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Sample records for chloride-epoxidized natural rubber

  1. 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 ...

  2. 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.

  3. 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 %.

  4. 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 %.

  5. Alternative sources of natural rubber

    NARCIS (Netherlands)

    Mooibroek, H.; Cornish, K.

    2000-01-01

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

  6. 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 ...

  7. 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...

  8. 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.

  9. 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

  10. 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.

  11. 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.

  12. 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

  13. 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. .

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

    Energy Technology Data Exchange (ETDEWEB)

    Barkakaty, Balaka [ORNL

    2014-01-01

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

  15. Isolation of Microorganisms Able To Metabolize Purified Natural Rubber

    OpenAIRE

    Heisey, R. M.; Papadatos, S.

    1995-01-01

    Bacteria able to grow on purified natural rubber in the absence of other organic carbon sources were isolated from soil. Ten isolates reduced the weight of vulcanized rubber from latex gloves by >10% in 6 weeks. Scanning electron microscopy clearly revealed the ability of the microorganisms to colonize, penetrate, and dramatically alter the physical structure of the rubber. The rubber-metabolizing bacteria were identified on the basis of fatty acid profiles and cell wall characteristics. Seve...

  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. 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

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

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    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.

  19. 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)

  20. 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.

  1. Cellulose nanocrystal reinforced oxidized natural rubber nanocomposites.

    Science.gov (United States)

    Mariano, Marcos; El Kissi, Nadia; Dufresne, Alain

    2016-02-10

    Natural rubber (NR) latex particles were oxidized using KMnO4 as oxidant to promote the insertion of hydroxyl groups in the surface polyisoprene chains. Different degrees of oxidation were investigated. Both unoxidized and oxidized NR (ONR) latex were used to prepare nanocomposite films reinforced with cellulose nanocrystals (CNCs) by casting/evaporation. The oxidation of NR was carried out to promote chemical interactions between the hydroxyl groups of ONR with those of CNCs through hydrogen bonding. The effect of the degree of oxidation of the NR latex on the rheological behavior of CNC/NR and CNC/ONR suspensions, as well as on the mechanical, swelling and thermal properties of ensuing nanocomposites was investigated. Improved properties were observed for intermediate degrees of oxidation but they were found to degrade for higher oxidation levels. PMID:26686118

  2. 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)

  3. 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...

  4. Occupational asthma caused by natural rubber latex.

    Science.gov (United States)

    Vandenplas, O

    1995-11-01

    IgE-mediated sensitization in protein allergens of natural rubber latex (NRL) can induce immediate hypersensitivity reactions ranging from mild urticaria in life threatening anaphylaxis after cutaneous, mucosal or visceral exposure. Elutable allergens from NRL gloves absorb to the cornstarch powder particles, become airborne, and have the potential to cause respiratory reactions. Recent studies indicate that asthma is a frequent manifestation of NRL allergy among workers manufacturing NRL materials and among health-care providers using NRL workers. NRL-induced asthma should receive increasing attention as it can lead to permanent respiratory sequelae and occupational disability. The need for early and accurate diagnosis is outlined and the different diagnostic approaches are reviewed. Specific issues pertaining to the management of affected subjects and to the prevention of exposure to airborne NRL are discussed. Ares of future research should include: 1) further characterization of relevant NRL allergens; 2) development and validation of methods for quantitative assessment of allergen content in NRL devices and workplace environment; 3) evaluation of the natural history and risk factors of NRL-induced asthma; and 5) analysis of effectiveness and cost of preventive strategies. PMID:8620969

  5. 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

  6. 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.

  7. 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...

  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. 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.

  10. SUPPLY-CHAIN OF NATURAL RUBBER IN INDONESIA

    Directory of Open Access Journals (Sweden)

    Bustanul Arifin

    2011-08-01

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

  11. 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.

  12. 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, ...

  13. 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.

  14. 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

  15. 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.

  16. 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)

  17. 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.

  18. 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...

  19. Nanocomposites of natural rubber and polyaniline-modified cellulose nanofibrils

    Science.gov (United States)

    Cellulose nanofibrils (CNF) were isolated from cotton microfibrils (CM) by acid hydrolysis and coated with polyaniline (PANI) by in situ polymerization of aniline onto CNF in the presence of hydrochloride acid and ammonium peroxydisulfate to produce CNF/PANI. Nanocomposites of natural rubber (NR) re...

  20. [Allergic reaction to products made of natural rubber].

    Science.gov (United States)

    Antczak, M; Kuna, P; Cieślewicz, G

    In the previous few years, there has been a startling escalation in intraoperative and radiologic anaphylactic episodes, some of them lethal, that have been assigned to rubber exposure. Immediate hypersensitivity reactions to natural rubber pose a significant risk to patient with spina bifida and urogenital abnormalities, health care workers, and rubber industry workers. It has been estimated that 2% to 10% of physicians and nursing personnel are latex allergic. The clinical syndromes associated with reactions to latex may be divided into three broad categories a) contact dermatitis--limited to skin directly in contact with latex, b) contact urticaria syndrome a broad spectrum of contact reactions including not only immediate wheal and flare reactions, but also dyshidrotic vesiculation, and accelerated contact reactions including erythema, burning or pruritus occurring within 10-30 minutes after contact, c) systemic allergic reactions-including generalized urticaria or pruritus, rhinoconjunctivitis or asthma, as well as the multiple presentations of anaphylaxis. Contact dermatitis reactions are thought to be a T-cell mediated type IV reaction, systemic reactions to latex appear to be an IgE-mediated phenomenon. Contact urticaria syndrome seems to be a heterogeneous group of reactions. Diagnosis of latex allergy is made on clinical grounds, however, history alone is insufficient to recognize all patients at risk, and conscientious testing materials are not yet available. Prick tests utilizing extracts from latex gloves or from raw latex preparation can be used but the specificity of this test remains unknown. Skin prick testing must be considered experimental and should be only done by experienced physician. Serologic testing for latex allergy remains a safe alternative, although the sensitivity and specificity of this procedure is still undefined. Prophylactic regimes to avoid rubber exposure and decrease the antigen content of natural rubber products by the rubber

  1. 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

  2. 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

  3. 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 ...

  4. 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...

  5. 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

  6. 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...

  7. 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

  8. Progress in radiation vulcanization of natural rubber latex

    Energy Technology Data Exchange (ETDEWEB)

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

    2000-03-01

    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)

  9. 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.

  10. Extractable proteins from field radiation vulcanized natural rubber latex

    Energy Technology Data Exchange (ETDEWEB)

    Parra, Duclerc F. [Chemical and Environmental Centre, Nuclear Energy Research Institute, Av. Lineu Prestes, 2242-CEP Sao Paulo (Brazil)]. E-mail: dfparra@ipen.br; Pinto Martins, Carlos Felipe [Chemical and Environmental Centre, Nuclear Energy Research Institute, Av. Lineu Prestes, 2242-CEP Sao Paulo (Brazil); Collantes, Hugo D.C. [Chemical and Environmental Centre, Nuclear Energy Research Institute, Av. Lineu Prestes, 2242-CEP Sao Paulo (Brazil); Lugao, Ademar B. [Chemical and Environmental Centre, Nuclear Energy Research Institute, Av. Lineu Prestes, 2242-CEP Sao Paulo (Brazil)

    2005-07-01

    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 {sup 60}Co 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.

  11. 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)

  12. 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

  13. 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.

  14. 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)

  15. 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.

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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...

  2. 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.

  3. Natural rubber latex allergy: spectrum, diagnostic approach, and therapy.

    Science.gov (United States)

    Woods, J A; Lambert, S; Platts-Mills, T A; Drake, D B; Edlich, R F

    1997-01-01

    Latex allergy has reached epidemic proportions in the United States and is increasingly recognized as a significant contributor to morbidity and mortality during medical and surgical procedures. Ultimately, many of the affected patients with recognized latex sensitivity and those who are not yet diagnosed will receive treatment for their allergic reactions to latex in emergency departments. Consequently, emergency physicians must have a comprehensive understanding of the etiology, epidemiology, pathogenesis, treatment, and management of these challenging patients. Groups at high risk include spina bifida cystica patients, health care workers, latex industry workers, specific food-allergy patients, and patients with a history of atopy or multiple surgical procedures. Sensitization to latex antigens is commonly encountered in health care workers wearing latex gloves with high latex allergen concentrations and in workers using powdered latex surgical gloves. Exposure to air-borne allergens and water-soluble IgE reactive latex antigens from natural rubber latex products in sensitized individuals can result in type I (immediate) hypersensitivity reactions. Clinical manifestations include contact urticaria, dermatitis, allergic rhinitis, conjunctivitis, asthma, angioedema, and anaphylaxis. Diagnostic tools include serological assays and skin prick testing. At present, latex avoidance is the only available treatment and is the key to preventing allergic reactions in latex-sensitized individuals. Health care worker sensitization to latex antigens in natural rubber products is becoming an increasing contributor to workers' liability and disability claims. Specific action can be taken to reduce occupational and patient exposure to latex antigens. PMID:9017491

  4. 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

  5. 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

  6. 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 ...

  7. 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...

  8. 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.

  9. 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

  10. 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

  11. 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)

  12. 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.

  13. Effect of concentrated epoxidised natural rubber and silica masterbatch for tyre application

    Science.gov (United States)

    Azira, A. A.; Verasamy, D.; Kamal, M. M.

    2016-07-01

    The availability of concentrated epoxidised natural rubber (ENR-LC) has provided a better opportunity for using epoxidised natural rubber (ENR) with silica to reinforce natural rubber for tyre application. ENR-LC mixed directly with silica to rubber by high speed stirrer without using any coupling agent. Some rubber compounds were prepared by mixing a large amount of precipitated amorphous white silica with natural rubber. The silica was prepared in aqueous dispersion and the filler was perfectly dispersed in the ENR-LC. The performance of the composites was evaluated in this work for the viability of ENR-LC/Si in tyre compounding. Compounding was carried out on a two roll mill, where the additives and curing agents was later mixed. Characterization of these composites was performed by Field Emission Scanning Electron Microscopy (FESEM) and Transmission Electron Microscopy (TEM) for dispersion as well as mechanical testing. C-ENR/Si showed efficient as primary reinforcing filler in ENR with regard to modulus and tensile strength, resulting on an increase in the stiffness of the rubbers compared to ENR latex. Overall improvement in the mechanical properties for the ENR-LC over the control crosslinked rubber sample was probably due to synergisms of silica reinforcement and crosslinking of the polymeric matrix phase.

  14. A study of protein and amino acids in guayule natural rubber

    Science.gov (United States)

    Natural rubber (NR) from Hevea brasiliensis (the Hevea rubber tree) is a critical agricultural material vital to United States industry, medicine, and defense, yet the country is dependent on NR imports to meet domestic needs. Parthenium argentatum (guayule), a woody desert shrub indigenous to the U...

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

    OpenAIRE

    Sawarni Hasibuan; E. Gumbira-Sa’id; Eriyatno Eriyatno; Illah Saillah; Suharto Honggokusumo; M. Romli

    2013-01-01

    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. i...

  16. 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

  17. 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)

  18. 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.

  19. 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)

  20. Complete genome sequence of Streptomyces sp. strain CFMR 7, a natural rubber degrading actinomycete isolated from Penang, Malaysia.

    Science.gov (United States)

    Nanthini, Jayaram; Chia, Kim-Hou; Thottathil, Gincy P; Taylor, Todd D; Kondo, Shinji; Najimudin, Nazalan; Baybayan, Primo; Singh, Siddharth; Sudesh, Kumar

    2015-11-20

    Streptomyces sp. strain CFMR 7, which naturally degrades rubber, was isolated from a rubber plantation. Whole genome sequencing and assembly resulted in 2 contigs with total genome size of 8.248 Mb. Two latex clearing protein (lcp) genes which are responsible for rubber degrading activities were identified.

  1. 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.

  2. ENHANCEMENT OF RESISTANCE TO OXIDATIVE DEGRADATION OF NATURAL RUBBER THROUGH LATEX DEGRADATION

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    A fully characterised natural rubber latex was subjected to mechanical degradation by stirring at intervals. The resistance to oxidative degradation of the different samples were studied by measuring the Plasticity retention indices (PRI).The results show that there is an enhancement of the PRI from 57% for the undegraded rubber to 79% for the one-hour degraded sample. Further degradation resulted in decrease of PRI as time of degradation increased. Therefore, the one-hour degraded sample is a special rubber with high oxidation resistance which is of great importance in engineering.

  3. 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

  4. 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.

  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. Studies on the Transport of Aromatic Solvents through Filled Natural Rubber

    Directory of Open Access Journals (Sweden)

    Isaac O. Igwe

    2012-01-01

    Full Text Available The transport of three aromatic solvents (benzene, toluene and xylene through snail shell powder filled natural rubber was studied at 313, 333, and 353 K by conventional weight-gain experiments. The effects of snail shell powder content, particle size, nature of solvent, and temperature on the transport characteristics of natural rubber were determined. The estimated Arrhenius activation energies for the processes of sorption, diffusion, and permeation showed that the activation energies were highest in xylene at all the filler contents investigated. The calculated enthalpies, and entropies of sorption were all positive for the solvents investigated. Similarly, the change in the estimated free energies of sorption were all positive; an indication of the non-spontaneity of the solubility of snail shell powder filled natural rubber in the aromatic solvents at 313 k.

  10. 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.

  11. 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.

  12. 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.

  13. 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

  14. New green polymeric composites based on hemp and natural rubber processed by electron beam irradiation.

    Science.gov (United States)

    Stelescu, Maria-Daniela; Manaila, Elena; Craciun, Gabriela; Dumitrascu, Maria

    2014-01-01

    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.

  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. 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.

  17. 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)

  18. 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

  19. Tailoring assembly of reduced graphene oxide nanosheets to control gas barrier properties of natural rubber nanocomposites.

    Science.gov (United States)

    Scherillo, Giuseppe; Lavorgna, Marino; Buonocore, Giovanna G; Zhan, Yanhu H; Xia, Hesheng S; Mensitieri, Giuseppe; Ambrosio, Luigi

    2014-02-26

    Self-assembling of reduced graphene oxide platelets, as a tailored interconnected network within a natural rubber matrix, is proposed as a mean for obtaining nanocomposites with improved gas barrier, as compared to neat natural rubber. Interestingly, this nanocomposite structure results to be much more effective than homogeneous dispersion of graphene platelike particles, even at low graphene loadings. Such behavior is interpreted on the grounds of a theoretical model describing permeability of heterogeneous systems specifically accounting for self-segregated graphene morphology. PMID:24490910

  20. 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

  1. 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

  2. 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

    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 Landsat...... time series when exploring the dynamics of human-induced land cover change....... for natural rubber and the annual rate of frontier forest clearing for rubber plantations on both sides of the border. We used LandTrendr (Landsat-based detection of trends in disturbance and recovery) for temporal segmentation of the Landsat time series and disturbance mapping. Our results show...

  3. 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.

  4. 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.

  5. 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...

  6. 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

  7. 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)

  8. 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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-02-15

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

  10. 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.

  11. 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)

  12. 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)

  13. 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.

  14. 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.

  15. 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.

  16. 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...

  17. Vacuum coagulation of natural rubber latex and the properties of the produced natural raw rubber%真空凝固天然橡胶胶乳及其生胶性能

    Institute of Scientific and Technical Information of China (English)

    雷统席; 蒋盛军; 符乃方; 李鸿; 谢飞扬; 马洪泉

    2011-01-01

    在真空条件下,天然胶乳橡胶粒子会膨胀、破裂,从而引起天然胶乳的凝固.本研究首次将真空技术引入天然胶乳凝固领域.真空凝固天然胶乳可物理控速、凝固彻底、胶清清澈、污染低.与酸凝固天然胶乳的生胶及微生物凝固天然胶乳的生胶相比,真空凝固胶具备多孔、叠层结构,干燥失水快、抗氧指数(PRI)高、硫化速度较快,硫化后物理机械性能在3种硫化胶中最优.本研究为天然胶乳的凝固提供了一种新的物理方法.%Under vacuum natural rubber particles in natural rubber latex will expand, burst and coagulate. In this study, vacuum technology was applied to coagulate natural rubber latex. This vacuum coagulation of natural rubber latex could be controlled physically. The skim latex obtained as a byproduct during this procedure was cleaner than that obtained from other procedures; this procedure would therefore reduce pollution from latex processing. The natural raw rubber produced by vacuum coagulation had a porous and layered structure. Compared with the natural raw rubber coagulated by acid and microbiological methods, the natural raw rubber produced in this study was faster to dehydrate and vulcanize, and had a higher plasticity retention index. The vulcanized rubber from vacuum coagulation had better physical and mechanical properties than that prepared by acid or microbiological coagulation. The method developed in this work is a novel physical way to coagulate natural rubber latex.

  18. 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.

  19. 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.

  20. 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

  1. 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.

  2. 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.

  3. Robust and biodegradable polymer of cassava starch and modified natural rubber.

    Science.gov (United States)

    Riyajan, Sa-Ad

    2015-12-10

    The application of starch based materials for packaging purposes has attracted significant interest because they are both cheap and renewable resources. The study investigated the preparation and properties of a novel biopolymer sheet produced from a blend of maleated epoxidized natural rubber (MENR) and natural rubber-g-cassava starch (NR-g-CSt). The water resistance, toluene resistance and elongation at break of the polymer blend were enhanced after the addition of the MENR compared to pristine NR-g-CSt. The maximum tensile strength and thermal stability of the NR-g-CSt/MENR blend were found in the 100:50 NR-g-CSt:MENR blend. The novel films demonstrated good biodegradability in soil.

  4. 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)

  5. Influence of NdFeB Fillers on Tensile and Electromagnetic Properties of Natural Rubber

    Directory of Open Access Journals (Sweden)

    Puripat LERTSURAWAT

    2009-06-01

    Full Text Available Tensile and electromagnetic properties of hard magnetic natural rubber composites were studied. In a fabrication stage, neodymium-iron-boron (NdFeB magnets were recycled from electronic wastes, broken and then ball-milled for 1 - 3 h. The NdFeB powder was then incorporated into natural rubber (NR by a 2-roll mill technique. Since the NdFeB powder behaved as a non-reinforced filler, thus, it inhibited cross-linking and stress-induced recrystallization. Therefore, the cure time and the tensile strength of the NdFeB-NR composites were reduced compared to the control sample without magnetic fillers. The addition of NdFeB fillers improved the electrical permittivity of NR and the magnetic moment in NdFeB-NR composites could be measured by a fluxmeter.

