. A nonisothermal vulcanization model with nonisothermal induction time is used in this numerical study. Numerical results are obtained for natural rubber (NR) thick-section part curing. A controlled gradient of the state of cure in the part thickness is obtained by a curing process that consists not only in mold heating phase, but also a forced convection mold cooling phase in order to stop the vulcanization process and to control the vulcanization distribution. The mold design that allows this control is described. In the heating phase, the state of cure is mainly controlled by the chemical kinetics (the induction time), but in the cooling phase, it is the heat diffusion that controls the state of cure distribution. A comparison among different cooling conditions is shown and a good state of cure gradient control is obtained.

  5. Prevalence of natural rubber latex allergy (type I and type IV) in laboratory workers in The Netherlands.

    Science.gov (United States)

    de Groot, H; de Jong, N W; Duijster, E; Gerth van Wijk, R; Vermeulen, A; van Toorenenbergen, A W; Geursen, L; van Joost, T

    1998-03-01

    The objective of the study was to study the prevalence of Type IV and Type I allergy to natural rubber latex (NRL) in a population at risk in the Netherlands. Laboratory workers regularly using gloves were invited to complete a questionnaire and to be tested. We performed patch tests with standard contact allergens, rubber additives, glove powder and pieces of 4 gloves; prick tests with inhalant allergens, glove extracts, glove powder and fruit extracts; and RASTs. Glove-related hand dermatitis was reported in 36.9% of the individuals interviewed. A positive patch test result for rubber additives was seen in only 6.6%. Glove-related urticaria, rhinoconjunctivitis and/or asthma were reported in 24.6% of all cases. Confirmation of an IgE-mediated reaction was achieved in 8.3% by prick test with glove extracts and 5.0% by RAST. No reaction to glove powder was noticed in patch testing or in prick testing. A high prevalence rate of glove-related symptoms and NRL Type I allergy was found in laboratory workers exposed to rubber gloves. Surprisingly, there was no co-existence of Type I and Type IV allergy in this population. PMID:9536409

  6. Preparation and mechanical properties of the magnetorheological elastomer based on natural rubber/rosin glycerin hybrid matrix

    Science.gov (United States)

    Ge, Lin; Gong, Xinglong; Fan, Yanceng; Xuan, Shouhu

    2013-11-01

    To improve the mechanical properties of the natural rubber based magnetorheological elastomers (MREs), rosin glycerin ester was added into the carrier matrix to enhance wettability and dispersibility of CI particles. Dynamic performance, including shear modulus, loss factor and viscosity of non-vulcanized matrix was measured by rheometer. In comparison to the natural rubber based MREs, the MR effect of these hybrid matrix MREs were higher and they can reach to 112% when the mass fraction of CI particles is only 60%. The contact angle was tested by drop shape analysis system (DSA) and it was found that the compatibility between the iron particles and matrix was improved. In combination of the microstructure and mechanical property analysis, a possible mechanism was proposed. Finally, the loss factor and tensile strength were studied.

  7. In situ synchrotron wide-angle X-ray diffraction investigation of fatigue cracks in natural rubber.

    Science.gov (United States)

    Rublon, Pierre; Huneau, Bertrand; Saintier, Nicolas; Beurrot, Stéphanie; Leygue, Adrien; Verron, Erwan; Mocuta, Cristian; Thiaudière, Dominique; Berghezan, Daniel

    2013-01-01

    Natural rubber exhibits remarkable mechanical fatigue properties usually attributed to strain-induced crystallization. To investigate this phenomenon, an original experimental set-up that couples synchrotron radiation with a homemade fatigue machine has been developed. Diffraction-pattern recording is synchronized with cyclic loading in order to obtain spatial distributions of crystallinity in the sample at prescribed times of the mechanical cycles. Then, real-time measurement of crystallinity is permitted during uninterrupted fatigue experiments. First results demonstrate the relevance of the method: the set-up is successfully used to measure the crystallinity distribution around a fatigue crack tip in a carbon black filled natural rubber for different loading conditions. PMID:23254662

  8. Sorption and desorption of toluene, m-xylene, p-cresol and water by natural rubber chips

    Directory of Open Access Journals (Sweden)

    Duangkamol Dechojarassri

    2006-09-01

    Full Text Available The transport mechanism of several pure liquid organic substances into natural rubber chips composed of different fillers was investigated. It was found that, for the same type of chips, the Fickian diffusion of toluene was the fastest, followed by m-xylene, water and p-cresol. The toluene uptake was highest which was as high as 3.42 times of the chip weight. This was closely followed by m- xylene uptake, which was much higher than p-cresol uptake and water uptake which was only 0.02 times of the chip weight, implying that natural rubber could be used to remove these organic substances contaminated in water. The desorption of substances into air followed the similar trend as sorption. Besides, for any substances, the results showed that unfilled chips had the largest sorption capacity, followed by ones with calcium carbonate and carbon black.

  9. Estimating the concentration of gold nanoparticles incorporated on natural rubber membranes using multi-level starlet optimal segmentation

    Energy Technology Data Exchange (ETDEWEB)

    Siqueira, A. F. de, E-mail: siqueiraaf@gmail.com; Cabrera, F. C., E-mail: flavioccabrera@yahoo.com.br [UNESP – Univ Estadual Paulista, Dep de Física, Química e Biologia (Brazil); Pagamisse, A., E-mail: aylton@fct.unesp.br [UNESP – Univ Estadual Paulista, Dep de Matemática e Computação (Brazil); Job, A. E., E-mail: job@fct.unesp.br [UNESP – Univ Estadual Paulista, Dep de Física, Química e Biologia (Brazil)

    2014-12-15

    This study consolidates multi-level starlet segmentation (MLSS) and multi-level starlet optimal segmentation (MLSOS) techniques for photomicrograph segmentation, based on starlet wavelet detail levels to separate areas of interest in an input image. Several segmentation levels can be obtained using MLSS; after that, Matthews correlation coefficient is used to choose an optimal segmentation level, giving rise to MLSOS. In this paper, MLSOS is employed to estimate the concentration of gold nanoparticles with diameter around 47  nm, reduced on natural rubber membranes. These samples were used for the construction of SERS/SERRS substrates and in the study of the influence of natural rubber membranes with incorporated gold nanoparticles on the physiology of Leishmania braziliensis. Precision, recall, and accuracy are used to evaluate the segmentation performance, and MLSOS presents an accuracy greater than 88 % for this application.

  10. The Role of Ammonia in Synthesis of Silver Nanoparticles in Skim Natural Rubber Latex

    Directory of Open Access Journals (Sweden)

    Panu Danwanichakul

    2016-01-01

    Full Text Available Silver nanoparticles (AgNPs were synthesized in skim natural rubber latex, the by-product from concentrated latex production. The role of ammonia was investigated by varying the concentration to be 0.217, 0.362, 0.377, 0.392, and 0.406 wt%. The emergence of AgNPs was detected by UV-visible spectrophotometer and electrical conductivity meter. Upon increasing ammonia concentration, the ABS peak increased to a maximum and slightly shifted to a higher wavelength and then it decreased afterward and slightly shifted to a lower wavelength. The shift of the ABS peak was consistent with the conductivity result. The kinetic model was proposed to explain the competition between the reducing effect and size-controlling effect of ammonia. The reducing effect seemed to dominate in the low range of concentration while the size-controlling effect via the formation of AgNH32+ complex ion was important in the higher range. The TEM figures evidently confirmed the effects.

  11. Investigation of miscibility of p(3hydroxybutyrate-co-3hydroxyhexanoate) and epoxidized natural rubber blends

    Science.gov (United States)

    Akram, Faridah; Chan, Chin Han; Natarajan, Valliyappan David

    2015-08-01

    Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate [P(3HB-co-3HHx)] produced by C. necator PHB-4 harboring phaCcs from crude palm kernel oil with 21 mol% of 3-hydroxyhexanoate and epoxidized natural rubber with 25 mol% of epoxy content (ENR-25) were used to study the miscibility of the blends by attenuated total reflection-Fourier transform infrared (ATR-FTIR) and differential scanning calorimetry (DSC). The polymers used were purified and the blends were prepared by solution casting method. Nuclear magnetic resonance (NMR) spectra confirm the purity and molecular structures of P(3HB-co-3HHx) and ENR-25. FTIR spectra for different compositions of P(3HB-co-3HHx) and ENR-25 blends show absorbance change of the absorbance bands but with no significant shifting of the absorbance bands as the P(3HB-co-3HHx) content decreases, which shows that there is no intermolecular interaction between the parent polymer blends. On top of that, there are two Tgs present for the blends and both remain constant for different compositions which corresponds to the Tgs of the parent polymers. This indicates that the blends are immiscible.

  12. Vulcanization characteristics and dynamic mechanical behavior of natural rubber reinforced with silane modified silica.

    Science.gov (United States)

    Chonkaew, Wunpen; Minghvanish, Withawat; Kungliean, Ulchulee; Rochanawipart, Nutthaya; Brostow, Witold

    2011-03-01

    Two silane coupling agents were used for hydrolysis-condensation reaction modification of nanosilica surfaces. The surface characteristics were analyzed using Fourier transform infrared spectroscopy (FTIR). The vulcanization kinetics of natural rubber (NR) + silica composites was studied and compared to behavior of the neat NR using differential scanning calorimetry (DSC) in the dynamic scan mode. Dynamic mechanical analysis (DMA) was performed to evaluate the effects of the surface modification. Activation energy E(a) values for the reaction are obtained. The presence of silica, modified or otherwise, inhibits the vulcanization reaction of NR. The neat silica containing system has the lowest cure rate index and the highest activation energy for the vulcanization reaction. The coupling agent with longer chains causes more swelling and moves the glass transition temperature T(g) downwards. Below the glass transition region, silica causes a lowering of the dynamic storage modulus G', a result of hindering the cure reaction. Above the glass transition, silica-again modified or otherwise-provides the expected reinforcement effect. PMID:21449342

  13. Reduction of residual n-butylacrylate sensitizer in radiation vulcanized natural rubber latex

    International Nuclear Information System (INIS)

    Radiation vulcanisation of natural rubber latex needs n-butyl acrylate (n-BA) to lessen required irradiation dose. Considerable amount of n-BA remains in the latex after the completion of radiation vulcanisation and tends to pollute the working environment in a dipping factory. A study has been carried out to reduce the residual n-BA after the radiation vulcanization. About 40% of added n-BA was found in the latex after irradiation to 20 kGy. Hydrolysis of n-BA was effective for reduction of the residual n-BA in the latex. No n-BA was found in the latex when the latex was stored for 4 weeks at room temperature due to its hydrolysis. Heating of the latex was effective to accelerate the rate of hydrolysis of n-BA. Almost all of n-BA in the latex was hydrolysed when the latex was heated for 4 hours at 800 degree C. Tensile strength of the latex films slightly decreased by heating treatment of the latex, but gradually recovered as storage time extended. Low viscosity was attained by the heat treatment of the latex

  14. Blunt Trauma Performance of Fabric Systems Utilizing Natural Rubber Coated High Strength Fabrics

    International Nuclear Information System (INIS)

    The blunt trauma performance of fabric systems against 9 mm bullets is reported. Three shots were fired at each fabric system with impact velocity of 367±9 m/s and the depth of indentation on the modeling clay backing was measured. The results showed that 18-layer and 21-layer all-neat fabric systems failed the blunt trauma test. However, fabric systems with natural rubber (NR) latex coated fabric layers gave lower blunt trauma of between 25-32 mm indentation depths. Deformations on the neat fabrics upon impact were identified as broken yarns, yarn stretching and yarn pull-out. Deflections of the neat fabrics were more localised. For the NR latex coated fabric layers, no significant deformation can be observed except for peeled-off regions of the NR latex film at the back surface of the last layer. From the study, it can be said that the NR latex coated fabric layers were effective in reducing the blunt trauma of fabric systems.

  15. Autonomous healing materials based on epoxidized natural rubber and ethylene methacrylic acid ionomers

    International Nuclear Information System (INIS)

    The development of autonomous healing material has an enormous scientific and technological interest. In this context, this research work deals with the investigation of autonomous healing behavior of epoxidized natural rubber (ENR) and its blends with ethylene methacrylic acid ionomers. The autonomous healing behavior of ENR and its blends containing two different ionomers [poly(ethylene-co-methacrylic acid sodium salt) (EMNa) and poly(ethylene-co-methacrylic acid zinc salt) (EMZn)] has been studied by ballistic puncture tests. Interestingly, EMNa/ENR blends exhibit complete healing just after the ballistic test but EMZn/ENR blends do not show full self-repairing. The healing efficiency has been evaluated by optical microscopy and a depressurized air-flow test. The healing mechanism has been investigated by characterizing thermal and mechanical properties of the blends. The chemical structure studied by FTIR and thermal analysis show that the ion content of ionomers and functionality of ENR has a significant influence on the self-healing behavior. (paper)

  16. Synthesis, characterization and impedance spectroscopy study of magnetite/epoxidized natural rubber nanocomposites

    International Nuclear Information System (INIS)

    Highlights: ► The Fe3O4/ENR nanocomposites have not been synthesized and reported. ► Nanocomposites were obtained via in situ synthesis of Fe3O4 in the presence of ENR. ► The use of ENR enabled control of the size of Fe3O4 particles to 3O4 loading. ► The equivalent circuit for the nanocomposites is proposed and discussed. -- Abstract: The magnetite (Fe3O4) particles were synthesized in situ in the presence of epoxidized natural rubber (ENR) to produce the various Fe3O4/ENR nanocomposites. The X-ray diffraction (XRD) analysis confirmed the existence of Fe3O4 particles in the composites. The FTIR and DSC studies suggested that no chemical interactions between the particles and the matrix. The SEM and X-mapping micrographs revealed that the Fe3O4 particles were distributed within the ENR matrix. The ENR matrix exerts control on the Fe3O4 particles with a size of 3O4 particles also affect the electrical properties of the composites. Impedance spectroscopy studies show that the electrical conductivity of the nanocomposites increases with the increase in Fe3O4 loading in the composite. The equivalent circuit for the Fe3O4/ENR nanocomposites is proposed and discussed

  17. Polymer Gel Electrolytes Based on 49 % Methyl-Grafted Natural Rubber

    International Nuclear Information System (INIS)

    Polymer gel electrolytes (PGEs) based on 49 % methyl-grafted natural rubber (MG49) were first prepared by dissolving ammonium triflate (NH4CF3SO3) in propylene carbonate (PC) by various molar concentrations of NH4CF3SO3 to obtain liquid electrolytes and were characterized by AC electrical impedance spectroscopy (EIS) measurements to study their conducting behaviour. The liquid electrolyte with optimum conductivity (0.7 M) was then gelled with MG49 and their conductivity was also studied. The highest conductivity of liquid electrolyte was 3.6 x 10-3 Scm-1 and 2.9x10-2 Scm-1 for PGEs. The molecular interactions between components of NH4CF3SO3, PC, and MG49 have been observed by ATR-FTIR spectroscopy study. The downshifting of C=O stretching frequency of PC from 1785 cm-1 to 1780 cm-1 and NH4+ band from 1634 cm-1 to 1626 cm-1 that has been obtained by spectroscopic data in addition of NH4CF3SO3 confirmed the complexation occurrence. Interaction between NH4CF3SO3 and MG49 has also been investigated. This study is focused on the interactions between components in the PGE system and relates them with their conducting behavior. (author)

  18. Irradiation Modification of Epoxidized Natural Rubber/ ethylene Vinyl Acetate/ carbon Nano tubes Nano composites

    International Nuclear Information System (INIS)

    The effect of CNTs with irradiation modification on the properties of Epoxidized Natural Rubber/ Ethylene Vinyl Acetate/ Carbon Nano tubes (ENR/EVA/CNTs) nano composites were investigated. The CNTs at various amount (2, 3, 4 and 6 wt%) were incorporated into ENR50 by solving casting method. The ENR/ CNTs were then blended with EVA by mixing in a Brabender Plasticoder at 120 degree Celsius. Next, the samples were irradiated by using electron beam with 3 MeV electron beam machine in a dose range of 50 to 200 kGy. The mechanical properties especially Tensile strength (Ts), modulus at 100 % elongation (M100), elongation at break (Eb) and hardness were studied as a function of radiation dose. The thermal properties of the nano composites was investigated by TGA and DSC. Results showed that the irradiation induced crosslinking lead to further improvement in mechanical properties, thermal properties and compatibility of the nano composites. The irradiation modification up to 150 kGy, has increased the Ts and M100 almost 2 times and a downward trend thereafter. (author)

  19. Investigation of miscibility of p(3hydroxybutyrate-co-3hydroxyhexanoate) and epoxidized natural rubber blends

    International Nuclear Information System (INIS)

    Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate [P(3HB-co-3HHx)] produced by C. necator PHB−4 harboring phaCcs from crude palm kernel oil with 21 mol% of 3-hydroxyhexanoate and epoxidized natural rubber with 25 mol% of epoxy content (ENR-25) were used to study the miscibility of the blends by attenuated total reflection-Fourier transform infrared (ATR-FTIR) and differential scanning calorimetry (DSC). The polymers used were purified and the blends were prepared by solution casting method. Nuclear magnetic resonance (NMR) spectra confirm the purity and molecular structures of P(3HB-co-3HHx) and ENR-25. FTIR spectra for different compositions of P(3HB-co-3HHx) and ENR-25 blends show absorbance change of the absorbance bands but with no significant shifting of the absorbance bands as the P(3HB-co-3HHx) content decreases, which shows that there is no intermolecular interaction between the parent polymer blends. On top of that, there are two Tgs present for the blends and both remain constant for different compositions which corresponds to the Tgs of the parent polymers. This indicates that the blends are immiscible

  20. Study on Kinetics of Natural Rubber Vulcanization by S/La(DiPDP)3

    Institute of Scientific and Technical Information of China (English)

    Lin Xinhua; Liu Qingting; Chen Zhaohui; Wang Dizhen

    2007-01-01

    Kinetics of natural rubber (NR) vulcanization by lanthanum O, O'-diisopropyldithiophosphate [La(DiPDP)3] was studied. La(DiPDP)3 had remarkable accelerating effect on the vulcanization of NR. The rate constant k6 of the reaction that turned polysulphidic cross-links into the modified main chain was higher than that of desulfuration reaction of polysulfidic cross-links (k3). The activation energies (Ea2, Ea3, and Ea6) of the formation, desulfuration, and decomposition of polysulfidic cross-links were 87.57, 102.34, and 95.01 kJ·mol-1, respectively. Activation energy (Ea5) of the reaction that turned the cross-link precursors into the modified main chain was 82.67 kJ·mol-1. It could be concluded that the proportion of polysulphidic cross-links was higher than mono- and di- sulphidic cross-links during induction and curing periods, mono- and di- sulphidic cross-links increased as curing temperature rose. In the temperature range of 140~160 ℃, the amounts of polysulphidic cross-links were similar. However, over 160 ℃, mono- and di- sulphidic cross-links increased rapidly. Moreover, cross-link density of the vulcanizates was determined from the equilibrium-swelling data. A chemical probe detected the concentration of polysulphidic cross-links of vulcanizates. The change trend of the results predicated from equation corresponded to that of the experimental results.

  1. Radiation vulcanization of natural rubber latex with low energy accelerator-II

    International Nuclear Information System (INIS)

    The natural rubber latex (NRL) was radiation vulcanized under a low energy electron accelerator. Accelerating voltage and maximum beam current of this accelerator are 250 kV and 10 mA respectively. Irradiation was carried out in a reaction vessel with constant stirring. The capacity of the vessel is 18 liters. Radiation vulcanization accelerators (RVA) were normal butyl acrylate (n-BA) and nonane-diol-diacrylate (NDDA). NDDA has no bad smell like that of n-BA. 20 minutes irradiation time is enough to vulcanize 14 liters of latex when 5 phr RVA (both types) are used. Maximum of ∼30 MPa tensile strength was obtained with 5 phr NDD-A. However the remained NDDA is difficult to remove due to high molecular weight. Water-extractable proteins content was determined in dipped films for various leaching conditions without and with additive (polyvinyl alcohol, PVA). Water extractable proteins content is reduced to ≤ 41 by adding 5 phr PVA and leaching for 8 hours. The tackiness of the dipped films is reduced to 0.1 from 9 gf by mixing 6 phr PVA with the irradiated latex. Hand gloves (surgical and examination) were successfully produced from the irradiated latex. (author)

  2. Cure and mechanical properties of recycled NdFeB–natural rubber composites

    Indian Academy of Sciences (India)

    P Saramolee; P Lertsuriwat; A Hunyek; C Sirisathitkul

    2010-10-01

    Magnetic polymer composites containing recycled neodymium–iron–boron (NdFeB) powder and natural rubber (NR) were prepared by the two-roll mill technique. Their mechanical and cure properties were studied as a function of NdFeB loading from 0–120 phr. With increasing magnetic loading, the cure time of the NdFeB–NR composites were exponentially decreased because of the reduction of the polymer chain crosslink. The tensile strength of the NR compound, related to the cure characteristics, was reduced by 40% by the addition of 10 phr NdFeB fillers because of the inhibition of the stress-induced crystallization. However, the variation in loading from 30–90 phr has modest effects on the tensile strength as well as elongation at break and the hardness. Furthermore, recycled NdFeB–NR composites had higher modulus and lower percentage of swelling in this magnetic loading regime. Simple tests confirmed the distribution of magnetic stray field around pieces of NdFeB–NR composites.

  3. Investigation of miscibility of p(3hydroxybutyrate-co-3hydroxyhexanoate) and epoxidized natural rubber blends

    Energy Technology Data Exchange (ETDEWEB)

    Akram, Faridah; Chan, Chin Han; Natarajan, Valliyappan David [Faculty of Applied Sciences, Universiti Teknologi MARA, Shah Alam, 40450 Selangor Darul Ehsan (Malaysia)

    2015-08-28

    Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate [P(3HB-co-3HHx)] produced by C. necator PHB{sup −}4 harboring phaC{sub cs} from crude palm kernel oil with 21 mol% of 3-hydroxyhexanoate and epoxidized natural rubber with 25 mol% of epoxy content (ENR-25) were used to study the miscibility of the blends by attenuated total reflection-Fourier transform infrared (ATR-FTIR) and differential scanning calorimetry (DSC). The polymers used were purified and the blends were prepared by solution casting method. Nuclear magnetic resonance (NMR) spectra confirm the purity and molecular structures of P(3HB-co-3HHx) and ENR-25. FTIR spectra for different compositions of P(3HB-co-3HHx) and ENR-25 blends show absorbance change of the absorbance bands but with no significant shifting of the absorbance bands as the P(3HB-co-3HHx) content decreases, which shows that there is no intermolecular interaction between the parent polymer blends. On top of that, there are two T{sub g}s present for the blends and both remain constant for different compositions which corresponds to the T{sub g}s of the parent polymers. This indicates that the blends are immiscible.

  4. Green natural rubber-g-modified starch for controlling urea release.

    Science.gov (United States)

    Riyajan, Sa-Ad; Sasithornsonti, Yodsathorn; Phinyocheep, Pranee

    2012-06-01

    The hydrophilicity of natural rubber (NR) was improved by grafting with modified cassava starch (ST) (NR-g-ST) by using potassium persulfate (K2S2O8) as a catalyst. The modified ST was added to NR latex in the presence of Terric16A16 as a non-ionic surfactant at 60 °C for 3 h and cast film on a glass plate to obtain NR-g-ST. The chemical structure of NR-g-ST was confirmed by FTIR. The swelling ratio of NR-g-ST was investigated in water and results showed that the swelling ratio of the modified NR decreased as function of ST. In addition, the tensile strength of the modified NR in the presence of modified ST at 50 phr was the highest value. Also, the thermal stability modified NR-g-ST was higher than of NR/ST blend confirmed by TGA. Finally, the NR-g-ST was used a polymer membrane for controlling urea fertilizer and it easily degraded in soil. This product with good controlled-release and water-retention could be especially useful in agricultural and horticultural applications. PMID:24750631

  5. Structural changes in the low-density polyethylene/natural rubber composites in the aqueous and soil media

    Science.gov (United States)

    Mastalygina, Elena E.; Varyan, Ivetta A.; Kolesnikova, Natalya N.; Popov, Anatoly A.

    2016-05-01

    The novel biodegradable materials based on polyethylene with different content of natural rubber have been developed. In this paper the regularities of changes in structure and properties of the composites under the influence of biological and non-biological factors have been investigated. High levels of biodegradability and satisfied mechanical properties of biocomposites, as well as the significant modification of the polyethylene crystalline phase in the composites affected by moisture and environmental factors have been determined.

  6. Characteristics of Self-Citation in Journal of Natural Rubber Research 1988-1997: a Ten-Year Bibliometric Study

    OpenAIRE

    Tiew, Wai Sin

    2000-01-01

    Analyses the extent of journal self-citation and author self-citation in the research articles and short communications published in Journal of Natural Rubber Research during 1988 to 1997. Results show that 53% of articles contained journal self-citations; the rate of journal self-citations per article ranges between 1 to 12; a high percentage of authors (61.4%) contributing articles to the journal cited themselves; a tendency is noticed for authors affiliated to the institution publishing th...

  7. The effects of gamma radiation and electron beam on the mechanical properties of polypropylene dominant natural rubber blend

    International Nuclear Information System (INIS)

    The effects of irradiation, with dose ranging from 20 to 100 kGy on the mechanical properties of polypropylene and natural rubber blends (PP/NR blends) were investigated. Crosslinking of the PP/NR blends proved to play a major role in the improvement of the mechanical properties of the blend. The results also revealed that the blend composition the enhancement in properties depend on the irradiation dose and on the concentration of the crosslinking agent. (author)

  8. Workers' compensation claims related to natural rubber latex gloves among Oregon healthcare employees from 1987–1998

    OpenAIRE

    Kammeyer-Mueller John; Horwitz Irwin B; McCall Brian P

    2002-01-01

    Abstract Background Occupational reaction to natural rubber latex (NRL) glove use by healthcare employees has been an area of increasing concern. Unfortunately, there is little data demonstrating the prevalence and severity of actual reactivity to NRL. Method Occupational reaction to NRL was estimated using workers' compensation claims filed by healthcare employees in Oregon for the period of 1987–1998. For the first ten years, these claims were estimated by source and conditions consistent w...

  9. Heavy duty piezoresistivity induced strain sensing natural rubber/carbon black nanocomposites reinforced with different carbon nanofillers

    Science.gov (United States)

    He, Qingliang; Yuan, Tingting; Zhang, Xi; Guo, Shimei; Liu, Jingjing; Liu, Jiurong; Liu, Xinyu; Sun, Luyi; Wei, Suying; Guo, Zhanhu

    2014-09-01

    Durable piezoresistive effects of natural rubber nanocomposites have been demonstrated, i.e., with stable and reversible electrical resistance change within the tested 3000 cycles upon applying a small compressive strain (˜16.7%) under a relatively high frequency (0.5 Hz, 2 s/cycle). This unique function was achieved for the first time by combining carbon nanotubes and carbon nanofibers with natural rubber composites pretreated with carbon black. Even though the combination of different carbon nanomaterials, such as graphene nanosheets and carbon nanotubes, can improve the dispersion quality of both the nanostructures in solution or in polymer matrices, this type of synergistic effect between carbon nanotubes and carbon nanofibers in producing stable and reversible piezoresistive effect has been rarely reported. Besides, the strong reinforcement (compressive stress at a maximum strain of 16.7% was increased from 12.6 for untreated to 18.5 MPa for the natural rubber/carbon black composites treated with a combination of 1.0 wt% carbon nanotubes and 1.0 wt% carbon nanofibers) makes the as-prepared composites promising for heavy duty pressure sensors, i.e., healthy motion monitoring of industrial machinery vibrations.

  10. Surface modification of argon/oxygen plasma treated vulcanized ethylene propylene diene polymethylene surfaces for improved adhesion with natural rubber

    International Nuclear Information System (INIS)

    Vulcanized ethylene propylene diene polymethylene (EPDM) rubber surface was treated in a radio frequency capacitatively coupled low pressure argon/oxygen plasma to improve adhesion with compounded natural rubber (NR) during co-vulcanization. The plasma modified surfaces were analyzed by means of contact angle measurement, surface energy, attenuated total reflection-infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, energy dispersive X-ray sulfur mapping and atomic force microscopy. Several experimental variables such as plasma power, length of exposure time and composition of the argon-oxygen gas mixture were considered. It was delineated that plasma treatment changed both surface composition and roughness, and consequently increased peel strength. The change in surface composition was mainly ascribed to the formation of C-O and -C=O functional groups on the vulcanized surfaces. A maximum of 98% improvement in peel strength was observed after plasma treatment.

  11. Evaluation of sodium diclofenac release using natural rubber latex as carrier

    Energy Technology Data Exchange (ETDEWEB)

    Aielo, Patricia B.; Borges, Felipe A.; Romeira, Karoline M.; Herculano, Rondinelli D., E-mail: rond@assis.unesp.br [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Assis, SP (Brazil). Fac. de Ciencias e Letras. Dept. de Ciencias Biologicas; Miranda, Matheus Carlos Romeiro [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Araraquara, SP (Brazil). Inst. de Quimica; Arruda, Larisa B. de; Lisboa Filho, Paulo Noronha; Drago, Bruno de C. [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Bauru, SP (Brazil). Fac. de Ciencias. Dept. de Fisica

    2014-08-15

    Sodium Diclofenac is a non-steroidal anti-inflammatory drug (NSAID) taken to reduce inflammation and, as an analgesic, reduce pain. Although this drug is widely used in the general population, properties such as the short half-time and some side effects restrict its clinical use. The most common side effects are: gastric irritation, gastritis, peptic ulcer and bleeding. Studies involving biomaterials as carrier for drug release have been proving their efficiency in overcoming those problems and better controlling the release rate and targeting of the drug. Natural rubber latex (NRL) has been proven excellent for its biocompatibility and ability to stimulate angiogenesis, cellular adhesion and the formation of extracellular matrix, promoting the replacement and regeneration of tissue. In this work, a NRL membrane is used to deliver sodium diclofenac. Sodium diclofenac (NaDic) was found to be adsorbed on the NRL membrane, with little or no incorporation into the membrane bulk, according to energy dispersive Scanning Electron Microscopy with X-Ray microanalysis (SEM-EDS) spectroscopy. In addition, FT-IR shows that there is no molecular-level interaction between drug and NRL. Already, the X-Ray Diffraction (XRD) of NaDic-NRL shows a broader one spectrum than the sharper halo (amorphous characteristic XRD spectrum) of pure NRL. More importantly, the release time of diclofenac in a NRL membrane in vitro was increased from the typical 2-3 h for oral tablets to ca. 74 h. The kinetics of the drug release could be fitted with a double exponential function, with two characteristic times of 0.899 and 32.102 h. In this study, we demonstrated that the interesting properties provided by NRL membranes combined with a controlled release of drug is relevant for biomedical applications.(author)

  12. Syntheses, spectroscopic characterization, crystal structure and natural rubber vulcanization activity of new disulfides derived from sulfonyldithiocarbimates

    Science.gov (United States)

    Alves, Leandro de Carvalho; Rubinger, Mayura Marques Magalhães; Tavares, Eder do Couto; Janczak, Jan; Pacheco, Elen Beatriz Acordi Vasques; Visconte, Leila Lea Yuan; Oliveira, Marcelo Ribeiro Leite

    2013-09-01

    The compounds (Bu4N)2[(4-RC6H4SO2NCS2)2] [Bu4N = tetrabutylammonium cation; R = H (1), F (2), Cl (3) and Br (4)] and (Ph4P)2[(4-RC6H4SO2NCS2)2]ṡH2O [Ph4P = tetraphenylphosphonium cation and R = I (5)] were synthesized by the reaction of the potassium dithiocarbimates (4-RC6H4SO2NCS2K2ṡ2H2O) with I2 and Bu4NBr or Ph4PCl. The IR data were consistent with the formation of the dithiocarbimatodisulfides anions. The NMR spectra showed the expected signals for the cations and anions in a 2:1 proportion. The structures of compounds 1-5 were determined by the single crystal X-ray diffraction. The compounds 2, 3 and 4 are isostructural and crystallise in the centrosymmetric space group C2/c of the monoclinic system. Compound 1 crystallises in the monoclinic system in the space group of P21/n and the compound 5 crystallises in the centrosymmetric space group P-1 of the triclinic system. The complex anions of compounds 2, 3 and 4 exhibit similar conformations having twofold symmetry, while in 1 and 5 the anions exhibit C1 symmetry. The activity of the new compounds in the vulcanization of the natural rubber was evaluated and compared to the commercial accelerators ZDMC, TBBS and TMTD. These studies confirm that the sulfonyldithiocarbimato disulfides anions are new vulcanization accelerators, being slower than the commercial accelerators, but producing a greater degree of crosslinking, and scorch time values compatible with good processing safety for industrial applications. The mechanical properties, stress and tear resistances were determined and compared to those obtained with the commercial accelerators.

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

    International Nuclear Information System (INIS)

    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.

  14. Novel mesoporous composites based on natural rubber and hexagonal mesoporous silica: Synthesis and characterization

    International Nuclear Information System (INIS)

    The present study is the first report on the synthesis and characterization of mesoporous composites based on natural rubber (NR) and hexagonal mesoporous silica (HMS). A series of NR/HMS composites were prepared in tetrahydrofuran via an in situ sol–gel process using tetraethylorthosilicate as the silica precursor. The physicochemical properties of the composites were characterized by various techniques. The effects of the gel composition on the structural and textural properties of the NR/HMS composites were investigated. The Fourier-transform infrared spectroscopy (FTIR) and 29Si magic angle spinning nuclear magnetic resonance (29Si MAS NMR) results revealed that the surface silanol groups of NR/HMS composites were covered with NR molecules. The powder X-ray diffraction (XRD) and transmission electron microscopy (TEM) data indicated an expansion of the hexagonal unit cell and channel wall thickness due to the incorporation of NR molecules into the mesoporous structure. NR/HMS composites also possessed nanosized particles (∼79.4 nm) as confirmed by scanning electron microscopy (SEM) and particle size distribution analysis. From N2 adsorption–desorption measurement, the NR/HMS composites possessed a high BET surface area, large pore volume and narrow pore size distribution. Further, they were enhanced hydrophobicity confirmed by H2O adsorption–desorption measurement. In addition, the mechanistic pathway of the NR/HMS composite formation was proposed. - Highlights: • NR molecules were incorporated into hexagonal meso-structure of HMS. • NR/HMS composites exhibited an expanded unit cell and channel wall thickness. • Nanosized NR/HMS composites with a lower particle size range were obtained. • NR/HMS had high surface area, large pore volume and narrow pore size distribution. • NR/HMS composites displayed an enhanced hydrophobicity

  15. Migration of BTEX and phthalates from natural rubber latex balloons obtained from the Sri Lankan market.

    Science.gov (United States)

    Jayawardena, Imanda; Godakumbura, Pahan I; Prashantha, M A B

    2016-01-01

    The current study evaluates the migration of benzene, toluene, ethylbenzene, xylene (BTEX) and phthalates into artificial saliva from natural rubber latex (NRL) balloons available for sale in Sri Lanka. It was discovered that at least one BTEX compound migrated from almost all the brands. The migration of four phthalates; diethyl phthalate, dibutyl phthalate, di-isobutyl phthalate and butyl benzyl phthalate were also observed. Migratory levels of BTEX and phthalates in most of the balloon brands were above the permissible levels set by the European Union. Assessment of factors affecting the migratory levels indicated migration under active mouthing conditions and migration from the neck region of the balloons were significantly higher. The migratory levels were observed to decrease with storage time, and in certain brands the BTEX levels decreased below the permissible level. One-way ANOVA indicated no significant differences (p ≥ 0.05) in migratory levels of each individual compound within the same brand for both BTEX and phthalates. When compared among different brands, BTEX levels indicated significant differences (p ≤ 0.05), while phthalate levels were observed to not be significantly different (p ≥ 0.05). A significant difference was also observed (p ≤ 0.05) among the migratory levels of compounds under each test condition evaluated as factors affecting the migratory level. Furthermore, the solvent based colorants added to color the latex were found to be the source of BTEX and phthalates in the NRL balloons. PMID:26759759

  16. Evaluation of sodium diclofenac release using natural rubber latex as carrier

    International Nuclear Information System (INIS)

    Sodium Diclofenac is a non-steroidal anti-inflammatory drug (NSAID) taken to reduce inflammation and, as an analgesic, reduce pain. Although this drug is widely used in the general population, properties such as the short half-time and some side effects restrict its clinical use. The most common side effects are: gastric irritation, gastritis, peptic ulcer and bleeding. Studies involving biomaterials as carrier for drug release have been proving their efficiency in overcoming those problems and better controlling the release rate and targeting of the drug. Natural rubber latex (NRL) has been proven excellent for its biocompatibility and ability to stimulate angiogenesis, cellular adhesion and the formation of extracellular matrix, promoting the replacement and regeneration of tissue. In this work, a NRL membrane is used to deliver sodium diclofenac. Sodium diclofenac (NaDic) was found to be adsorbed on the NRL membrane, with little or no incorporation into the membrane bulk, according to energy dispersive Scanning Electron Microscopy with X-Ray microanalysis (SEM-EDS) spectroscopy. In addition, FT-IR shows that there is no molecular-level interaction between drug and NRL. Already, the X-Ray Diffraction (XRD) of NaDic-NRL shows a broader one spectrum than the sharper halo (amorphous characteristic XRD spectrum) of pure NRL. More importantly, the release time of diclofenac in a NRL membrane in vitro was increased from the typical 2-3 h for oral tablets to ca. 74 h. The kinetics of the drug release could be fitted with a double exponential function, with two characteristic times of 0.899 and 32.102 h. In this study, we demonstrated that the interesting properties provided by NRL membranes combined with a controlled release of drug is relevant for biomedical applications.(author)

  17. Progress in radiation vulcanization of natural rubber latex through international cooperation

    International Nuclear Information System (INIS)

    In 1982 IAEA implemented a regional Project of RVNRL as a part of Cooperation Program for Asia and the Pacific region. Bangladesh, China, India, Indonesia, Japan, Malaysia, Sri Lanka, Thailand and Vietnam are now participating in the Project. The work plan of the Project consists of R and D program, products development program and cost estimation of RVNRL. The main achievement of the R and D program are 1) reduction in vulcanization dose from 40 kGy to 8 kGy and 2) improvement in the quality of products. The advantages of RV NR latex rubbers over NR latex rubbers vulcanized using sulfur are 1) absence of nitrosamine, 2) low cytotoxicity, 3) absence of sulfur and zinc oxide, 4) transparency, and 5) softness. Test production of various rubber products such as condom, surgical gloves are being carrying out in each participating country. In March 1989 rubber gloves for workers in nuclear power plants have been commercialized in Japan. Optical laser balloon for diagnosis and treatment of gastric cancer and drainage are also developed in Japan. Three types of irradiators were designed for the cost estimation of RVNRL. (author)

  18. Implications of non-carcinogenic pah-free extender oils in natural rubber based tire compounds

    NARCIS (Netherlands)

    Petchkaew, Anida

    2015-01-01

    The oils are generally added in the rubber compounds to improve processing properties, low temperature properties, dispersion of fillers, and to reduce cost. The conventionally widely used oils in tire compounds are Distillate Aromatic Extract (DAE) oils, which contain a high concentration of Polycy

  19. Qualitative theory of rubber friction

    OpenAIRE

    Persson, B.N.J.; E. Tosatti

    2000-01-01

    When rubber is slid on a hard, rough substrate, the surface asperities of the substrate exert oscillating forces on the rubber surface leading to energy "dissipation" via the internal friction of the rubber. We present a qualitative discussion of how the resulting friction force depends on the nature of the surface roughness and comment on the origin of the wear of sliding rubber surfaces. (C) 2000 American Institute of Physics. [S0021-9606(00)51404-4].

  20. Prevalence of Allergy to Natural Rubber Latex and Potential Cross Reacting Food in Operation Room Staff in Shiraz Hospitals -2006

    Directory of Open Access Journals (Sweden)

    H Nabavizade

    2007-07-01

    Full Text Available Introduction & Objective: Allergic reactions to natural rubber latex have increased during past 10 years especially among health care workers and patients with high exposure to latex allergens. Allergic reaction to latex is related to many diseases like occupational asthma. This study was performed to determine the prevalence of allergy to natural rubber latex and potential cross reacting food in operation room staff in Shiraz hospitals. Materials & Methods: In this cross-sectional descriptive study five hundred eighty operation room staff of ten private and state hospitals in Shiraz completed latex allergy questionnaire. They were questioned about personal history and previous history of latex sensitivity, symptoms of latex reactivity and about other allergies particularly to foods that may cross react with latex. Informed consent was obtained and skin prick testing was performed with natural rubber latex. Skin prick tests were done with three potentially cross reacting food (banana, Kiwi, and potato. The obtained data were analyzed with SPSS software and Chi-square test. Results: Among the 580 operation room workers 104 (17.9 % of participants were positive to latex skin test. We found a significant association between positive skin test to latex in operation room staff and atopy, urticaria and food allergy. Positive skin test to latex related to positive kiwi skin test (p<0.05. The prevalence did not vary by sex, age, education, surgical and non surgical glove users, history of contact dermatitis or smoking status. Conclusion: Latex allergy has a high prevalence in personnel of operation room. Evaluation of present symptom and prediction of future disease necessitate screening test in individuals at risk.

  1. Report on the socio-economic impact of Natural Rubber cultivation under the block planting scheme in Tripura

    OpenAIRE

    Joseph, Joby; George K., Tharian; S.K, Dey

    2010-01-01

    The study is a pioneering attempt to assess the socio-economic impact of the Block Planting Scheme (BPS) from the angle of the beneficiaries,implementing agencies and the policymakers.The report is based on the primary information gathered from 480 households drawn from Block Planting Units with mature (Mature BPUs)and immature (Immature BPUs) area under Natural Rubber (NR) as well as households attached to Group Processing Scheme (GPUs) with mature area under NR during the year 2008.The trip...

  2. Sorption and desorption of toluene, m-xylene, p-cresol and water by natural rubber chips

    OpenAIRE

    Duangkamol Dechojarassri; Savalee Jaroenkarn; Pore Jumpathi; Panu Danwanichakul

    2006-01-01

    The transport mechanism of several pure liquid organic substances into natural rubber chips composed of different fillers was investigated. It was found that, for the same type of chips, the Fickian diffusion of toluene was the fastest, followed by m-xylene, water and p-cresol. The toluene uptake was highest which was as high as 3.42 times of the chip weight. This was closely followed by m- xylene uptake, which was much higher than p-cresol uptake and water uptake which was only 0.02 times of...

  3. A simplified technique for sizing solar-assisted fixed-bed batch dryers: application to granulated natural rubber

    Energy Technology Data Exchange (ETDEWEB)

    Pratoto, Adjar; Daguenet, M. [Universite de Perpignan, Lab. de Thermodynamique et Energetique, Perpignan, 66 (France); Zeghmati, B. [IUT de Belfort-Montbeliard, Lab. de Metrologie des Interfaces Techniques, Belfort, 90 (France)

    1998-12-01

    This work concerns the design of solar-assisted drying systems. The system considered is of indirect type where an air collector field is associated to a fixed-bed batch dryer. For a given system configuration, the heat savings fraction is defined. Partial drying air recirculation and the possible heat dumping are taken into account. The importance of the collector array is underlined. A simplified technique for sizing is developed with application to granulated natural rubber for fixed drying conditions. The development consists in relating empirically the heat savings fraction to design parameters by simulations. (Author)

  4. Radio-vulcanization of natural rubber in the latex phase. Study of an experimental 1 tonne per hour production

    International Nuclear Information System (INIS)

    After briefly reviewing the main research carried out on the radio-vulcanization of latex and elastomers, a description is given of 4 types of cell which have been used successively with a view to industrial irradiation. They have made it possible to acquire the information necessary for resolving the main problem arising during irradiation - the formation of coagulum. The first two cell are designed for irradiation by a horizontal beam ('Dynamitron'), the two others use a vertical beam ('Circe'). The study of the properties of the rubber obtained shows it to compare favorably with 'Revultex'. In the appendix are given some characteristics of natural latex and information about its processing. (authors)

  5. 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...

  6. Prevalence of type I allergy to natural rubber latex and type IV allergy to latex and rubber additives in operating room staff with glove-related symptoms.

    Science.gov (United States)

    Miri, Sara; Pourpak, Zahra; Zarinara, Alireza; Zarinara, Alam; Heidarzade, Marzieh; Kazemnejad, Anoushirvan; Kardar, Gholamali; Firooz, Alireza; Moin, Athar

    2007-01-01

    There is lack of data on the prevalence of latex allergy in the health care setting in Iran. This study was performed to determine the prevalence of type I latex allergy and type IV allergy to latex and rubber additives among the operating room staff with glove-related symptoms in 13 general hospitals in Tehran. Skin-prick tests with commercial latex extract, patch tests with latex and 25 rubber additive series, and total and latex-specific IgE detection were performed on the operating room staff who reported latex glove-related symptoms. Five hundred twelve self-administered questionnaires (100%) were completed by all operating room staff and latex glove-related symptoms were reported by 59 (11.5%) employees. Among all symptomatic operating room staff tested, the prevalence of type I latex allergy was 30.5% and the prevalence rates of type IV allergy to latex and rubber additives were 16.7 and 14.6%, respectively. The most positive patch test result with rubber additives was related to tetramethylthiuram monosulfide (38.5%). The risk factors for type I latex allergy were female sex (p = 0.009) and positive patch test with rubber additives (p = 0.012). Subjects who had positive patch test with latex were significantly more likely to have positive patch test with rubber additives (p rubber additives. Based on this study, we recommend eliminating powdered latex gloves from the operating rooms of the 13 studied general hospitals and support the substitution of powder-free latex gloves. PMID:18034975

  7. Evaluation of natural rubber from IAC series clones by solid state {sup 13}C NMR; Avaliacao da borracha natural de clones da serie IAC por {sup 13}C RMN no estado solido

    Energy Technology Data Exchange (ETDEWEB)

    Martins, Maria A.; Moreno, Rogerio M.B.; Goncalves, Paulo S. [Instituto Agronomico de Campinas, SP (Brazil). Centro de Cafe e Plantas Tropicais. Programa Seringueira]. E-mails: paulog@iac.sp.gov.br; mariaalice@cnpdia.embrapa.br; Forato, Lucimara A.; Colnago, Luiz A.; Mattoso, Luiz H.C. [EMBRAPA Instrumentacao Agropecuaria, Sao Carlos, SP (Brazil)]. E-mail: colnago@cnpdia.embrapa.br; forato@cnpdia.embrapa.br; rogerio@cnpdia.embrapa.br; mattoso@cnpdia.embrapa.br; Job, Aldo E. [Universidade Estadual Paulista (UNESP), Presidente Prudente, SP (Brazil). Departamento de Fisica, Quimica e Biologia

    2005-07-01

    Agronomic Institute (IAC) and EMBRAPA Agricultural Instrumentation (EMBRAPA/CNPDIA) have been studied Hevea species in order to increase the production of the natural rubber and to develop new clones more appropriated to Brazil's soil and climate. Structural characterization of natural rubber [Hevea brasiliensis (Willd. ex Adr. de Juss.) Muell. - Arg.] from new clones of the IAC series (IAC 300, 301, 302, 303, 35, 40, and 56) and from RRIM 600 clone has been studied by high-resolution solid-state {sup 13}C NMR and by single pulse technique. The results have shown that the application of solid-state {sup 13}C NMR using the single pulse technique is a powerful tool to study natural rubber. The spectra obtained through this technique confirmed that natural rubber from all clones studied are cis-1,4-polyisoprene (author) form.(author)

  8. The use of natural rubber-based material for the preparation of radiation-curable resin. I. The reaction of epoxidised natural rubbers of low molecular weight with acrylic acid

    International Nuclear Information System (INIS)

    A synthesis method for the preparation of a new radiation-curable resin based on natural rubber has been established. The method was based on the reaction between epoxidised natural rubbers (ENR) of low molecular weight, i.e. Mn 0f 5,800 to 82,000, with acrylic acid in the presence of a catalyst and an inhibitor. Two grades of ENR namely ENR-25 and ENR-50 corresponding to 25 and 50 mole % epoxidation levels, respectively were used. The acrylation was carried out at temperatures between 95-105 degree C and was monitored by the measurements of the acid value of the reaction mixture as the reaction proceeded. It was confirmed by IR spectroscopic technique that the reaction occurred through the ring opening of the epoxide group of ENR. As a result, the new resin contains radiation-curable acrylate groups as well as hydroxyl groups on its main chain. When formulated with benzophenone, it solidified upon with UV light

  9. Effect of molecular weight and testing rate on adhesion property of pressure-sensitive adhesives prepared from epoxidized natural rubber

    International Nuclear Information System (INIS)

    Research highlights: → Elucidation of adhesion property of epoxidized natural rubber (ENR 25). → Correlation of peel and shear strength with molecular weight and rate of testing. → Confirmation of miscibility of tackifier and ENR 25 by DSC and FTIR study. → Applicability of Fox equation in ENR 25/coumarone-indene resin system. -- Abstract: The dependence of peel strength and shear strength of epoxidized natural rubber (ENR 25)-based pressure-sensitive adhesive on molecular weight and rate of testing was investigated using coumarone-indene as the tackifying resin. Toluene and polyethylene terephthalate (PET) were used as the solvent and substrate respectively throughout the study. A SHEEN hand coater was used to coat the adhesive on the substrate at a coating thickness of 120 μm. All the adhesion properties were determined by a Llyod Adhesion Tester operating at different rates of testing. Result shows that peel strength and shear strength increases up to an optimum molecular weight of 6.5 x 104 of ENR 25. For peel strength, the observation is attributed to the combined effects of wettability and mechanical strength of rubber at the optimum molecular weight, whereas for the shear strength, it is ascribed to the increasing amount of adhesive present in the coating layer which enhances the shear resistance of the adhesive. Peel strength and shear strength also increases with increase in rate of testing, an observation which is associated to the viscoeslastic response of the adhesive. Differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR) study confirms the miscibility of tackifier and the ENR 25.