  6. 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.

  7. Simple green approach to reinforce natural rubber with bacterial cellulose nanofibers.

    Science.gov (United States)

    Trovatti, Eliane; Carvalho, Antonio J F; Ribeiro, Sidney J L; Gandini, Alessandro

    2013-08-12

    Natural rubber (NR) is a renewable polymer with a wide range of applications, which is constantly tailored, further increasing its utilizations. The tensile strength is one of its most important properties susceptible of being enhanced by the simple incorporation of nanofibers. The preparation and characterization of natural-rubber based nanocomposites reinforced with bacterial cellulose (BC) and bacterial cellulose coated with polystyrene (BCPS), yielded high performance materials. The nanocomposites were prepared by a simple and green process, and characterized by tensile tests, dynamical mechanical analysis (DMA), scanning electron microscopy (SEM), and swelling experiments. The effect of the nanofiber content on morphology, static, and dynamic mechanical properties was also investigated. The results showed an increase in the mechanical properties, such as Young's modulus and tensile strength, even with modest nanofiber loadings. PMID:23782026

  8. 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)

  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. 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...

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

    Energy Technology Data Exchange (ETDEWEB)

    Predeep, P. [Condensed Matter Physics Laboratory, Sree Narayana College, Kollam 691 001, Kerala (India)]. E-mail: predeep@vsnl.com; Najidha, S. [Semiconductor and Polymer Science Laboratory, Department of Physics, University of Rajasthan, Jaipur 302 004 (India); Sreeja, R. [Condensed Matter Physics Laboratory, Sree Narayana College, Kollam 691 001, Kerala (India); Saxena, N.S. [Semiconductor and Polymer Science Laboratory, Department of Physics, University of Rajasthan, Jaipur 302 004 (India)

    2005-12-15

    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{sup +} ions to the fluences of 10{sup 11}-10{sup 15} cm{sup -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. Surface modification of Natural Rubber by ion implantation: Evidence for implant doping

    Science.gov (United States)

    Predeep, P.; Najidha, S.; Sreeja, R.; Saxena, N. S.

    2005-12-01

    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 10 11-10 15 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 & 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.

  14. 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)

  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. 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

  17. 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.

  18. Effect of Silane Treatment on Hybridized Use of Short Cellulose Fibers and Silica Particles for Natural Rubber Reinforcement

    Science.gov (United States)

    Lopattananon, Natinee; Jitkalong, Dolmalik; Seadan, Manus; Sakai, Tadamoto

    Processability, swelling and tensile properties of natural-rubber-based hybrid composites prepared by mixing short cellulose fibers and fine silica particles of equal contents with total loading of 20 phr using a two-roll mill were analyzed. Their properties were compared with those of natural rubber reinforced with single filler (silica or cellulose fiber) and corresponding unfilled natural rubber. The tensile test showed the reinforcing effect of both single filler system and hybrid filler system in relation to natural rubber. The tensile modulus and tensile strength of hybrid composites generally laid between those of fiber-reinforced and silica-reinforced natural rubber composites, whereas the elongation at break of hybrid composites was equal to that of single filler reinforcement system. The Mooney viscosity of silica-filled compound was much higher than that of unfilled natural rubber and short fiber-filled compounds, and was significantly reduced when hybridized fillers were used. Furthermore, a silane coupling agent, Si 69, was used to modify the surface properties of cellulose fibers and silica particles. Three microscopic evaluation techniques, that is, elemental X-ray mapping (EDX), 3D microfocus X-ray scanning, and N-ARC methods were applied to investigate the filler dispersion/mixing effects. It was found that both of the fillers were more homogeneously dispersed in the hybrid composites, and the affinity between the fillers and natural rubber was improved after the silane treatment. The results from this work suggested that the better dispersion of short cellulose fiber/silica hybrid fillers had great advantages in rubber processing, and allowed for equal or higher composite strength compared to a simply silica-filled composite system.

  19. 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.

  20. 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.

  1. 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

    2016-01-01

    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.

  2. 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

  3. 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.  

  4. 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.

  5. 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.

  6. 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

  7. 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)

  8. 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

  9. 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.

  10. 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)

  11. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Kong, Ing, E-mail: kong_ing_2005@yahoo.co [School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor Darul Ehsan (Malaysia); Hj Ahmad, Sahrim; Hj Abdullah, Mustaffa [School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor Darul Ehsan (Malaysia); Hui, David [Department of Mechanical Engineering, University of New Orleans, New Orleans, LA 70148 (United States); Nazlim Yusoff, Ahmad [Diagnostic Imaging and Radiotherapy Programme, Faculty of Allied Health Sciences, Universiti Kebangsaan Malaysia, 50300 Jalan Raja Muda Abdul Aziz, Kuala Lumpur (Malaysia); Puryanti, Dwi [School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor Darul Ehsan (Malaysia)

    2010-11-15

    Magnetic and microwave absorbing properties of thermoplastic natural rubber (TPNR) filled magnetite (Fe{sub 3}O{sub 4}) 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-Fe{sub 3}O{sub 4} nanocomposites with 4-12 wt% Fe{sub 3}O{sub 4} as filler were prepared via a Thermo Haake internal mixer using a melt-blending method. XRD reveals the presence of cubic spinel structure of Fe{sub 3}O{sub 4} with the lattice parameter of a=8.395 A. TEM micrograph shows that the Fe{sub 3}O{sub 4} nanoparticles are almost spherical with the size ranging 20-50 nm. The values of saturation magnetization (M{sub S}), remanence (M{sub R}), initial magnetic susceptibility ({chi}{sub i}) and initial permeability ({mu}{sub i}) increase, while the coercivity (H{sub C}) decreases with increasing filler content for all compositions. For nanocomposites, the values of the real ({epsilon}{sub r}') and imaginary permittivity ({epsilon}{sub r}'') and imaginary permeability ({mu}{sub r}'') increase, while the value of real permeability ({mu}{sub r}') decreases as the filler content increases. The absorption or minimum reflection loss (R{sub L}) 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 R{sub L} is -25.51 dB at 12.65 GHz and the absorbing bandwidth in which the R{sub L} is less than -10 dB is 2.7 GHz when the filler content is 12 wt% at 9 mm sample thickness.

  13. 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)

  14. 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)

  15. 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.

  16. 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.

  17. Influence of the Surfactant Nature on the Occurrence of Self-Assembly between Rubber Particles and Thermally Reduced Graphite Oxide during the Preparation of Natural Rubber Nanocomposites

    Directory of Open Access Journals (Sweden)

    Héctor Aguilar-Bolados

    2015-01-01

    Full Text Available The natural rubber (NR latex consists of polymer particles charged negatively due to the adsorbed phospholipids and proteins molecules. The addition of stable aqueous suspension of thermally reduced graphite oxide (TRGO stabilized by ionic surfactants to NR latex can favor the occurrence of interaction between the stabilized TRGO and NR particles. Herein, the use of two surfactants of different nature, namely, sodium dodecyl sulfate (SDS and dodecyltrimethylammonium bromide (DTAB, for the preparation of (TRGO/NR nanocomposites, is reported. Zeta potential and particle size measurements indicated that the use of DTAB as cationic surfactant results in the flocculation of NR particles and promoted the formation of ion-pair interactions between TRGO and the proteins and/or phospholipids present on the NR surface. This indicates that the use of DTAB can promote a self-assembly phenomenon between TRGO with adsorbed DTAB molecules and NR particles. The occurrence of self-assembly phenomenon allows obtaining homogenous dispersion of TRGO particles in the polymer matrix. The TRGO/NR nanocomposites prepared by the use of DTAB exhibited superior mechanical properties and excellent electrical conductivities reaching values of stress at 500% strain of 3.02 MPa and 10−4 S/cm, respectively.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Keong, C C; Zin, W M Wan; Ibrahim, P; Ibrahim, S, E-mail: chai@nuclearmalaysia.gov.my [Malaysian Nuclear Agency, Bangi, 43000 Kajang, Selangor (Malaysia)

    2010-05-15

    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

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

    Science.gov (United States)

    Keong, C. C.; Zin, W. M. Wan; Ibrahim, P.; Ibrahim, S.

    2010-05-01

    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

  5. 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

  6. Preparation of antibacterial composite material of natural rubber particles coated with silica and titania

    Science.gov (United States)

    Wisutiratanamanee, Apisit; Poompradub, Sirilux; Poochinda, Kunakorn

    2014-06-01

    Silica coating, followed by titania coating, was performed over spray-dried natural rubber (NR) compound for physical and anti-bacterial characterizations. Titania has a strong photo-oxidative catalytic property, which can disinfect bacteria, but may degrade NR. Therefore, silica coating was intended to form a barrier between NR and titania. First, NR particles were prepared by spray-drying of NR compound latex, formulated for household glove products, mixed with sodium dodecyl sulfate (SDS) to reduce particle agglomeration. The factorial experimental design was employed to investigate the effects of nozzle flow rate (500-700 Lh-1), inlet air temperature (110-150 °C), SDS content (35-55 phr) and mass flow rate (1.2-1.7 g rubber/min) on NR yield and moisture content. Then, the NR compound particles prepared at the optimum condition were coated with silica, using tetraethoxysilane (TEOS) as the precursor, by chemical vapor deposition (CVD) at 60 °C for 2-48 hours. Next, the particles were coated with titania using titanium tetrafluoride (TiF4) by liquid phase deposition (LPD) at 60 ºC for 4-8 hours. The NR composites were characterized for surface morphology by SEM, silica and titania content by TGA and EDX. The NR composites were found to cause more than 99% reduction of Escherichia coli and Staphylococcus aureus under 1-hour exposure to natural light.

  7. 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)

  8. Effect of neodymium stearate on cure and mechanical properties of epoxidized natural rubber

    Institute of Scientific and Technical Information of China (English)

    LUO Yongyue; YANG Changjin; WANG Yueqiong; HE Canzhong; ZHONG Jieping; LIAO Shuangquan; PENG Zheng; LIU Xingxun

    2012-01-01

    The effect of neodymium stearate (NdSt) on cure and mechanical properties of expoxidized natural rubber with 25 mol.% epoxidation (ENR25) was studied in the concentration range of 0 to 2 phr,and the relationship between structure and mechanical properties of ENR25 vulcanizates was also discussed.Neodymium sterate was synthesized by saponification of stearic acid with newly formed rare earth hydroxide in water medium,and the structure of NdSt was investigated by Fourier transform infrared spectroscopy (FTIR).Crosslinking density of vulcanized natural rubber was studied by equilibrium swelling method.The results indicated that the interaction force between carboxylic ion of NdSt prepared in the lab and Nd ion was mainly ionic bond through FTIR analysis.NdSt could accelerate the vulcanization of ENR25 and influence the network structure of ENR25 vulcanizates.The incorporation of 1 phr NdSt for ENR25 vulcanizates showed the optimal aging resistance.

  9. 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 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.

  10. 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)

  11. 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

  12. 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.

  13. The effect of remaining SDS on protein release in later leaching steps of deproteinized natural rubber

    Directory of Open Access Journals (Sweden)

    Adisara Yooyanyong

    2016-02-01

    Full Text Available The effect of remaining sodium dodecyl sulfate (SDS used in washing steps on further leaching of proteins from the deproteinized rubber films was investigated. High-Ammonia Natural Rubber Latex (HANRL was diluted with 0.01% w/v potassium hydroxide solution to obtain about 30% dry rubber content (DRC and it is called diluted NRL. The untreated NRL was directly casted to a film (sample 0. Sample 1 was prepared by centrifugation of diluted NRL at 5000 rpm for 1 min. Sample 1-2 was prepared by washing Sample 1 with 0.5%wt SDS solution. Sample 1-3 was prepared by washing Sample 1-2 with 0.1%wt SDS solution. After that they were casted into films. The dried films were checked for the extractable protein (EP content by modified Lowry method and nitrogen content according to SMR: Bulletin No.7-1992. The EP content of Sample 1 film was less than the untreated (Sample 0 one but the EP content was increased after washing with 0.5%wt SDS solution and then dropped slightly after washing again with 0.1%wt SDS solution. In contrast, nitrogen content and FTIR spectra confirmed that the total amount of proteins in films was decreased when they underwent more treating steps. This finding suggested that although overall protein content decreased, the remaining SDS on the films could facilitate further leaching of EP from the film surface when it was in contact with extraction medium (PBS or synthetic sweat under condition with shear force. The use of this deproteinized film should, therefore, be done with care.

  14. 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.

  15. 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.

  16. 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

  17. 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.

  18. 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

  19. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Khalid, M., E-mail: khalids@engineer.co [Nanoscience and Nanotechnology Research Group, International Islamic University Malaysia, P.O. Box 10, 50728 Kuala Lumpur (Malaysia); Ismail, A.F. [Nanoscience and Nanotechnology Research Group, International Islamic University Malaysia, P.O. Box 10, 50728 Kuala Lumpur (Malaysia); Ratnam, C.T., E-mail: chantara@nuclearmalaysia.gov.m [Radiation Processing Technology Division, Malaysian Nuclear Agency, Bangi 43000 Kajang (Malaysia); Faridah, Y.; Rashmi, W.; Al Khatib, M.F. [Nanoscience and Nanotechnology Research Group, International Islamic University Malaysia, P.O. Box 10, 50728 Kuala Lumpur (Malaysia)

    2010-12-15

    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 (M{sub 100}) 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, M{sub 100} 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.

  1. 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.

  2. Particle size and particle-particle interactions on tensile properties and reinforcement of corn flour particles in natural rubber

    Science.gov (United States)

    Renewable corn flour has a significant reinforcement effect in natural rubber. The corn flour was hydrolyzed and microfluidized to reduce its particle size. Greater than 90% of the hydrolyzed corn flour had an average size of ~300 nm, a reduction of 33 times compared to unhydrolyzed corn flour. Comp...

  3. 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.

  4. Morphological Study on Room-Temperature-Cured PMMA-Grafted Natural Rubber-Toughened Epoxy/Layered Silicate Nanocomposite

    Directory of Open Access Journals (Sweden)

    N. Y. Yuhana

    2012-01-01

    Full Text Available A morphological study was conducted on ternary systems containing epoxy, PMMA-grafted natural rubber, and organic chemically modified montmorillonite (Cloisite 30B. Optical microscopy, transmission electron microscopy (TEM, scanning electron microscopy (SEM, energy dispersive X-ray (EDX, and wide-angle X-ray diffraction (WAXD analysis were used. The following four materials were prepared at room temperature: cured unmodified epoxy, cured toughened epoxy, cured unmodified epoxy/Cloisite 30B nanocomposites, and cured toughened epoxy/Cloisite 30B nanocomposites. Mixing process was performed by mechanical stirring. Poly(etheramine was used as the curing agent. The detailed TEM images revealed co-continuous and dispersed spherical rubber in the epoxy-rubber blend, suggesting a new proposed mechanism of phase separation. High-magnification TEM analysis showed good interactions between rubber and Cloisite 30B in the ternary system. Also, it was found that rubber particles could enhance the separation of silicates layers. Both XRD and TEM analyses confirmed that the intercalation of Cloisite 30B was achieved. No distinct exfoliated silicates were observed by TEM. Aggregates of layered silicates (tactoids were observed by SEM and EDX, in addition to TEM at low magnification. EDX analysis confirmed the presence of organic and inorganic elements in the binary and ternary epoxy systems containing Cloisite 30B.

  5. Kenaf Powder Filled Recycled High Density Polyethylene/Natural Rubber Biocomposites: The Effect of Filler Content

    Directory of Open Access Journals (Sweden)

    Xuan Viet Cao

    2012-09-01

    Full Text Available The performance of kenaf powder (KP as filler for recycled high density polyethylene (rHDPE/natural rubber (NR thermoplastic elastomer (TPE composites was investigated. The composites with different filler loading were prepared in a Haake internal mixer. Increasing KP loading in rHDPE/NR/KP biocomposites reduced the tensile strength, elongation at break but increased the stabilization torque and the tensile modulus. SEM study of fracture surface indicated that fibrillation of rHDPE was reduced and detachment of kenaf powder from polymer matrix was present particularly at high filler loading. These observations were responsible for the deterioration of tensile strength and elongation at break of rHDPE/NR/KP biocomposites. Water absorption study also showed that the water absorption of these biocomposites increased with increasing KP content.

  6. 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.

  7. 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.

  8. 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

  9. Suitability of Natural Rubber Latex and Waste Foundry Sand in Cement Concrete

    Directory of Open Access Journals (Sweden)

    Samuel Idiculla Thomas

    2016-06-01

    Full Text Available Suitability of Natural Rubber Latex (NRL as an additive and Waste Foundry Sand (WFS as partial replacement to river sand, in cement concrete was investigated. Experimental study was performed with concrete mixtures containing 1% latex to water ratio, along with 5% and 10% replacement of river sand by WFS. Properties of concrete were studied in both fresh and hardened state. The results of laboratory tests indicate that WFS and NRL reduces the workability of concrete. Slight reduction in splitting tensile strength was observed for mixtures containing NRL and WFS, in comparison to conventional mix. No specific trend was observed for flexural strength at 7 days, but at 28 days the difference was within ±3%, when compared to conventional mix. Strength development for mixtures containing NRL and WFS was slightly lower than conventional mix. The limited results of this study show that concrete containing NRL and WFS do have potential for use as non- structural concrete.

  10. 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.

  11. Effect of bentonite modification on hardness and mechanical properties of natural rubber nanocomposites

    Science.gov (United States)

    Santiago, Denise Ester O.; Pajarito, Bryan B.; Mangaccat, Winna Faye F.; Tigue, Maelyn Rose M.; Tipton, Monica T.

    2016-05-01

    The effect of sodium activation, ion-exchange with tertiary amine salt, surface treatment with non-ionic surfactant, and wet grinding of bentonite on hardness and mechanical properties of natural rubber nanocomposites (NRN) was studied using full factorial design of experiment. Results of X-ray diffraction (XRD) show increase in basal spacing d of bentonite due to modification, while attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) confirm the organic modification of bentonite. Analysis of variance (ANOVA) shows that the main effect of surface treatment increases the hardness and decreases the tensile modulus of the NRN. The surface treatment and wet grinding of bentonite decrease the tensile stresses at 100, 200 and 300% strain of NRN. Sodium activation and ion-exchange negatively affect the compressive properties, while surface treatment significantly improves the compressive properties of NRN.