  10. ESTIMATION OF THE DYNAMIC PROPERTIES OF EPOXY GLASS FABRIC COMPOSITES WITH NATURAL RUBBER PARTICLE INCLUSIONS

    OpenAIRE

    H. Ravi Sankar; Srikant, R. R.; P. Vamsi Krishna; V. Bhujanga Rao; P. Bangaru Babu

    2013-01-01

    Conventional materials are being replaced in the field of engineering by composite materials, due to their tailorable properties and high specific properties. These materials are extensively used in structural applications. Damping is one of the important properties of the materials used in structures, and needs to be enhanced in order to reduce structural vibrations. In the present work, the improvement of the material damping of glass fabric epoxy composites with particle rubber inclusions ...

  11. Implications of non-carcinogenic pah-free extender oils in natural rubber based tire compounds

    OpenAIRE

    Petchkaew, Anida

    2015-01-01

    The oils are generally added in the rubber compounds to improve processing properties, low temperature properties, dispersion of fillers, and to reduce cost. The conventionally widely used oils in tire compounds are Distillate Aromatic Extract (DAE) oils, which contain a high concentration of Polycyclic Aromatic Hydrocarbons (PAHs). PAHs that can be released from tires by tire wear are harmful to health and environment, so safe process oils are needed to replace aromatic oil in tire compounds...

  12. Rubber molds for investment casting

    International Nuclear Information System (INIS)

    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)

  13. Production Of Hollow Toy Product From Radiation Pre vulcanized Natural Rubber Latex (RVNRL) By Using Casting And Moulding Technique

    International Nuclear Information System (INIS)

    Hollow toy products are very synonym to the child from the age of months since it able to stimulating each of their sense such as sight, hearing, taste, touch and smell. Most of hollow toy products are made from natural rubber latex by using moulding and casting technique. The moulding and casting technique is a manufacturing process by pored liquid latex into a mould, which contain cavity of the desired shape. The mould made from plaster of Paris able to absorbs water from latex meanwhile the presence of calcium ions from plaster of Paris will tend to diffuse into latex thus promote formation of deposit on surface of cavity mould. To improve the quality and safety of hollow toy product made from latex, Radiation Pre vulcanized Natural Rubber Latex (RVNRL) has been identified to be used because it can fulfill the standard requirement for latex and also due to its special abilities such as lower modulus (soft latex products), nitrosamines free, low in nitrosatables, free from chemical accelerators induced allergies and better biodegradability. This paper identify the problem appears from the process of making hollow toy products from RVNRL by using moulding and casting technique. (author)

  14. Effect of epoxidation level on thermal properties and ionic conductivity of epoxidized natural rubber solid polymer nanocomposite electrolytes

    International Nuclear Information System (INIS)

    Effect of epoxide content on the thermal and conductivity properties of epoxidized natural rubber (ENR) solid polymer nanocomposite electrolytes was investigated. Commercial available epoxidized natural rubber having 25 (ENR25) and 50 mole% (ENR50) epoxide, respectively were incorporated with lithium perchlorate (LiClO4) salt and titanium dioxide (TiO2) nanofiller via solution casting method. The solid polymer nanocomposite electrolytes were characterized by differential scanning calorimetry (DSC) and impedance spectroscopy (IS) for their thermal properties and conductivity, respectively. It was evident that introduction of LiClO4 causes a greater increase in glass transition temperature (Tg) and ionic conductivity of ENR50 as compared to ENR25. Upon addition of TiO2 in ENR/LiClO4 system, a remarkable Tg elevation was observed for both ENRs where ENR50 reveals a more pronounced changes. It is interesting to note that they exhibit different phenomenon in ionic conductivity with TiO2 loading where ENR25 shows enhancement of conductivity while ENR50 shows declination

  15. Effect of epoxidation level on thermal properties and ionic conductivity of epoxidized natural rubber solid polymer nanocomposite electrolytes

    Science.gov (United States)

    Harun, Fatin; Chan, Chin Han; Sim, Lai Har; Winie, Tan; Zainal, Nurul Fatahah Asyqin

    2015-08-01

    Effect of epoxide content on the thermal and conductivity properties of epoxidized natural rubber (ENR) solid polymer nanocomposite electrolytes was investigated. Commercial available epoxidized natural rubber having 25 (ENR25) and 50 mole% (ENR50) epoxide, respectively were incorporated with lithium perchlorate (LiClO4) salt and titanium dioxide (TiO2) nanofiller via solution casting method. The solid polymer nanocomposite electrolytes were characterized by differential scanning calorimetry (DSC) and impedance spectroscopy (IS) for their thermal properties and conductivity, respectively. It was evident that introduction of LiClO4 causes a greater increase in glass transition temperature (Tg) and ionic conductivity of ENR50 as compared to ENR25. Upon addition of TiO2 in ENR/LiClO4 system, a remarkable Tg elevation was observed for both ENRs where ENR50 reveals a more pronounced changes. It is interesting to note that they exhibit different phenomenon in ionic conductivity with TiO2 loading where ENR25 shows enhancement of conductivity while ENR50 shows declination.

  16. Effect of epoxidation level on thermal properties and ionic conductivity of epoxidized natural rubber solid polymer nanocomposite electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Harun, Fatin; Chan, Chin Han; Winie, Tan [Faculty of Applied Sciences, UniversitiTeknologi MARA (UiTM), Shah Alam, 40450 Selangor Darul Ehsan (Malaysia); Sim, Lai Har; Zainal, Nurul Fatahah Asyqin [Center of Foundation Studies, PuncakAlam Campus, UniversitiTeknologi MARA, 40430 Selangor Darul Ehsan (Malaysia)

    2015-08-28

    Effect of epoxide content on the thermal and conductivity properties of epoxidized natural rubber (ENR) solid polymer nanocomposite electrolytes was investigated. Commercial available epoxidized natural rubber having 25 (ENR25) and 50 mole% (ENR50) epoxide, respectively were incorporated with lithium perchlorate (LiClO{sub 4}) salt and titanium dioxide (TiO{sub 2}) nanofiller via solution casting method. The solid polymer nanocomposite electrolytes were characterized by differential scanning calorimetry (DSC) and impedance spectroscopy (IS) for their thermal properties and conductivity, respectively. It was evident that introduction of LiClO{sub 4} causes a greater increase in glass transition temperature (T{sub g}) and ionic conductivity of ENR50 as compared to ENR25. Upon addition of TiO{sub 2} in ENR/LiClO{sub 4} system, a remarkable T{sub g} elevation was observed for both ENRs where ENR50 reveals a more pronounced changes. It is interesting to note that they exhibit different phenomenon in ionic conductivity with TiO{sub 2} loading where ENR25 shows enhancement of conductivity while ENR50 shows declination.

  17. Use of radiation vulcanized natural rubber latex in small and medium scale industries in Sri Lanka

    International Nuclear Information System (INIS)

    The latex based industry is fast growing with the setting up of several units to produce household and examination gloves. Production of rubberized coir using concentrated latex is also growing rapidly while more and more small scale industries have been set up. There is also a growth in the large scale sector in the dipped goods manufacture. Use of irradiated latex in the manufacture of dipped products has good potential as the efficiency of production is enhanced in the case of latex containing less additives. (author)

  18. Effect of Molecular Weight on the Properties of Liquid Epoxidized Natural Rubber Acrylate (LENRA)/ Silica Hybrid Composites

    International Nuclear Information System (INIS)

    This paper reports on the effect of molecular weight on the morphological and mechanical properties of liquid epoxidized natural rubber acrylate (LENRA)/ silica hybrid composites prepared by sol-gel technique. The sol-gel reaction was conducted at different concentration of tetraethyl orthosilicate (TEOS), used as a precursor of silica. TEOS were introduced in 10, 20, 30, 40 and 50 parts per hundred rubber (phr) in the composites. Two different molecular weights of ENR were used to study the effect of molecular weight on the mechanical and morphological properties of the compounds. These compounds were cured by ultraviolet (UV) irradiation. The mechanical properties were studied through pendulum hardness and scratch tests. Higher molecular weight of ENR showed better mechanical properties than lower molecular weight. Transmission electron microscope was used to determine the silica size and to study the distribution and dispersion of the silica particles. High molecular weight showed greater distribution and dispersion of silica particles with diameter of 13 - 256 nm. Morphological and mechanical properties of LENRA/ silica hybrid composites were improved by using high molecular weight of ENR. (author)

  19. New Insights into the Relationship Between Network Structure and Strain Induced Crystallization in Unvolcanized Natural Rubber by Synchrotron X-ray Diffraction

    International Nuclear Information System (INIS)

    The relationship between the network structure and strain-induced crystallization in un-vulcanized as well as vulcanized natural rubbers (NR) and synthetic poly-isoprene rubbers (IR) was investigated via synchrotron wide-angle X-ray diffraction (WAXD) technique. It was found that the presence of a naturally occurring network structure formed by natural components in un-vulcanized NR significantly facilitates strain-induced crystallization and enhances modulus and tensile strength. The stress-strain relation in vulcanized NR is due to the combined effect of chemical and naturally occurring networks. The weakness of naturally occurring network against stress and temperature suggests that vulcanized NR has additional relaxation mechanism due to naturally occurring network. The superior mechanical properties in NR compared with IR are mainly due to the existence of naturally occurring network structure.

  20. ESTIMATION OF THE DYNAMIC PROPERTIES OF EPOXY GLASS FABRIC COMPOSITES WITH NATURAL RUBBER PARTICLE INCLUSIONS

    Directory of Open Access Journals (Sweden)

    H. Ravi Sankar

    2013-06-01

    Full Text Available Conventional materials are being replaced in the field of engineering by composite materials, due to their tailorable properties and high specific properties. These materials are extensively used in structural applications. Damping is one of the important properties of the materials used in structures, and needs to be enhanced in order to reduce structural vibrations. In the present work, the improvement of the material damping of glass fabric epoxy composites with particle rubber inclusions is studied. The effect of particle size on the damping and stiffness parameters at different frequencies and temperatures is studied experimentally. Considerable enhancement in damping without significant reduction in stiffness is observed at lower particle sizes. The damping property in both bending and shear modes is more with 0.254 mm rubber particle inclusions among the selected sizes. A lower reduction in stiffness is observed with the inclusion of lower particle sizes (0.254 mm and 0.09 mm when compared with higher particle sizes. An ANN-based prediction model is developed to predict these properties for a given frequency/temperature and particle size. The predicted values are very close to the experimental values with an maximum error of 5%.

  1. Performance of sand and shredded rubber tire mixture as a natural base isolator for earthquake protection

    Science.gov (United States)

    Bandyopadhyay, Srijit; Sengupta, Aniruddha; Reddy, G. R.

    2015-12-01

    The performance of a well-designed layer of sand, and composites like layer of sand mixed with shredded rubber tire (RSM) as low cost base isolators, is studied in shake table tests in the laboratory. The building foundation is modeled by a 200 mm by 200 mm and 40 mm thick rigid plexi-glass block. The block is placed in the middle of a 1m by 1m tank filled with sand. The selected base isolator is placed between the block and the sand foundation. Accelerometers are placed on top of the footing and foundation sand layer. The displacement of the footing is also measured by LVDT. The whole setup is mounted on a shake table and subjected to sinusoidal motions with varying amplitude and frequency. Sand is found to be effective only at very high amplitude (> 0.65 g) of motions. The performance of a composite consisting of sand and 50% shredded rubber tire placed under the footing is found to be most promising as a low-cost effective base isolator.

  2. Investigation on dielectric relaxation of PMMA-grafted natural rubber incorporated with LiCF3SO3

    International Nuclear Information System (INIS)

    Natural rubber (NR) grafted with 30 wt% poly (methyl methacrylate) (PMMA) and designated as MG30 has been added with varying amounts of LiCF3SO3. X-ray diffraction (XRD) shows the samples to be amorphous. Fourier transform infrared (FTIR) spectroscopy indicates complexation between the cation of the salt and the oxygen atom of the C=O and -COO- groups of MG30. From electrochemical impedance spectroscopy (EIS), MG30 with 30 wt% LiCF3SO3 salt exhibits the highest ambient conductivity of 1.69×10-6 S cm-1 and lowest activation energy of 0.24 eV. The dielectric behavior has been analyzed using dielectric permittivity (ε′), dissipation factor (tan δ) and dielectric modulus (M⁎) of the samples. The dielectric constant of pure MG30 has been estimated to be ∼1.86.

  3. Effect of volatile fatty acid number and irradiation dose in the quality of irradiated natural rubber latex

    International Nuclear Information System (INIS)

    Radiation vulcanization of natural rubber latex with volatile fatty acid (VFA) number of 0.01; 0.02; 0.04; and 0.06 at irradiation dose of 20 and 30 kGy has been studied. The quality of irradiated latex such as the properties of latex and its film, has been evaluated. It was indicated that increasing VFA number, could decrease the tensile strenght, but other physical properties are relative the same. The lower VFA (0.01-0.02) number could decrease the irradition dose of vulcanization, and it can produce more stable irradiated during storage, than those with high VFA numbers. (author). 11 refs.; 3 tabs.; 2 figs

  4. Combination of Tung oil and Natural Rubber Latex in PVA as Water Based Coatings for Paperboard Application

    Directory of Open Access Journals (Sweden)

    Jianprasert Apichaya

    2015-01-01

    Full Text Available This research is focused on the preparation of the PVA/TO/NRL coatings for paperboard by using poly(vinyl alcohol (PVA as substance and blending with Tung oil (TO and/or natural rubber latex (NRL in order to enhance water resistance and dynamic mechanical properties. The effects of TO: NRL ratios on the structures were investigated by water resistance property and dynamic mechanical thermal analysis (DMA. The results showed that the water resistance property was improved by crosslinking of TO and film forming of NRL. The PVA/TO/NRL coating containing both TO and NRL gave better thermal behavior than those with only TO or NRL. For paperboard application, the PVA/TO/NRL coatings were applied on the paperboard to study water affinity and absorption rate on the coated surface. The rate of contact angle change of water on coated paperboards decreased depending on the ratios of TO and NRL.

  5. Development of Crystal Structure in Natural Rubber during Uniaxial Deformation as Revealed by X-ray Scattering Method

    International Nuclear Information System (INIS)

    The as-collected natural rubber latex (NRL) was centrifuged three times in order to obtain successively purified single centrifuge latex (SCL), double centrifuge latex (DCL) and triple centrifuge latex (TCL). By x-ray diffraction, the films of these latexes are found to be in amorphous state. Development of crystalline structure of the NRL, SCL, DCL and TCL films were investigated by drawing them along one direction with draw-ratio, λ=1, 2.5, 5 and 10. When λ=5, each film clearly exhibits c-aixs oriented crystalline reflections in the wide-angle x-ray scattering pattern, showing that the crystalline packing is orthorhombic. Besides, the crystallinity increases with the increasing order of the centrifuging process. Small-angle x-ray diffraction study ensures the alignment of the amorphous molecules that induce the nucleation of the oriented crystal

  6. Toxicological evaluation of natural rubber films from vulcanized latex by the conventional process and the alternative process with ionizing radiation

    International Nuclear Information System (INIS)

    The industrial vulcanization of natural rubber latex (NRL) is made all over the world by conventional process using sulphur and heat but it can be made by an alternative process using ionizing radiation. In this research the NRL was tested by 13 physical, chemical and mechanical assays which showed its good quality. It was done a preliminary study of the toxicological properties of 4 natural rubber films obtained by casting process of NRL: one non vulcanized, other vulcanized by the conventional process and two vulcanized by the alternative process. In the alternative process the films were obtained by irradiation of NRL by gamma rays from the 60 Co source at 250 kGy in the absence of sensitizer and irradiated NRL at 12 kGy in the presence of 4ph r of n-butyl acrylate / 0.2 phr of KOH. These vulcanization doses were determined from broken tensile strength. In the conventional process, sulphur vulcanized NRL was made using a classical composition. Another film was made with non vulcanized NRL. The preliminary evaluation of the toxicological properties was made from in vitro cytotoxicity and in vivo systemic toxicity assays. The LBN films vulcanized by the alternative process have less cytotoxicity than the NRL film vulcanized by the conventional process. The sensitized vulcanized films by gamma rays and non vulcanized films showed similar cytotoxicity while the vulcanized films without sensitizer showed a slight lower cytotoxicity. The non vulcanized NRL film and the NRL films vulcanized by the alternative process did not show toxic effects int he 72 hours period of the systemic toxicity assay. However the NRL film vulcanized with sulphur induced effects like allaying and motor in coordination on the animals treated with an oil extract at the fourth hour and recovering after that. The alternative process promoted lower toxic effects than conventional process because there was no toxic substances present. (author)

  7. The potential for sunflower as a rubber-producing crop for the United States

    OpenAIRE

    Cornish K.; Pearson C.H.; Rath D.J.; Dong N.; Mcmahan C.M.; Whalen M.

    2007-01-01

    There are strategic as well as economic incentives to develop a renewable, United States-based supply of natural rubber. Currently, nearly all commercial natural rubber comes from a single species, the Brazilian rubber tree (Hevea brasiliensis) and the US is almost completely dependent on imports from distant countries. Global natural rubber production will be best served in the future by multiple natural rubber crops. However, for most rubber crops, the ability to produce rubber that is econ...

  8. 西双版纳更新橡胶林地套种星油藤技术%Plukenetia volubilis Intercropping with Renew Natural Rubber Plantations in Xishuangbanna

    Institute of Scientific and Technical Information of China (English)

    梅正强; 王权宝; 丁传; 郭芳祥; 何建芬

    2013-01-01

    There will be eight or nine years for putting into production of natural rubber tree after replanted. Plukenetia volubi-lis intercropped in several rubber farms showed good in land use and economic benefit during rubber non-production.%  介绍了在橡胶树更新林地套种星油藤技术,大大提高了景洪农场现有土地利用率和经济收入,在长达8~9年的橡胶树更新定植非生产期间保证了职工的收益,实现以短补长,可有效缓解职工收入偏低,农场发展困难的矛盾。

  9. Isoprene Rubber Has Broad Market Potential

    Institute of Scientific and Technical Information of China (English)

    Xu Qingsbeng

    2007-01-01

    @@ Isoprene Rubber (IR) is a macro molecular substance polymerized from isoprene monomer, with a structure and properties that are basically similar to those of natural rubber (NR). It features excellent elasticity, wear resistance,heat resistance, low temperature flexibility, etc.

  10. BIODEGRADATION, MORPHOLGICAL, AND FTIR STUDY OF RATTAN POWDER-FILLED NATURAL RUBBER COMPOSITES AS A FUNCTION OF FILLER LOADING AND A SILANE COUPLING AGENT

    Directory of Open Access Journals (Sweden)

    Komethi Muniandy,

    2012-01-01

    Full Text Available Natural rubber (NR composites were prepared by the incorporation of rattan (Calamus Manan powder at filler loadings in the range of 0 to 30 phr into a natural rubber matrix with a laboratory size two roll mill. The particle size of rattan powder was less than 180 µm. The biodegradation of the rattan powder-filled natural rubber (NR composites were investigated as a function of filler loading and a silane coupling agent. A soil burial test was carried out for six months, and the degradation of the NR compound and the NR composites was evaluated through tensile testing. Morphological properties were determined using scanning electron microscopy (SEM to evaluate the degradation of the samples after six months of soil exposure. The results indicate that the tensile strength, elongation at break, and stress at 100% elongation (M 100 all decreased after soil burial testing due to the biological attack by microbes onto the sample. Improvement in tensile properties was seen with the addition of the silane coupling agent due to better adhesion between the rattan filler and the rubber matrix. The deterioration in tensile properties due to the biodegradation process was confirmed by SEM and FTIR studies.

  11. Rubber Dams

    OpenAIRE

    Kumaraswamy, Mohan

    2002-01-01

    One element of the CIVCAL project Web-based resources containing images, tables, texts and associated data on the construction of the Rubber Dams. Rubber dam construction is a relatively recent technological breakthrough. It was introduced to Hong Kong in the early 1960's and to date (Jan '99), 20 rubber dams have been installed in Hong Kong. Most of the dams are used to impound water for irrigation.

  12. Rubber gloves

    International Nuclear Information System (INIS)

    Rubber gloves are made by irradiating rubber latex containing a sensitizer with ionizing radiation to effect cross-linking. A glove shaped former is then dipped into the irradiated material and dried. The sensitizer can be a mono- or di-unsaturated monomer, such as 1,3-butylene glycol diacrylate. The rubber gloves are capable of maintaining stable quality without any time elapsing deterioration and of preventing any pollutive exhaust gases such as SOx, NOx, hydrogen cyanide, carbon monoxide and the like when old rubber gloves are burned in the scrap treatment in an incinerator. (author)

  13. Epoxidised Natural Rubber Based Composite Polymer Electrolyte Systems For Use In Electrochemical Device Applications

    International Nuclear Information System (INIS)

    Composite polymer electrolyte (CPE) comprising epoxy-fimctionalized rubber (ENR), HDDA monomer, mixed plasticizer-propylene carbonate/ethylene carbonate, silica filler and lithium bis(trifluoromethanesulfonylimide), Li[(CF3SO2)2N]have been prepared using photo-induced polymerization by UV irradiation technique. The irradiated samples of filled and non-filled silica of composites electrolytes have formed dry solid-flexible and transparent films in the self-constructed Teflon mould. Thermal behaviors, FTIR, morphology and ionic conductivity were performed on such ENR based PE polymer composites having varied compositions. The thermal stability has improved slightly in the temperature range 120-200 deg. C with optimized composition. FTIR measurements data revealed that the interaction of lithium with the epoxy groups of the un-bonded electrons within polymer occurred. The results suggest that the variation of conductivity with temperature indicates that the silica filled composite has achieved optimal ionic conductivity 10-4 S cm-1 and retained high percent of plasticizer. The ionic conductivity behavior of the silica-filled ENR based composite polymer electrolyte is consistent at elevated temperature compared to non-filled CPE system. This finding opens a new pathway for further investigation to diffusion of ions in the complex polymer electrolyte systems.

  14. 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…

  15. Synchrotron X-ray Scattering; Tensile Strength and Strain-Induced Crystallization in Carbon Black Filled Natural Rubber

    International Nuclear Information System (INIS)

    The tensile strength of rubber depends on a combination of contributions, in particular on the finite extensibility of chain segments between network points and on strain-induced crystallization. In order to achieve high tensile strength at high strain at break, we optimized the composition and processing parameters to gain high molecular flexibility by the cure conditions, to acquire high flexibility of sulfur bridges by the accelerator, and to increase the modulus level without losing rubber molecule flexibility by carbon black. As a result, our formula performed a tensile strength of 42.5 MPa at 25 C under ISO-37, as officially measured by the Society of Rubber Industry, Japan, in 2004.

  16. Regulamentação pública e conduta das firmas no sistema agroindustrial da borracha natural entre 1997 e 2000 Regulation and behavior of firms in Brazil's natural rubber agro-industrial system between 1997-2000

    Directory of Open Access Journals (Sweden)

    Augusto Hauber Gamero

    2002-01-01

    Full Text Available A necessidade de regulamentação no sistema agroindustrial (SAG da borracha natural no Brasil é evidente. Desde a metade do século, quando o país passou a importar esse produto, vários esforços governamentais vêm sendo definidos, objetivando o desenvolvimento sustentável do setor da produção agrícola nacional de borracha. No ano de 1997, criou-se uma política de subvenção direta à produção. Dada a estrutura desse SAG, associada à conjuntura do mercado internacional e a uma regulamentação falha do governo federal, começaram a surgir indícios de abuso de poder de mercado pela indústria pneumática instalada no país, principal consumidora do produto. Utilizando o arcabouço teórico da organização industrial, neste artigo se procurou levantar evidências nesse sentido.The need for regulation of Brazil’s natural rubber agro-industrial system (SAG is evident. Since the middle of the 20th century, when the country began importing rubber, many governmental efforts have been made to promote the sustainable development of Brazil’s natural rubber productive sector. In 1997, the Brazilian government created a direct subvention policy to assist rubber producers. Given the structure of Brazil’s SAG, the international rubber market, and imperfect regulation by the Federal Government, it would not be unexpected to find signs that Brazil’s largest natural rubber consumer, the domestic tire industry, has begun to abusively exercise its market power. Using the theoretical structure of Industrial Organization, this paper tries to show evidences of this abuse.

  17. Failure studies on rubber and rubber composites

    Science.gov (United States)

    Tao, Zhenghong

    A research study has been conducted to investigate selected failure processes in rubber and rubbery composites. Specific failure modes and materials considered included mechanical tearing of rubber-coated fabrics and mechanical/thermal fatigue of carbon black-filled elastomers. Experimental efforts developed novel evaluation techniques that were used to access failure resistance of the materials, as well as to elucidate molecular structure/physical properties relationships. Results are presented in multi-monograph format consisting of a series of four interdependent papers published in peer-reviewed journals. The first monograph measures the tear resistance of a series of polyester fabrics, of controlled fill-yarn size, coated with a compounded butyl rubber resin. A constrained trouser tear test is used to quantify the role of yarn mobility on crack-tip development and the resultant tear strength. As the area around a propagating crack is constrained, tear strength decreases by several orders of magnitude, indicating that the ability of the composite structure to dissipate energy away from the crack tip contributes more to tear resistance than the intrinsic strength of the concomitant materials. Monograph number two continues the work of the first by developing a novel cutting technique to monitor the role of the fiber/rubber interphase during tear propagation. This approach was applied to five different elastomers coated onto one of the polyester yarns. These data show a threefold increase in strength is possible by proper optimization of the fiber/rubber bond. In the third monograph, five different rubber bushing compounds were evaluated for mechanical/thermal fatigue resistance. Samples were dynamically excited in combined compression and shear loadings using a specially designed test fixture. Results indicated that heat build-up was a major contributing factor to the eventual failure of the materials via a complex fracture mechanism, with epoxidized natural

  18. Carboxymethyl Cellulose From Kenaf Reinforced Composite Polymer Electrolytes Based 49 % Poly (Methyl Methacrylate)-Grafted Natural Rubber

    International Nuclear Information System (INIS)

    Composite polymer electrolytes based 49 % poly(methyl methacrylate)-grafted natural rubber (MG49) incorporating lithium triflate (LiCF3SO3) were prepared. The study mainly focuses on the ionic conductivity performances and mechanical properties. Prior to that, carboxymethyl cellulose was synthesized from kenaf fiber. The films were characterized by electrochemical impedance (EIS) spectroscopy, linear sweep voltammetry (LSV), universal testing machine and scanning electron microscopy (SEM). The conductivity was found to increase with carboxymethyl cellulose loading. The highest conductivity value achieved was 6.5 x 10-6 Scm-1 upon addition of 6 wt % carboxymethyl cellulose. LSV graph shows the stability of this film was extended to 2.7 V at room temperature. The composition with 6 wt % carboxymethyl cellulose composition showed the highest tensile strength value of 7.9 MPa and 273 MPa of Young's modulus. The morphology of the electrolytes showed a smooth surface of films after addition of salt and filler indicating amorphous phase in electrolytes system. Excellent mechanical properties and good ionic conductivity are obtained, enlightening that the film is suitable for future applications as thin solid polymer electrolytes in lithium batteries. (author)

  19. The Influence of Irganox 245 on Crystallinity and Mechanics Stability of Polypropylene-Natural Rubber Poly blends

    International Nuclear Information System (INIS)

    The influence of irganox 245 on crystallinity and mechanics stability of polyethylene (PP)- Natural Rubber (NR) poly blends exposure by sunlight for 12 weeks has been studied. For optimalization of antioxidant function to reduce oxidation in PP-NR (4:1) poly blends irganox 245 with variation concentration of 4 %, 6 %, 8 % and 10 % vol were added. Poly blends was made by blending method at 170oC for 10 minutes with form an 30 rpm. The result showed that irganox 245 could not increasing adhesion at the interface between PP-NR, so PP-NR still immiscible blends. The optimal concentrations of irganox 245 as antioxidant on PP-NR poly blends is 8 % vol. PP-NR-irganox 245 8 % vol have decreasing tensile strength up to 6 % and increasing elongation at break up to 50 % in exposure by sunlight at long time 8 weeks but for 12 weeks tensile strength and elongation at break very weaks. Crystallinity and mechanics stability of PP-NR-irganox 245 8 % vol better than PP-NR poly blends, it is showed by slowly defects and decreasing crystallinity up to 9 % for exposure 12 weeks. (author)

  20. Preparation and characterization of nanocomposites of natural rubber with polystyrene and styrene-methacrylic acid copolymer nanoparticles

    Directory of Open Access Journals (Sweden)

    T. Nuruk

    2012-06-01

    Full Text Available Composites of natural rubber (NR/vinyl polymer nanoparticles as polystyrene (PS and poly(styrenemethacrylic acid (P(S-MAA were prepared by heterocoagulation technique. The polymer nanoparticles were prepared by emulsifier-free emulsion polymerizations at 70°C using potassium persulfate as initiator. Under acidic condition where positive charge was present on the NR latex (NRL surface, the nanoparticles having negative charge mainly from sulfate group of initiator were able to adsorb on the NRL surface, the electrostatic interaction being the driving force. The scanning electron micrographs showed that the polymer nanoparticles are homogenously distributed throughout NR matrix as nanoclusters with an average size of about 500 and 200 nm for PS and P(S-MAA, respectively. The mechanical properties of NR/PS and NR/P(S-MAA composite films were compared with the NR host. The nanocomposites, particularly when the polymer nanoparticles are uniformly dispersed, possess significantly enhanced mechanical properties strongly depending on the morphology of the nanocomposites.

  1. Tailoring percolating conductive networks of natural rubber composites for flexible strain sensors via a cellulose nanocrystal templated assembly.

    Science.gov (United States)

    Wang, Shuman; Zhang, Xinxing; Wu, Xiaodong; Lu, Canhui

    2016-01-21

    Conductive polymer composites (CPCs) just above the percolation threshold exhibit a unique strain-reversible electric response upon application of tensile strain, which can be used to prepare strain sensors. However, it is difficult to balance the electric conductivity which is fundamental to a stable output signal and the strain sensing sensitivity due to the relatively dense conductive pathways of the traditional CPCs. Constructing a "brittle" but effective conductive network structure in CPCs is the essential foundation of a desirable sensing material. Here, we demonstrate for the first time that highly flexible, stretchable, sensitive, and reversible strain sensors can be fabricated by a facile latex assembly approach, in which nontoxic, sustainable and biodegradable cellulose nanocrystals played a key role in tailoring the percolating network of conductive natural rubber (NR)/carbon nanotube (CNT) composites. The resulting nanocomposites with a continuous 3D conductive structure exhibited a very low electrical conductivity percolation threshold (4-fold lower than that of the conventional NR/CNT composites), high resistivity and sensitivity (gauge factor ≈ 43.5) and meanwhile good reproducibility of up to 100% strain. The proposed materials and principles in this study open up a novel practical approach to design high performance flexible sensors for a broad range of multifunctional applications. PMID:26542376

  2. Assessment of the genetic diversity of natural rubber tree clones of the SINCHI Institutes clone collection, using of morphological descriptors

    International Nuclear Information System (INIS)

    Genetic diversity of natural rubber clones of the in SINCHI Institute’s clone collection was assessed. Clones of Hevea brasiliensis (Willd. ex Adr. De Juss.) Muell.Arg., Hevea spp. (H. brasiliensis x H. benthamiana), and three more species of Hevea genus are a part of the collection. Seventy-two materials were characterized with twenty-eight morphological descriptors. They were later used to generate a similarity matrix through the analysis of multi-categorical variables, and to obtain clusters based on the matrix. A low variability between clones of H. brasiliensis and H. spp. was observed, presumably because of the direct descendants of most of the materials from crosses of parental PB 80, PB 5/51, PB 49 and Tjir, exception made of clone GU 1410. Clustering between some materials product of exclusive cross of PB series, a group between clones descendants of parental clones PB 86, and clustering between descendants of parental clones PB 5/51, were observed. Clones from other species of Hevea differ from this big group.

  3. Reinforcement of natural rubber hybrid composites based on marble sludge/Silica and marble sludge/rice husk derived silica

    Directory of Open Access Journals (Sweden)

    Khalil Ahmed

    2014-03-01

    Full Text Available A research has been carried out to develop natural rubber (NR hybrid composites reinforced with marble sludge (MS/Silica and MS/rice husk derived silica (RHS. The primary aim of this development is to scrutinize the cure characteristics, mechanical and swelling properties of such hybrid composite. The use of both industrial and agricultural waste such as marble sludge and rice husk derived silica has the primary advantage of being eco-friendly, low cost and easily available as compared to other expensive fillers. The results from this study showed that the performance of NR hybrid composites with MS/Silica and MS/RHS as fillers is extremely better in mechanical and swelling properties as compared with the case where MS used as single filler. The study suggests that the use of recently developed silica and marble sludge as industrial and agricultural waste is accomplished to provide a probable cost effective, industrially prospective, and attractive replacement to the in general purpose used fillers like china clay, calcium carbonate, and talc.

  4. Efficiency of 1,9- Nonane-diol-diacrylate as a radiation vulcanization accelerator for natural rubber latex

    International Nuclear Information System (INIS)

    The efficiency of 1,9- Nonane-diol-diacrylate (NDDA) as a radiation vulcanization accelerator (RVA) for natural rubber latex (NRL) was investigated. Both gamma rays and electron beam (EB) were used for vulcanizing NRL with NDDA. The radiation dose of gamma rays, concentration of NDDA required to vulcanize the latex were optimized. 20 kGy radiation dose of gamma rays and 5 phr concentration of NDDA were found optimum to get maximum tensile and related properties. NRL was vulcanized under EB to find out the optimum condition of irradiation with this RVA. The defoamer concentrations, length of irradiation time under EB, concentration of RVA were optimizer by changing various parameters of the EB machine with a constant set of the others. 0.2 phr defoamer concentration, 30 minutes irradiation time and 5 phr concentration of NDDA were found optimum for irradiation of NRL under the EB machine. Effect of low current and optimum volume of latex charged in the reaction vessel suitable for vulcanization at a time were found out. (author)

  5. Tolerogenic Dendritic Cells Derived from Donors with Natural Rubber Latex Allergy Modulate Allergen-Specific T-Cell Responses and IgE Production

    OpenAIRE

    Escobar, Alejandro; Aguirre, Adam; Guzmán, María Antonieta; González, Rodrigo; Catalán, Diego; Acuña-Castillo, Claudio; Larrondo, Milton; López, Mercedes; Pesce, Barbara; Rolland, Jennifer; O’Hehir, Robyn; Aguillón, Juan Carlos

    2014-01-01

    Natural rubber latex (NRL; Hevea brasiliensis) allergy is an IgE-mediated reaction to latex proteins. When latex glove exposure is the main sensitizing agent, Hev b 5 is one of the major allergens. Dendritic cells (DC), the main antigen presenting cells, modulated with pharmacological agents can restore tolerance in several experimental models, including allergy. In the current study, we aimed to generate DC with tolerogenic properties from NRL-allergic patients and evaluate their ability to ...

  6. Chemicals used in the rubber industry.

    Science.gov (United States)

    Fishbein, L

    1991-01-01

    Hundreds of chemicals and mixtures illustrative of many structural and use categories are employed in the rubber industry. Global utilization of natural rubber and synthetic elastomers as well as rubber-processing chemicals are projected to increase in the foreseeable future. Primary focus is centered on the major rubber processing chemicals and elastomer monomers in regard to their utility, production trends, structural characteristics, nature of potential impurities, and toxicology (primarily carcinogenicity and genotoxicity). Additionally, areas of specific exposure concern and epidemiology in the rubber industry are considered. PMID:2057768

  7. Effect of the [TiO2] on the radiation attenuation properties on the human tissue simulator obtained from radiovulcanized natural rubber latex

    International Nuclear Information System (INIS)

    In this paper was studied the concentration effect of TiO2 used as filler in the radiation attenuation properties of human tissue simulator obtained from radio vulcanized natural rubber. The studied parameters were the following: the mass stopping power (Smas), the depth at maximum dose (Zmax), the depth at 50% of maximum dose (R50) the radiotherapeutic range (RR80) and the electrons range (R). The natural rubber latex was formulated with [n-butyl acrylate ] = e phr and [KOH] = 0,2 phr and radio vulcanized by gamma rays (10 kGy) from 60 Co source. The filler TiO2 was added (0-16 phr). The natural rubber slabs were obtained by casting method and theirs absorbed dose behavior was studied for each filler concentration using electrons beam (6 MeV) from an accelerator. The results showed that the addition of each phr of filler promoted the decrease of 0.019 cm for Zmax, 0.021 cm for RR80, 0.033 cm for R and 0.026 cm for R50 up to [Ti O2] 15 phr. The Smas increased from 1.72 MeVcm2g-1 to 2.00 MeVcm2g-1 in the filler concentration range of 0-16 phr. The filler must be used in the 12-15 phr range. (author)

  8. Effect of different plasticizers on the properties of bio-based thermoplastic elastomer containing poly(lactic acid and natural rubber

    Directory of Open Access Journals (Sweden)

    V. Tanrattanakul

    2014-06-01

    Full Text Available Bio-based thermoplastic elastomers (TPE containing natural rubber and poly(lactic acid were prepared by melt blending in an internal mixer. The blend ratio was 60% of natural rubber and 40% of poly(lactic acid. Dynamic vulcanization of natural rubber was performed with the sulfur system. The 2 mm – thick sheet samples were prepared by compression molding. The objective of this study was to investigate the effect of plasticization of PLA on the mechanical and physical properties of the derived TPE. Four plasticizers were selected: tributyl acetyl citrate (TBAC, tributyl citrate (TBC, glycerol triacetate (GTA, and triethyl-2-acetyl citrate (TEAC. The investigated properties were the tensile properties, tear strength, thermal ageing and ozone resistance, hardness, resilience, tension set and compression set. All plasticizers increased the strain at break. TBAC and TBC increased the stress at break. All plasticizers decreased the tear strength, hardness and resilience, and slightly changed the tension and compression set. TBAC seemed to be the best plasticizer for the TPE. The presence of 4 pph (parts per hundred resin of plasticizer provided the highest strength and tensile toughness and the strain at break increased with the increasing plasticizer content. The plasticizers decreased the Tg and Tcc of the PLA and did not affect the degree of crystallinity of PLA in the TPE.

  9. Technological properties of latex and natural rubber of Hevea brasiliensis clones Propriedades tecnológicas do látex e da borracha natural de clones de Hevea brasiliensis

    Directory of Open Access Journals (Sweden)

    Rogério Manoel Biagi Moreno

    2005-04-01

    Full Text Available Rubber industry has increased the requirements for quality and uniformity of natural rubber produced in Brazil. Technological properties of latex and natural rubber of clones GT 1, PB 235, IAN 873 and RRIM 600 [Hevea brasiliensis (Willd. Former Adr. de Juss. Muell.- Arg] were evaluated by standard methods of the dry rubber content (DRC%, percentage of nitrogen (N% and percentage of ashes (ASH% in two consecutive years; data were correlated with temperature and precipitation. Properties of latex and natural rubber varied (P A indústria da borracha está cada vez mais exigente em relação à qualidade e a uniformidade da borracha natural produzida no Brasil. Neste trabalho as propriedades tecnológicas do látex e da borracha natural dos clones de seringueira GT 1, PB 235, IAN 873 e RRIM 600 [Hevea brasiliensis (Willd. ex Adr. de Juss. Muell.-.Arg] foram avaliadas pelos ensaios padrões do conteúdo de borracha seca (DRC%, porcentagem de nitrogênio (N% e porcentagem de cinzas (CNZ% por dois anos consecutivos; os dados obtidos foram correlacionados com dados de temperatura e precipitação. As propriedades do látex e da borracha natural variaram (P < 0.01 em função do tipo de clone e entre coletas. O DRC% diminuiu no início da estação seca (maio a junho, enquanto N% e CNZ% aumentaram. O período de abril a junho revelou ser crítico, pois os valores da N% oscilaram acima 0,60%, fora dos padrões estabelecidos pela norma técnica brasileira ABNT/NBR. O clone RRIM 600 foi menos suscetível às variações climáticas.

  10. Workers' compensation claims related to natural rubber latex gloves among Oregon healthcare employees from 1987–1998

    Directory of Open Access Journals (Sweden)

    Kammeyer-Mueller John

    2002-09-01

    Full Text Available Abstract Background Occupational reaction to natural rubber latex (NRL glove use by healthcare employees has been an area of increasing concern. Unfortunately, there is little data demonstrating the prevalence and severity of actual reactivity to NRL. Method Occupational reaction to NRL was estimated using workers' compensation claims filed by healthcare employees in Oregon for the period of 1987–1998. For the first ten years, these claims were estimated by source and conditions consistent with NRL glove reactions, while in the last two years a specific code developed in 1997 for NRL glove reactions was also employed. Results The claim rate was on average 0.58 per 10,000 healthcare workers annually, which constituted 0.29% of all workers' compensation claims. The most common condition experienced was dermatitis (80% and most common body part affected was the hands (55.4%. The majority of claimants, 45 (69.2%, reported taking less than a month off work, suggesting most reactions were minor in nature, although one fatality was reported. The average NRL claim cost was $8,309.48. Overall the average cost per insured healthcare worker was approximately $0.50 per year. The occupational groups with the highest number of claims were nurses (30.8% of claimants and nursing aides and orderlies (24.6% of claimants. Conclusions In comparison with other workers' compensation claims filed by healthcare workers during this period, 0.25% of the total was potentially related to NRL gloves. The rare incidence of respiratory and ocular claims is inconsistent with the hypothesis that asthmatic or conjunctival reactions to NRL gloves are common.

  11. Mass spectrometric characterization of the rubber elongation factor - major allergen in natural latex gloves

    International Nuclear Information System (INIS)

    The aim of the present work is the mass spectrometric characterization of the possible latex allergens present in natural latex gloves. The introduction covers a brief description of the molecular basis and types of allergens, and some of the promising therapeutic possibilities. It shows the composition of the natural latex milk and gives a summary of the conversion of the raw material into its products. The most important natural latex allergens are described and the knowledge about the medical aspects of this illness are summarized. The different chemical and biological methods applied during this study are also introduced in this chapter from the simple methods for protein extraction to the sophisticated ones for primary structure characterization. Chapter 4.1. describes the mass spectrometric analysis of the natural latex milk. Different samples - representing subsequent steps of processing of the raw material before the production of the gloves - were investigated. The effects of the sample preparation methods on the MALDI MS measurements were studied and compared. Several compounds could be detected in the freshly tapped natural latex sap and the change of the composition of the milk following the steps of preparation could be observed. Natural latex gloves were investigated in chapter 4.2. without extraction, directly by means of MALDI mass spectrometry. The protein pattern of the gloves during production - before and after the washing steps - was investigated. We found not only a difference between these two stages of the process, but also a variation of the protein pattern on the inner and outer sides of the gloves. Several types of finished products were studied and it could be concluded, that the detection of a part of the proteins revealed in the natural latex milk is still possible in this goods with MALDI mass spectrometry, without extraction and purification. It turned out, that the characteristics of the surface and the pore structure of the gloves

  12. A study on existing rubber elasticity theories for stress-strain behavior of rubber-like networks

    Czech Academy of Sciences Publication Activity Database

    Meissner, Bohumil

    2003-01-01

    Roč. 38, č. 2 (2003), s. 157-166. [International Rubber Conference. Prague, 01.07.2002-04.07.2002] R&D Projects: GA AV ČR KSK4050111 Keywords : rubber elasticity theory * natural rubber * isoprene rubber Subject RIV: CD - Macromolecular Chemistry

  13. Reaction of oxygen with γ, δ-ethylenic phenylhydrazones. Model reaction of end-group behavior in phenylhydrazine-accelerated oxidation of natural rubber

    International Nuclear Information System (INIS)

    An accurate definition of terminal groups of chains in the liquid polymers obtained by the phenylhydrazine-accelerated oxidation of natural rubber is needed. The object of the work was to use model molecules to explore the behavior of γ,δ-ethylenic methylketone phenylhydrazone end-groups in oxidation conditions. We have investigated the synthesis and characterization of models of these hypothetical end-groups, methylketones and phenones 1, their phenylhydrazones 2, the α-(phenyldiazenyl)hydroperoxides 3 resulting from reaction of 2 with oxygen, and the α-(phenyldiazenyl)alcohols 4 as characteristic derivatives of 3 or as models of possible reduced structures in oxidized liquid natural rubber. Three original syntheses of γ,δ-ethylenic ketones were carried out. In the case of γ,δ-ethylenic phenylhydrazones, the oxidation led to the expected α-(phenyldiazenyl)hydroperoxides and to epoxide derivatives of α-(phenyldiazenyl)alcohols 5 and ketones 6. An intramolecular mechanism is proposed. The results are used to predict the possibilities of identification of the corresponding end-groups in liquid rubbers produced in this way. (authors). 16 refs., 12 figs., 3 tabs

  14. Comparative properties of natural rubber vulcanisates filled with defatted rice bran, clay and calcium carbonate

    Directory of Open Access Journals (Sweden)

    Darinya Moonchai

    2012-07-01

    Full Text Available The effects of defatted rice bran (DRB as a filler for natural rubbervulcanisate on its cure characteristics, mechanical properties and morphology wereinvestigated. The properties of the DRB-filled vulcanisate were also compared with clayfilledand CaCO3-filled vulcanisates. At similar loading level (50 parts per hundred ofrubber, DRB-filled vulcanisate gave the shortest cure time. Clay-filled vulcanisateshowed highest tensile and tear strength followed by DRB-filled vulcanisate. However,CaCO3-filled vulcanisate gave highest rebound resilience while DRB-filled vulcanisateexhibited highest modulus, hardness and abrasion resistance. Scanning electronmicrographs revealed that the morphology of clay-filled vulcanisate was morehomogenous than that of DRB-filled and CaCO3-filled vulcanisates. According to theseobservations, DRB can potentially be used as a cheap and more environment-friendlynatural filler when an improvement in mechanical properties was not so critical.

  15. Aspects of Degradability and Aging of Natural Rubber Latex Films Obtained by Induced Ionizing Radiation Processes of Latex Vulcanization

    International Nuclear Information System (INIS)

    This study refers to the degradability of NRLF, natural rubber latex films, obtained by ionizing radiation. Three types of NRLF were prepared: irradiated latex, irradiated latex with about 1% of soy lecithin and sulfur-vulcanized latex, by cold vulcanization process. The films were buried in vases of two different kinds of soil: common soil and common soil with earthworm humus. Fast aging tests in laboratory with exposition to ultraviolet rays were done in irradiated latex films and irradiated latex films with soy lecithin. The results obtained after ten months of tests with buried films agree with the results of the fast aging tests, showing singularities of each type of soil and each kind of latex process. It also shows how weather inclemency can induce the films degradation process. The sulfur-vulcanized films were weakly degraded when buried. The films with lecithin and buried in vase with only common soil showed the biggest mass loss, but the films with lecithin buried in vases with common earthworm humus and soil increased their weigh and dimensions due to fungi formation. The irradiated latex films are more degradable then the sulfur-vulcanized films. The irradiated latex film, unlike the sulfur vulcanized film, showed high fungi colonization when buried. We conclude that the irradiated latex films are more easily biodegradable than the sulfur vulcanized latex films. The biodegradability increases with the addition of small amounts of soy lecithin (∼1%). The mechanical resistance of the buried films decreased related to the non-buried ones, proving that the outdoor aging in soil and the presence of fungi in the films can modify the mechanical properties of the irradiated latex owing to the biodegradation

  16. Compósitos de borracha natural ou policloropreno e celulose II: influência do tamanho de partícula Natural rubber or chloroprene rubber and cellulose II composites: influence of particle size

    Directory of Open Access Journals (Sweden)

    Bruno de A. Napolitano

    2004-01-01

    Full Text Available O objetivo deste trabalho foi o desenvolvimento de compósitos claros com propriedades de interesse tecnológico utilizando elastômeros com diferentes polaridades. Para que este objetivo fosse atingido, celulose II em pó foi usada como carga, em borracha natural (NR ou policloropreno (CR. A celulose II foi obtida por coagulação da solução de xantato de celulose em meio ácido, sob agitação constante e à temperatura ambiente, constituindo uma nova forma de obtenção deste tipo de carga. Compósitos com 10 phr de celulose II com NR e CR, respectivamente, foram desenvolvidos tendo como variável o tamanho de partícula da carga. As propriedades mecânicas e os aspectos microscópicos dos diferentes compósitos foram avaliados e comparados com aqueles das formulações sem carga. Os resultados permitiram identificar o compósito como o de melhor resultado, influenciado pela polaridade da matriz elastomérica e pelo tamanho de partícula da carga, conseqüência das condições de moagem usadas.The aim of this work was to develop light composites with properties of technological interest by using elastomers of different polarities. This was achieved by employing cellulose II, in the powder form, as filler in natural rubber (NR and chloroprene (CR. Cellulose II was obtained by coagulation of cellulose xanthate solution, in acid medium, under stirring and at room temperature, which represents, to our knowledge, a new way of obtaining this type of filler. Composites with 10phr of cellulose II and NR or CR were prepared having the particle size as variable. The mechanical properties and the microscopic aspect of the different composites were evaluated and compared with compounds without filler. The results indicated best results for the CR composite, influenced by the polarity of the elastomeric matrix and by the particle size, as a consequence of the milling conditions of the filler used.