  12. Mechanical characterization and morphology of polylactic acid /liquid natural rubber filled with multi walled carbon nanotubes

    Science.gov (United States)

    Ali, Adilah Mat; Ahmad, Sahrim Hj.

    2013-11-01

    In this paper the polymer nanocomposite of multi-walled carbon nanotubes (MWCNTs) nanoparticles was incorporated with polylactic acid (PLA) and liquid natural rubber (LNR) as compatibilizer were prepared via melt blending method. The effect of MWCNTs loading on the tensile and impact properties of nanocomposites was investigated. The result has shown that the sample with 3.5 wt % of MWCNTs exhibited higher tensile strength, Young's modulus and impact strength. The elongation at break decreased with increasing percentage of MWCNTs. The SEM micrographs confirmed the effect of good dispersion of MWCNTs and their interfacial bonding in PLA/LNR composites. The improved dispersion of MWCNTs can be obtained due to altered interparticle interactions, MWCNTs-MWCNTs and MWCNTs-matrix networks are well combined to generate the synergistic effect of the system as shown by SEM micrographs which is improved the properties significantly.

  13. 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.

  14. 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...

  15. 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)

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

    Energy Technology Data Exchange (ETDEWEB)

    Poompradub, Sirilux, E-mail: sirilux.p@chula.ac.th [Department of Chemical Technology, Faculty of Science, Chulalongkorn University, 254 Phayathai Road, Bangkok 10330 (Thailand); Thirakulrati, Mantana [Program in Petrochemistry and Polymer Science, Faculty of Science, Chulalongkorn University, 254 Phayathai Road, Bangkok 10330 (Thailand); Prasassarakich, Pattarapan [Department of Chemical Technology, Faculty of Science, Chulalongkorn University, 254 Phayathai Road, Bangkok 10330 (Thailand)

    2014-03-01

    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.

  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. 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

  19. 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.

  20. Mechanical Properties and Morphological Characterization of PLA/Chitosan/Epoxidized Natural Rubber Composites

    Directory of Open Access Journals (Sweden)

    Zainoha Zakaria

    2013-01-01

    Full Text Available Poly (lactic acid (PLA/chitosan (CS natural polymer/epoxidised natural rubber (ENR composites were successfully prepared through a solution casting method. The morphological characteristics of fabricated composites were investigated by scanning electron microscopy (SEM and optical microscopy. The microstructure of PLA/ENR was significantly altered with the addition of CS. SEM analysis of composites fractured surfaces revealed smooth and homogeneous texture and good dispersion of CS. However for 15 wt% CS composites, the phase segregation and poor adhesion between the polymers were observed. Fourier transform infrared spectroscopy revealed some levels of attractive interaction between CS, PLA, and ENR in the composites. The mechanical properties of composites in terms of tensile strength and tensile modulus were significantly improved with the addition of CS into the matrix while the percent elongation at break decreased. The tensile strength increased up to 5 wt% CS loading for both PLA/CS and PLA/ENR/CS and thereafter decreased while Young’s modulus increased up to 10 wt%. However, when the CS content was increased to 15 wt%, the tensile strength and tensile modulus were slightly decreased. These improvements were attributed to good dispersion of CS at the optimum filler levels and attractive interaction between the composites components.

  1. 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.

  2. 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.

  3. Research progress of the modification of natural rubber latex%天然胶乳改性研究进展

    Institute of Scientific and Technical Information of China (English)

    刘东辉; 徐亚丽; 孟丽丰

    2012-01-01

    介绍了天然胶乳的特点,综述了天然胶乳填料改性(纳米粒子改性和非纳米粒子改性)及化学改性(氯化、环化、环氧化、接枝聚合)的研究进展,分析了目前天然胶乳改性存在的问题,并展望了未来的发展趋势.%The characteristics of natural rubber latex had been introduced. The research progress of modification on the natural rubber latex was reviewed. Filler modification (including nano-particles and other particles) and chemical modification (including chlorination, cyclization, epoxidation, graft polymerization) were all studied. The main problems that existed at present were analyzed,and finally the future research trend was prospected.

  4. 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.

  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. 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.

  8. 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.

  9. 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.

  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. Natural rubber latex used as drug delivery system in guided bone regeneration (GBR

    Directory of Open Access Journals (Sweden)

    Rondinelli Donizetti Herculano

    2009-06-01

    Full Text Available In this work, we propose natural rubber latex (NRL membranes as a protein delivery system. For this purpose Bovine Serum Albumin (BSA was incorporated into the latex solution for in vitro protein delivery experiments. Different polymerization temperatures were used, from -10 to 27 °C, in order to control the membrane morphology. These membranes were characterized by Scanning Electron Microscopy (SEM, Atomic Force Microscopy (AFM, as well as the Lowry Method to measure the BSA release. SEM and AFM microscopy analysis showed that the number, size and distribution of pores in NRL membranes can be varied, as well as its overall morphology. We have found that the morphology of the membrane is the predominant factor for higher protein release, compared with pore size and number of pores. Results demonstrated that the best drug-delivery system was the membrane polymerized at RT (27 °C, which does release 66% of its BSA content for up to 18 days. Our results indicate that NRLb could be used in the future as an active membrane that could accelerate bone healing in GBR.

  12. Preparation and structural characterization of vulcanized natural rubber nanocomposites containing nickel-zinc ferrite nanopowders.

    Science.gov (United States)

    Bellucci, F S; Salmazo, L O; Budemberg, E R; da Silva, M R; Rodríguez-Pérez, M A; Nobre, M A L; Job, A E

    2012-03-01

    Single-phase polycrystalline mixed nickel-zinc ferrites belonging to Ni0.5Zn0.5Fe2O4 were prepared on a nanometric scale (mean crystallite size equal to 14.7 nm) by chemical synthesis named the modified poliol method. Ferrite nanopowder was then incorporated into a natural rubber matrix producing nanocomposites. The samples were investigated by means of infrared spectroscopy, X-ray diffraction, scanning electron microscopy and magnetic measurements. The obtained results suggest that the base concentration of nickel-zinc ferrite nanoparticles inside the polymer matrix volume greatly influences the magnetic properties of nanocomposites. A small quantity of nanoparticles, less than 10 phr, in the nanocomposite is sufficient to produce a small alteration in the semi-crystallinity of nanocomposites observed by X-ray diffraction analysis and it produces a flexible magnetic composite material with a saturation magnetization, a coercivity field and an initial magnetic permeability equal to 3.08 emu/g, 99.22 Oe and 9.42 x 10(-5) respectively. PMID:22755110

  13. Preparation and characterization of potato starch nanocrystal reinforced natural rubber nanocomposites.

    Science.gov (United States)

    Rajisha, K R; Maria, H J; Pothan, L A; Ahmad, Zakiah; Thomas, S

    2014-06-01

    Potato starch nanocrystals were found to serve as an effective reinforcing agent for natural rubber (NR). Starch nanocrystals were obtained by the sulfuric acid hydrolysis of potato starch granules. After mixing the latex and the starch nanocrystals, the resulting aqueous suspension was cast into film by solvent evaporation method. The composite samples were successfully prepared by varying filler loadings, using a colloidal suspension of starch nanocrystals and NR latex. The morphology of the nanocomposite prepared was analyzed by field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). FESEM analysis revealed the size and shape of the crystal and their homogeneous dispersion in the composites. The crystallinity of the nanocomposites was studied using XRD analysis which indicated an overall increase in crystallinity with filler content. The mechanical properties of the nanocomposites such as stress-strain behavior, tensile strength, tensile modulus and elongation at break were measured according to ASTM standards. The tensile strength and modulus of the composites were found to improve tremendously with increasing nanocrystal content. This dramatic increase observed can be attributed to the formation of starch nanocrystal network. This network immobilizes the polymer chains leading to an increase in the modulus and other mechanical properties. PMID:24657376

  14. Remarkable reinforcement of natural rubber by deformation-induced crystallization in the presence of organophilic montmorillonite

    Energy Technology Data Exchange (ETDEWEB)

    Qu Liangliang [College of Polymer Science and Engineering, State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu 610065 (China); Huang Guangsu, E-mail: guangsu-huang@hotmail.com [College of Polymer Science and Engineering, State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu 610065 (China); Liu Zhiyuan; Zhang Peng; Weng Gengsheng; Nie Yijing [College of Polymer Science and Engineering, State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu 610065 (China)

    2009-10-15

    A remarkable reinforcement of natural rubber (NR) was achieved by adding a low content of organically modified montmorillonite (OMMT). Mechanical tests demonstrated that the most noticeable enhancement in the tensile strength of NR was at a OMMT content of 5 wt.%. In order to gain further insight into the mechanism of reinforcement by OMMT, the deformation-induced crystallization behavior and morphology of NR/OMMT nanocomposites with different OMMT contents were investigated by synchrotron wide angle X-ray diffraction and transmission electron microscopy. The results show that the variation in the degree of strain-induced crystallization is consistent with that of tensile strength. The peak in tensile strength at 5 wt.% OMMT content can be ascribed to the fact that strain-induced crystallization is the essential factor in reinforcement of NR. Further, the nanomorphology of OMMT dispersed in a NR matrix plays a decisive role in the crystallization behavior of NR during deformation. An increase in the exfoliation of OMMT leads to an increase in the promotion of deformation-induced crystallization of NR.

  15. Enhanced dispersion of multiwall carbon nanotubes in natural rubber latex nanocomposites by surfactants bearing phenyl groups.

    Science.gov (United States)

    Mohamed, Azmi; Anas, Argo Khoirul; Bakar, Suriani Abu; Ardyani, Tretya; Zin, Wan Manshol W; Ibrahim, Sofian; Sagisaka, Masanobu; Brown, Paul; Eastoe, Julian

    2015-10-01

    Here is presented a systematic study of the dispersibility of multiwall carbon nanotubes (MWCNTs) in natural rubber latex (NR-latex) assisted by a series of single-, double-, and triple-sulfosuccinate anionic surfactants containing phenyl ring moieties. Optical polarising microscopy, field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and Raman spectroscopy have been performed to obtain the dispersion-level profiles of the MWCNTs in the nanocomposites. Interestingly, a triple-chain, phenyl-containing surfactant, namely sodium 1,5-dioxo-1,5-bis(3-phenylpropoxy)-3-((3-phenylpropoxy)carbonyl) pentane-2-sulfonate (TCPh), has a greater capacity the stabilisation of MWCNTs than a commercially available single-chain sodium dodecylbenzenesulfonate (SDBS) surfactant. TCPh provides significant enhancements in the electrical conductivity of nanocomposites, up to ∼10(-2) S cm(-1), as measured by a four-point probe instrument. These results have allowed compilation of a road map for the design of surfactant architectures capable of providing the homogeneous dispersion of MWCNTs required for the next generation of polymer-carbon-nanotube materials, specifically those used in aerospace technology. PMID:26070188

  16. 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.

  17. Reinforcement of Natural Rubber with Core-Shell Structure Silica-Poly(Methyl Methacrylate Nanoparticles

    Directory of Open Access Journals (Sweden)

    Qinghuang Wang

    2012-01-01

    Full Text Available A highly performing natural rubber/silica (NR/SiO2 nanocomposite with a SiO2 loading of 2 wt% was prepared by combining similar dissolve mutually theory with latex compounding techniques. Before polymerization, double bonds were introduced onto the surface of the SiO2 particles with the silane-coupling agent. The core-shell structure silica-poly(methyl methacrylate, SiO2-PMMA, nanoparticles were formed by grafting polymerization of MMA on the surface of the modified SiO2 particles via in situ emulsion, and then NR/SiO2 nanocomposite was prepared by blending SiO2-PMMA and PMMA-modified NR (NR-PMMA. The Fourier transform infrared spectroscopy results show that PMMA has been successfully introduced onto the surface of SiO2, which can be well dispersed in NR matrix and present good interfacial adhesion with NR phase. Compared with those of pure NR, the thermal resistance and tensile properties of NR/SiO2 nanocomposite are significantly improved.

  18. Radiation vulcanization of natural rubber latex (part 6). Improvement of aging propreties of latex lubber vulcanized with radiation

    Energy Technology Data Exchange (ETDEWEB)

    Makuuchi, Keizo; Tsushima, Kyogo

    1988-10-15

    Concerning the vulcanization of natural rubber latex with radiation by using acrylic ester as accelerator, causes for loss of anti-aging property by leaching and counter-measure against it were reported. For the experiment, 2-ethyl hexyl acrylate with carbon tetra-chloride as accelerator, 2% aqueous solution of ammonia or acetic acid as leaching water, were used. For the analysis of extracts, ultra-violet absorption and gas chromatography were applied. As the result of the experiment, it was recognized that anti-aging property was more decreased by more increased quantity of extracted protein which was naturally contained in the natural rubber latex and functioned as anti-aging material, and that by radiation vulcanization, non-rubber components were destroyed to result the increased quantity of extracts compared with that of non-vulcanized. Concerning the improvement of anti-aging property, experimental comparison of miscellaneous methods resulted that the addition of sodium di-n-buthyl di-thiocarbamate was most effective. 3 references, 3 figures, 5 tables.

  19. Supply Security of Natural Rubber Industry%天然橡胶产业供给安全研究

    Institute of Scientific and Technical Information of China (English)

    江军; 方佳

    2011-01-01

    以环境要求相类似的橡胶、木薯、甘蔗、油棕为例,在探讨以上作物环境适应性和产量变化的基础上,对世界各主要产胶国的种植选择做出总结,提出中国天然橡胶产业供给安全对策,包括从政策上加大对小胶园的改造管理与扶持力度,进一步加大力度实施天然橡胶良种补贴,对天然橡胶实行指导价收购政策,建立胶农合作社,加强天然橡胶种植区域的基础设施建设等。%A case study about tropical energy crops with similar environment adaptability to natural rubber,like cassava,sugar cane and oil palm.Based on environment adaptability and production history research,then made summaries towards cultivation choice for the main natural rubber production countries world,and finally supply security policies of natural rubber industry in China were put forward,include support to small farm from policy level,allowance to improved variety,purchasing at threshold price,establishment of farmers co-op and construction of infrastructure.

  20. 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

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

    Energy Technology Data Exchange (ETDEWEB)

    Nuntang, Sakdinun; Poompradub, Sirilux [Fuels Research Center, Department of Chemical Technology, Faculty of Science, Chulalongkorn University, Patumwan, Bangkok 10330 (Thailand); Butnark, Suchada [PTT Research and Technology Institute, PTT Public Company Limited, Wangnoi, Ayutthaya 13170 (Thailand); Yokoi, Toshiyuki; Tatsumi, Takashi [Division of Catalytic Chemistry, Chemical Resources Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503 (Japan); Ngamcharussrivichai, Chawalit, E-mail: Chawalit.Ng@Chula.ac.th [Fuels Research Center, Department of Chemical Technology, Faculty of Science, Chulalongkorn University, Patumwan, Bangkok 10330 (Thailand); Center of Excellence on Petrochemical and Materials Technology (PETROMAT), Chulalongkorn University, Patumwan, Bangkok 10330 (Thailand)

    2014-02-14

    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 {sup 29}Si magic angle spinning nuclear magnetic resonance ({sup 29}Si 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 N{sub 2} 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 H{sub 2}O 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.

  2. 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)

  3. 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].

  4. Effects of partial replacement of rattan powder by commercial fillers on the properties of natural rubber composites

    Directory of Open Access Journals (Sweden)

    Nadras Othman

    2012-11-01

    Full Text Available The effects of partial replacement of rattan powder (RP by carbon black (CB, mica, and calcium carbonate (CaCO3 on the curing characteristics, tensile properties, rubber-filler interaction, and morphological studies of natural rubber (NR composites were investigated. Rattan powder with an average particle size of less than 180 µm was used in this study. NR/RP/CB, NR/RP/mica, and NR/RP/CaCO3 composites with five different RP/commercial fillers loadings (i.e. 30/0, 20/10, 15/15, 10/20, 0/30 phr were prepared using a laboratory size two-roll mill. Results showed that the maximum torque (MH of the NR/RP/CB, NR/RP/mica, and NR/RP/CaCO3 composites increased with increasing the commercial filler-loading ratio. The scorch time (ts2 and cure time (t90 of NR/RP/CB composites decreased as the ratio of CB loading was increased, whereas, ts2 and t90 of NR/RP/mica and NR/RP/CaCO3 composites increased as mica and CaCO3 loading ratio were raised, respectively. The tensile strength, elongation at break (Eb, stress at 100% elongation (M100, and stress at 300% elongation (M300 of all the composites increased as the commercial filler-loading ratio increased. This is due to the presence of the commercial filler, which brought a better rubber-filler interaction, as confirmed by the rubber-filler interaction and scanning electron microscopy (SEM studies.

  5. 75 FR 7586 - Baled Natural Rubber in Tires; TSCA Section 21 Petition; Agency Response

    Science.gov (United States)

    2010-02-22

    .... Allergens in Paved Road Dust and Airborne Particles. Environmental Science Technology. 1999. 33:4159-4168... manufacture of tires, wherein said rubber fails to satisfy The American Society for Testing Materials method... Society for Testing Materials method ASTM D1076-06 (Category 5),'' because ``Implementation of an...

  6. 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

  7. 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...

  8. 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.

  9. 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...

  10. 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...