  17. MAGNESIUM ION REGULATION OF THE IN VITRO RUBBER BIOSYNTHESIS BY PARTHENIUM ARGENTATUM GRAY

    Science.gov (United States)

    Natural rubber is produced by a rubber transferase (a cis-preny transferase). Rubber transferase uses allylic pyrophosphate to initiate the rubber molecule and isopentenyl pyrophosphate (IPP) to form the polymer. Rubber biosynthesis also requires a divalent metal cation. Understanding how molecular ...

  18. How to Develop Rubber Production in Xishuangbanna Dai Autonomous Prefecture?

    Institute of Scientific and Technical Information of China (English)

    Huide; HUANG; Haolun; HUANG; Wanzhen; ZHANG

    2015-01-01

    The natural rubber planting area in Xishuangbanna Dai Autonomous Prefecture accounts for about 30% of rubber planting area in China. At the end of 2013,the rubber planting area in Xishuangbanna Dai Autonomous Prefecture was 29. 4 ha,the tapped rubber plantation area was 17. 49 ha,and the dry rubber production was 317000 t. Currently,the production and management level of rubber plantation has declined in Xishuangbanna Dai Autonomous Prefecture,the tapping technique is outdated,and the tapping technology management system is difficult to implement. Therefore,some ways can be employed to promote the development of rubber industry such as enhancing the operation and management level of rubber industry,organizing the rubber production team,and developing the new rubber farmers’ cooperatives.

  19. 丝胶接枝物改性天然乳胶的研究%Research of using silk sericin to modify natural rubber latex

    Institute of Scientific and Technical Information of China (English)

    孙金煜; 田晓慧; 元以中; 龚淑婷; 冯佼姣; 刘虎邱

    2011-01-01

    利用丝胶优良的抗氧化性和亲肤性等特点,将丝胶包覆在天然乳胶粒表面,从而隔绝了天然乳胶膜与皮肤的直接接触,改善天然乳胶制品对皮肤的过敏性反应,使其不仅具有耐氧化性,而且与皮肤接触后可有效防止肌肤干燥,抑制肌肤黑色素生成等.同时将水性聚氨酯通过先接枝后杂凝聚的方法,在不改变乳胶断裂伸长率的情况下,提高拉伸强度,实现了对天然乳胶过敏性和机械性能的双重改善.%By the use of excellent oxidation resistance and skin friendly of silk sericin, silk sericin coats the surface of natural rubber latex particles which could cut off the direct contact with the skin and improve allergy. It makes natural latex rubber could not only resist oxidation but also effectively avoid skin drying and prevent melanin' s generating. After heterocoagulating with aqueous polyure-thane grafting with silk sericin, natural rubber latex membrane could improve fracture strength without reducing its breaking elongation,realize the improvement of its anaphylaxis and mechanical properties.

  20. The immobilisation of trypsin and glucose oxidase onto natural rubber-g.co-HEMA - high energy radiation derived copolymeric support systems

    International Nuclear Information System (INIS)

    Natural rubber has been grafted with 2-HEMA by three different methods each involving Co(60)γ-radiation as the initiation source. The grafted samples were used in the immobilisation of glucose oxidase and trypsin. Optimisation of immobilisation involving trypsin was studied with regard to the pH and the type of crosslinking agent. It was observed that the immobilised enzyme had superior stability over a wider pH range when compared to the free trypsin. The retention of activity demonstrated by the immobilised trypsin was significant. That of immobilised glucose oxidase was far from being satisfactory. (author)

  1. 白炭黑用量对氯丁橡胶/天然橡胶共混物性能的影响%Influence of silica loading on performance of chloroprene rubber/natural rubber blends

    Institute of Scientific and Technical Information of China (English)

    武卫莉

    2007-01-01

    研究了不同用量的沉淀法白炭黑填充质量比75/25的氯丁橡胶/天然橡胶共混物的物理机械性能、耐热老化性能和耐油性能,并用扫描电镜研究了共混物的结构.结果显示,白炭黑的加入改善了共混硫化物的拉伸强度、100%定伸应力和邵尔A硬度.压缩永久变形减小,黏度增大,从而导致在形变的过程中天然橡胶分散相占有率相对减少.相关性能也证明随着白炭黑用量的增加,硫化胶的耐热和耐油性能显著提高.%Blends of 75/25 ( mass ratio) chloroprene rubber ( CR )/natural rubber ( NR ) filled with various loadings of precipitated silica were prepared, and their mechanical properties as well as the resistances to thermal aging and oil were studied. The blend morphology was also studied by scanning electron microscope. The results show that the tensile strength, modulus and Shore A hardness of the blend vulcanizates are found to be improved noticeably with increasing silica loading, the compression set is impaired with increasing silica loading. In terms of phase morphology, the size of NR dispersed phase decreases with increasing silica loading due to the increase of compound viscosity. The results also demonstrate that both thermal aging resistance and oil resistance of the blend vulcanizates, as represented by the relative properties, are remarkably enhanced with increasing silica loading.

  2. 中国橡胶种植生命周期评价研究%Assessment of natural rubber plantation life cycle in China

    Institute of Scientific and Technical Information of China (English)

    徐杰峰; 王小文; 王乐力; 王伯铎; 林积泉; 宋超山

    2011-01-01

    Using China's natural rubber plantation as a case study, this paper classified natural rubber plantation life cycle into four stages-raw material, agrochemical production, natural rubber cultivation and transportation stages. The life-cycle assessment (LCA) method was used to evaluate potential environmental impacts of tapping 1.00 kg dry rubber under identified potential impacts, including global warming potential (GWP), acidification potential (AP), eutrophication potential (EP), photochemical ozone creation potential (POCP), human toxicity potential (HTP) and abiotic depletion potential (ADP). This inventory analysis showed that the order of potential impacts of China's natural rubber plantation was as follows: AP > EP > GWP > HTP > POCP > ADP. The respective impact indices were 1 .76× 10-12, 4.31×10-13, 1.37×10-13, 1.96×10-15, 9.69×10-18 and 4.88×10-19, with an average impact index of 4.32× l0-13. Reduced chemical fertilizer utilization and enhanced fertilization efficiency were critical for mitigating the impact of rubber plantation on the environment. This could be achieved via effective reduced energy consumption, fertilizer production emissions, and soil fertilizer loss.%应用生命周期评价方法,以我国橡胶种植为例,把橡胶种植生命周期划分为原料、农资化、橡胶种植、运输等4个阶段,考虑了全球变暖(GWP)、环境酸化(AP)、水体富营养化(EP)、光化学烟雾形成(POCP)、人体健康损害(HTP)、不可更新资源消耗(ADP)等 6类潜在影响,对得到1 kg橡胶(以干胶计)的潜在环境影响进行了分析评价.结果表明,我国橡胶种植的各类影响排序为AP>EP>GWP>HTP>POCP>ADP,其影响指数分别为1.76E-12、4.31E-13、1.37E-13、1.96E-15、9.69E-18、4.88E-19,单一环境影响指数为4.32E-13.减少化肥施用量、提高施肥有效率是控制整个橡胶种植潜在影响大小的关键,其在有效降低上游直接生产能耗及其相应排放和下游损失

  3. Preparation and Characterization of Marble Powder/Natural Rubber Composites%大理石粉/NR复合材料的制备与性能研究

    Institute of Scientific and Technical Information of China (English)

    王继虎; 陈有双; 唐忠锋; 陶冶

    2011-01-01

    将石材加工过程中产生的废弃大理石粉碎,采用硬脂酸偶联剂对大理石粉进行改性.将改性后大理石粉混炼到NR中制备复合材料,通过不同测试手段研究材料的性能变化.结果表明,球磨后大理石粉的平均粒径为24.18μm.采用硬脂酸改性后大理石粉添加量为10%时性能最佳,拉伸强度达到20.11MPa.与大理石/NR及纯橡胶材料相比,改性后大理石粉/NR复合材料的耐热性能明显提高.活化后大理石粉作为橡胶填料,可替代炭黑降低橡胶制品生产成本,同时有利于环保.%Marble powder was modified by stearic acid coupling agent after marble scraps were grinded. Natural rubber/marble powder composites were prepared by direct blending technology. The results showed that the average particle size of marble powder was 24.18μm. The best mechanical properties of composites were obtained after modified marble powder content were 10 percent in the natural rubber, and the tensile strength was 20.11 Mpa. The heat resistance of composites was higher than unmodified marble powder/NR composites. Activated marble powder has excellent reinforcement effect and ideal processing characteristics, and can replace carbon black in rubber to achieve its application.

  4. Treatment of natural rubber processing wastewater using a combination system of a two-stage up-flow anaerobic sludge blanket and down-flow hanging sponge system.

    Science.gov (United States)

    Tanikawa, D; Syutsubo, K; Hatamoto, M; Fukuda, M; Takahashi, M; Choeisai, P K; Yamaguchi, T

    2016-01-01

    A pilot-scale experiment of natural rubber processing wastewater treatment was conducted using a combination system consisting of a two-stage up-flow anaerobic sludge blanket (UASB) and a down-flow hanging sponge (DHS) reactor for more than 10 months. The system achieved a chemical oxygen demand (COD) removal efficiency of 95.7% ± 1.3% at an organic loading rate of 0.8 kgCOD/(m(3).d). Bacterial activity measurement of retained sludge from the UASB showed that sulfate-reducing bacteria (SRB), especially hydrogen-utilizing SRB, possessed high activity compared with methane-producing bacteria (MPB). Conversely, the acetate-utilizing activity of MPB was superior to SRB in the second stage of the reactor. The two-stage UASB-DHS system can reduce power consumption by 95% and excess sludge by 98%. In addition, it is possible to prevent emissions of greenhouse gases (GHG), such as methane, using this system. Furthermore, recovered methane from the two-stage UASB can completely cover the electricity needs for the operation of the two-stage UASB-DHS system, accounting for approximately 15% of the electricity used in the natural rubber manufacturing process. PMID:27120630

  5. A test trial irradiation of natural rubber latex on large scale for the production of examination gloves in a production scale

    International Nuclear Information System (INIS)

    Radiation Vulcanization of natural rubber latex has been developed extensively through various research and development programme. During these investigations many data was collected and from these data it was proved that radiation vulcanized natural rubber latex (RVNRL) can be used as a new material for industry (RVNRL symposium 1989; Makuuchi IAEA report). This material has been extensively tested in making of dipped goods and extruded products. However these investigations were confined only to laboratory experiments and these experiments mainly reflected material properties of RVNRL and only a little was observed about its behavior in actual production scale operation. The present exercise was carried out mainly to study the behavior of the material in production scale by irradiating latex on a large scale and producing gloves in a production scale plant. It was found that RVNRL can be used in conventional glove plants without making major alteration to the plant. Quality of the gloves that were produced using RVNRL is acceptable. It was also found that the small deviation of vulcanization dose will affect the crosslinking density of films. This will drastically reduce the tensile strength of the film. Crosslinking density or pre-vulcanized relax modulus (PRM) at 100% is a reliable property to control the pre vulcanization of latex by radiation

  6. Effects of Cassava Starch and Natural Rubber as Binders on the Flexural and Water Absorption Properties of Recycled Paper Pulp Based Composites

    Directory of Open Access Journals (Sweden)

    Oladele Isiaka Oluwole

    2015-10-01

    Full Text Available Responsiveness was given to the effects of cassava starch and natural rubber as binders on the flexural strength and the water absorptivity properties of the developed rattan particulate reinforced paper pulp based composites. Paper pulp was produced by chopping waste papers into smaller pieces and soaked in boiled water after which it was stirred thoroughly to form paper pulp. Rattan particulate was produced by hammering, chopping, pounding and milling of rattan canes followed by sieving into a particle size of 437 µ. Varying mass of paper from 300-400 g and particulate rattan in treated and untreated form of 2-8 g were mixed and bonded with natural rubber and cassava starch, respectively for the various samples developed. The mixtures were thoroughly mixed to produce homogenous pastes and poured into 150 x 50 x 30 mm detachable mould and compacted for 5 minutes using a laboratory compaction machine maintained at 20 KN. The developed composites were allowed to cure at room temperature for 27 days after which flexural and water absorptivity tests were carried out on the samples. It was noticed that the composite samples ST4 and S5 containing cassava starch happen to be the best in terms of flexural strength while NR2 gave the best water- repellent outcome.

  7. Effects of Rice Husk Modification with Liquid Natural Rubber and Exposure to Electron Beam Radiation on the Mechanical Properties of NR/ HDPE/ Rice Husk Composites

    International Nuclear Information System (INIS)

    Rice husk (RH) powder is a natural fibre capable of reinforcing natural rubber thermoplastic (TPNR) NR/ HDPE composites on specific modification of the particle surface. In this study the modification of RH powder involved pre-treatment with 5 % sodium hydroxide (NaOH) solution, soaking in LNR solution and exposure of LNR coated RH to electron beam (EB) irradiation. Preparation of NR/ HDPE/ RH composites was via melt-mixing in an internal mixer at predetermined conditions. Morphology study of the composites using scanning electron microscope (SEM) showed a homogeneous distribution of modified RH particles and particle-matrix interaction in the composite. Modified RH filled composites exhibited a significant change in mechanical properties. The maximum stress and impact strength were 6.7 MPa and 13.2 kJ/ m2, respectively at 20 kGy radiation, while the tensile modulus was 79 MPa at 30 kGy dose. The interfacial RH-TPNR interaction for the LNR-EB treated RH particles had improved in the EB dosage range of 20-30 kGy. However, over exposure to radiation caused degradation of rubber coat and interaction between particles to increase. Agglomeration of filler particles would occur and caused inhomogeneous distribution of filler in the composite. (author)

  8. Innovative synthetic rubbers via ruthenium catalyst systems

    OpenAIRE

    Tuba, Robert; Grubbs, Robert H.

    2013-01-01

    The trans-polypentenamer has unique relevance among the synthetic rubbers since it has similar phys. properties to the natural rubber. The polypentenamer additives have propitious effect on the tire properties and have been studied extensively for this application. Polypentenamer synthetic rubber was synthesized by ringopening metathesis polymn. (ROMP) using ruthenium catalyst systems. It was found that the cyclopentene conversion does not depend on the catalyst activity and catal...

  9. Effect of heterogeneous distribution of crosslink density on physical properties of radiation vulcanized NR (Natural Rubber) latex film

    International Nuclear Information System (INIS)

    Thus a study has been carried out to investigate the effect of particle to particle variation in crosslink density on physical properties of radiation vulcanized NR latex film. NR latex was irradiated in small bottle by γ rays without vulcanization accelerator to provide latex rubber particles having homogeneous distribution of crosslink density. The doses were 30, 50, 100, 250, 300, 400, 500 and 600 kGy. Weight swelling ratio, gel fraction, tensile strength and elongation at break of the latex film from the mixed latex were measured. The vulcanization dose of this latex was 250 kGy. Then the two different latexes were mixed in a such way to adjust the average dose of 250 kGy to prepare a latex consisting of rubber particles having heterogeneous distribution of crosslink density. Tensile strength of the latex film was depressed by mixing. The reduction increased with increasing the decrease of gel fraction by mixing. However the reduction was not serious when the dose difference of two latexes was less than 200 kGy

  10. A sustainability review of domestic rubber from the guayule plant

    Science.gov (United States)

    Guayule (Parthenium argentatum Gray) is an arid-adapted, low-input perennial shrub native to Mexico and southern Texas that has received considerable attention as an alternative source of natural rubber. It has potential to replace the most common types of rubbers, including synthetic rubber derived...

  11. Greenhouse Gas Emissions from Rubber Industry in Thailand

    NARCIS (Netherlands)

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

    2010-01-01

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

  12. Stress-induced melting of crystals in natural rubber: a new way to tailor the transition temperature of shape memory polymers.

    Science.gov (United States)

    Heuwers, Benjamin; Quitmann, Dominik; Katzenberg, Frank; Tiller, Joerg C

    2012-09-26

    Lightly cross-linked natural rubber (NR, cis-1,4-polyisoprene) was found to be an exceptional cold programmable shape memory polymer (SMP) with strain storage of up to 1000%. These networks are stabilized by strain-induced crystals. Here, we explore the influence of mechanical stress applied perpendicular to the elongation direction of the network on the stability of these crystals. We found that the material recovers its original shape at a critical transverse stress. It could be shown that this is due to a disruption of the strain-stabilizing crystals, which represents a completely new trigger for SMPs. The variation of transverse stress allows tuning of the trigger temperature T(trig) (σ) in a range of 45 to 0 °C, which is the first example of manipulating the transition of a crystal-stabilized SMP after programming. PMID:22760997

  13. Large-scale orientation in a vulcanized stretched natural rubber network: proved by in situ synchrotron X-ray diffraction characterization.

    Science.gov (United States)

    Weng, Gengsheng; Huang, Guangsu; Qu, Liangliang; Nie, Yijing; Wu, Jinrong

    2010-06-01

    In situ studies of strain-induced crystallization in unfilled and multiwalled carbon nanotube (MWCNT)-filled natural rubber (NR) were carried out by using synchrotron wide-angle X-ray diffraction (WAXD). Synchrotron WAXD results indicate that more nuclei appear in the MWCNT-filled NR sample, leading to higher crystallinity, lower onset strain of crystallization, and remarkable enhancement in tensile strength. During deformation, despite the amorphous chains remaining in isotropic orientation, the domains of larger scale (10-100 nm) with high network chain density in the NR matrix are oriented. The MWCNTs induce significant variation of this orientational process, and it is monitored by the stearic acid (SA) crystallites, which are effective nanoprobes of the amorphous phase. The results indicate that a small amount of MWCNTs and SA crystallites can be used as new tools to analyze the microstructural orientation of NR during deformation. The results also yield new insight into the strain-induced crystallization mechanism. PMID:20455577

  14. Comparison of epoxidised natural rubber (enr) 37.5 and enr 25/ enr 50 physical blend: Specialty polymer for 'green tyre' application

    International Nuclear Information System (INIS)

    A comparison study of new grade epoxidised natural rubber (ENR) containing 37.5 mole % epoxidation (ENR 37.5) with ENR 25/ ENR 50 blend, prepared by physical blending of ENR 25 with ENR 50, was done using truck tyre formulation. The ENR 25 / ENR 50 physical blend exhibited certain similar physical properties to ENR 37.5 even though Dynamic Mechanical Thermal Analyser (DMTA) analysis showed two glass transition temperatures (Tg) in the ENR 25/ ENR 50 vulcanisate. ENR 37.5 and ENR 25 / ENR 50 blend vulcanizates exhibited similar DMTA tan delta (tan Δ) curves at 0deg. C and 60deg. C, indicating potentially comparable wet grip and rolling resistance in 'green tyre' tread. Moreover, the heat build-up property for both vulcanizates is low, which is advantageous for tyre application.

  15. Comparison of epoxidised natural rubber (enr) 37.5 and enr 25/ enr 50 physical blend: Specialty polymer for 'green tyre' application

    Science.gov (United States)

    Wan, N. Y.; Chin, K. P.; Saad, C. S. Mt

    2010-05-01

    A comparison study of new grade epoxidised natural rubber (ENR) containing 37.5 mole % epoxidation (ENR 37.5) with ENR 25/ ENR 50 blend, prepared by physical blending of ENR 25 with ENR 50, was done using truck tyre formulation. The ENR 25 / ENR 50 physical blend exhibited certain similar physical properties to ENR 37.5 even though Dynamic Mechanical Thermal Analyser (DMTA) analysis showed two glass transition temperatures (Tg) in the ENR 25/ ENR 50 vulcanisate. ENR 37.5 and ENR 25 / ENR 50 blend vulcanizates exhibited similar DMTA tan delta (tan Δ) curves at 0°C and 60°C, indicating potentially comparable wet grip and rolling resistance in 'green tyre' tread. Moreover, the heat build-up property for both vulcanizates is low, which is advantageous for tyre application.

  16. 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.

  17. The role of the small rubber particle protein in determining rubber yields and polymer length in Russian dandelion

    Science.gov (United States)

    Several proteins have been identified and implicated in natural rubber biosynthesis, one of which, the small rubber particle protein (SRPP), was originally identified in Hevea brasiliensis as an abundant protein associated with cytosolic vesicles known as rubber particles. While previous in vitro s...

  18. Anaerobic desulfurization of ground rubber with the thermophilic archaeon Pyrococcus furiosus--a new method for rubber recycling.

    Science.gov (United States)

    Bredberg, K; Persson, J; Christiansson, M; Stenberg, B; Holst, O

    2001-01-01

    The anaerobic sulfur-reducing archaeon Pyrococcus furiosus was investigated regarding its capacity to desulfurize rubber material. The microorganism's sensitivity towards common rubber elastomers and additives was tested and several were shown to be toxic to P. furiosus. The microorganism was shown to utilize sulfur in vulcanized natural rubber and an increase in cell density was obtained when cultivated in the presence of spent tire rubber. Ethanol-leached cryo-ground tire rubber treated with P. furiosus for 10 days was vulcanized together with virgin rubber material (15% w/w) and the mechanical properties of the resulting material were determined. The increase in the stress at break value and the decrease in swell ratio and stress relaxation rate obtained for material containing microbially treated rubber (compared to untreated material) show the positive effects of microbial desulfurization on rubber. PMID:11234957

  19. Fire safety of rubber bearings

    International Nuclear Information System (INIS)

    The objective of the study is to experimentally evaluate the fire resistance of the natural-rubber bearings to be incorporated into a Fast Reactor (FBR) under study. Four experiments were performed to look at the effect of bearing diameters and heating conditions on the performance. The full-scale specimen sustained the design-basis load for more than 3.5 hours under 'standard fire.' Medium-size bearings showed resistance for 2-4 hours, according to heating temperatures. The paper also summarizes the methods and the results of simulation analyses of rubber bearings subjected to load/temperature conditions under fire. The vertical deformation of the bearings can be calculated very well, using the temperature profiles obtained from testing. However, the heat transfer analyses did not give good results, especially in the cases/portions where heat was generated due to rubber combustion. (author)

  20. Rubber glove wearing device

    International Nuclear Information System (INIS)

    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.)

  1. Characterization of rubber particles and rubber chain elongation in Taraxacum koksaghyz

    Directory of Open Access Journals (Sweden)

    Prüfer Dirk

    2010-02-01

    Full Text Available Abstract Background Natural rubber is a biopolymer with exceptional qualities that cannot be completely replaced using synthetic alternatives. Although several key enzymes in the rubber biosynthetic pathway have been isolated, mainly from plants such as Hevea brasiliensis, Ficus spec. and the desert shrub Parthenium argentatum, there have been no in planta functional studies, e.g. by RNA interference, due to the absence of efficient and reproducible protocols for genetic engineering. In contrast, the Russian dandelion Taraxacum koksaghyz, which has long been considered as a potential alternative source of low-cost natural rubber, has a rapid life cycle and can be genetically transformed using a simple and reliable procedure. However, there is very little molecular data available for either the rubber polymer itself or its biosynthesis in T. koksaghyz. Results We established a method for the purification of rubber particles - the active sites of rubber biosynthesis - from T. koksaghyz latex. Photon correlation spectroscopy and transmission electron microscopy revealed an average particle size of 320 nm, and 13C nuclear magnetic resonance (NMR spectroscopy confirmed that isolated rubber particles contain poly(cis-1,4-isoprene with a purity >95%. Size exclusion chromatography indicated that the weight average molecular mass (w of T. koksaghyz natural rubber is 4,000-5,000 kDa. Rubber particles showed rubber transferase activity of 0.2 pmol min-1 mg-1. Ex vivo rubber biosynthesis experiments resulted in a skewed unimodal distribution of [1-14C]isopentenyl pyrophosphate (IPP incorporation at a w of 2,500 kDa. Characterization of recently isolated cis-prenyltransferases (CPTs from T. koksaghyz revealed that these enzymes are associated with rubber particles and are able to produce long-chain polyprenols in yeast. Conclusions T. koksaghyz rubber particles are similar to those described for H. brasiliensis. They contain very pure, high molecular mass

  2. Compósitos de Borracha Natural com Compostos Condutivos à Base de Negro de Fumo e Polímero Condutor Natural Rubber Composites with Conductive Compounds based on Carbon Black and Conducting Polymers

    Directory of Open Access Journals (Sweden)

    Marinalva A. dos Santos

    2001-09-01

    Full Text Available Neste trabalho foram desenvolvidos compósitos condutores elétricos de borracha natural contendo negro de fumo e compostos condutivos baseados em polímeros condutores (Eenomer®. Os compósitos foram processados a quente num reômetro de torque HAAKE e moldados por prensagem. Foram obtidas placas homogêneas, flexíveis e com ótimo acabamento superficial. Os compósitos foram analisados pelas medidas de torque no processamento, medidas de condutividade elétrica, análise termogravimétrica (TGA, calorimetria diferencial de varredura (DSC e ensaios de tração. Estes compósitos apresentaram valores de condutividade elétrica entre 10-7 a 10-1 S/cm, dependendo do tipo de negro de fumo ou composto condutivo utilizado e da quantidade destes no compósito. A análise térmica demonstrou que os compósitos são termicamente estáveis até cerca de 300°C. Os compostos condutivos atuam como reforço para a borracha natural melhorando suas propriedades mecânicas sem perder significativamente sua flexibilidade.In this work, electrically conducting composites of natural rubber with carbon black and natural rubber with conductive compounds containing electrically conducting polymers (Eenomer® were developed. The composites were processed in a torque reometer HAAKE and then hot pressed. Homogeneous and flexible plates were obtained with excellent surface finish. The composites were analysed by the torque measurement during processing, electrical conductivity, thermogravimetric analysis (TGA, differential scanning calorimetric (DSC and mechanical analysis. Conductivity in the order of 10-7 to 10-1 S/cm were achieved, depending on the type of carbon black or conductive compound used and their content in the composite. Thermal analysis demonstrated that the compounds are thermally stable until 300°C. The conductive compounds act as reinforcements in the natural rubber matrix, improving its mechanical properties without significant loss on its

  3. A novel approach to investigate effect of magnetic field on dynamic properties of natural rubber based isotropic thick magnetorheological elastomers in shear mode

    Institute of Scientific and Technical Information of China (English)

    Sriharsha Hegde; Katari Kiran; K V Gangadharan

    2015-01-01

    The preparation of natural rubber based isotropic thick magnetorheological elastomers (MRE) was focused on by varying the percentage volume concentration of carbonyl iron powder and developing a test set up to test the dynamic properties. Effect of magnetic field on the damping ratio was studied on the amplification region of the transmissibility curve. The viscoelastic dynamic damping nature of the elastomer was also studied by analyzing the force-displacement hysteresis graphs. The results show that MR effect increases with the increase in magnetic field as well as carbonyl iron powder particle concentration. It is observed that softer matrix material produces more MR effect. A maximum of 125% improvement in the loss factor is observed for the MRE with 25% carbonyl iron volume concentration. FEMM simulation shows that as carbonyl iron particle distribution becomes denser, MR effect is improved. FEMM analysis also reveals that if the distance between the adjacent iron particles are reduced from 20μm to 10μm, a 40% increase in stored energy is observed.