  11. Organosulfonic acid-functionalized mesoporous composites based on natural rubber and hexagonal mesoporous silica

    Energy Technology Data Exchange (ETDEWEB)

    Nuntang, Sakdinun; Poompradub, Sirilux [Fuels Research Center, Department of Chemical Technology, Faculty of Science, Chulalongkorn University, Patumwan, Bangkok 10330 (Thailand); Butnark, Suchada [PTT Research and Technology Institute, PTT Public Company Limited, Wangnoi, Ayutthaya 13170 (Thailand); Yokoi, Toshiyuki; Tatsumi, Takashi [Chemical Resources Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503 (Japan); Ngamcharussrivichai, Chawalit, E-mail: Chawalit.Ng@Chula.ac.th [Fuels Research Center, Department of Chemical Technology, Faculty of Science, Chulalongkorn University, Patumwan, Bangkok 10330 (Thailand); Center of Excellence on Petrochemical and Materials Technology (PETROMAT), Chulalongkorn University, Patumwan, Bangkok 10330 (Thailand)

    2014-10-15

    This study is the first report on synthesis, characterization and catalytic application of propylsulfonic acid-functionalized mesoporous composites based on natural rubber (NR) and hexagonal mesoporous silica (HMS). In comparison with propylsulfonic acid-functionalized HMS (HMS-SO{sub 3}H), a series of NR/HMS-SO{sub 3}H composites were prepared via an in situ sol–gel process using tetrahydrofuran as the synthesis media. Tetraethylorthosilicate as the silica source, was simultaneously condensed with 3-mercaptopropyltrimethoxysilane in a solution of NR followed by oxidation with hydrogen peroxide to achieve the mesoporous composites containing propylsulfonic acid groups. Fourier-transform infrared spectroscopy and {sup 29}Si MAS nuclear magnetic resonance spectroscopy results verified that the silica surfaces of the NR/HMS-SO{sub 3}H composites were functionalized with propylsulfonic acid groups and covered with NR molecules. After the incorporation of NR and organo-functional group into HMS, the hexagonal mesostructure remained intact concomitantly with an increased framework wall thickness and unit cell size, as evidenced by the X-ray powder diffraction analysis. Scanning electron microscopy analysis indicated a high interparticle porosity of NR/HMS-SO{sub 3}H composites. The textural properties of NR/HMS-SO{sub 3}H were affected by the amount of MPTMS loading to a smaller extent than that of HMS-SO{sub 3}H. NR/HMS-SO{sub 3}H exhibited higher hydrophobicity than HMS-SO{sub 3}H, as revealed by H{sub 2}O adsorption–desorption measurements. Moreover, the NR/HMS-SO{sub 3}H catalysts possessed a superior specific activity to HMS-SO{sub 3}H in the esterification of lauric acid with ethanol, resulting in a higher conversion level. - Highlights: • Acidic NR/HMS-SO{sub 3}H composites were prepared by in situ sol–gel process. • Propylsulfonic acid was functionalized onto HMS surface by direct co-condensation. • NR/HMS-SO{sub 3}H exhibited a hexagonal

  12. 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...

  13. 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 ...

  14. 微生物凝固天然橡胶的性能%Properties of Natural Rubber Coagulated by Microorganisms

    Institute of Scientific and Technical Information of China (English)

    李新红; 廖双泉; 肖迪娥; 廖小雪; 李思东; 黄俊良; 滕飞

    2012-01-01

    One kind of microorganisms what selected from rubber latex was applied to prepare natural rubber coagulated by microorganisms(NR-m).The physical and chemical properties,thermooxidative degradation properties,curing characteristics and mechanical properties of NR-m were investigated comprehensively,which compared with acid coagulated natural rubber(NR-a).The results show that the plasticity before aging,ash content and number average molecular weight of NR-m is high and the molecular weight distribution is narrow,while the content of volatile matter,impurity and nitrogen,and plasticity retention index is low.The maximum torque(MH) of mixed NR-m and curing rate index is higher,t10 and t90 is shorter than that of NR-a.As to the cured rubber,the mechanical properties of cured NR-m is stronger than that of cured NR-a before aging,but it changes greatly after aging.The thermooxidative degradation of NR can be divided into two stages,the characteristic temperatures of NR-m are lower than NR-a at each stage.%采用从胶乳中分离、筛选出来的菌种凝固天然胶乳,制备微生物凝固天然橡胶(NR-m)。研究了NR-m的理化性能、热氧降解性能、硫化特性和硫化胶力学性能,并与酸凝固天然橡胶(NR-a)进行了对比。结果表明:与NR-a相比,NR-m的P0和灰分含量高,而挥发物含量、杂质含量、PRI、氮含量低,数均分子量(Mn)大,分子量分布(MWD)窄;混炼胶的最大扭矩值(MH)高,t10和t90短,硫化速率指数(Vc)大;硫化胶力学性能好,老化前、后性能变化较大;NR热氧降解可分为两个阶段,NR-m热氧降解的特征温度T0、TP和Tf均比NR-a低。

  15. 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.

  16. 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

  17. Studies on the Biological Coagulation Technology of Fresh Natural Rubber Latex%鲜胶乳生物凝固工艺技术研究

    Institute of Scientific and Technical Information of China (English)

    姜士宽; 邹建云; 张桂梅; 徐荣; 郭刚军; 黄克昌

    2011-01-01

    研究了生物凝固液用量、鲜胶乳浓度、气候条件、氨含量等因素对鲜胶乳生物凝固效果的影响。结果表明:凝固剂适宜用量为10%;鲜胶乳浓度对凝固影响较小;当全天最高气温在25DC以下时,胶乳完全凝固需16h以上;氨含量达0.02%时即可显著影响胶乳的凝固,用量达到0.08%时。胶乳不能凝固;添加辅助凝固剂可加快胶乳的凝固。%The effects of dosage of bio-coagulation liquid, concentration of natural rubber latex, climate condition and content of ammonia on the speed of bio-coagulation of fresh natural rubber latex were studied. The results showed that the suitable dosage of bio-coagulation liquid was 10% and the influence of content concentration of natural rubber latex on the speed of bio-coagulation was less. It needs more than 16h for natural rubber latex coagulation completely when the temperature was lower than 25 ℃, the content of ammonia had significant effect on bio-coagulation of fresh natural rubber latex and the latex can't coagulation when reached 0.8%and booster can increase the speed of bio-coagulation of fresh natural rubber latex.

  18. Research Advances in Coagulation Methods of Natural Rubber Latex%天然胶乳凝固方法的研究进展

    Institute of Scientific and Technical Information of China (English)

    邱于献; 廖双泉; 何映平

    2012-01-01

    对多年来天然胶乳凝固方法及其研究进展进行综述并作比较分析,指出盐凝固将有望取代目前常用的酸凝固,满足制胶工业规模化生产。%The coagulation methods for natural rubber latex and their research advances in recent years are reviewed.In addition,the differences among the coagulation methods are analyzed,indicating that salted solidification is expected to replace acid solidification to satisfy the large scale production of nature rubber.

  19. 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)

  20. Characterisation of macrogel composition from industrial natural rubber samples: Influence of proteins on the macrogel crosslink density

    Directory of Open Access Journals (Sweden)

    S. Rolere

    2016-05-01

    Full Text Available The insoluble (macrogel and soluble fractions of 11 commercial natural rubber (NR samples (Technically specified rubber were separated. Nitrogen titrations and lipid extractions enabled a quantitative assessment of the proteins and extractable lipids in each fraction. Swelling was measured in tetrahydrofuran in order to evaluate the crosslink density (Mc–1 of each macrogel. While the soluble fraction had a high lipid concentration, the majority of non-isoprene compounds of the macrogel were found to be proteins, which accounted for 4.6 to 50.8% (w/w of the macrogel. Indeed, the macrogels contained less than 0.5% (w/w extractable lipids. However, our results showed that the soluble fraction contained large quantities of proteins (16–66% of the nitrogen content of the raw NR sample, probably structuring microaggregates. An exponential correlation (R2 > 0.96 was found between the crosslink density and the protein concentration of macrogel, suggesting that proteins are involved in the majority of crosslinks in macrogel.

  1. Mechanical Enhancement of Sensitivity in Natural Rubber Using Electrolytic Polymerization Aided by a Magnetic Field and MCF for Application in Haptic Sensors

    Directory of Open Access Journals (Sweden)

    Kunio Shimada

    2016-09-01

    Full Text Available Sensors are essential to the fulfillment of every condition of haptic technology, and they need simultaneously to sense shear stress as well as normal force, and temperature. They also must have a strong and simple structure, softness, and large extension. To achieve these conditions simultaneously, we enhanced the sensitivity of sensors utilizing natural rubber (NR-latex through the application of electrolytic polymerization focused on the isoprene C=C bonds in natural rubbers such as NR-latex, and then applied a magnetic field and magnetic compound fluid (MCF as magnetically responsive fluid. When an electric field alone was used in the rubber, the effect of electrolytic polymerization was very small compared to the effect in well-known conductive polymer solution such as plastic. The MCF developed by Shimada in 2001 involved magnetite and metal particles, and acts as a filler in NR-latex. By utilizing the magnetic, electric fields and the MCF, we aligned the electrolytically polymerized C=C along the magnetic field line with the magnetic clusters formed by the aggregation of magnetite and metal particles so as to enhance the effect of electrolytic polymerization. We then demonstrated the effectiveness of the new method of rubber vulcanization on the sensitivity of the rubber by experimentally investigating its electric and dynamic characteristics.

  2. 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%.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-06-15

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

  4. Utilization of sludge waste from natural rubber manufacturing process as a raw material for clay-ceramic production.

    Science.gov (United States)

    Vichaphund, S; Intiya, W; Kongkaew, A; Loykulnant, S; Thavorniti, P

    2012-12-01

    The possibility of utilization of the sludge waste obtained from the natural rubber manufacturing process as a raw material for producing clay ceramics was investigated. To prepared clay-based ceramic, the mixtures of traditional clay and sludge waste (10-30 wt%) were milled, uniaxilly pressed and sintered at a temperature between 1000 and 1200 degrees C. The effect of sludge waste on the properties of clay-based ceramic products was examined. The results showed that the amount of sludge waste addition had an effect on both sinterability and properties of the clay ceramics. Up to 30 wt% of sludge waste can be added into the clay ceramics, and the sintered samples showed good properties. PMID:23437647

  5. 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.

  6. Mechanical properties of natural rubber nanocomposites reinforced with high aspect ratio cellulose nanocrystals isolated from soy hulls.

    Science.gov (United States)

    Flauzino Neto, Wilson Pires; Mariano, Marcos; da Silva, Ingrid Souza Vieira; Silvério, Hudson Alves; Putaux, Jean-Luc; Otaguro, Harumi; Pasquini, Daniel; Dufresne, Alain

    2016-11-20

    Cellulose nanocrystals (CNCs) were isolated from soy hulls by acid sulfuric hydrolysis. The resulting CNCs were characterized using TEM, AFM, WAXS, elemental analysis and TGA. The CNCs have a high crystallinity, specific surface area and aspect ratio. The aspect ratio (around 100) is the largest ever reported in the literature for a plant cellulose source. These CNCs were used as a reinforcing phase to prepare nanocomposite films by casting/evaporation using natural rubber as matrix. The mechanical properties were studied in both the linear and non-linear ranges. The reinforcing effect was higher than the one observed for CNCs extracted from other sources. It may be assigned not only to the high aspect ratio of these CNCs but also to the stiffness of the percolating nanoparticle network formed within the polymer matrix. Moreover, the sedimentation of CNCs during the evaporation step was found to play a crucial role on the mechanical properties. PMID:27561481

  7. 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.

  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. 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.

  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 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…

  12. Análise econométrica da demanda brasileira de importação de borracha natural, de 1964 a 2005 Econometric analysis of Brazilian import demand for natural rubber during 1964-2005

    Directory of Open Access Journals (Sweden)

    Naisy Silva Soares

    2008-12-01

    Full Text Available Este trabalho teve por objetivos especificar e estimar a demanda brasileira de importação de borracha natural, no período de 1964 a 2005. As variáveis explicativas do modelo de demanda de importação foram: preço de importação da borracha natural, PIB per capita, taxa de câmbio, taxa de juros, quantidade de borracha natural produzida internamente e tendência. As estimativas obtidas utilizando o modelo de ajustamento parcial confirmaram que as variáveis explicativas afetam, significativamente, a demanda brasileira de importação de borracha natural. Os resultados apontaram que a demanda brasileira de importação de borracha natural é inelástica com relação ao preço de importação e à renda; é pouco sensível a variações no preço de importação, à taxa de câmbio, à renda e à taxa de juros, mas é sensível às variações na quantidade de borracha natural produzida internamente, no curto e longo prazos; e a borracha natural é um bem normal.This work aimed to specify and estimate the Brazilian import demand for natural rubber from 1964 to 2005. The variables applied to explain import demand were: natural rubber import price, GNP per capita, exchange nominal rate (R$/US$, "overnight" interest rate, natural rubber domestic production and trend. The estimates showed that the variables significantly affected the Brazilian import demand for natural rubber. The results indicated that the Brazilian import demand for natural rubber is inelastic in relation to import price and income; little sensitive to variations in import price, exchange nominal rate (R$/US$, income and "overnight" interest rate but it is sensitive to domestic rubber production variations , in the short and long runs; and that natural rubber is a regular commodity.

  13. Polyacrylamido-2-methyl-1-propane sulfonic acid-grafted-natural rubber as bio-adsorbent for heavy metal removal from aqueous standard solution and industrial wastewater.

    Science.gov (United States)

    Phetphaisit, Chor Wayakron; Yuanyang, Siriwan; Chaiyasith, Wipharat Chuachuad

    2016-01-15

    Bio-adsorbent modified natural rubber (modified NR) was prepared, by placing the sulfonic acid functional group on the isoprene chain. This modification was carried out with the aim to prepare material capable to remove heavy metals from aqueous solution. The structures of modified NR materials were characterized by FT-IR and NMR spectroscopies. Thermal gravimetric analysis of modified NR showed that the initial degradation temperature of rubber decreases with increasing amount of polyacrylamido-2-methyl-1-propane sulfonic acid (PAMPS) in the structure. In addition, water uptake of the rubber based materials was studied as a function of time and content of PAMPS. The influence of the amount of PAMPS grafted onto NR, time, pH, concentration of metal ions, temperature, and regeneration were studied in terms of their influence on the adsorption of heavy metals (Pb(2+), Cd(2+) and Cu(2+)). The adsorption isotherms of Pb(2+) and Cd(2+) were fitted to the Freundlich isotherm model, while Cu(2+) was fitted to the Langmuir isotherm. However, the results from these two isotherms resulted in a similar behavior. The adsorption capacity of the modified NR for the various heavy metals was in the following order: Pb(2+)∼Cd(2+)>Cu(2+). The maximum adsorption capacities of Pb(2+), Cd(2+), and Cu(2+) were 272.7, 267.2, and 89.7 mg/g of modified rubber, respectively. Moreover, the modified natural rubber was used for the removal of metal ions in real samples of industrial effluents where the efficiency and regeneration were also investigated.

  14. 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.

  15. Advances in rubber/halloysite nanotubes nanocomposites.

    Science.gov (United States)

    Jia, Zhixin; Guo, Baochun; Jia, Demin

    2014-02-01

    The research advances in rubber/halloysite nanotubes (rubber/HNTs) nanocomposites are reviewed. HNTs are environmentally-friendly natural nanomaterials, which could be used to prepare the rubber-based nanocomposites with high performance and low cost. Unmodified HNTs could be adopted to prepare the rubber/HNTs composites with improved mechanical properties, however, the rubber/HNTs nanocomposites with fine morphology and excellent properties were chiefly prepared with various modifiers by in situ mixing method. A series of rubber/HNTs nanocomposites containing several rubbers (SBR, NR, xSBR, NBR, PU) and different modifiers (ENR, RH, Si69, SA, MAA, ILs) have been investigated. The results showed that all the rubber/HNTs nanocomposites achieved strong interfacial interaction via interfacial covalent bonds, hydrogen bonds or multiple interactions, realized significantly improved dispersion of HNTs at nanoscale and exhibited excellent mechanical performances and other properties. PMID:24749454

  16. 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.

  17. 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.

  18. 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

  19. Polymer blends made of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) and epoxidized natural rubber: Thermal and mechanical response

    Science.gov (United States)

    Salim, Yoga Sugama; Han, Chan Chin; Kammer, Hans-Werner; Kumar, Sudesh; Neon, Gan Seng

    2015-08-01

    The ever-increasing demand of biodegradable over conventional polymers places microbial polyhydroxyalkanoates (PHA) as an ideal choice of research material for specific applications. In this study, polymer blends made of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) [P(3HB-co-3HHx) and epoxidized natural rubber (ENR) were prepared using solution casting technique. The influence of ENR on thermal, morphological and mechanical properties of P(3HB-co-3HHx) was investigated. There are two glass transition (Tg) temperatures observed using differential scanning calorimeter. This indicates that P(3HB-co-3HHx) and ENR are immiscible at macroscopic level. Although the Tg of P(3HB-co-3HHx) is seen to shift toward ENR in the least manner, infrared analysis suggests that the crystal structure of P(3HB-co-3HHx) retains its conformational structure. In terms of morphology, ENR exists as droplets in P(3HB-co-3HHx)-rich phase, e.g. at ENR weight fraction (wENR) of 0.3. In dynamic mechanical analysis, all blend compositions exhibit solid-like behavior, with storage moduli larger than loss moduli, across the frequency sweep at room temperature.

  20. 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.

  1. Properties of natural rubber coagulated by microwave radiation%微波辐射凝固天然橡胶的性能研究

    Institute of Scientific and Technical Information of China (English)

    李一民; 廖建和; 赵艳芳; 廖禄生; 黄桂春; 陈桂雄

    2011-01-01

    A new coagulation method,that is microwave radiation coagulation ( MRC ), and traditional coagulation methods were used to coagulate natural rubber and then compared properties of the rubbers. Suitable laboratory microwave coagulation conditions were explored by orthogonal test. Microwave radiation coagulation natural rubber (NR - m) , acid coagulation natural rubber (NR - a) and natural coagulation natural rubber (NR- n)were prepared and their properties were studied, the results showed that,as to the physical and chemical properties,nitrogen content of NR- m are much higher than NR - a and NR - n, initial plasticity of NR - m is higher than NR - a. As to physical and mechanical properties, stretching stress and tensile strength of NR - m are higher than NR - a before aging, while tensile strength retention after aging of NR- m is lower than NR- a,but relatively higher than NR ~ n. As to the curing behaviors, vulcanization induction time of NR - m is shorter than either NR -a and NR - n, while maximum torque and curing rate are much higher.%采用新型微波辐射凝固法凝固天然橡胶,并与传统天然橡胶凝固方法作比较,对其性能进行了全面研究.通过正交实验探索了实验室微波辐射凝固的适宜工艺条件.对比了微波辐射凝固胶(NR - m)、酸凝固胶(NR-a)和自然凝固胶(NR -n)的性能,结果表明,在理化性能方面,NR-m的氮含量比NR-a和NR-n高,塑性初值比NR-a高;在物理机械性能方面,NR -m硫化胶老化前的定伸应力和拉伸强度比NR-a高,老化后的拉伸强度保持率比NR-a低,但比NR-n高;在硫化特性方面,NR -m的硫化诱导时间比NR-a和NR-n的短,最大转矩和硫化速度更高.

  2. Fabrication and investigation on field-dependent properties of natural rubber based magneto-rheological elastomer isolator

    Science.gov (United States)

    Ain Abd Wahab, Nurul; Amri Mazlan, Saiful; Ubaidillah; Kamaruddin, Shamsul; Intan Nik Ismail, Nik; Choi, Seung-Bok; Haziq Rostam Sharif, Amirul

    2016-10-01

    This study presents a laminated magnetorheological elastomer (MRE) isolator which applies to vibration control in practice. The proposed isolator is fabricated with multilayer MRE sheets associated with the natural rubber (NR) as a matrix, and steel plates. The fabricated MRE isolator is then magnetically analysed to achieve high magnetic field intensity which can produce high damping force required for effective vibration control. Subsequently, the NR-based MRE specimen is tested to identify the field-dependent rheological properties such as storage modulus with 60 weight percentage of carbonyl iron particles. It is shown from this test that the MR effect of MRE specimen is quantified to reach up to 120% at 0.8 T. Following the design stage, the electromagnetic simulation using the finite element method magnetic (FEMM) software is carried out for analysing the magnetic flux distribution in the laminated MRE isolator. The laminated MRE isolator is then examined to a series of compression for static and dynamic test under various applied currents using the dynamic fatigue machine and biaxial dynamic testing machine. It is shown that the static compression force is increased by 14.5% under strong magnetic field compared to its off-state. Meanwhile, the dynamic compression test results show that the force increase of the laminated MRE isolator is up to 16% and 7% for low and high frequency respectively. From the results presented in this work, it is demonstrated that the full-scale concept of the MRE isolator can be one of the potential candidates for vibration control applications by tunability of the dynamic stiffness.

  3. 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.

  4. 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.

  5. 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.

  6. 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)

  7. 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.

  8. 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

  9. 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.

  10. 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...

  11. Research on Properties of Natural Rubber of Different Strains%不同品系天然橡胶性能的研究

    Institute of Scientific and Technical Information of China (English)

    王开典; 杨春亮; 吕明哲; 曾宗强; 梁志雄; 黄茂芳

    2013-01-01

    [Objective] To study properties of natural rubber of different strains.[Method] The physiological parameters of 7 strains of natural rubber fresh latex were observed.And then centrifuge enrichment to compare the performance of concentrated latex from each district and each lines,and made research on mechanical properties of vulcanized rubber latex concentrate.[Result] The results showed that the content of sucrose was the highest in strain Yunyan77-4,the content of thioalcohol was the highest in strain Reyan 7-33-97,the content of total dry solid containing was the highest in strain Zhanshi 93-114,the number of volatile fatty acid in concentrated latex was the highest in strain RRIM600,the strain Reken525 had the best physical and mechanical properties in these strains.[Conclusion] The study can provide reference for selecting high yield and high quality rubber strain.%[目的]研究不同品系天然橡胶的性能.[方法]观察7个品系天然橡胶的新鲜胶乳的生理参数,将其离心浓缩后比较各个地区品系浓缩胶乳的性能,并且对浓缩胶乳硫化胶膜的物理机械性能进行研究.[结果]试验表明,云研774的蔗糖含量最高,热研7-33-的硫醇含量最高,湛试93-114的总固干含最高,RRIM600浓缩胶乳的挥发脂肪酸值最高,热垦525胶膜的物理机械性能最好.[结论]研究可为橡胶栽培种植和产品性能需求选育高产、优质、优良的橡胶品系提供参考.

  12. 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

  13. 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

  14. 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.

  15. Comparative Study of Natural Rubber Latex Condom Labeling Regulation in USA and China%中美天然胶乳避孕套说明书及标签管理法规比较研究

    Institute of Scientific and Technical Information of China (English)

    杨晓冬

    2012-01-01

    Objective Provide references for the standardized management of labeling for natural rubber latex condom in China. Methods By content analysis, compare U.S. FDA regulations on labeling for natural rubber latex condom with China SFDA's. Results U.S. FDA regulatory system for natural rubber latex condom labeling is complete, which can effectively control the risk of natural rubber latex condom, being operational, it is worth for the relevant regulatory authorities in China to learn from. Conclusion China can improve the natural rubber latex condom labeling regulations construction and management from the following areas: to amend the medical equipment manuals, labels and packaging and labeling regulations, as soon as possible, it is necessary to formulate the terms of natural rubber latex condoms; to establish guidance document of labeling for natural rubber latex condom; to create the database platform of labeling for natural rubber latex condom to query.%目的 为我国天然胶乳橡胶避孕套标签的规范化管理提供借鉴.方法 采用内容分析的方法,对目前美国FDA及我国SFDA关于天然胶乳橡胶避孕套标签的管理法规进行对比分析.结果 美国FDA关于天然胶乳橡胶避孕套标签的管理法规体系完整、完善,对产品的风险可以进行有效控制,操作性强,值得我国有关监管机构借鉴.结论 我国可从以下方面完善天然胶乳橡胶避孕套标签的法规建设和管理:①尽快修订《医疗器械说明书、标签及包装标识的管理规定》,对天然胶乳橡胶避孕套制订针对性条款;②配套出台天然胶乳橡胶避孕套标签指导原则;③建立标签查询数据库平台.

  16. 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...

  17. 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

  18. 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.

  19. 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.

  20. 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

  1. Avaliação do látex e da borracha natural de clones de seringueira no Estado de São Paulo Evaluation of latex and of raw natural rubber of rubber tree clones recommended for the São Paulo State, Brazil

    Directory of Open Access Journals (Sweden)

    Rogério Manoel Biagi Moreno

    2003-05-01

    Full Text Available Este trabalho teve como objetivo avaliar parâmetros do látex e da borracha natural de quatro clones de seringueira [Hevea brasiliensis (Willd. ex Adr. de Juss. Muell.-Arg.] cultivados em larga escala na Fazenda Cambuhy no Município de Matão, Estado de São Paulo. Foram utilizados látex de 20 árvores do estande de cada um dos clones, GT 1, PB 235, IAN 873 e RRIM 600, com 12 anos de idade, no quarto ano de sangria sob o sistema 1/2S d/3 6d/7. 11m/y. ET 5,0%. Pa 12/y. Foram analisados o conteúdo de borracha seca, porcentagem de cinzas, porcentagem de nitrogênio, plasticidade Wallace (P O, índice de retenção de plasticidade e viscosidade Mooney (V R. O conteúdo de borracha seca apresentou tendência de queda com o decréscimo da temperatura ao longo do ano (r = 0,75. Contrário ao conteúdo de borracha seca, as propriedades porcentagem de nitrogênio e porcentagem de cinzas apresentaram tendência de aumento com a redução da temperatura ao longo do período das coletas. A correlação entre P O e V R foi linear e elevada (r = 0,93. Os altos valores de P O e V R indicam que as borrachas dos clones estudados são consideradas como borrachas duras. Os valores do índice de retenção de plasticidade foram baixos, indicando baixa resistência à degradação térmica. Os resultados mostram influência marcante dos fatores climáticos em algumas propriedades dos látices e da borracha natural dos clones estudados, sugerindo condição importante para se entender o comportamento dos mesmos.The objective of the present paper was to evaluate the parameters of latex and natural rubber from four clones of rubber tree [Hevea brasiliensis (Willd. ex Adr. de Juss. Muell.Arg.] planted in large scale in Cambuhy plantations in São Paulo State, Brazil. Latex from 20 trees of each 12-year-old clones viz. GT 1, PB 235, IAN 873 and RRIM 600 following the 1/2S d/3 6d/7. 11m/y. ET 5.0%. Pa 12/y tapping system in the fourth year of yielding. The studied

  2. 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

  3. Experimental Investigation into Mechanical Properties of Nanomaterial-reinforced Table Tennis Rubber

    Directory of Open Access Journals (Sweden)

    Yu-Fen Chen

    2016-10-01

    Full Text Available A new table tennis rubber is prepared consisting of carbon nanotubes, zinc oxide and titanium oxide added to a mixture of natural and synthesized rubber. The Nano-reinforced rubber is attached to wooden table tennis blades and patterned with four different surface structures, namely flat, long pimples, short pimples and medium pimples. The results show that of the five rubbers, the Nano-reinforced rubber with a flat surface offers a significantly improved elastic and mechanical performance

  4. 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

  5. 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.

  6. 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

  7. Research on Structure and Properties of Rapid Coagulation Natural Rubber%快速凝固天然橡胶的结构和性能的研究∗

    Institute of Scientific and Technical Information of China (English)

    张胜君; 于人同; 白晓莹; 候雪; 廖双泉

    2016-01-01

    采用硬脂酸、异辛醇以及羟丙基甲基纤维素作为辅助剂制备了快速凝固天然橡胶,并对凝固后天然生胶的结构、加工性能、热稳定性和力学性能进行研究。研究表明快速凝固橡胶的蛋白质含量增加。与乙酸凝固相比,快速凝固天然橡胶具有更高的热稳定性、较低的损耗因子。同时,快速凝固天然橡胶的拉伸强度和撕裂强度相对乙酸凝固天然橡胶分别由18.0 MPa 与28.9 kN·m-1提高到21.1 MPa 和35.5 kN·m-1,交联密度由4.39×105 mol/cm3提高到5.09×105 mol/cm3。%Rapid coagulation natural rubber was prepared by using of stearic acid, 2-ethylhexanol and hydroxypropyl methyl cellulose as auxiliary agents.And the structure,processability,thermal stability and mechani-cal property of the rubber were studied.The protein content of the resulting natural rubber was higher than that of natural rubber coagulated with acetic acid.Results showed that thermal stability was improved and the loss factor was decreased via rapid coagulation method.Comparing with acetic acid coagulation rubber,the tensile strength of the rapid coagulation natural rubber was enhanced from 18.0 MPa to 21.1 MPa,the tear strength was improved from 28.9 kN·m-1 to 35.5 kN·m-1 as well,the crosslinked density was increased from 4.39×10 5 mol/cm3 to 5.09×10 5 mol/cm3 .

  8. 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.

  9. 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.

  10. Biotemplate synthesis of polyaniline@cellulose nanowhiskers/natural rubber nanocomposites with 3D hierarchical multiscale structure and improved electrical conductivity.

    Science.gov (United States)

    Wu, Xiaodong; Lu, Canhui; Xu, Haoyu; Zhang, Xinxing; Zhou, Zehang

    2014-12-10

    Development of novel and versatile strategies to construct conductive polymer composites with low percolation thresholds and high mechanical properties is of great importance. In this work, we report a facile and effective strategy to prepare polyaniline@cellulose nanowhiskers (PANI@CNs)/natural rubber (NR) nanocomposites with 3D hierarchical multiscale structure. Specifically, PANI was synthesized in situ on the surface of CNs biotemplate to form PANI@CNs nanohybrids with high aspect ratio and good dispersity. Then NR latex was introduced into PANI@CNs nanohybrids suspension to enable the self-assembly of PANI@CNs nanohybrids onto NR latex microspheres. During cocoagulation process, PANI@CNs nanohybrids selectively located in the interstitial space between NR microspheres and organized into a 3D hierarchical multiscale conductive network structure in NR matrix. The combination of the biotemplate synthesis of PANI and latex cocoagulation method significantly enhanced the electrical conductivity and mechanical properties of the NR-based nanocomposites simultaneously. The electrical conductivity of PANI@CNs/NR nanocomposites containing 5 phr PANI showed 11 orders of magnitude higher than that of the PANI/NR composites at the same loading fraction,; meanwhile, the percolation threshold was drastically decreased from 8.0 to 3.6 vol %.

  11. Biocomposites from Natural Rubber: Synergistic Effects of Functionalized Cellulose Nanocrystals as Both Reinforcing and Cross-Linking Agents via Free-Radical Thiol-ene Chemistry.

    Science.gov (United States)

    Parambath Kanoth, Bipinbal; Claudino, Mauro; Johansson, Mats; Berglund, Lars A; Zhou, Qi

    2015-08-01

    Natural rubber/cellulose nanocrystals (NR/CNCs) form true biocomposites from renewable resources and are demonstrated to show significantly improved thermo-mechanical properties and reduced stress-softening. The nanocomposites were prepared from chemically functionalized CNCs bearing thiols. CNCs served as both reinforcing and cross-linking agents in the NR matrix, and the study was designed to prove the cross-linking function of modified CNCs. CNCs were prepared from cotton, and the cross-linkable mercapto-groups were introduced onto the surface of CNCs by esterification. Nanocomposite films were prepared by dispersing the modified CNCs (m-CNCs) in NR matrix by solution casting. The cross-links at the filler-matrix (m-CNCs-NR) interface were generated by photochemically initiated thiol-ene reactions as monitored by real-time FTIR analysis. The synergistic effects of reinforcement and chemical cross-linking at the m-CNCs-NR interface on structure, thermo-mechanical, and stress-softening behavior were investigated. Methods included field emission scanning electron microscopy (FE-SEM), swelling tests, dynamic mechanical analysis, and tensile tests. Compared to biocomposites from NR with unmodified CNCs, the NR/m-CNCs nanocomposites showed 2.4-fold increase in tensile strength, 1.6-fold increase in strain-to-failure, and 2.9-fold increase in work-of-fracture at 10 wt % of m-CNCs in NR. PMID:26151647

  12. Biotemplate synthesis of polyaniline@cellulose nanowhiskers/natural rubber nanocomposites with 3D hierarchical multiscale structure and improved electrical conductivity.

    Science.gov (United States)

    Wu, Xiaodong; Lu, Canhui; Xu, Haoyu; Zhang, Xinxing; Zhou, Zehang

    2014-12-10

    Development of novel and versatile strategies to construct conductive polymer composites with low percolation thresholds and high mechanical properties is of great importance. In this work, we report a facile and effective strategy to prepare polyaniline@cellulose nanowhiskers (PANI@CNs)/natural rubber (NR) nanocomposites with 3D hierarchical multiscale structure. Specifically, PANI was synthesized in situ on the surface of CNs biotemplate to form PANI@CNs nanohybrids with high aspect ratio and good dispersity. Then NR latex was introduced into PANI@CNs nanohybrids suspension to enable the self-assembly of PANI@CNs nanohybrids onto NR latex microspheres. During cocoagulation process, PANI@CNs nanohybrids selectively located in the interstitial space between NR microspheres and organized into a 3D hierarchical multiscale conductive network structure in NR matrix. The combination of the biotemplate synthesis of PANI and latex cocoagulation method significantly enhanced the electrical conductivity and mechanical properties of the NR-based nanocomposites simultaneously. The electrical conductivity of PANI@CNs/NR nanocomposites containing 5 phr PANI showed 11 orders of magnitude higher than that of the PANI/NR composites at the same loading fraction,; meanwhile, the percolation threshold was drastically decreased from 8.0 to 3.6 vol %. PMID:25384188

  13. Impact of aluminum chloride on process performance and microbial community structure of granular sludge in an upflow anaerobic sludge blanket reactor for natural rubber processing wastewater treatment.

    Science.gov (United States)

    Thanh, Nguyen Thi; Watari, Takahiro; Thao, Tran Phuong; Hatamoto, Masashi; Tanikawa, Daisuke; Syutsubo, Kazuaki; Fukuda, Masao; Tan, Nguyen Minh; Anh, To Kim; Yamaguchi, Takashi; Huong, Nguyen Lan

    2016-01-01

    In this study, granular sludge formation was carried out using an aluminum chloride supplement in an upflow anaerobic sludge blanket (UASB) reactor treating natural rubber processing wastewater. Results show that during the first 75 days after the start-up of the UASB reactor with an organic loading rate (OLR) of 2.65 kg-COD·m(-3)·day(-1), it performed stably with a removal of 90% of the total chemical oxygen demand (COD) and sludge still remained in small dispersed flocs. However, after aluminum chloride was added at a concentration of 300 mg·L(-1) and the OLR range was increased up to 5.32 kg-COD·m(-3)·day(-1), the total COD removal efficiency rose to 96.5 ± 2.6%, with a methane recovery rate of 84.9 ± 13.4%, and the flocs began to form granules. Massively parallel 16S rRNA gene sequencing of the sludge retained in the UASB reactor showed that total sequence reads of Methanosaeta sp. and Methanosarcina sp., reported to be the key organisms for granulation, increased after 311 days of operation. This indicates that the microbial community structure of the retained sludge in the UASB reactor at the end of the experiment gave a good account of itself in not only COD removal, but also granule formation.

  14. Crosslinking of allergy proteins in natural rubber latex by transglutaminase%生物酶法催化天然乳胶中过敏蛋白质交联的研究

    Institute of Scientific and Technical Information of China (English)

    冯屏; 程必影; 孙金煜; 田晓慧; 王彦超

    2012-01-01

    利用谷氨酰胺转氨酶催化天然乳胶(NRL)水溶性蛋白质(WSP)发生交联,减少天然乳胶中水溶性蛋白质的含量.利用粒径分析、结构表征、十二烷基硫酸钠凝胶电泳实验证明了交联反应的发生.采用这一新技术可以降低天然乳胶制品的过敏性,拓展了其在医疗卫生领域、食品加工等领域的应用空间.%Water-soluble proteins existed in natural rubber latex can easily cause allergic reaction in people. Microbial Transglutaminase (MTGase)can modify latex proteins by means of covalent crosslinking to reduce the content of water-soluble proteins in natural rubber latex. The allergy proteins were considered to be catalysis of crosslinking reaction with MTGase, which were verified by particle-size analysis,characterization of structure and SDS-PAGE. Using this new technology can reduce allergic reaction of natural rubber latex products and expand the application space in the area of health,food processing and other fields.

  15. 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)

  16. 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.

  17. 乳液法天然橡胶/丁腈橡胶/蒙脱土纳米复合材料的结构与性能%Structure and properties of natural rubber/nitrile rubber/montmorillonite nanocomposites prepared by emulsion method

    Institute of Scientific and Technical Information of China (English)

    高利; 宋国君

    2011-01-01

    The natural rubber ( NR )/nitrile rubber (NBR)/montmorillonite ( M MT) nanocomposite was prepared by emulsion method, and the micromorphology, cure characteristics, static and dynamic mechanical properties of nanocomposite were investigated. The results showed that MMT dispersed uniformly in NBR matrix. The rubber molecular chains had not intercalated into MMT layers. MMT improved the scorch time, optimum cure time and the static mechanical properties of nanocomposite significantly. The nanocomposite had the similiar rolling resistance compared to NR/NBR blend.%采用乳液法制备了天然橡胶/丁腈橡胶/蒙脱土纳米复合材料,考察了其微观形态,探讨了复合材料的硫化特性及静态和动态力学性能.结果表明,蒙脱土以纳米尺寸均匀分布于丁腈橡胶基质中,橡胶分子链并未插层进入蒙脱土片层;蒙脱土使复合材料的焦烧时间和正硫化时间增加,可明显提高复合材料的静态力学性能;复合材料具有与天然橡胶/丁腈橡胶共混胶相似的滚动阻力.