  4. Chemistry of rubber processing and disposal.

    Science.gov (United States)

    Bebb, R L

    1976-01-01

    The major chemical changes during the processing of rubber occur with the breakdown in mastication and during vulcanization of the molded tire. There is little chemical change during the compounding, calendering, extrusion, and molding steps. Reclaiming is the process of converting scrap rubber into an unsaturated, processible product that can be vulcanized with sulfur. Pyrolysis of scrap rubber yields a complex mixture of liquids, gas, and residue in varying ratios dependent on the nature of the scrap and the conditions of pyrolysis. PMID:799964

  5. Preparation and pre-characterization of epoxidized natural rubber (ENR) / poly(vinylidene fluoride) (PVDF) (ENR/PVDF) thin film composite membrane

    Science.gov (United States)

    Mod, Norliyana; Othaman, Rizafizah

    2015-09-01

    Epoxidised Natural Rubber (ENR) / Poly (Vinylidene Fluoride) (PVDF) (ENR/PVDF) (60:40 wt%) thin film composite membrane was prepared by using solution casting technique. The focuses of this paper are to prepare ENR/PVDF membrane with ratio of ENR to PVDF 60:40 wt%, and to study the effectiveness of treating Palm Oil Mill Effluent (POME) using the membrane. The prepared membrane was analyzed using optical microscope and the treatment of POME was investigated using dead-end stirred cell. Treated and untreated POME was analyzed to test the percentage of biochemical oxygen demand (BOD) and chemical oxygen demand (COD) removal. Optical microscope micrographs showed that the surface of the membrane was slightly uneven. The rate of flux which passed through the membrane was 0.60 L/hm2. Both BOD and COD decreased by 23.6 % and 49.32 % respectively, after single treatment. This showed that the membrane can be used for POME treatment. The value of BOD and COD removal can be increased by recycling the treated POME for more than two cycles, which will be further studied by authors.

  6. Investigation on dielectric relaxation of PMMA-grafted natural rubber incorporated with LiCF{sub 3}SO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Yap, K.S.; Teo, L.P.; Sim, L.N.; Majid, S.R. [Centre for Ionics University of Malaya, Physics Department, University of Malaya, 50603 Kuala Lumpur (Malaysia); Arof, A.K., E-mail: akarof@um.edu.my [Centre for Ionics University of Malaya, Physics Department, University of Malaya, 50603 Kuala Lumpur (Malaysia)

    2012-07-01

    Natural rubber (NR) grafted with 30 wt% poly (methyl methacrylate) (PMMA) and designated as MG30 has been added with varying amounts of LiCF{sub 3}SO{sub 3}. X-ray diffraction (XRD) shows the samples to be amorphous. Fourier transform infrared (FTIR) spectroscopy indicates complexation between the cation of the salt and the oxygen atom of the C=O and -COO- groups of MG30. From electrochemical impedance spectroscopy (EIS), MG30 with 30 wt% LiCF{sub 3}SO{sub 3} salt exhibits the highest ambient conductivity of 1.69 Multiplication-Sign 10{sup -6} S cm{sup -1} and lowest activation energy of 0.24 eV. The dielectric behavior has been analyzed using dielectric permittivity ({epsilon} Prime), dissipation factor (tan {delta}) and dielectric modulus (M{sup Low-Asterisk }) of the samples. The dielectric constant of pure MG30 has been estimated to be {approx}1.86.

  7. The Optimum Processing Parameter of Carbon Nano tubes and Thermoplastic Natural Rubber (NR/LNR/LLDPE) Composites Based on Tensile Properties

    International Nuclear Information System (INIS)

    In this study, the exact processing parameter including mixing time, rotor speed and temperature of CNTs and TPNR (NR/LNR/LLDPE) composite has been examined using tensile properties. To prepare the composite, the matrix NR/LLDPE will compatabilized using liquid natural rubber (LNR) with 40 % NR, 10 % LNR and 50 % LLDPE. Then, 2 % CNTs will be incorporated into the matrix using different processing temperature, rotor speed and mixing time. For the temperature, different temperature that used are 135, 140, 145, 150 and 155 degree and for the rotor speed 45, 50, 55, 60 and 65 rpm have been used. As for the mixing time, five different time have been investigated which is 9 min,11 min, 13 min, 15 min and 17 min. The results for Young's modulus and elongation at break show that there is the maximum increment for the composite that have been prepared using 140 degree Celsius, 55 rpm and 13 min. However when the temperature has been increased, both of these properties has been decreased. Based on these results we can conclude that the optimum processing parameter for these CNTs composite is quite similar with the composite of the matrix (TPNR) itself. (author)

  8. The effect of concentration of acrylic acid, dose rates and temperature on preirradiated graft of natural rubber-based thermoplastic elastomer

    International Nuclear Information System (INIS)

    Grafting acrylic acid (AAc) onto thermoplastic elastomer (TE) films, a kind of product from natural rubber latex block-grafted by methyl methacrylate monomer was investigated. The preirradiated dose from a gamma Co-60 source for TE at 75 kGy was considered to be useful. Significant concentration of AAc aqueous solution for the grafting process is 20% (vol%). Dose rate of about 3.4 kGy/h is more effective for the graft. The temperature of around 90 deg. C is suitable for obtaining a higher degree of graft. It is observed that the rate of grafting of AAc onto TE is proportional to 0.48 power of dose rate and 1.9 power of AAc concentration. The rate of grafting can be expressed as Rg=k·I0.48·M1.9. On the other hand, overall activation energy of the graft is estimated about 7.2 Kcal/mol. The FTIR spectrum analysis of TE and TE-g-AAc films was proceeded

  9. Graphene networks and their influence on free-volume properties of graphene-epoxidized natural rubber composites with a segregated structure: rheological and positron annihilation studies.

    Science.gov (United States)

    He, Canzhong; She, Xiaodong; Peng, Zheng; Zhong, Jieping; Liao, Shuangquan; Gong, Wei; Liao, Jianhe; Kong, Lingxue

    2015-05-14

    Epoxidized natural rubber-graphene (ENR-GE) composites with segregated GE networks were successfully fabricated using the latex mixing combined in situ reduced technology. The rheological behavior and electrical conductivity of ENR-GE composites were investigated. At low frequencies, the storage modulus (G') became frequency-independent suggesting a solid-like rheological behavior and the formation of GE networks. According to the percolation theory, the rheological threshold of ENR-GE composites was calculated to be 0.17 vol%, which was lower than the electrical threshold of 0.23 vol%. Both percolation thresholds depended on the evolution of the GE networks in the composites. At low GE concentrations (polymer-bridged GE network" was constructed in the composites when GE concentrations exceeded 0.17 vol%. Finally, a "three-dimensional GE network" with percolation conductive paths was formed with a GE concentration of 0.23 vol%, where a remarkable increase in the conductivity of ENR-GE composites was observed. The effect of GE on the atom scale free-volume properties of composites was further studied by positron annihilation lifetime spectroscopy and positron age momentum correlation measurements. The motion of ENR chains was retarded by the geometric confinement of "GE networks", producing a high-density interfacial region in the vicinity of GE nanoplatelets, which led to a lower ortho-positronium lifetime intensity and smaller free-volume hole size. PMID:25881784

  10. Thermal-kinetic study of natural rubber latex films vulcanized by using gamma radiation; Estudo termo-cinetico de filmes de latex de borracha natural de Hevea brasiliensis vulcanizada por radiacao gama

    Energy Technology Data Exchange (ETDEWEB)

    Leal, Ana Paula Pinho Rodrigues; Barros, Glaucione Gomes de [Brasilia Univ., DF (Brazil). Inst. de Quimica; Guedes, Selma M.L. [Instituto de Pesquisa em Energia Nuclear, Sao Paulo, SP (Brazil)

    1999-07-01

    Vulcanization of natural rubber latex by ionization radiation produces the crosslink in disperse latex particles. Advantages over conventional process of vulcanization are: the absence of carcinogenic nitrosamines, low cytotoxicity and better degradation at room conditions, due to mainly to the absence of sulfur, zinc oxide and dithiocarbamates. Thermogravimetric analysis (TG) is the measurement of the weight change of a material as a function of temperature and time. TG data different heat speed provide an alternative model of the kinetics of degradation of polymeric materials. The kinetic studies of this material showed a single degradation process at least for 76,5% of mass loss. The activation energy was 49 Kcal/mol. For higher mass loss (85%) the degradation was characterized by associate mechanism. (author)

  11. Long-term mechanical properties of rubber

    OpenAIRE

    Bin Kamaruddin, Shamsul

    2013-01-01

    Natural rubber has a good potential to be used as a material for the development of wave energy converters (WECs). Generally, rubber has the ability to withstand very large strains without permanent deformation or fracture and is not much affected by exposure to water. This makes it ideal for applications related to wave energy converter (WECs). However, there is a need to predict the efficiency of performance over the full lifetime of such an application given that WECs will represent large,...

  12. A quinozolinone derivative as a novel rubber additive

    Energy Technology Data Exchange (ETDEWEB)

    Roy, B.C.; Khanra, T.K.; Maiti, S.; Adhikari, B. [Indian Institute of Technology, Kharagpur (India)

    1993-12-31

    A new quinozolinone derivative containing -NH and -SH functional sites has been developed as a novel antioxidant for diene rubbers. A sulfenamide derivative was prepared from the above compound which acts as an excellent accelerator cum antioxidant for natural rubber. This sulfenamide compound even when used at 50% concentration of the combined amount of commercial accelerator (CBS) and antioxidant (MBI) exhibits comparable accelerating characteristics and superior antiaging performance in the vulcanization of natural rubber. This dual function sulfenamide promises to offer better dispersion in the rubber matrix than two separate chemicals - one accelerator and the other antioxidant - used commercially.

  13. Influence of crumb rubber gradation on asphalt-rubber properties

    OpenAIRE

    Neto, Silvrano Adonias Dantas; Farias, Márcio Muniz de; Pais, Jorge C.; Pereira, Paulo A. A.

    2006-01-01

    Asphalt rubber is a material produced by the incorporation of crumb rubber obtained from ground tires in straight asphalt and its properties are influenced by the components properties. The crumb rubber gradation is one of the variables which have a significant influence on asphalt rubber properties. Thus, this work studies the influence of crumb rubber gradation on the asphalt rubber properties expressed by penetration, rotational viscosity (using the Brookfield viscometer), r...

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

    Science.gov (United States)

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

    2000-08-01

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

  15. Failure tests of laminated rubber bearings

    International Nuclear Information System (INIS)

    Three different types of rubber bearing - natural rubber bearing (NRB), lead-rubber bearing (LRB), and high-damping rubber bearing (HRB) - were tested up to failure under various combinations of axial and shear forces. The test results are summarized as follows: 1) Offset shear strain greatly affects tensile behavior and failure. 2) Axial stress or strain does not so greatly affect shear behavior and failure. 3) The characteristics of NBR and LRB are almost independent of strain rate, but those of HRB depend greatly on it. 4) Cyclic loading affects large-deformation behavior and failure to some extent. 5) failure limits which include the interaction between axial stress and shear strain were quantitatively evaluated. 6) A lead plug of LRB has no bad influence on failure. These will be very useful for developing an ultimate response prediction technique, which is necessary to establish rational design philosophy of base isolation systems for FBR plants. (author)

  16. Tolerogenic dendritic cells derived from donors with natural rubber latex allergy modulate allergen-specific T-cell responses and IgE production.

    Science.gov (United States)

    Escobar, Alejandro; Aguirre, Adam; Guzmán, María Antonieta; González, Rodrigo; Catalán, Diego; Acuña-Castillo, Claudio; Larrondo, Milton; López, Mercedes; Pesce, Barbara; Rolland, Jennifer; O'Hehir, Robyn; Aguillón, Juan Carlos

    2014-01-01

    Natural rubber latex (NRL; Hevea brasiliensis) allergy is an IgE-mediated reaction to latex proteins. When latex glove exposure is the main sensitizing agent, Hev b 5 is one of the major allergens. Dendritic cells (DC), the main antigen presenting cells, modulated with pharmacological agents can restore tolerance in several experimental models, including allergy. In the current study, we aimed to generate DC with tolerogenic properties from NRL-allergic patients and evaluate their ability to modulate allergen-specific T and B cell responses. Here we show that dexamethasone-treated DC (dxDC) differentiated into a subset of DC, characterized by low expression of MHC class II, CD40, CD80, CD86 and CD83 molecules. Compared with LPS-matured DC, dxDC secreted lower IL-12 and higher IL-10 after CD40L activation, and induced lower alloantigenic T cell proliferation. We also show that dxDC pulsed with the dominant Hev b 5 T-cell epitope peptide, Hev b 5(46-65), inhibited both proliferation of Hev b 5-specific T-cell lines and the production of Hev b 5-specific IgE. Additionally, dxDC induced a subpopulation of IL-10-producing regulatory T cells that suppressed proliferation of Hev b 5-primed T cells. In conclusion, dxDC generated from NRL-allergic patients can modulate allergen-specific T-cell responses and IgE production, supporting their potential use in allergen-specific immunotherapy. PMID:24465795

  17. Magnetic rubber inspection (MRI)

    International Nuclear Information System (INIS)

    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

  18. Effect of Chipped Rubber Aggregates on Performance of Concrete

    Directory of Open Access Journals (Sweden)

    Sunil N. Shah

    2014-12-01

    Full Text Available Due to rapid growth in automobile industry, use of tyre increases day to day and there is no reuse of the same to decrease the environmental pollution. The decomposition and disposing of waste tyre rubber is harmful to environment. This research reflects the reuse of waste tyre rubber into concrete after observing their properties. In that experimental work chipped rubber aggregates replaced to the natural coarse aggregates by varying percentage of 3, 6, 9 and 12 with comparison of 0% replacement. Silica fume is replaced in 10% with cement for improving the bond properties between cement paste and rubber. In evaluation, test has been carried out to determine the properties of concrete such as workability, unit weight, flexural strength and split tensile strength. The workability of fresh concrete is observed with the help of compaction factor test. From the test of compaction factor, workability is decrease with increasing percentage of chipped rubber. The specific gravity of chipped rubber aggregates is lower as compared to natural aggregates therefore decrease the unit weight of rubber mix concrete. Increasing chipped rubber aggregates as partial replacement into concrete reduces compressive strength. So these can use in non-primary structural applications of medium to low strength requirements. The overall results of study show that it is possible to use recycled rubber tyre aggregates in concrete construction as partial replacement to natural coarse aggregates.

  19. Effect of lithium salt concentrations on blended 49% poly(methyl methacrylate) grafted natural rubber and poly(methyl methacrylate) based solid polymer electrolyte

    International Nuclear Information System (INIS)

    The effect of lithium salts (lithium tetrafluoroborate, LiBF4 and lithium perchlorate, LiClO4) as doping salts in rubber-polymer blends, 49% poly(methyl methacrylate) grafted natural rubber (MG49) and poly(methyl methacrylate) (PMMA) in solid polymer electrolyte (SPE) film for electrochemical devices application was investigated. The electrolyte films were prepared via the solution casting technique using 0–25 wt.% lithium salt. The effect of the lithium salts on chemical interaction, ionic conductivity and structural and morphological studies of (70:30) MG49-PMMA films was analyzed using Fourier Transform Infrared (FT-IR) Spectroscopy, Electrochemical Impedance Spectroscopy (EIS), X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). Infrared analysis showed that the interactions between lithium ions and oxygen atoms occur at the ether group (C–O–C) (1500–1100 cm−1) on the MMA structure in both MG49 and PMMA. The oxygen atoms in the structure of the polymer host act as electron donor atoms and form a coordinate bond with the lithium ions from the doping salt to form polymer–salt complexes. The ionic conductivity was investigated at room temperature as well as at a temperature range from 303 K to 373 K. The ionic conductivity without the addition of salt was 1.1 × 10−12 S cm−1. The highest conductivity at room temperature for (70:30) MG49-PMMA–LiBF4 was 8.6 × 10−6 S cm−1 at 25 wt.% of LiBF4. The ionic conductivity of (70:30) MG49-PMMA–LiClO4 was 1.5 × 10−8 S cm−1 at 25 wt.% of LiClO4. However, both electrolyte systems do not exhibit Arrhenius-like behavior. Systems with LiBF4 salt have higher ionic conductivity than those with LiClO4 salt because of the differences in anionic size and lattice energy of the appropriate salt. The observations from structural and morphology studies showed that complexation and re-crystallization occur in the system. The XRD studies showed a reduction of the MMA peak intensity at 29.5° after

  20. Predicting the glass transition temperature as function of crosslink density and polymer interactions in rubber compounds

    Science.gov (United States)

    D'Escamard, Gabriella; De Rosa, Claudio; Auriemma, Finizia

    2016-05-01

    Crosslink sulfur density in rubber compounds and interactions in polymer blends are two of the composition elements that affect the rubber compound properties and glass transition temperature (Tg), which is a marker of polymer properties related to its applications. Natural rubber (NR), butadiene rubber (BR) and styrene-butadiene rubber (SBR) compounds were investigated using calorimetry (DSC) and dynamic mechanical analysis (DMA). The results indicate that the Di Marzio's and Schneider's Models predict with accuracy the dependence of Tg on crosslink density and composition in miscible blends, respectively, and that the two model may represent the base to study the relevant "in service" properties of real rubber compounds.

  1. 海南农垦天然橡胶生产科技进步贡献率的测算与分析%Calculation and Analysis on Science and Technology Progress Contribution Rate of Natural Rubber Industry in Hainan State Farms

    Institute of Scientific and Technical Information of China (English)

    刘海清; 张以山

    2011-01-01

    为分析海南农垦天然橡胶产业的科技投入对产业的影响程度,运用Cobb-Douglas生产函数构建海南农垦天然橡胶生产函数模型.以海南农垦1995-2009年天然橡胶生产的有关数据为例,测算了海南农垦天然橡胶产业科技进步贡献率为80.04%,说明科学技术的发展对海南农垦天然橡胶产业做出了较大的贡献.最后提出了实现海南农垦天然橡胶生产稳定发展的对策建议,即加快更新、增加科技投入、加强人才队伍建设等.%In order to analyze the degree of influence of science and technology input in Hainan State Farms natural rubber industry, this paper used Cobb-Douglas production function to build a Hainan State Farms natural rubber production function model. Data was taken from Hainan State Farms natural rubber production during 1995 to 2009 period. Then results showed that contribution rate of science and technology progress of natural rubber production of Hainan State Farms was 80.04% , that is to say, science and technology contributed to the development of Hainan State Farms natural rubber. At last some countermeasures and suggestions on stable development of natural rubber production were proposed, I.e. Accelerating the rate of updating, increasing science and technology input, enhancing the construction of talents in natural rubber production and research.

  2. Biological feedstock development as part of the domestication and commercialization of Taraxacum kok-saghyz, a potential domestic source of natural rubber and inulin: progress and outlook

    Science.gov (United States)

    Wild-collected F0 seed was found to contain a mixture Taraxacum species (i.e., highly variable seedling phenotypes), a likely drag on TKS germplasm enhancement. Also, roots of unselected, wild-collected Taraxacum genotypes were found to contain, on average, 1.4 and 56.4 percent rubber and inulin, re...

  3. A study on nonlinear finite element analysis of laminated rubber bearings. Pt.1. Development of evaluation method for mechanical properties of laminated rubber bearings for horizontal base isolation system considering volumetric deformation of rubber material

    International Nuclear Information System (INIS)

    The purpose of this research is to develop the evaluation method for mechanical properties of laminated rubber bearings by nonlinear finite element method (FEM) considering the volumetric deformation of natural rubber material. Relationship between pressure and volumetric strain of the natural rubber is obtained from the volumetric tests and is introduced into user-subroutine of the FEM code (ABAQUS). Finite element analyses of natural rubber bearings (NRB) and the natural rubber bearing with lead plug (LRB) are carried out. The results may be summarized as follows; 1) Horizontal, vertical stiffness and effect of shear deformation on vertical stiffness of natural rubber bearings that have various shape are simulated with enough accuracy. 2) Horizontal and vertical stiffness of LRB are also simulated well. (author)

  4. The rubber tree genome shows expansion of gene family associated with rubber biosynthesis

    Science.gov (United States)

    Lau, Nyok-Sean; Makita, Yuko; Kawashima, Mika; Taylor, Todd D.; Kondo, Shinji; Othman, Ahmad Sofiman; Shu-Chien, Alexander Chong; Matsui, Minami

    2016-01-01

    Hevea brasiliensis Muell. Arg, a member of the family Euphorbiaceae, is the sole natural resource exploited for commercial production of high-quality natural rubber. The properties of natural rubber latex are almost irreplaceable by synthetic counterparts for many industrial applications. A paucity of knowledge on the molecular mechanisms of rubber biosynthesis in high yield traits still persists. Here we report the comprehensive genome-wide analysis of the widely planted H. brasiliensis clone, RRIM 600. The genome was assembled based on ~155-fold combined coverage with Illumina and PacBio sequence data and has a total length of 1.55 Gb with 72.5% comprising repetitive DNA sequences. A total of 84,440 high-confidence protein-coding genes were predicted. Comparative genomic analysis revealed strong synteny between H. brasiliensis and other Euphorbiaceae genomes. Our data suggest that H. brasiliensis’s capacity to produce high levels of latex can be attributed to the expansion of rubber biosynthesis-related genes in its genome and the high expression of these genes in latex. Using cap analysis gene expression data, we illustrate the tissue-specific transcription profiles of rubber biosynthesis-related genes, revealing alternative means of transcriptional regulation. Our study adds to the understanding of H. brasiliensis biology and provides valuable genomic resources for future agronomic-related improvement of the rubber tree. PMID:27339202

  5. Study on mechanical properties of laminated rubber bearing with small shape factor

    International Nuclear Information System (INIS)

    Laminated rubber bearings with a small shape factor are regarded as one of the most promising isolation devices to reduce the vertical seismic load of a nuclear power plant. In this study, three types of natural rubber bearings with different aspect ratios (diameter/total thickness of rubber) and one high-damping rubber bearing are tested under varied loading conditions. Basic characteristics and ultimate characteristics of the bearings are made clear, and applicability of estimation formula and analysis method are verified

  6. Effect of electron beam irradiation on the properties of crosslinked rubbers

    International Nuclear Information System (INIS)

    Influence of electron beam (EB) irradiation on the mechanical and dynamic mechanical properties of crosslinked fluorocarbon (FKM) rubber, natural rubber (NR), ethylene propylene diene monomer (EPDM) rubber and nitrile rubber (NBR) has been investigated. The modulus, gel fraction, glass transition temperature (Tg) and storage modulus increased, while the elongation at the break and the loss tangent (tan δ)Tg decreased. FKM and NBR vulcanizates have been shown to have EB radiation resistance up to 1500 kGy. (author)

  7. Effect of electron beam irradiation on the properties of crosslinked rubbers

    Science.gov (United States)

    Banik, Indranil; Bhowmick, Anil K.