  18. 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...

  19. 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

  20. Effect of Chipped Rubber Aggregates on Performance of Concrete

    OpenAIRE

    Sunil N. Shah; Pradip D. Jadhao; S. M. Dumne

    2014-01-01

    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% repl...

  1. 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)

  2. The Process and Properties of Natural Rubber Coagulated by Microwave Radiation%微波辐射凝固天然橡胶的工艺与性能研究

    Institute of Scientific and Technical Information of China (English)

    马志武; 陈永平; 田小明; 廖建和; 廖双泉

    2012-01-01

    The process of natural rubber (NR) coagulated by microwave radiation was observed through the transmission electron microscopy(TEM), and the conditions of microwave coagulation of NR were investigated. The physical and chemical properties, mechanic properties and dynamic mechanical properties of microwave coagulated natural rubber (m-NR)were compared with that of the acid coagulated natural rubber (a-NR)and the thermal coagulated natural rubber(t-NR). The results showed that the content of ammonia had a great influence on the process of m-NR, the mechanical properties of m-NR was better than that of a-NR and t-NR; the physical and chemical properties of m-NR achieved the standard of the 5# NR, and the Rubber Processing Analyzer (RPA) informed that the m-NR possessed the highest elastic modulus (G′)and the lowest loss factor(tanS).%采用透射电镜(TEM)对微波辐射凝固天然橡胶的凝固过程进行观察,并对微波凝固天然橡胶的凝固条件进行研究.将微波凝固天然橡胶(m-NR)与酸凝固天然橡胶(a-NR)和热凝固天然橡胶(t-NR)的理化性能、机械性能、动态力学性能进行对比研究.结果表明,氨含量对m-NR的凝固效果有很大影响;与a-NR和t-NR相比,m-NR的机械性能较好;理化性能中,m-NR各项指标都能达到5#NR的标准;通过橡胶加工分析仪(RPA)温度扫描NR的混炼胶表明,m-NR的弹性模量(G’)最大,损耗因子(tanδ)最小.

  3. 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.

  4. Tolerogenic dendritic cells derived from donors with natural rubber latex allergy modulate allergen-specific T-cell responses and IgE production.

    Directory of Open Access Journals (Sweden)

    Alejandro Escobar

    Full Text Available 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.

  5. Influence of Rubber Size on Properties of Crumb Rubber Mortars

    Directory of Open Access Journals (Sweden)

    Yong Yu

    2016-06-01

    Full Text Available Studies on the properties and applications of rubber cement-based materials are well documented. The sizes of rubbers used in these materials varied. However, information about the effects of rubber size on the properties of rubber cement-based materials, especially pore structure, mechanical strengths, and drying shrinkage properties, remains limited. Three groups of rubber with major particle sizes of 2–4 mm, 1–3 mm, and 0–2 mm were selected in this study. This paper presents experimental studies on the effects of rubber size on the consistency, fresh density, pore structure, mechanical properties, and drying shrinkage properties of crumb rubber mortars (CRMs. Results demonstrated that the consistency and fresh density of CRMs decreased with the rubber size. As to the pore structure, the total pore volume increased with the decrease of the rubber size. By contrast, the influence of the rubber size on the mesopore (<50 nm volume is not as significant as that of the rubber content. The mechanical properties of CRMs decreased with the rubber size. Low rubber stiffness and large pore volumes, especially those of small sized rubbers, contribute to the reduction of CRMs strength. The drying shrinkage of CRM increases as the rubber size decreases. The influences of rubber size on capillary tension are not significant. Thus, the shrinkage increases with the decrease of rubber size mainly because of its function in the deformation modulus reduction of CRMs.

  6. 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.

  7. Analysis of Status Quo in Pilot Production of Natural Rubber Latex by Biological Coagulation%天然乳胶生物凝固法试生产现状分析

    Institute of Scientific and Technical Information of China (English)

    曹海燕; 阮林光

    2012-01-01

    The experiment on producing rubber latex by the bio-coagulation method was carried out after discussion. The six biological properties of the two kinds of rubber were compared, and the storage time that affect the Po and PRI of the natural rubber, the factors that influence the bio-solidi-fication liquid and the latex coagulation effect were analyzed and discussed. The results showed that six properties of the bio-solidification latex were fine, and its Po was two units higher than that of the formic coagulation latex, but the PRI of the two kinds of latex was similar. According to the the-oretical calculation, we knew that the direct cost using in the production of dry rubber by the bio-so-lidification method was cheaper for 41 -43.5 yuan/t than by the formic coagulation method.%经研究后,对生物凝固法进行试生产,对比研究了2种胶的6项性能,贮存时间对天然橡胶P0和PRI值的影响,对影响生物凝固液及胶乳凝固效果的因素进行了分析与讨论。结果表明:生物凝固胶的6项性能较好,生物凝固胶的Po值比甲酸凝固胶的Po值高2个单位以上,2种胶的PRI值较接近。从理论计算可看出生物凝固直接费用比甲酸凝固直接费用每吨干胶可节约41~43.5元。

  8. 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.

  9. VARIATION OF PHYSICO-CHEMICAL PROPERTIES OF RADIATION CROSSLINKED RUBBER WITH STORAGE TIME

    Institute of Scientific and Technical Information of China (English)

    N.C. Dafader; M.E. Haque; F. Akhtar

    2005-01-01

    The effect of storage on physico-chemical properties of non-irradiated natural rubber and radiation vulcanized natural rubber (RVNR) were evaluated. The rubber films were stored under two different conditions, namely in open air and sealed polyethylene bags. The antioxidant, tris(nonylated phenyl) phosphite (TNPP) was used for preventing degradation of RVNR films. Gel content, cross-link density, tensile strength at break and 500% elongation of rubber films were measured.The results show that the retention (%) of tensile properties of rubber films with TNPP is higher than that of rubber films without antioxidants. The rubber films stored in polyethylene bags also show better retention of tensile properties than those of rubber films stored in open air.

  10. 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...

  11. 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

  12. 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

  13. 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.

  14. 纳米SiOx补强天然乳胶膜抗剪切机理的研究%Study on Shear Strength of Nature Rubber Latex Film reinforced with n-SiOx

    Institute of Scientific and Technical Information of China (English)

    刘东辉; 杨波; 黄俊; 徐亚丽

    2012-01-01

    Using the surface treatment agent, the high density dispersed suspension of n-SiOx was prepared though shear action, agitation-blend and ultrasonic wave. By suitable shear force, the suspension that the mass percentage of n-SiOx was 2.0% was evenly dispersed into nature rubber latex, and the nature rubber film sample reinforced with n-SiOx was prepared. The test results of angle tear strength and the SEM analysis showed that the n-SiOx particles could homogeneously disperse into the nature rubber latex, and form firm structure with the nature rubber latex s molecular chains, and the angle tear strength was 152. 32% of the film sample filled with silica. The main effecting factor was the density of the n-SiOx suspension, the secondary factors were the dispersing time of ultrasonic wave,the running frequency of 25G head and the emulsification time.%使用合适表面处理剂,通过剪切、搅拌混合和超声波处理,制备了高浓度n-SiOx分散悬浮液;在合适的剪切强度下,将分散悬乳液按n- SiOx质量分数为2.0%均匀分散在天然乳胶中,制备了n- SiOx补强型天然乳胶膜试样.乳胶膜直角撕裂强度测试结果和扫描电子显微镜图像分析表明,n- SiOx粒子较好地分散在天然乳胶中,能与乳胶分子链形成较为牢固的整体结构,其剪切强度较白炭黑试样提高了52.32%;n - SiOx悬浮液浓度是实验的主要影响因素,超声波分散时间、25G工作头转速和均质分散时间次之.

  15. The Influence of Microwave Drying on Thermal-oxidation Ageing Properties of Nature Rubber Vulcanized%微波干燥对天然橡胶硫化胶热氧老化性能的影响

    Institute of Scientific and Technical Information of China (English)

    张福全; 陈美; 王永周; 廖建和; 黄茂芳

    2011-01-01

    研究3种不同干燥方式所得天然橡胶硫化胶的热氧老化性能.采用TG和DTG测定了空气氛围下干燥后样品硫化胶的热氧降解温度,运用Coats-Red fern方程计算N2氛围下样品硫化胶热降解活化能;采用RPA 2000在应变为0.5 deg下进行频率扫描来评估样品耐热老化性能,并测定了样品硫化胶老化前后的力学性能.结果表明,微波干燥天然橡胶的力学性能明显优于热空气干燥和自然干燥,性能变化率和老化系数更大,样品RPA频率扫描tanδ值的增值更大,微波干燥样品的热降解活化能高于热空气干燥9 kJ/mol,与自然干燥样品接近,说明微波干燥天然橡胶硫化胶的热稳定性好,耐热氧老化性能得到显著提高.%The thermal -oxidation ageing properties of nature rubber vulcanized dried by three methods was studied. TC and DTG was used to determine the thermal-oxidation degradation temperature in air atmosphere and thermal degradation active energy in N2 atmosphere using Coats-Redfern equation; the frequency sweep was used to estimate the ageing resistance of nature rubber vulcanized at strain of 0.5, also, the mechanical properties of rubber vulcanized was tested before and after ageing. Showed from the results, the mechanical properties of NR dried by microwave was higher than the hot -air drying and nature drying; the increasing value of tanS in frequency sweep was larger than the other drying methods; the degradation active energy dried by microwave was 9 kj/mol bigger than hot-air drying, so, the thermal stability of nature rubber dried by microwave was remarkably improved compared with the other two drying methods.

  16. Study on the Properties of Natural Rubber Filled with Attapulgite Modiifed by Silica%二氧化硅改性凹凸棒土/天然橡胶复合材料的研究

    Institute of Scientific and Technical Information of China (English)

    王继虎; 陈大俊; 杨涛; 苏月

    2014-01-01

    In this paper, purified attapulgite modified by silica (AS) was prepared. The morphology of the filler particles was described by transmission electron microscopy (TEM). The reinforcement effect of natural rubber composites iflled by different content ifller was studied. TEM indicated that silica nanoparticles had a good dispersion on the surface of attapulgite powder. The smooth surface of attapulgite became rough. Compared with blank sample, the performance of AS/NR nanocomposites improved signiifcant. The tensile strength and coefifcient of nanocomposites were increased and the trend when iflling content of AS increased. The optimum properties of composites were iflled with 1 g. The tensile strength of AS41/NR nanocomposite was up to 26.10 MPa, increased by 70% compared to the neat natural rubber sample. AS particles could improve the heat resistance of natural rubber composites.T5% andTmax were increased 40~70℃ and 20℃ than natural rubber.%以提纯凹凸棒土表面负载纳米二氧化硅粒子(AS)作为补强剂,将其填充到天然橡胶(NR)中,制备了复合材料。采用透射电镜(TEM)观察了凹凸棒土的形貌,分析了复合材料的力学性能。结果表明,棒状结构的凹凸棒土表面分散了纳米级的二氧化硅,光滑的表面变得粗糙。随着AS含量的增加,复合材料的拉伸强度,补强系数先上升后下降。当AS添加量为1 g时,复合材料的性能最佳,AS41/NR硫化胶拉伸强度达26.10 MPa,比空白样品提高了70%。AS粉体可以提高天然橡胶复合材料的耐热性能,T5%和Tmax比纯天然橡胶分别提高了40~70℃和20℃。

  17. Global Synethetic Rubber Industrial Outlook

    Institute of Scientific and Technical Information of China (English)

    Dr.Leon Loh

    2011-01-01

    @@ This paper is to compile and analyze the statistical data of synthetic rubber capacity and consumption to understand its impact of supply/demand on the global synthetic rubber market.Some forecasted consumption data were generated and published by the joint efforts of both IISRP(International Institute of Synthetic Rubber Producers)and IRSG(International Rubber Study group).The report also covers the observed industrial trends as well as some emerging issues in the synthetic rubber industry.

  18. 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...

  19. Properties of natural rubber latexes modified by different processes%不同改性方法对天然胶乳的性能影响

    Institute of Scientific and Technical Information of China (English)

    廖小雪; 唐冰; 吴翠; 谭海生

    2011-01-01

    The natural rubber (NR) latex modified by chlorinated paraffin and antimony oxide blending was prepared; the NR latex addition polymerizaion modified by trichlorobromomethane was prepared;the NR latex graft copolymerization modified by tribromopropylene was prepared. A comparison of the colloidal properties, flame-resistance properties and solvent-resistance properties was made between NR latex and the three kinds of modified latex. The results showed that the viscosity of the three kinds of modified latex was higher than the non-modified latex' s, the viscosity of graft copolymerization and halogenation modified latex changed greatly,blend modified latex's viscosity had little change; the flame-resistance properties of the three kinds of modified latex were higher than the nonmodified latex's; solvent-resistance of the films of graft copolymerization modified latex and halogenation modified latex was superior to the films of non-modified latex's, solvent-resistance of the films of blend modified latex was worse than the ones of non-modified latex's.%分别采用氯化石蜡与Sb2O3共混改性天然胶乳、用三氯澳甲烷卤化加成改性天然胶乳、以3-澳丙烯接枝共聚改性天然胶乳,对3种不同工艺所制备的改性天然胶乳与未改性天然胶乳进行了胶体性能、阻燃性及耐溶剂性能的比较.研究结果表明:3种改性胶乳的粘度比未改性天然胶乳的要高,且接枝改性胶乳和卤化改性胶乳变化较大,共混改性胶乳的变化较少;3种改性胶乳的阻燃性能高于未改性天然胶乳的;卤化改性天然胶乳和接枝改性天然胶乳的耐溶剂性较好,而共混改性天然胶的耐溶剂性较差.

  20. 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.

  1. 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

  2. Study on Intercalating Stage of Natural Rubber/Clay Nanocomposites by X-ray Diffraction%X射线衍射法研究天然橡胶/黏土纳米复合材料的插层过程

    Institute of Scientific and Technical Information of China (English)

    戈明亮; 贾德民

    2012-01-01

    利用十六烷基季铵盐在固相条件下对黏土进行有机化插层改性,制备出有机黏土;采用机械混炼插层法制备了天然橡胶/有机蒙脱土纳米复合材料,用X射线衍射(XRD)和透射电镜(TEM)表征了纳米复合材料的结构和形态.利用XRD探讨了有机黏土在混炼和硫化过程中的插层行为,结果表明:天然橡胶的插层行为在机械混炼的过程中就已经发生,在硫化过程中,随着硫化时间的增加,黏土的层间距略微增加,黏土片层间的橡胶分子并不稳定.硫化过程结束后,黏土片层间的橡胶分子链随着交联固化而稳定地保持在黏土片层间.%The organic clay(Org-clay) was prepared by alkyl ammonium ions treating of Na-montmo-rillonite, and then the natural rubber(NR)/Org-clay nanocomposites were prepared by intercalation method. The structure and morphology of the nanocomposites were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM), the results show that Org-clay can disperse in the rubber matrix at nanometer size. The result of XRD indicated that natural rubber chains could be intercalated into the interlayer of the Org-clay during the mixing stage. During the vulcanizing stage, with increasing vulcanization time the basal space of Org-clay was slightly increased. At the end of rubber vulcanization process, the NR chains were fixed in the interlayer of the Org-clay because of cross-linked network structure of vulcanizate.

  3. 天然胶乳橡胶避孕套老化前爆破体积和压力分析%Analysis of the explosion volume and pressure of the aged natural latex rubber condom

    Institute of Scientific and Technical Information of China (English)

    王海艳; 康炜; 李丹丹

    2015-01-01

    天然胶乳橡胶避孕套已列为国家食品药品监督管理总局重点监管的医疗器械之一。2014年我们针对贵州省内的经营渠道进行了专项监督抽验,并进行检验,通过对不同生产企业的15个批次的避孕套产品检验结果的统计分析,从而了解避孕套在老化前爆破体积和压力对产品质量的影响。%Natural Latex rubber condom is listed in the list of medical us mainly supervised by the State Administration of Food and Drug Supervision and Management. In 2014, we carried out a sampling checkup of the products from business channels in Guizhou Province and implemented a static analysis of the condoms from 15 batches of condom products, we obtained the effect of the explosion volume and pressure of the aged natural latex rubber to the product quality.

  4. Study on Cross-link of Allergy Protein of Natural Rubber Latex Catalyzed by Microbial Transglutaminase%天然乳胶中过敏蛋白质的酶催化交联研究

    Institute of Scientific and Technical Information of China (English)

    冯屏; 闫伟; 田晓慧; 程必影

    2011-01-01

    天然乳胶中普遍存在引起人体过敏反应的水溶性蛋白质.用谷氨酰胺转氨酶催化天然乳胶中的蛋白质使其发生不同结构层次上的改变,致使水溶性蛋白质含量降低,在提高乳胶强度等性能的同时解决蛋白质过敏问题.通过响应面试验设计获得了MTGase催化天然乳胶蛋白交联的优化条件.%Water-soluble proteins which contained in natural rubber latex are potent allergens capable of inducing potentially fatal anaphylaxis.Microbial Transglutaminase(MTGase),considered being stable over a wide pH range,can modify latex proteins by the covalent incorporation which maintain or increase the stability of natural rubber latex.The major impact factors were optimized by using response surface methodology.

  5. 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.

  6. 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.

  7. 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.