    2000-05-01

    Influence of electron beam (EB) irradiation on the mechanical and dynamic mechanical properties of crosslinked fluorocarbon (FKM) rubber, natural rubber (NR), ethylene propylene diene monomer (EPDM) rubber and nitrile rubber (NBR) has been investigated. The modulus, gel fraction, glass transition temperature ( Tg) and storage modulus increased, while the elongation at the break and the loss tangent (tan δ) Tg decreased. FKM and NBR vulcanizates have been shown to have EB radiation resistance up to 1500 kGy.

  8. Study on mechanical properties of laminated rubber bearing with small shape factor

    Energy Technology Data Exchange (ETDEWEB)

    Mazda, T. [Kyushu Univ., Fukuoka (Japan); Ootori, Y.; Yabana, S.; Hirata, K.; Ishida, K. [Central Research Inst. of Electric Power Industry, Chiba (Japan)

    1995-12-01

    Laminated rubber bearings with a small shape factor are regarded as one of the most promising isolation devices to reduce the vertical seismic load of a nuclear power plant. In this study, three types of natural rubber bearings with different aspect ratios (diameter/total thickness of rubber) and one high-damping rubber bearing are tested under varied loading conditions. Basic characteristics and ultimate characteristics of the bearings are made clear, and applicability of estimation formula and analysis method are verified.

  9. Radiation vulcanization of rubbers

    International Nuclear Information System (INIS)

    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.)

  10. US rubber markets recover

    International Nuclear Information System (INIS)

    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

  11. Performance of asphalt rubber mixtures

    OpenAIRE

    Thives, Liseane Padilha; Trichês, Glicério; Pereira, Paulo A. A.; Pais, Jorge C.

    2010-01-01

    Asphalt rubber mixtures are one of the most promising techniques to extend the service life of asphalt pavement overlays. Asphalt rubber binder is composed of crumb rubber from reclaimed tires and conventional asphalt. The asphalt rubber binder can be obtained through wet process in two different systems: terminal blending (produced at industrial plants) and continuous blending (produced in asphalt plants). This study presents a laboratory evaluation of asphalt rubber mixtures produced with d...

  12. A study of using polythiol compounds and 2-ethyl-hexyl-acrylate with carbon tetrachloride as sensitizers for radiation vulcanization of natural rubber latex

    International Nuclear Information System (INIS)

    Experiments on using 3 different compounds of polythiol and an acrylate as sensitizer for radiation vulcanization were conducted. It was found that 1,4 butane diol propane tris-3-mercapto propionate showed the tendency to be a good sensitizer. The tensile strength of the rubber film prepared from the irradiated latex was found to be 14 MPa at sensitizer concentration of 1 phr and radiation dose of 45 kGy. As for 2-ethyl hexyl acrylate (2EHA), the maximum tensile strength of rubber film was found to be 23 MPa at concentration of 3 phr and radiation dose of 35 kGy. The mixture of 2 EHA and CCl4 at various ratio was also used as sensitizer. The optimum ratio was found to be 5:1 at concentration of 6 phr and radiation dose of 15 kGy. The maximum tensile strength was as high as 25 MPa. The study also revealed that the radiation vulcanized latex with crosslink density of about 18x1018 C.L./cm3 would give the rubber film of highest tensile strength

  13. Cinética de vulcanização de composições de borracha natural com incorporação de cinza de casca de arroz Vulcanization kinetics of natural rubber filled with rice husk ash

    Directory of Open Access Journals (Sweden)

    Helson M. da Costa

    2003-06-01

    Full Text Available Cinza da casca de arroz foi incorporada em borracha natural (NR utilizando-se um misturador de cilindros. O sistema de vulcanização convencional (CV foi escolhido e os estudos sobre a cura das composições foram conduzidos em um Curômetro TI-100. As curvas de torque foram obtidas em 150, 160, 170 e 180 °C. A velocidade global e a energia de ativação aparente para o processo de vulcanização foram calculadas para cada composição, assumindo que a vulcanização segue uma cinética de primeira ordem. Para fins de comparação, duas cargas comerciais, sílica precipitada (Zeosil-175 e negro de fumo (N762, foram também usadas. Foi observado que a adição da cinza da casca de arroz às composições de NR, em comparação às outras cargas utilizadas, aumentou a velocidade de reticulação e diminuiu a energia de ativação aparente de modo mais marcante.Rice husk ash was incorporated into natural rubber (NR using a laboratory size two-roll mill. A conventional vulcanization system (CV was chosen and cure studies were carried out on a TI-100 Curometer. The torque curves were obtained at 150, 160, 170, and 180 °C. The overall rate and the apparent activation energy for the vulcanization process were calculated for each compound assuming that vulcanization follows first-order kinetics. For the purpose of comparison, two commercial fillers, precipitated silica (Zeosil-175 and carbon black (N762, were also used. In comparison to the other fillers used, the addition of rice husk ash to NR compounds increased the crosslinking rate and lowered the apparent activation energy in a more marked way.

  14. Performance of carbon fiber reinforced rubber composite armour against shaped charge jet penetration

    Directory of Open Access Journals (Sweden)

    Yue Lian-yong

    2016-01-01

    Full Text Available Natural rubber is reinforced with carbon fiber; the protective performances of the carbonfiber reinforced rubber composite armour to shaped charge jet have been studied based on the depth of penetration experiments. The craters on the witness blocks, the nature rubber based composite plates’ deformation and the Scanning Electron Microscopy for the hybrid fiber reinforced rubber plate also is analyzed. The results showed that the composite armour can affect the stability of the jet and made part of the jet fracture. The carbon fiber reinforced rubber composite armour has good defence ablity especially when the nature rubber plate hybrid 15% volume percentage carbonfiber and the obliquity angle is 68°. The hybrid fiber reinforced rubber composite armour can be used as a new kind of light protective armour.

  15. 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

  16. Radiation degradation of spent butyl rubbers

    Science.gov (United States)

    Telnov, A. V.; Zavyalov, N. V.; Khokhlov, Yu. A.; Sitnikov, N. P.; Smetanin, M. L.; Tarantasov, V. P.; Shadrin, D. N.; Shorikov, I. V.; Liakumovich, A. L.; Miryasova, F. K.

    2002-03-01

    Radiation methods of materials modification applied in technological chains can have significant economical and ecological advantages as compared to the established chemical, thermal and mechanical methods. Each year the problems of nature resources economy through the use of production and consumption wastes acquire a more significant value, as it allows to solve also ecological issues along with economical ones. This is mostly acute in relation to polymeric systems based on saturated rubbers, for example butyl rubber (BR) used in the tyre industry, as due to their high resistance to the action of oxygen, ozone, solar radiation and bacteria, they contaminate the environment for rather a long period. At VNIIEF and KSPU experiments were carried out on application of electron beams with energy from 6 to 10 MeV for radiation destruction of spent rubber based on BR. The radiation-degraded material was tested for re-use in the formulation of initial diaphragm mixture, rubber mixture for producing rubberized fabric and roofing.

  17. Radiation degradation of spent butyl rubbers

    International Nuclear Information System (INIS)

    Radiation methods of materials modification applied in technological chains can have significant economical and ecological advantages as compared to the established chemical, thermal and mechanical methods. Each year the problems of nature resources economy through the use of production and consumption wastes acquire a more significant value, as it allows to solve also ecological issues along with economical ones. This is mostly acute in relation to polymeric systems based on saturated rubbers, for example butyl rubber (BR) used in the tyre industry, as due to their high resistance to the action of oxygen, ozone, solar radiation and bacteria, they contaminate the environment for rather a long period. At VNIIEF and KSPU experiments were carried out on application of electron beams with energy from 6 to 10 MeV for radiation destruction of spent rubber based on BR. The radiation-degraded material was tested for re-use in the formulation of initial diaphragm mixture, rubber mixture for producing rubberized fabric and roofing

  18. Development of rubber gloves by radiation vulcanization

    International Nuclear Information System (INIS)

    The processes of radiation vulcanization and production of protective rubber gloves for radioactive contamination are described. A newly developed sensitizing system consisting of 5 phr 2-ethylhexyl acrylate and 1 phr carbon tetrachloride was used to vulcanize natural rubber latex at 12 kGy. Transparent and soft gloves were obtained from the radiation vulcanized latex by a coagulant dipping process. The mechanical properties of the gloves meet Japanese Industrial Standard specification for protective gloves. Combustion analysis of the gloves revealed that the amount of evolved sulfur dioxide and remaining ashes are less than those from commercially available rubber gloves. A trial usage of the gloves at a nuclear power plant showed that the gloves were easy to use for delicate work without undergoing fatigue. (author)

  19. Development of rubber gloves by radiation vulcanization

    Science.gov (United States)

    Makuuchi, K.; Yoshii, F.; Ishigaki, I.; Tsushima, K.; Mogi, M.; Saito, T.

    The processes of radiation vulcanization and production of protective rubber gloves for radioactive contamination are described. A newly developed sensitizing system consisting of 5 phr 2-ethylhexyl acrylate and 1 phr carbon tetrachloride was used to vulcanize natural rubber latex at 12 kGy. Transparent and soft gloves were obtained from the radiation vulcanized latex by a coagulant dipping process. The mechanical properties of the gloves meet Japanese Industrial Standard specification for protective gloves. Combustion analysis of the gloves revealed that the amount of evolved sulfur dioxide and remaining ashes are less than those from commercially available rubber gloves. A trial usage of the gloves at a nuclear power plant showed that the gloves were easy to use for delicate work without undergoing fatigue.

  20. Supply of Rubber Wood Log in Malaysia

    Directory of Open Access Journals (Sweden)

    A. W. Noraida

    2014-06-01

    Full Text Available Issue on shortage of raw material for wood processing solved by discovery of rubber wood log as one of the substitutes the natural log. This paper examines the supply of rubber wood log in Malaysia. We employ ARDL Bound Approach Test and time series data from 1980 to 2010 which represented the whole Malaysia are used to achieve the established objectives. The result shown, in the long run harvested area and wages have 1% and 10% significant level respectively. While in the short run, there was only harvested area having an impact with 1% significant level. This result indicates that, the harvested area become the most impact towards supply of rubber wood log either in short run or in the long run. While wages as input cost gave less impact in another word it become unburden to the producers.

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

    International Nuclear Information System (INIS)

    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 60Co 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)

  2. Improving Filler Dispersion And Physical Properties Of Epoxidized Natural Rubber/ Silica Compound By Using Dual fillers And Coupling Agent In Mixing Process

    International Nuclear Information System (INIS)

    Since the introduction of Green Tyre concept, in the early 90s, the use of silica as reinforcing fillers has spread and grown worldwide. The general advantages of silica as reinforcing filler over carbon black filler are better rolling resistance by achieving at least equal wet traction while tread wear should not be adversely affected. In general, high filler loading in ENR attributes poor dispersion and lack of adhesion to the rubber matrix which in turn affect the processability and physical properties of the rubber compounds. In this work, effect of dual fillers (silica and carbon black) and coupling agent in ENR/ silica compound was studied respectively. The mixing was done in a Banbury® BR 1600 internal mixer and the filler dispersion and physical properties were analysed. The carbon black filler was varied from 5 phr to 20 phr, where the total filler was fixed at 60 phr for truck tyre tread compound. The coupling agent was mixed in the mixing at two different stages which is first stage and finalizing stage of mixing. The rheological properties test was conducted by using Mooney Viscometer. The hardness, abrasion and tensile strength for physical properties evaluation were also conducted in this study. In addition, the filler dispersion property was determined by using disperGraderTM. The results showed that some of ENR/silica compound properties such as tensile, hardness, filler dispersion and abrasion resistance were slightly improved as compared to control compound. (author)

  3. Theory of powdery rubber wear

    Science.gov (United States)

    Persson, B. N. J.

    2009-12-01

    Rubber wear typically involves the removal of small rubber particles from the rubber surface. On surfaces with not too sharp roughness, e.g. most road surfaces, this involves (slow) crack propagation. In this paper I shall present a theory of mild rubber wear. I shall derive the distribution of wear particle sizes Φ(D), which is in excellent agreement with experiment. I shall also show that the calculated wear rate is consistent with experimental data for tire tread block wear.

  4. Theory of powdery rubber wear

    International Nuclear Information System (INIS)

    Rubber wear typically involves the removal of small rubber particles from the rubber surface. On surfaces with not too sharp roughness, e.g. most road surfaces, this involves (slow) crack propagation. In this paper I shall present a theory of mild rubber wear. I shall derive the distribution of wear particle sizes Φ(D), which is in excellent agreement with experiment. I shall also show that the calculated wear rate is consistent with experimental data for tire tread block wear.

  5. Pneumoconiosis in rubber workers

    International Nuclear Information System (INIS)

    Radiographic survey carried out on rubber workers revealed that 32 % (24/76) of the workers showed pneumoconiosis. The cases of pneumoconiosis were found in workers who had been exposed to dust for more than 10 years. Among the 24 cases of pneumoconiosis, 15 workers had been exposed to talc dust for more than 12 years. Chest radiographs of the rubber workers who had been exposed to dust for more than 10 years demonstrated radiographic findings and incidences as follows; nodular pattern (16 %), fine reticular and granular pattern (52 %), reticular pattern (36 %), irregularity of lung markings (61 %), ground-glass appearance (8 %), and pleural thickening (15 %). Irregular opacities such as fine reticular and granular pattern, reticular pattern and irregularity of lung markings seen to be major radiographic findings of pneumoconiosis of the rubber workers. While, nodular pattern seen in upper and middle lung zones and pleural thickening seen in apices and upper lung zones seen to be minor changes. (author)

  6. New application of crystalline cellulose in rubber composites

    Science.gov (United States)

    Bai, Wen

    Rubber without reinforcement has limited applications. The strength of reinforced rubber composites can be ten times stronger than that of unreinforced rubbers. Therefore, rubber composites are widely used in various applications ranging from automobile tires to seals, valves, and gaskets because of their excellent mechanical elastic properties. Silica and carbon black are the two most commonly used reinforcing materials in rubber tires. They are derived from non-renewable materials and are expensive. Silica also contributes to a large amount of ash when used tires are disposed of by incineration. There is a need for a new reinforcing filler that is inexpensive, renewable and easily disposable. Cellulose is the most abundant natural polymer. Native cellulose includes crystalline regions and amorphous regions. Crystalline cellulose can be obtained by removing the amorphous regions with the acid hydrolysis of cellulose because the amorphous cellulose can be hydrolyzed faster than crystalline cellulose. We recently discovered that the partial replacement of silica with microcrystalline cellulose (MCC) provided numerous benefits: (1) low energy consumption for compounding, (2) good processability, (3) strong tensile properties, (4) good heat resistance, and (5) potential for good fuel efficiency in the application of rubber tires. Strong bonding between fillers and a rubber matrix is essential for imparting rubber composites with the desired properties for many specific applications. The bonding between hydrophilic MCC and the hydrophobic rubber matrix is weak and can be improved by addition of a coupling agent or surface modifications of MCC. In this study, MCC was surface-modified with acryloyl chloride or alkenyl ketene dimer (AnKD) to form acrylated MCC (A-MCC) and AnKD-modified MCC (AnKD-MCC). The surface modifications of MCC did not change the integrity and mechanical properties of MCC, but provided functional groups that were able to form covalent linkages with

  7. Estudo do efeito do ozônio gerado durante ensaios elétricos em equipamentos de segurança confeccionados em borracha natural The behavior of natural rubber used in line-life equipment submitted to ozone concentration observed during the electrical test

    Directory of Open Access Journals (Sweden)

    Caroline I. Lisevski

    2012-01-01

    Full Text Available A borracha natural é muito empregada na confecção de equipamentos de proteção individual e coletiva para o setor elétrico devido à sua excelente flexibilidade e isolamento elétrico. Para garantir a segurança dos eletricistas, os equipamentos são testados periodicamente, por ensaios elétricos. Durante esses ensaios ocorrem descargas corona que ionizam o ar, gerando ozônio, que pode reagir com a borracha natural mudando suas características iniciais. Neste trabalho são apresentadas as alterações provocadas pela exposição ao ozônio, em concentração medida durante os ensaios elétricos, nos equipamentos confeccionados em borracha natural. As amostras foram testadas com e sem tensão mecânica e avaliadas por microscopia e ensaios mecânicos. Foi observada alteração superficial nas amostras sem tensão mecânica, para as amostras tensionadas houve aparecimento de fissuras macroscópicas e decréscimo na resistência mecânica.Natural rubber is used to manufacture line-life equipment due to its insulating and flexibility characteristics. In order to provide safety to lineman, these pieces of equipment are periodically submitted to electrical maintenance tests. During these tests, corona discharges occur generating ozone gas which can react with natural rubber, thus ageing it and affecting its initial characteristics. This study shows changes caused by ozone exposure with concentrations prevailing during electrical tests in equipment made of natural rubber. The samples were tested with and without mechanical deformation and evaluated by microscopy and mechanical properties. Superficial changes were observed in samples which were not exposed to mechanical stress, while for mechanically stressed samples there were macroscopic cracks and decrease in the mechanical properties.

  8. Rubber - application of radiation to tire manufacture

    International Nuclear Information System (INIS)

    Since the advent of commercial accelerators during the last several years capable of producing controllable electron beams of high energy, Firestone has devoted a considerable effort to the better understanding of the possible applications of such radiation to the production of tires or tire components. A number of chemical reactions can occur when elastomeric compounds are exposed to high energy waves, but crosslinking and degradation are the most important. The degree to which the crosslinking reaction predominates depends upon the nature of the rubber, compounding ingredients and the dosage. In general then, the effects achieved by the radiation of a rubber are quite similar to those resulting from heat. However, radiation cure or precure of compounds offers the advantage that the degree of crosslinking can be better controlled. Uniform crosslinking is possible since the high speed electrons penetrate uniformly throughout the sample. Curing with heat on the other hand may result in a greater degree of crosslinking on the surface of the sample than the center because of low heat conductivity. In general, radiation can be used to advantage to crosslink partially rubber tire components so that they retain better their shape and dimension during tire assembly and final cure or vulcanization. Added advantages of radiation precure include: a reduction of material usage, substitution of synthetic for natural rubber without loss in strength and the fact that partially crosslinked components will not thin out or become displaced during construction and vulcanization of the tire. (author)

  9. Evaluation of mechanical properties of laminated rubber bearings as three-dimensional base isolation device for Fast Breeder Reactor

    International Nuclear Information System (INIS)

    Rubber bearings with thick rubber layers to be used for 3-dimensional base isolation system are developed. Design parameters of the rubber bearings are determined to effectively reduce both horizontal and vertical seismic loads especially for equipment in the system; horizontal natural period and vertical natural frequency of the system supported by the rubber bearings are 3 sec. and 3 Hz, respectively. Furthermore, primary and secondary shape factors and design vertical stress of the rubber bearings are determined to give stable mechanical properties. Using scale models of the rubber bearings, static, dynamic and failure tests were carried out to evaluate the mechanical characteristics and the performance of the rubber bearings. From these tests, it is shown that the developed rubber bearings are efficient as 3-dimensional base isolation device. (author)

  10. Effect of Organo-Modified Nanoclay on the Thermal and Bulk Structural Properties of Poly(3-hydroxybutyrate-Epoxidized Natural Rubber Blends: Formation of Multi-Components Biobased Nanohybrids

    Directory of Open Access Journals (Sweden)

    Ali Salehabadi

    2014-06-01

    Full Text Available Multi-component nanohybrids comprising of organo-modified montmorillonite (MMT and immiscible biopolymer blends of poly(3-hydroxybutyrate (PHB and epoxidized natural rubber (ENR-50 were prepared by solvent casting technique. The one and three dimensional morphology of PHB/ENR-50/MMT systems were studied using Polarizing Optical Microscopy (POM and Scanning Electron Microscopy (SEM. Differential scanning calorimetry (DSC technique was used to evaluate the thermal properties of the nanohybrids. The melting temperature (Tm and enthalpy of melting (ΔHm of PHB decrease with respect to the increase in ENR-50 as well as MMT content. The non-isothermal decomposition of the nanohybrids was studied using thermogravimetric (TG-DTG analysis. FTIR-ATR spectra supported ring opening of the epoxide group via reaction with carboxyl group of PHB and amines of organic modifier. The reaction mechanism towards the formation of the nanohybrids is proposed.

  11. An Analysis on the Present Situation and Trend of the Development of the Natural Rubber Industry in the Sub- regional Areas of the Great Mekong River%大湄公河次区域天然橡胶产业发展现状及趋势分析

    Institute of Scientific and Technical Information of China (English)

    刘文; 齐欢

    2004-01-01

    Caoutchouc, or natural rubber, is one of the major economic crops in the countries of the sub-region along the Great Mekong River. Through the analysis on the tendency for future development and conditions for planting the crop in the area, the paper offers beneficial suggestions and countermeasures for their further economic cooperation.

  12. Genome-wide identification of rubber tree (Hevea brasiliensis Muell. Arg.) aquaporin genes and their response to ethephon stimulation in the laticifer, a rubber-producing tissue

    OpenAIRE

    Zou, Zhi; Gong, Jun; An, Feng; Xie, Guishui; Wang, Jikun; Mo, Yeyong; Yang, Lifu

    2015-01-01

    Background Natural rubber, an important industrial raw material, is specifically synthesized in laticifers located inside the rubber tree (Hevea brasiliensis Muell. Arg.) trunk. Due to the absence of plasmodesmata, the laticifer water balance is mediated by aquaporins (AQPs). However, to date, the characterization of H. brasiliensis AQPs (HbAQPs) is still in its infancy. Results In this study, 51 full-length AQP genes were identified from the rubber tree genome. The phylogenetic analysis assi...

  13. Complex processing of rubber waste through energy recovery

    OpenAIRE

    2015-01-01

    This article deals with the applied energy recovery solutions for complex processing of rubber waste for energy recovery. It deals specifically with the solution that could maximize possible use of all rubber waste and does not create no additional waste that disposal would be expensive and dangerous for the environment. The project is economically viable and energy self-sufficient. The outputs of the process could replace natural gas and crude oil products. The other part of the pro...

  14. Economic Efficiency in Indian Rubber Industry

    Directory of Open Access Journals (Sweden)

    Sarba Priya Ray

    2011-12-01

    Full Text Available The article tries to assess the utilization efficiency of capacity of Indian rubber industry in terms of econometric framework for the period,1979-80 to 2008-09.Capacity output has been  obtained at the minimum point of short run average cost curve. The result suggests that there has been declining growth rate of capacity utilization in rubber industry of India during the post reforms period accompanied by declining output growth as well as capacity growth. There exists some excess capacity in the rubber industry which remains unutilized during our study period. The result exhibits that  high correlation coefficient between actual output and capacity output for Indian rubber sector implies that  major part of under utilization of capacity is intended and low correlation  between capacity expansion (CE and past utilization(CUL seems to suggest that under utilization, if any, is mainly of the unintended nature, capacity expansions do not  move in line with past utilization rates and it also indicates that abolition of restrictions on licensing due to trade liberalization do not  help industry to expand capacity. On the other hand, low correlation between capacity expansion (CE and lagged output (QL indicates that unintended excess capacity is varying from year to year in an unsystematic matter.

  15. Caracterização mecânica e térmica da borracha natural formulada e vulcanizada dos clones: GT 1, IAN 873, PB 235 e RRIM 600 Mechanical and thermal characterization of compounds of natural rubber of the clones: GT 1, IAN 873, PB 235 and RRIM 600

    Directory of Open Access Journals (Sweden)

    Ana C. Dall'Antonia

    2009-01-01

    Full Text Available Neste trabalho estudou-se o desempenho mecânico e térmico de compostos de borracha natural (Hevea brasiliensis de 4 diferentes clones (GT 1, IAN 873, PB 235 e RRIM 600 cultivados no Estado de São Paulo, assim como de uma mistura destes clones e de uma borracha comercial, GEB-1. Estas borrachas foram formuladas e vulcanizadas com tempos de 5, 7 e 9 minutos. A caracterização foi realizada por calorimetria exploratória diferencial, termogravimetria, ensaios de resistência à tração, análise dinâmico-mecânica, medidas de dureza Shore A, microscopia eletrônica de varredura e espectroscopia na região do infravermelho. Os resultados permitiram concluir que o tempo de vulcanização e o tipo de clone não influenciaram na temperatura de transição vítrea (Tg dos compostos. Os valores de Tg obtidos por DMA foram de cerca de -62 °C, e os resultados ensaios de dureza apresentaram valores próximos de 60 para todos os compostos estudados. Os ensaios de resistência à tração mostraram que o melhor desempenho mecânico foi obtido pelo clone RRIM 600. De acordo com os resultados obtidos neste trabalho, todos os clones atingiram as propriedades reportadas na literatura, podendo ser utilizados, em princípio, nas indústrias de artefatos de borracha separadamente ou na forma de mistura.The objective of this work was to study the mechanical and thermal performance of natural rubber (Hevea brasiliensis compounds of different types of clones (GT 1, IAN 873, PB 235 and RRIM 600, as well as a mixture made from these clones and a commercial rubber GEB-1. These rubbers were formulated and prepared in a two-roll mill and vulcanized at different times (5, 7 and 9 minutes. The evaluation of the mechanical and thermal performance of different natural rubber compounds was carried out by differential scanning calorimetry (DSC, thermogravimetry analysis (TGA, mechanical properties (tensile and hardness tests, dynamic mechanic thermal analysis (DMTA

  16. Modifiction Study of Natural Rubber Latex by Sericin Grafted Polyurethane%丝胶接枝水性聚氨酯乳液对天然乳胶的改性研究

    Institute of Scientific and Technical Information of China (English)

    刘虎邱; 田晓慧; 宋玲; 元以中

    2011-01-01

    利用丝胶优良的生物相容性、抗氧化性等特点,结合水性聚氨酯优良的机械性能,合成了丝胶接枝水性聚氨酯乳液(1).采用杂凝聚技术用1改善天然乳胶手套的机械性能和过敏性.结果表明,经1改性后的天然乳胶手套在断裂伸长率基本不变的情况下,断裂强度有了明显的提高;杂凝聚方法形成的核壳结构使丝胶包裹在手套的内表面,达到了改善过敏性的目的.%Sericin grafted waterborne polyurethane emulsion(l) was synthesized by graft-copolymeri-zation of silk sericin(SS) onto waterborne polyurethane(2), which SS had excellent biocompatibility and oxidation resistance and 2 exhibited good mechanical properties. The mechanical performance and allergy to skin of natural rubber latex gloves were modified by heterocoagulation method using 1 as a processing aid. The results showed that elongation at break of modified the gloves almost had no change, and tensile strength was significantly improved. Core-shell structure formed by heterocoagulation made sericin wrapped in the inner surface of rubber gloves, achieving the purpose of improving allergy.