  8. Structure and property of natural rubber/montmorillonite nanocomposites prepared by adhesive accelerator PBS%用附着型促进剂制备橡胶/蒙脱土纳米复合材料

    Institute of Scientific and Technical Information of China (English)

    欧阳星; 罗远芳; 贾德民; 傅伟文; 刘岚

    2006-01-01

    用附着型促进剂PBS在机械混炼插层法的基础上制备了天然橡胶/蒙脱土纳米复合材料.由于硫化后大部分促进剂基团都连在橡胶分子链上,因此用分子一端能和蒙脱土片层有相互作用的附着型硫化促进剂,可以大大增强蒙脱土和橡胶基体的相互作用,得到性能优良纳米复合材料.用PBS制备纳米复合材料其硫化体系活性能低,硫化胶交联密度增大,有机蒙脱土片层在橡胶基体中达到纳米级的分散,具有优良的力学性能,加入8%有机蒙脱土100%模量从1.2 MPa增至2.2 MPa,500%模量从8.12 MPa增至18.23 MPa,邵氏GA硬度从45增至55,而加入2%有机蒙脱土500%模量从8.12 MPa增至17.06 MPa,撕裂强度从36.31 kN/m增至43.65 kN/m,加入2~10份有机蒙脱土时其效果相当于加入40份半补强炭黑.%The natural rubber-montmorillonite nanocomposites were prepared with adhesive accelerator PBS by mixing intercalation method. Because most of the accelerator radical group was linked on the rubber chains after curing, using the accelerator whose radical group′s end could interact with the montmorillonite layers, the interaction between montmorillonite fleets and rubber chains could be enhanced,and natural rubber-montmorillonite nanocomposites with good comprehensive properties could be prepared. On the effect of the adhesive accelerator PBS, itcould decrease activation energy of curing and the new system with the organic montmorillonite (HMT) had larger crosslinking density. And the natural rubber/montmorillonite nanocomposites had good mechanical properties. When adding 8% HMT,100% modulus increased from 1.20 Mpa to 2.20 Mpa, 500% modulus increased from 8.12 Mpa to 18.23 Mpa Shore A hardness enhanced from 45 to 55. When just add 2 phr HMT it came out a big value, 500% modulus ranges from 8.12 Mpa to 17.06 Mpa and tear strenth ranges from 36.31 kN/m to 43.65 kN/m, in other words,8 phr HMT was comparable to 40 phr semi rein forced carbon

  9. 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)

  10. 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)

  11. 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

  12. 聚苯胺改性蒙脱土/天然橡胶纳米复合材料的制备与性能%Preparation and properties of polyaniline-montmorillonite/natural rubber nanocomposites

    Institute of Scientific and Technical Information of China (English)

    张茂峰; 王鑫; 姜菲; 韩林林; 钟玲

    2012-01-01

    采用原位聚合法制备了聚苯胺质量分数为20%的聚苯胺改性蒙脱土,并以此作为增强剂利用机械混炼法制备了聚苯胺改性蒙脱土(PANI - MMT)/天然橡胶(NR)纳米复合材料.使用X射线衍射仪、傅里叶变换红外光谱仪及扫描电镜等对PANI - MMT和PANI - MMT/NR复合材料的结构进行了表征,并考察了PANI - MMT/NR复合材料的力学性能.结果表明,PANI - MMT/NR复合材料形成了插层型纳米结构;与普通的有机蒙脱土/NR复合材料相比,PANI - MMT/NR复合材料的力学性能明显提高,PANI - MMT添加质量为20份时其力学性能达到最好,并超过了添加40份炭黑N 660的NR的力学性能.%The polyaniline modified montmorillon-ite(PANI-MMT) with mass fraction 20% of polyaniline was prepared by in-situ polymerization, which was used as a reinforcing agent to prepare PANI-MMT/natural rubber(PANI- MMT/NR)nanocom-posite by mechanical mixing method. The structures of PANI-MMT and PANI-MMT/NR composite were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy , and the mechanical properties of the compositeswere investigated. The results showed that PANI-MMT/NR nanocomposites had intercalated structure, its mechanical properties were obviously high compared to those of common organic montmorillon-ite/natural rubber composites and reached the best when 20 phr PANI-MMT was filled, exceeding those of natural rubber filled with 40 phr carbon black N 660.

  13. 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...

  14. 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.

  15. 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.

  16. 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.

  17. 浓缩天然胶乳规格标准的变化与质量控制%Changes in Specification Standards of Natural Rubber Latex Concentrate and Its Quality Control

    Institute of Scientific and Technical Information of China (English)

    卢光; 余和平

    2012-01-01

    介绍浓缩天然胶乳规格国际标准和国家标准的最新修订情况.分析修订的技术指标对浓缩胶乳质量的影响。并提出采用最新国际标准修订现行国家标准的必要性。%In this paper, the recently revisions of the national and international standards on natural rubber (NR) latex concentrate are introduced. The influences of the revised technical requirements on the quality of NR latex concentrate are analyzed. And the necessity to revise the national standard by adopting the new edition of international standard is put forward.

  18. 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...

  19. 橡胶产业升级与关键技术调研——橡胶树采胶及病虫害防控%Investigation about Upgrading and Key Technology of Natural Rubber Industry-Latex Harvest and Pests Prevention

    Institute of Scientific and Technical Information of China (English)

    祁栋灵; 王秀全; 黄月球; 张志扬; 高宏华

    2011-01-01

    Based on the survey of rubber industry in Chinese three major rubber planting areas,this paper briefly illustrated the status of rubber tree latex harvest and pests prevention.Its existing challenges were as follows.Firstly,latex harvest technology management is not good enough.Secondly,tapping panel dryness is still not a breakthrough.Thirdly,rubber tree growing conventional pest damage and new emerging pest,fourthly,technical and economic rationality research of rubber cultivation is not enough.The suggestions were proposed as follows: performing the management of the latex harvest technology,prevention and control of RD for rubber panel dryness,efficient and safe exploitation techniques and new rubber compound to stimulate the development of agent,pest monitoring and forecasting emerging technologies and emergency prevention and control,integrated prevention and control root disease of rubber tree and developing plant protection drugs,which aimed at promoting the overall level of natural rubber industry in China.%通过对我国海南、云南、广东三大植胶区橡胶产业发展情况的调研,简要阐述橡胶采胶及病虫害防控方面的现状。探讨分析橡胶采胶及病虫害方面所面临的采胶技术管理执行不够好,橡胶树割面干涸病防控技术仍未获得突破,橡胶树常规病虫危害日趋严重及新病虫害不断涌现,橡胶栽培技术经济合理性研究不够等问题。提出通过切实做好采胶技术管理,割面干涸病防控技术研发,高效安全的采胶技术及新型刺激剂复方的研发,橡胶树突发病虫害监测预报及应急防控技术,橡胶树根病综合防控及植保药物技术研发等建议,发展提升橡胶产业整体水平。

  20. 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.

  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. 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

  3. 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.

  4. 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.

  5. Preparation of Pressure Sensitive Adhesives Based on Visible Light-Cured Natural Rubber Latex%可见光固化天然胶乳压敏胶的研制

    Institute of Scientific and Technical Information of China (English)

    唐盛斌; 徐志义; 廖建和; 陈永平; 廖双泉; 桂红星

    2009-01-01

    Degraded natural latex was mixed with terpene resin emulsion and other additives and then cured under the visible light initiator system to prepare oil-in-water emulsion type of pressure-sensitive adhesive (PSA). The ratio of degraded natural rubber to terpene resin emulsion,molecular weight and amounts of other additives were measured to observe their effects on the properties of PSA under a given light intensity. The results showed that the PSA with optimum properties was prepared under the following conditions: the ratio of the degraded natural latex and terpene resin emulsion was 1:1,molecular weight of the degraded natural rubber latex 19.8×10~4,the amount of initiator 1.2%,the amount of cross-linker 15%,and the amount of accelerant 0.4%. The DSC and TG/DTG showed that the PSA was improved in thermal stability after the PSA containing photo-initiator was cured by visible light. The PSA containing photo-initiator showed an increase of 5℃ in Tg,and was still available under a very low temperature.%采用可见光引发体系固化将降解天然胶乳与萜烯树脂乳液的其他助剂组合制备水乳型压敏胶,研究在一定光照强度下,降解天然胶乳与萜烯树脂乳液的不同配比,天然胶乳不同分子量,其他助剂的用量对压敏胶性能的影响.结果表明,降解天然胶乳与萜烯树脂乳液质量比为1:1、降解天然胶乳分子量为19.8×10~4、引发剂1.2%、交联剂15%、促进剂0.4%时压敏胶性能最优.DSC和TG/DTG表明含有光引发剂的压敏胶在光照后热稳定性提高,压敏胶的Tg升高了5℃,仍具有很低的使用温度.

  6. 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 ...

  7. 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

  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)

    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)

    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.  ……

  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. CRIA Sians A areement with Rubber Valley

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The signing ceremony of establishing strategic partnership between China Rubber Industry Association and Rubber Valley Co., Ltd. was held in Rubber Valley on September 13. Leaders such as Xu Wenying, Deputy Secretary-General of CRIA, repre-senting CRIA, and Zhang Yan, Deputy Director of Rubber Valley Management Committee and General Manager of Rubber Valley Co., Ltd., representing Rubber Valley, signed on the cooperation agreement. Fan Rende, President of CRIA, Cai Quanji,

  15. Effect of Electrolytes and pH on the Electrophoretic Characteristics of Fresh Natural Rubber Latex%电解质和酸碱性对天然鲜胶乳电动特性的影响

    Institute of Scientific and Technical Information of China (English)

    白晓莹; 张会丰; 金林赫; 廖双泉

    2016-01-01

    Fresh natural rubber latex was used to prepare centrifuged latex through high-speed refrigerated cen-trifuge.Combining laser Doppler electrophoresis,scanning electron microscope and inductively coupled plasma mass spectrometer and other instruments,the writer analyzed the electric properties,morphology and metal ion content of freshed and centrifuged natural rubber latex by changing the pH and electrolyte.The results showed that as the pH was lowered,the plus or minus of latex electrophoretic mobility was inverted.With the increasing electrolyte concen-tration,the negative electrophoretic mobility of natural fresh latex decreased accordingly.Under the same condition of concentration,the order of anions′effects on natural rubber latex′s electrophoretic mobility and conductivity was NaCl>NaBr>NaNO3>SDS (sodium dodecyl sulfate sodium).The descending order of compressing the electric double layer efficiency of metal cation was Al3+>Fe3+?Fe2+>Cu2+?Mn2+>Co2+>Ca2+>Na+.There was a special si-tuation that high metal cations such as copper ions,iron ions and aluminum ions could invert the latex′s charged na-ture.pH and electrolyte and the Morphology analysis showed that these electrolytes change latex′s pH environment, leading to latex agglomeration,even emulsion breaking.%采用高速冷冻离心处理天然鲜胶乳制备离心胶乳,通过改变胶乳中酸碱度和电解质,结合激光多普勒技术、扫描电子显微镜以及电感耦合等离子体质谱仪等仪器对处理前后的胶乳进行电动特性、形貌及金属离子含量分析.结果表明pH值的降低能使胶乳电泳迁移率的正负发生反转.增加电解质浓度,天然鲜胶乳负的电泳迁移率随之降低,相同浓度条件下阴离子电解质对天然胶乳电泳迁移率与电导率的影响顺序为NaCl>NaBr>NaNO3>SDS(十二烷基硫酸钠).金属阳离子压缩天然胶乳双电层效率由大到小依次为Al3+>Fe3+?Fe2+>Cu2+?Mn2+>Co2+>Ca2+>Na+.高价金属阳离子如

  16. 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。

  17. Caracterização das propriedades reológicas e dinâmicas de composições de borracha natural com resíduo de EVA Characterization of rheological and dynamic properties of natural rubber compositions with waste EVA

    Directory of Open Access Journals (Sweden)

    Marcia G. Oliveira

    2004-12-01

    Full Text Available O resíduo de EVA oriundo das indústrias calçadistas é um material reticulado, que apresenta grande potencial de uso como carga em composições elastoméricas. Neste trabalho, foram avaliadas as propriedades reológicas e dinâmicas das composições de borracha natural (NR com resíduo de EVA (EVAR, determinadas com o auxílio do analisador de processamento de borracha (RPA. As composições não-vulcanizadas tiveram a sua viscosidade aumentada pela adição de teores crescentes de EVAR. Após a vulcanização essas composições apresentaram menor elasticidade que a NR pura, como evidenciado nas maiores taxas de relaxamento do módulo e nos maiores valores de tan delta. Este comportamento foi confirmado pelos resultados de tensão e alongamento na ruptura.The EVA waste (EVAR is a crosslinked material, which can be used as filler in rubber compositions. In this work, rheological and dynamic properties of natural rubber (NR compositions with EVAR were investigated before and after vulcanization with the help of a rubber processing analyzer (RPA. The filler content varied from 0 to 60 phr. The results showed that rheological properties of nonvulcanized compositions were clearly modified by the addition of EVAR, which contributed to an increase in viscosity. The modulus relaxation and the dynamic properties such as tan delta of vulcanized compositions were also affected, by the reduction of the elasticity of the compositions. The mechanical properties corroborated the behavior revealed by RPA analysis and indicated that EVAR acted as a non-reinforcing filler.

  18. 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...

  19. The Effects of Bromination Methods on the Microstructure of Brominated Natural Rubbers from Latex%溴化方式对胶乳法溴化天然橡胶结构的影响

    Institute of Scientific and Technical Information of China (English)

    赵法敏; 薛行华; 张子琦; 张利伟; 李光

    2013-01-01

    为改善溴化天然橡胶(BNR)的溶解性能,在胶乳法的基础上改变溴化方式,以常规溴化方式和分步溴化方式分别制备了BNR.通过实验发现,体系溴浓度相同时分步溴化方式的溴含量比常规溴化方式高,而凝胶含量较低,所以分步溴化方式在甲苯中的溶解性能较好.通过傅里叶红外光谱对样品进行表征,并使用核磁共振对其微观结构进行了定性定量分析.红外光谱分析表明,2种溴化方式制备的BNR产物均发生了一定程度的溴加成反应和溴取代反应;核磁共振的分析证实了在体系溴浓度较低的情况下,与胶乳法常规溴化相反,胶乳法分步溴化的溴化过程主要以溴加成反应为主,少量发生溴取代反应.%In order to improve the solubility property of the brominated natural rubbers (BNR)from latex, BNR were prepared by changing the bromination ways from conventional bromination to step bromination. Through the experiment, it was discovered that the bromine content of the latter was higher than the former, but the gel content was less under the same bromine concentration. The latter showed much better solubility in the solvent of toluene. The structure of the procured sample was characterized by Fourier transform infrared spectroscopy (FTIR), and the microstructures of brominated nature rubber were qualitatively and quantitatively analyzed by nuclear magnetic resonance (NMR). FTIR showed that there were both a degree of brominated addition reaction and brominated substitution reaction in the obtained BNR by two different methods; Contrary to the conventional bromination from latex, the analysis of NMR proved that the bromination process of step bromination from latex was mainly in the form of addition reaction, and only a small amount of the substitution reaction did occur.

  20. Study on preparation and bonding properties of natural rubber latex grafted and modified by HEMA%HEMA接枝改性天然胶乳的制备及其粘接性能研究

    Institute of Scientific and Technical Information of China (English)

    卫飞云; 刘宏超; 曹端林; 余和平

    2013-01-01

    以甲基丙烯酸羟乙酯(HEMA)作为天然胶乳(NRL)的接枝改性剂,采用乳液聚合法制备了NR-g-HEMA[HEMA接枝NR(天然橡胶)]胶乳;然后以此为基体,并以水溶性松香树脂为增黏树脂、邻苯二甲酸二丁酯(DBP)为增塑剂等,制备相应的NR-g-HEMA胶粘剂;最后,用该胶粘剂压制胶合板,并对胶合板的粘接性能进行了测定.结果表明:采用单因素试验法优选出制备NR-g-HEMA胶乳的最佳工艺条件为m(干态单体)∶m(NRL)∶m(引发剂)∶m(活化剂)∶m(交联剂)=20∶100∶0.2∶0.2∶0.1、反应时间为8h和反应温度为16℃,此时相应胶合板的剪切强度(1.88MPa)符合Ⅲ类胶合板的指标要求.%Abstract:With hydroxyethyl methacrylate (HEMA) as graft modifier of natural rubber latex (NRL),a NR-g-HEMA[NR(natural rubber) grafted by HEMA] latex was prepared by emulsion polymerization.Then,with NR-g-HEMA latex as matrix,water-soluble rosin resin as tackifying resin,and dibutyl phthalate(DBP) as plasticizer,a corresponding NR-g-HEMA adhesive was prepared.Finally,the plywood was pressed by the adhesive,and the bongding properties of plywood were mensurated.The results showed that the optimal process conditions of preparing NR-g-HEMA latex were preferred by single-factor experiment method when mass ratio of m(dry monomer)∶m(NRL)∶m(initiator)∶m(activating agent)∶m(cross linker) was 20∶100∶0.2∶0∶2∶0.1,reaction time was 8h and reaction temperature was 16℃.Here,the shear strength (1.88MPa) of corresponding plywood could meet index requirement of Ⅲ class-plywood.

  1. Rubber composition compatible with hydrazine

    Science.gov (United States)

    Repar, J.

    1973-01-01

    Formulation improves compatibility of butyl rubbers with hydrazine while reducing permeation to low levels necessary for prolonged storage in space. This is accomplished by replacing carbon-black filler with inert materials such as hydrated silica or clay. Pressure increases suggest that hydrazine is decomposed only slightly by new type of rubber.

  2. 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.

  3. Phenology-Based Vegetation Index Differencing for Mapping of Rubber Plantations Using Landsat OLI Data

    Directory of Open Access Journals (Sweden)

    Hui Fan

    2015-05-01

    Full Text Available Accurate and up-to-date mapping and monitoring of rubber plantations is challenging. In this study, we presented a simple method for rapidly and accurately mapping rubber plantations in the Xishuangbanna region of southwest China using phenology-based vegetation index differencing. Temporal profiles of the Normalized Difference Vegetation Index (NDVI, Enhanced Vegetation Index (EVI, Atmospherically Resistant Vegetation Index (ARVI, Normalized Difference Moisture Index (NDMI, and Tasselled Cap Greenness (TCG for rubber trees, natural forests and croplands were constructed using 11 Landsat 8 OLI images acquired within one year. These vegetation index time series accurately demonstrated the unique seasonal phenological dynamics of rubber trees. Two distinct phenological phases (i.e., defoliation and foliation of rubber trees were clearly distinguishable from natural forests and croplands. Rubber trees undergo a brief defoliation-foliation process between late December and mid-March. Therefore, vegetation index differencing between the nearly complete defoliation (leaf-off and full foliation (leaf flushing phases was used to delineate rubber plantations within fragmented tropical mountainous landscapes. The method presented herein greatly improved rubber plantation classification accuracy. Overall classification accuracies derived from the differences of the five vegetation indices varied from 92% to 96% with corresponding kappa coefficients of 0.84–0.92. These results demonstrate the promising potential of phenology-based vegetation index differencing for mapping and monitoring rubber expansion at the regional scale.