  17. Effect of expanded graphite and modified graphite flakes on the physical and thermo-mechanical properties of styrene butadiene rubber/polybutadiene rubber (SBR/BR) blends

    International Nuclear Information System (INIS)

    Highlights: • Modified graphite flakes/carbon black filled SBR and SBR/BR blend were synthesized. • Mechanical and thermomechanical properties of the composites were widely studied. • Composites with improved antiskid property and low rolling resistance were obtained. - Abstract: The aim of the present research work is to develop expanded graphite (EG) and isocyanate modified graphite nanoplatelets (i-MG) filled SBR/BR blends, which can substitute natural rubber (NR) in some application areas. The present study investigated the effect of i-MG on the physical, mechanical and thermo-mechanical properties of polybutadiene rubber (BR), styrene butadiene rubber (SBR) and SBR/BR blends in the presence of carbon black (CB). Graphite sheets were modified to enhance its dispersion in the rubber matrices, which resulting in an improvement in the overall physical and mechanical properties of the rubber vulcanizates. Compounds based on 50:50 of BR and SBR with ∼3 wt% nanofillers with CB were fabricated by melt mixing. The morphology of the filled rubber blends was investigated by wide angle X-ray diffraction (WAXD) and high resolution transmission electron microscopic (HR-TEM) analyses. The intercalated and delaminated structures of the nanofiller loaded rubber blends were observed. Scanning electron microscopic (SEM) analysis of the cryo-fractured surfaces of the rubber compounds showed more rough and tortuous pathway of the fractured surfaces compared to the fractured surfaces of the only CB loaded rubber composites. Filled rubber compounds exhibit increase in the ΔS (torque difference) value, reduced scorch and cure time compared to their respective controls. Dynamic mechanical thermal analysis (DMTA) of the filled rubber compounds shows an increase in the storage modulus compared to the controls. Isocyanate modified graphite nanoplatelets (i-MG) containing rubber compounds in the presence of CB showed an increase in the mechanical, dynamic mechanical, hardness

  18. Mapping Deciduous Rubber Plantation Areas and Stand Ages with PALSAR and Landsat Images

    Directory of Open Access Journals (Sweden)

    Weili Kou

    2015-01-01

    Full Text Available Accurate and updated finer resolution maps of rubber plantations and stand ages are needed to understand and assess the impacts of rubber plantations on regional ecosystem processes. This study presented a simple method for mapping rubber plantation areas and their stand ages by integration of PALSAR 50-m mosaic images and multi-temporal Landsat TM/ETM+ images. The L-band PALSAR 50-m mosaic images were used to map forests (including both natural forests and rubber trees and non-forests. For those PALSAR-based forest pixels, we analyzed the multi-temporal Landsat TM/ETM+ images from 2000 to 2009. We first studied phenological signatures of deciduous rubber plantations (defoliation and foliation and natural forests through analysis of surface reflectance, Normal Difference Vegetation Index (NDVI, Enhanced Vegetation Index (EVI, and Land Surface Water Index (LSWI and generated a map of rubber plantations in 2009. We then analyzed phenological signatures of rubber plantations with different stand ages and generated a map, in 2009, of rubber plantation stand ages (≤5, 6–10, >10 years-old based on multi-temporal Landsat images. The resultant maps clearly illustrated how rubber plantations have expanded into the mountains in the study area over the years. The results in this study demonstrate the potential of integrating microwave (e.g., PALSAR and optical remote sensing in the characterization of rubber plantations and their expansion over time.

  19. preparation of rubber gypsum composite by using cold method moulding and radiation finishing process

    International Nuclear Information System (INIS)

    Natural rubber latex (NRL) as a liquid rubber was mixed with anhydrous calcium sulphate (gypsum ) at room temperature using full hydrolyzed polyvinyl alcohol as a protective colloid for rubber part and cellulo sic stabilizer for gypsum part to stabilize and control the mixing process from the fast coagulation. the liquid mix ure was moulded in a 10 m3 cubic cavity to obtain rubber- gypsum blocks. the minimum amount of calcium sulphate which was required to induce moulding state of natural rubber latex was 3.97% of the total weight of formulation and 6.24% of rubber - gypsum total ratio. radiation finishing process was applied on the dried composite blocks for three different reasons. first was to sterilize the prepared mould, second was to activate the mould surface to be self adhesive product, the third was to obtain a soft rubber mould with 7% dioctyl phthalate as a plasticizer. the prepared rubber - gypsum moulds were passed through a serious of measurements such as setting time , weight loss, bulk density, abrasion surface ,hardness, scanning electron microscopy (sem), tensile strength, elongation at break, compression set and water absorption . the use of the prepared rubber gypsum moulds as wet moulding and dry articles via extrusion processes for auto motives and machines and also hygienic sterilized products as nontoxic rubber tools for kids and children

  20. Effects of forests, roads and mistletoe on bird diversity in monoculture rubber plantations

    Science.gov (United States)

    Sreekar, Rachakonda; Huang, Guohualing; Yasuda, Mika; Quan, Rui-Chang; Goodale, Eben; Corlett, Richard T.; Tomlinson, Kyle W.

    2016-01-01

    Rising global demand for natural rubber is expanding monoculture rubber (Hevea brasilensis) at the expense of natural forests in the Old World tropics. Conversion of forests into rubber plantations has a devastating impact on biodiversity and we have yet to identify management strategies that can mitigate this. We determined the life-history traits that best predict bird species occurrence in rubber plantations in SW China and investigated the effects of surrounding forest cover and distance to roads on bird diversity. Mistletoes provide nectar and fruit resources in rubber so we examined mistletoe densities and the relationship with forest cover and rubber tree diameter. In rubber plantations, we recorded less than half of all bird species extant in the surrounding area. Birds with wider habitat breadths and low conservation value had a higher probability of occurrence. Species richness and diversity increased logarithmically with surrounding forest cover, but roads had little effect. Mistletoe density increased exponentially with rubber tree diameters, but was unrelated to forest cover. To maximize bird diversity in rubber-dominated landscapes it is therefore necessary to preserve as much forest as possible, construct roads through plantations and not forest, and retain some large rubber trees with mistletoes during crop rotations. PMID:26903032

  1. Effects of forests, roads and mistletoe on bird diversity in monoculture rubber plantations

    Science.gov (United States)

    Sreekar, Rachakonda; Huang, Guohualing; Yasuda, Mika; Quan, Rui-Chang; Goodale, Eben; Corlett, Richard T.; Tomlinson, Kyle W.

    2016-02-01

    Rising global demand for natural rubber is expanding monoculture rubber (Hevea brasilensis) at the expense of natural forests in the Old World tropics. Conversion of forests into rubber plantations has a devastating impact on biodiversity and we have yet to identify management strategies that can mitigate this. We determined the life-history traits that best predict bird species occurrence in rubber plantations in SW China and investigated the effects of surrounding forest cover and distance to roads on bird diversity. Mistletoes provide nectar and fruit resources in rubber so we examined mistletoe densities and the relationship with forest cover and rubber tree diameter. In rubber plantations, we recorded less than half of all bird species extant in the surrounding area. Birds with wider habitat breadths and low conservation value had a higher probability of occurrence. Species richness and diversity increased logarithmically with surrounding forest cover, but roads had little effect. Mistletoe density increased exponentially with rubber tree diameters, but was unrelated to forest cover. To maximize bird diversity in rubber-dominated landscapes it is therefore necessary to preserve as much forest as possible, construct roads through plantations and not forest, and retain some large rubber trees with mistletoes during crop rotations.

  2. Failure mechanisms in thin rubber sheet composites under static solicitation

    Directory of Open Access Journals (Sweden)

    E. Bayraktar

    2007-03-01

    Full Text Available Purpose: Mechanical behaviour and damage mechanisms in thin rubber sheet composites were investigated under static solicitation at room temperature. Two types of rubber are used in this study; Natural rubber, NR vulcanised and reinforced by carbon black and Synthetic rubber (styrene-butadiene-rubber, SBR.Design/methodology/approach: A comprehensive study has been carried out in order to identify a threshold criterion for the damage mechanism to explain a tearing criterion for the concept of tearing energy of the elastomers and also to give a detail for the damage mechanism depending on the loading conditions. A typical type of specimen geometry of thin sheet rubber composite materials was studied under static tensile tests conducted on the smooth and notched specimens with variable depths. In this way, the effects of the plane stress on the damage mechanism are characterized depending on the rubber materials.Findings: Damage mechanisms during tensile test have been described for both of rubber types and the criteria which characterize the tearing resistance, characteristic energy for tearing (T was explained. Damage in the specimens were evaluated just at the beginning of the tearing by means of the observations in the scanning electron microscopy (SEM.Practical implications: A tearing criterion was suggested in the case of simple tension conditions by assuming large strain. In the next step of this study, a finite element analysis (FEA will be applied under the same conditions of this part in order to obtain the agreement between experimental and FEA results.Originality/value: This study propses a threshold criterion for the damage just at the beginning of the tearing for thin sheet rubber composites and gives a detail discussion for explaining the damage mechanisms by SEM results. This type of study gives many facilities for the sake of simplicity in industrial application.

  3. Elastic instabilities in rubber

    Science.gov (United States)

    Gent, Alan

    2009-03-01

    Materials that undergo large elastic deformations can exhibit novel instabilities. Several examples are described: development of an aneurysm on inflating a rubber tube; non-uniform stretching on inflating a spherical balloon; formation of internal cracks in rubber blocks at a critical level of triaxial tension or when supersaturated with a dissolved gas; surface wrinkling of a block at a critical amount of compression; debonding or fracture of constrained films on swelling, and formation of ``knots'' on twisting stretched cylindrical rods. These various deformations are analyzed in terms of a simple strain energy function, using Rivlin's theory of large elastic deformations, and the results are compared with experimental measurements of the onset of unstable states. Such comparisons provide new tests of Rivlin's theory and, at least in principle, critical tests of proposed strain energy functions for rubber. Moreover the onset of highly non-uniform deformations has serious implications for the fatigue life and fracture resistance of rubber components. [4pt] References: [0pt] R. S. Rivlin, Philos. Trans. Roy. Soc. Lond. Ser. A241 (1948) 379--397. [0pt] A. Mallock, Proc. Roy. Soc. Lond. 49 (1890--1891) 458--463. [0pt] M. A. Biot, ``Mechanics of Incremental Deformations'', Wiley, New York, 1965. [0pt] A. N. Gent and P. B. Lindley, Proc. Roy. Soc. Lond. A 249 (1958) 195--205. [0pt] A. N. Gent, W. J. Hung and M. F. Tse, Rubb. Chem. Technol. 74 (2001) 89--99. [0pt] A. N. Gent, Internatl. J. Non-Linear Mech. 40 (2005) 165--175.

  4. CHARACTERIZATION OF RUBBER DEGRADING ISOLATES

    Directory of Open Access Journals (Sweden)

    M. D. Chengalroyen

    2012-12-01

    Full Text Available Sixteen soil samples were screened for the presence of rubber degrading strains. Twenty-five strains displaying clear zone formation on latex agar plates were purified. Identification revealed that twenty three of these isolates were Streptomyces species, one Pseudonocardia species and one Methylibium species. The addition of carbon sources with the exception of tween 80 enhanced extracellular rubber biodegradation. Scanning electron microscopy revealed that the isolates were able to colonize and penetrate vulcanized glove rubber.

  5. Exploratory Study of Rubber Seed Shell as Partial Coarse Aggregate Replacement in Concrete

    OpenAIRE

    K. Muthusamy; Nordin, N.; G. Vesuvapateran; M. Ali; N.A. Mohd Annual; H. Harun; H. Ullap

    2014-01-01

    Malaysia being a major rubber trees growing country has been generating a large amount of rubber seed shell which regarded as waste. At the same time, the growing construction industry which boosts the concrete production trade has results in higher consumption of natural coarse aggregate which open the door for depletion of this material in future. This study focuses on investigating the possibility of integrating crushed rubber seed shell as partial coarse aggregate replacement material in ...

  6. Pushing the Limits: The Pattern and Dynamics of Rubber Monoculture Expansion in Xishuangbanna, SW China.

    Directory of Open Access Journals (Sweden)

    Huafang Chen

    Full Text Available The rapidly growing car industry in China has led to an equally rapid expansion of monoculture rubber in many regions of South East Asia. Xishuangbanna, the second largest rubber planting area in China, located in the Indo-Burma biodiversity hotspot, supplies about 37% of the domestic natural rubber production. There, high income possibilities from rubber drive a dramatic expansion of monoculture plantations which poses a threat to natural forests. For the first time we mapped rubber plantations in and outside protected areas and their net present value for the years 1988, 2002 (Landsat, 30 m resolution and 2010 (RapidEye, 5 m resolution. The purpose of our study was to better understand the pattern and dynamics of the expansion of rubber plantations in Xishuangbanna, as well as its economic prospects and conservation impacts. We found that 1 the area of rubber plantations was 4.5% of the total area of Xishuangbanna in 1988, 9.9% in 2002, and 22.2% in 2010; 2 rubber monoculture expanded to higher elevations and onto steeper slopes between 1988 and 2010; 3 the proportion of rubber plantations with medium economic potential dropped from 57% between 1988 and 2002 to 47% in 2010, while the proportion of plantations with lower economic potential had increased from 30% to 40%; and 4 nearly 10% of the total area of nature reserves within Xishuangbanna has been converted to rubber monoculture by 2010. On the basis of our findings, we conclude that the rapid expansion of rubber plantations into higher elevations, steeper terrain, and into nature reserves (where most of the remaining forests of Xishuangbanna are located poses a serious threat to biodiversity and environmental services while not producing the expected economic returns. Therefore, it is essential that local governments develop long-term land use strategies for balancing economic benefits with environmental sustainability, as well as for assisting farmers with the selection of land suitable

  7. Pushing the Limits: The Pattern and Dynamics of Rubber Monoculture Expansion in Xishuangbanna, SW China.

    Science.gov (United States)

    Chen, Huafang; Yi, Zhuang-Fang; Schmidt-Vogt, Dietrich; Ahrends, Antje; Beckschäfer, Philip; Kleinn, Christoph; Ranjitkar, Sailesh; Xu, Jianchu

    2016-01-01

    The rapidly growing car industry in China has led to an equally rapid expansion of monoculture rubber in many regions of South East Asia. Xishuangbanna, the second largest rubber planting area in China, located in the Indo-Burma biodiversity hotspot, supplies about 37% of the domestic natural rubber production. There, high income possibilities from rubber drive a dramatic expansion of monoculture plantations which poses a threat to natural forests. For the first time we mapped rubber plantations in and outside protected areas and their net present value for the years 1988, 2002 (Landsat, 30 m resolution) and 2010 (RapidEye, 5 m resolution). The purpose of our study was to better understand the pattern and dynamics of the expansion of rubber plantations in Xishuangbanna, as well as its economic prospects and conservation impacts. We found that 1) the area of rubber plantations was 4.5% of the total area of Xishuangbanna in 1988, 9.9% in 2002, and 22.2% in 2010; 2) rubber monoculture expanded to higher elevations and onto steeper slopes between 1988 and 2010; 3) the proportion of rubber plantations with medium economic potential dropped from 57% between 1988 and 2002 to 47% in 2010, while the proportion of plantations with lower economic potential had increased from 30% to 40%; and 4) nearly 10% of the total area of nature reserves within Xishuangbanna has been converted to rubber monoculture by 2010. On the basis of our findings, we conclude that the rapid expansion of rubber plantations into higher elevations, steeper terrain, and into nature reserves (where most of the remaining forests of Xishuangbanna are located) poses a serious threat to biodiversity and environmental services while not producing the expected economic returns. Therefore, it is essential that local governments develop long-term land use strategies for balancing economic benefits with environmental sustainability, as well as for assisting farmers with the selection of land suitable for rubber

  8. QENS investigation of filled rubbers

    CERN Document Server

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

    2002-01-01

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

  9. QENS investigation of filled rubbers

    International Nuclear Information System (INIS)

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

  10. Preparation of Hydrogenated Nitrile Rubber

    Institute of Scientific and Technical Information of China (English)

    LIU; ZhiCai

    2001-01-01

    Hydrogenated nitrile rubber is an oil and solvent resistant rubber and particularly give more resistant to heat, ozone, light. It is generally prepared from nitrile rubber by selective hydrogenation using a suitable catalyst system. In the present work a prepared method was adapted for the hydrogenation reaction of nitrile rubber using homogeneous tris(tri-phenlphosphine)chlorhodium(I) catalyst (RhCl(PPh3)) system.  The hydrogenation reaction was carriedout at different temperature, pressure, time and catalyst concentration, the concentration, the conditions of hydrogenation are stated in table 1.  ……

  11. Preparation of Hydrogenated Nitrile Rubber

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@ Hydrogenated nitrile rubber is an oil and solvent resistant rubber and particularly give more resistant to heat, ozone, light. It is generally prepared from nitrile rubber by selective hydrogenation using a suitable catalyst system. In the present work a prepared method was adapted for the hydrogenation reaction of nitrile rubber using homogeneous tris(tri-phenlphosphine)chlorhodium(I) catalyst (RhCl(PPh3)) system. The hydrogenation reaction was carriedout at different temperature, pressure, time and catalyst concentration, the concentration, the conditions of hydrogenation are stated in table 1.

  12. Laboratory optimization of continuous blend asphalt rubber

    OpenAIRE

    Fontes, Liseane P. T. L.; Pereira, Paulo A. A.; Trichês, Glicério; Pais, Jorge C.; Luzia, Rosa

    2008-01-01

    Asphalt rubber from wet process requires batching blending and reaction time associated to blending rubber and conventional asphalt to produce asphalt rubber. The ideal blending of these materials depends on the combination of very important variables, such as the amount of rubber, reaction time and temperature reaction. This paper intends to optimize the laboratory production of asphalt rubber using the continuous blend process. The rubber from waste tyres was reduced by ambient grinding and...

  13. Laboratory performance of asphalt rubber mixtures

    OpenAIRE

    Fontes, Liseane; Trichês, Glicério; Pais, Jorge; Pereira, Paulo; Minhoto, Manuel

    2009-01-01

    Asphalt rubber mixtures are one of the most promising techniques to extend the service life of asphalt pavement overlays. Asphalt rubber binder is composed of crumb rubber from reclaimed tires and conventional asphalt. The asphalt rubber binder can be obtained through wet process in two different systems: tire rubber modified asphalt binder (produced at industrial plants) and continuous blending (produced in asphalt plants). This study presents a laboratory evaluation of asphalt rubber mixtur...

  14. 中国天然橡胶供求影响因素实证研究--基于VAR模型的经济计量分析%Empirical study on the influence factors of supply and demand of China’s natural rubber-an econometric analysis based on VAR model

    Institute of Scientific and Technical Information of China (English)

    张志耀; 邵晓燕

    2013-01-01

    In the study of supply and demand of natural rubber, a general regression model cannot fit the time series data correctly. This paper carries on through the stationary test by unit root test, and takes the logarithm and the differential treatment to the consumption quantity and supply quantity of natural rubber, per capita gross domestic product of natural rubber, the annual average value of natural rubber and the export amount of natural rubber from 1991 to 2012. Based on ensuring the smoothness of data, this paper makes Granger causality test to the system of supply and demand, and established VAR model. Finally, we analyze the impulse response function on the status of demand and supply of China’s natural rubber by making impulse response analysis to the model, which has some certain value for confirming the intensity of influence factors.%在对天然橡胶的供求研究中,一般的回归模型不能很好地对时间序列数据进行拟合。本文应用单位根检验,对1991-2012年中国天然橡胶消费量、供给量、人均国内生产总值、天然橡胶年均价和橡胶制品出口金额等非平稳数据进行取对数和差分处理,在保证数据平稳性的基础上对中国天然橡胶供求系统进行Granger因果检验并建立VAR模型。通过模型的脉冲响应函数对中国天然橡胶供求状况的影响因素进行冲击响应分析,这对影响因素的影响力度确认有一定的参考意义。

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

    International Nuclear Information System (INIS)

    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

  16. Radiation Sterilization of Naturual Rubber Examination Gloves

    International Nuclear Information System (INIS)

    The sterilization dose setting by ISO 11137 method 1 was conducted for natural rubber examination gloves provided by a local factory. The suitable sterilization dose for an average product bioburden falls between 20 - 25 kilogray. Maximum dose of 25 or 50 kilogray results in no changes of tensile s and elongation at break. Samples of examination glove were irradiated using various doses between 10 - 50 kilogray. Analysis of soluble protein content using modified Lowry method was carried out and the results revealed that irradiation did not affect the decrement of soluble protein content in this case. However, thin film samples were prepared in laboratory and treated in the same procedure. The results were also the same. The results did not show any correlation. Two factors are possibly presumed : un consistency of samples and the irradiation of finished products could not affect those soluble proteins in rubber gloves

  17. Through the Technology Lens: The Expansion of Rubber and its Implications in Montane Mainland Southeast Asia

    OpenAIRE

    Jefferson Fox

    2014-01-01

    Natural latex from the rubber tree (Hevea brasiliensis) is a hot commodity, with consumption increasing worldwide at an average rate of 5.8% per year since 1900. The vast majority of the world′s rubber supply has historically come from the wet-humid tropics of Southeast Asia, but researchers in China have successfully developed new hybrids that grow well in areas with cooler temperatures and a distinct dry season. Today, investors are promoting rubber plantations in non-traditional rubber gro...

  18. Effect of electron beam irradiation on the properties of crosslinked rubbers

    Energy Technology Data Exchange (ETDEWEB)

    Banik, Indranil; Bhowmick, Anil K. E-mail: anilkb@rtc.iitkgp.ernet.in

    2000-05-01

    Influence of electron beam (EB) irradiation on the mechanical and dynamic mechanical properties of crosslinked fluorocarbon (FKM) rubber, natural rubber (NR), ethylene propylene diene monomer (EPDM) rubber and nitrile rubber (NBR) has been investigated. The modulus, gel fraction, glass transition temperature (T{sub g}) and storage modulus increased, while the elongation at the break and the loss tangent (tan {delta}){sub T{sub g}} decreased. FKM and NBR vulcanizates have been shown to have EB radiation resistance up to 1500 kGy. (author)

  19. Investigations of the mixing behaviour of pin-type rubber extruders

    Science.gov (United States)

    Schöppner, Volker; Schadomsky, Michael; Hopmann, Christian; Lemke, Florian

    2016-03-01

    This paper deals with investigations of the mixing behaviour of rubber extruders. The requirement to obtain a high-quality elastomer product is a thermally and materially homogenous rubber mixture. Because of the highly viscous and multicomponent nature of rubber mixture, extruders require a thoroughly distributive and dispersive mixing behaviour. The current state of the art is the pin-type rubber extruder with cylindrical pins which extend radially into the screw channel, causing a constant deformation and reorientation of the rubber melt. As mixing is of crucial importance, the mixing behaviour of pin-type rubber extruders is analysed with the goal of optimising it. The starting point of the optimisation is the current cylindrical pins. Over the course of the investigation, new pin designs and geometrical arrangements are investigated.

  20. Engineered Plastics Containing Recycled Rubber

    Institute of Scientific and Technical Information of China (English)

    Dong Yang Wu

    2000-01-01

    @@ 1. Introduction In Australia 10.5 million rubber tyres are discarded annually, representing 120,000 tonnes of wasted rubber resource. Growing local and global concern about the impact of this waste on the environment requires action for the management and recycling of this highly valuable resource through the development of recycling technologies and innovative recycled/recyclable products.