  4. Down-regulation of small rubber particle protein expression affects integrity of rubber particles and rubber content in Taraxacum brevicorniculatum.

    Directory of Open Access Journals (Sweden)

    Andrea Hillebrand

    Full Text Available The biosynthesis of rubber is thought to take place on the surface of rubber particles in laticifers, highly specialized cells that are present in more than 40 plant families. The small rubber particle protein (SRPP has been supposed to be involved in rubber biosynthesis, and recently five SRPPs (TbSRPP1-5 were identified in the rubber-producing dandelion species Taraxacum brevicorniculatum. Here, we demonstrate by immunogold labeling that TbSRPPs are localized to rubber particles, and that rubber particles mainly consist of TbSRPP3, 4 and 5 as shown by high-resolution two-dimensional gel electrophoresis and mass spectrometric analysis. We also carried out an RNA-interference approach in transgenic plants to address the function of TbSRPPs in rubber biosynthesis as well as rubber particle morphology and stability. TbSRPP-RNAi transgenic T. brevicorniculatum plants showed a 40-50% reduction in the dry rubber content, but neither the rubber weight average molecular mass nor the polydispersity of the rubber were affected. Although no phenotypical differences to wild-type particles could be observed in vivo, rubber particles from the TbSRPP-RNAi transgenic lines were less stable and tend to rapidly aggregate in expelling latex after wounding of laticifers. Our results prove that TbSRPPs are very crucial for rubber production in T. brevicorniculatum, probably by contributing to a most favourable and stable rubber particle architecture for efficient rubber biosynthesis and eventually storage.

  5. The working of RVNRL pilot plant of Rubber Board and it's safety devices

    International Nuclear Information System (INIS)

    A pilot plant for producing radiation vulcanized natural rubber latex (RVNRL) was established at Rubber Board, India in 1992. Irradiation is done by a batch process in the plant. The plant has a versatile safety system for safety of operators and people working in and around the plant

  6. Natural Rubber Latex Modified by Nano SiO2 to Prepare Medical Gloves%用纳米SiO2改性胶乳制备新型医用橡胶手套

    Institute of Scientific and Technical Information of China (English)

    敖宁建

    2005-01-01

    Nano SiO2 modified natural rubber latex treated by ultrasonic and special dispersing agent was used to prepare medical gloves, and the mechanical and aging properties of the product were investigated. The results show that the tensile strength of the glove with 0.5% (mass fraction) nano SiO2 was 20.2MPa when the contrast was 15.9MPa. After 2% (mass fraction) nano SiO2 was filled in the latex, the tensile strength of the product increased to 25.5MPa. With the increase of the nano SiO2 content, strength at 300% and 500% elongation of the products increased gradually. Addition of nano SiO2 particles didn't change the elongation at break and elasticity of the glove. After 33 hours aging in hot air at 100℃, the tensile strength of the glove with 2% (mass fraction) nano SiO2 was as high as 12.7MPa.

  7. Radio-vulcanization of natural rubber in the latex phase. Study of an experimental 1 tonne per hour production; Radio-vulcanisation du caoutchouc naturel en phase latex. Etude d'une production experimentale de 1 tonne par heure

    Energy Technology Data Exchange (ETDEWEB)

    Leveque, P.; Puig, J.R.; Roudeix, H. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1968-07-01

    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) [French] Apres un rappel des principales etudes sur la radio-vulcanisation du latex et des elastomeres, on decrit les quatre types de cellules successivement essayes en vue de l'irradiation industrielle. Ils ont permis d'acquerir les informations necessaires a la resolution du probleme principal pose par l'irradiation, la formation de coagulum au cours de celle,-ci. Les deux premiers sont concus pour l'irradiation par un faisceau horizontal ('Dynamitron'), les derniers par un faisceau vertical ('Circe'). L'etude des proprietes du caoutchouc obtenu montre qu'il se compare favorablement au 'Revultex'. Un apercu est donne en annexe des caracteristiques du latex naturel et de sa mise en oeuvre. (auteurs)

  8. Rubber friction on (apparently) smooth lubricated surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Mofidi, M; Prakash, B [Division of Machine Elements, Luleaa University of Technology, Luleaa SE-97187 (Sweden); Persson, B N J [IFF, FZ-Juelich, 52425 Juelich (Germany); Albohr, O [Pirelli Deutschland AG, 64733 Hoechst/Odenwald, Postfach 1120 (Germany)

    2008-02-27

    We study rubber sliding friction on hard lubricated surfaces. We show that even if the hard surface appears smooth to the naked eye, it may exhibit short-wavelength roughness, which may make the dominant contribution to rubber friction. That is, the observed sliding friction is mainly due to the viscoelastic deformations of the rubber by the counterface surface asperities. The results presented are of great importance for rubber sealing and other rubber applications involving (apparently) smooth surfaces.

  9. Draft genome sequence of the rubber tree Hevea brasiliensis

    Directory of Open Access Journals (Sweden)

    Rahman Ahmad Yamin Abdul

    2013-02-01

    Full Text Available Abstract Background Hevea brasiliensis, a member of the Euphorbiaceae family, is the major commercial source of natural rubber (NR. NR is a latex polymer with high elasticity, flexibility, and resilience that has played a critical role in the world economy since 1876. Results Here, we report the draft genome sequence of H. brasiliensis. The assembly spans ~1.1 Gb of the estimated 2.15 Gb haploid genome. Overall, ~78% of the genome was identified as repetitive DNA. Gene prediction shows 68,955 gene models, of which 12.7% are unique to Hevea. Most of the key genes associated with rubber biosynthesis, rubberwood formation, disease resistance, and allergenicity have been identified. Conclusions The knowledge gained from this genome sequence will aid in the future development of high-yielding clones to keep up with the ever increasing need for natural rubber.

  10. SILICONE RUBBER MOULDS FOR FOOTWEAR

    Directory of Open Access Journals (Sweden)

    Cornelia LUCA

    2013-05-01

    Full Text Available The leather confections industry uses the silicone rubber moulds for the symbols,notices and models stamping on the footwear or morocco goods parts. The paper presents somecontributions in this kind of devices manufacturing technology

  11. SILICONE RUBBER MOULDS FOR FOOTWEAR

    OpenAIRE

    LUCA Cornelia; Rãzvan MOCANU

    2013-01-01

    The leather confections industry uses the silicone rubber moulds for the symbols,notices and models stamping on the footwear or morocco goods parts. The paper presents somecontributions in this kind of devices manufacturing technology

  12. Quantification of the effects of crumb rubber in CRM binders

    Science.gov (United States)

    Putman, Bradley James

    Since the mid-1960s, crumb rubber has been used to modify asphalt binders. The crumb rubber, also referred to as crumb rubber modifier (CRM), is produced by grinding scrap tires into fine powders with particulate sizes generally smaller than 2 mm. In most cases, CRM is incorporated into binder using the "wet" method, where the crumb rubber is blended with the asphalt binder. The binder modification that occurs during this blending process is physical in nature, where the lighter oils of the binder diffuse into the CRM particles. As the rubber particles absorb the oils, the particles swell; therefore, increasing the viscosity and stiffness of the CRM binder. This research evaluated the viscosity and complex shear modulus (G*) of 36 different laboratory-produced CRM binder combinations (two CRM processing methods, two CRM contents, three CRM sizes, and three binder sources) and three base binders. From this investigation, a method was developed to quantify the effects of the crumb rubber modification. These effects were identified as the interaction effect (IE) resulting from the diffusion of the lighter binder factions into the rubber particles and the particle effect (PE), which is the result of the change in the rheological properties due to the filling effect of the particulate CRM. Following statistical analyses of the results, it was determined that CRM binders had greater viscosity and complex shear modulus (G*) values than the base binders. These values increased with CRM content. The CRMs having higher surface area (i.e., ambient ground and finer CRM) generally had higher IE values, while the PE generally increased with particle size. HP-GPC testing indicated that the CRM binders also had higher large molecular size (LMS) fractions and lower small molecular size (SMS) fractions as determined from the HP-GPC profiles. As the LMS increased and the SMS decreased, the IE increased. Two of the three binder sources followed this trend, indicating that those

  13. Silicone-Rubber Stitching Seal

    Science.gov (United States)

    Wang, D. S.

    1985-01-01

    Fabric products protected from raveling by coating threads and filling stitching holes with silicone rubber. Uncored silicone rubber applied to stitching lines with air-pressurized sealant gun. Next, plastic release film placed on coated side, and blanket flipped over so release film lies underneath. Blanket then bagged and adhesive cured under partial vacuum of about 3.5 psi or under pressure. Applications include balloons, parachutes, ultralight aircraft, sails, rescue harnesses, tents, or other fabric products highly stressed in use.

  14. Rubber friction on smooth surfaces

    OpenAIRE

    Persson, B.N.J.; Volokitin, A. I.

    2006-01-01

    We study the sliding friction for viscoelastic solids, e.g., rubber, on hard flat substrate surfaces. We consider first the fluctuating shear stress inside a viscoelastic solid which results from the thermal motion of the atoms or molecules in the solid. At the nanoscale the thermal fluctuations are very strong and give rise to stress fluctuations in the MPa-range, which is similar to the depinning stresses which typically occur at solid-rubber interfaces, indicating the crucial importance of...

  15. Tribology Aspect of Rubber Shock Absorbers Development

    Directory of Open Access Journals (Sweden)

    M. Banić

    2013-09-01

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

  16. Choice of Regions for China's Natural Rubber Industry in Pursuing“Go Global” Strategy%我国天然橡胶“走出去”战略的区域选择研究

    Institute of Scientific and Technical Information of China (English)

    许灿光; 刘贞平; 吴家政; 石靓

    2015-01-01

    用SWOT分析方法,研究我国企业“走出去”投资橡胶种植、加工和贸易的区域选择。在种植方面,柬埔寨、老挝和缅甸三国以及非洲主产国是重点投资区域;在加工方面,基础较好的马来西亚、泰国以及基础较落后的柬埔寨、缅甸和斯里兰卡等国为较佳选择;在贸易方面,以新加坡为宜。%Based on analyzing methods provided by SWOT, the paper has done some study on how to choose proper regions for rubber planting, processing and trading for Chinese enterprises that aim go global. As regards rubber planting, Cambodia, Laos, Myanmar and some African rubber producing countries are deemed as key areas for investment; with respect to rubber processing, countries like Malaysia and Thailand with relatively better infrastructure, as well as countries including Cambodia, Myanmar and Sri Lanka with relatively backward infrastructure are both proved to be good choices; and in terms of rubber trading, Singapore is the most proper destination.

  17. Vitro Cytotoxicity Test of Natural Latex Rubber Condom%天然胶乳橡胶避孕套的体外细胞毒性试验研究

    Institute of Scientific and Technical Information of China (English)

    王叔桥; 陈齐英; 张丽宏; 马晶

    2012-01-01

    Objective To study in vitro cytotoxicity of natural latex rubber condom and investigate the present situation of domestic marketing condom in cytotoxicity. Methods According to the experimental principle for vitro cytotoxicity in GB/T16886. 5 and GB/T14233. 2 -2005 (Part 2: Biological test methods), the cytotoxicity test of condoms was respectively performed in mouse fibroblast cells ( L929) by agar diffusion test, microscopic observation test and MTT assay. Results By agar diffusion test, the cytotoxicity of the 6 brathes condoms with different brands was Grade 2. By microscopic observation test, when the concentration of the extract (6 cm2/ml) was 100% , 50% , 20% and 10% , the cytotoxicity of the 6 brathes condoms with different brands was Grade 4, Grade 4, Grade 2, Grade 1 or 0, respectively. By MTT assay, when the concentration of the extract (6cm2/ ml) was 50% , 20% and 10% , the cytotoxicity of the 15 brathes of condoms from 6 brands was Grade 4 (RGR≤l5%), Grade 2 (RGR: 50%-70%) and Grade 1 (RGR≥80%), respectively. Conclusion This study represents that the tested natural latex rubber condom has different grade cytotoxicity. MTT assay has a quantitative assessment advantage and is liable to operation and more suitable for the cytotoxicity test of condom compared with agar diffusion and microscopic observation test.%目的 研究天橡避的体外细胞毒性,调查国内市售避孕套的细胞毒性现状.方法 遵照GB/T16886.5和GB/T14233.2 - 2005(第2部分:生物学试验方法)体外细胞毒性的实验原则,采用琼脂覆盖法、显微镜观察法、噻唑蓝(MTT)比色法,在小鼠成纤维细胞(L929株)上对受试避.结果 用琼脂覆盖法检测,6批不同品牌避孕套均具有2级细胞毒性反应.用显微镜观察法检测,6批不同品牌避孕套(按6 cm2/ml比例浸提)在浸提液浓度为100%、50%、20%和10%时,分别具有4级、4级、2级、1或0级细胞毒性反应.用MTT比色法检测,来自6个品牌的15

  18. Management of dermatitis in the rubber manufacturing industry.

    Science.gov (United States)

    Toeppen-Sprigg, B

    1999-01-01

    Dermatitis in the rubber industry has diminished markedly in this century, but the problem still is the second most common occupational disease. Contributing agents include natural rubber, as latex concentrate or dry crumb, as well as the various additives used for conditioning. Primary, secondary, and tertiary prevention all have roles in reduction of incidence and severity of impairment. The choice of gloves and skin care methods must be based on a consideration of the efficacy of the materials and the environment in which they will be used. Careful attention to diagnosis yields benefits in treatment course and impairment reduction. Teamwork by occupational physicians, nurses, industrial hygienists, employees, and management is required. PMID:10495486

  19. Reinforcement of magnesium methacrylate prepared in situ to natural rubber%原位生成甲基丙烯酸镁补强天然橡胶的研究

    Institute of Scientific and Technical Information of China (English)

    陈玉坤; 贾德民; 王小萍; 贾志欣; 丁剑平

    2005-01-01

    研究了过氧化物硫化体系下,甲基丙烯酸镁(MDMA)、炭黑(CB)/MDMA补强天然橡胶的力学性能和交联密度.利用X射线衍射(XRD)证明了:在天然橡胶混炼过程中,氧化镁(MgO)和甲基丙烯酸(MAA)通过中和反应原位生成甲基丙烯酸镁.研究表明:MDMA和 CB/MDMA可以有效地补强天然橡胶.交联密度的测定暗示NR/CB/MDMA和NR/MDMA硫化胶的离子键交联密度有着密切的联系,CB和MDMA的并用导致了离子键交联密度的增加,进而对天然橡胶硫化胶产生了协同补强效果.%The mechanical properties and crosslink density of peroxide-cured natural rubber (NR) reinforced with magnesium methacrylate (MDMA) and carbon black(CB)/MDMA were studied. The formation in situ of MDMA through the neutralization reaction of magnesia (MgO) and methacrylate acid (MAA) in the NR compounding process was peroved by wide-angle X-ray diffraction (XRD). The results showed that NR can be remarkably reinforced by MDMA and CB/MDMA. Crosslink density determinations imply that the mechanical properties of NR/CB/MDMA and NR/MDMA vulcanizates are closely related with ionic crosslink density,and the combination of CB and MDMA leads the increase of ionic crosslink density and hence produces synergistic reinforcement to NR vulcanizates.

  20. Bladder Molding Technique of Natural Rubber Latex for Golf Club Head%高尔夫球杆杆头固化用天然胶乳气囊成型工艺研究

    Institute of Scientific and Technical Information of China (English)

    南博华; 邵丁伟

    2011-01-01

    The effects of stability,film forming and molding parameters of natural rubber latex on the bladder molding for golf club head were studied, and the molding process was determined. First, the mold with coagulating agent was immerged in the latex for about 15 minutes as the thickness of latex film was about 1. O mm. Then the mold with film was taken out of the latex,and put into the oven for about 1. 5 h at 85 ℃. After that,the film was coated with a layer of talcum powder,and unloaded after 5 min at room temperature. In the final step,the film was dried for 1. 5 h at 85 ℃ and then cured.%研究天然胶乳稳定性、成膜性以及成型参数对高尔夫球杆杆头固化用天然胶乳气囊成型工艺的影响,确定成型工艺为:在成型模具上浸渍一层凝固剂,然后将模具置于配置好的胶乳中浸渍15 min,胶膜沉积厚度约为1.0mm,将覆有胶膜的模具取出,置于85℃的烘箱中干燥1.5 h,取出后在胶膜上均匀涂抹一层滑石粉,在室温下晾置5min后脱模,脱模后,将试样继续置于85℃下烘干1.5 h后进行硫化.

  1. Toxicological evaluation of natural rubber films from vulcanized latex by the conventional process and the alternative process with ionizing radiation; Avaliacao toxicologica de filmes de borracha natural obtidos do latex vulcanizado pelo processo convencional e pelo processo alternativo com radiacao ionizante

    Energy Technology Data Exchange (ETDEWEB)

    Campos, Vania Elisabeth

    1997-07-01

    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 {sup 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 in the 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)

  2. Mechanical and thermal properties of sisal fiber-reinforced rubber seed oil-based polyurethane composites

    International Nuclear Information System (INIS)

    The development of high-performance composite materials from locally sourced and renewable materials was investigated. Rubber seed oil polyurethane resin synthesized using rubber seed monoglyceride derived from glycerolysis of the oil was used as matrix in the composite samples. Rubber seed oil-based polyurethane composite reinforced with unidirectional sisal fibers were prepared and characterized. Results showed that the properties of unidirectional fiber-reinforced rubber seed oil-based polyurethane composites gave good thermal and mechanical properties. Also, the values of tensile strengths and flexural moduli of the polyurethane composites were more than tenfold and about twofold higher than un-reinforced rubber seed oil-based polyurethane. The improved thermal stability and the scanning electron micrographs of the fracture surface of the composites were attributed to good fiber-matrix interaction. These results indicate that high-performance 'all natural products' composite materials can be developed from resources that are readily available locally.

  3. THERMAL CONDUCTIVITY OF RUBBERIZED GYPSUM BOARD

    Directory of Open Access Journals (Sweden)

    Taher Abu-Lebdeh

    2014-01-01

    Full Text Available The disposal of scrap tires is a challenging task and hence an innovative solution to meet these challenges is needed. Extensive work has been done on the utilization of waste tires in a variety of applications in asphalt pavements and concrete. However, previous investigations focus only on the mechanical properties of the rubberized materials, but few on the thermal performance. This is especially true for rubberized gypsum. Limited or no experimental data on the thermal performance of rubberized gypsum board are available. In this study, an experimental program is established to investigate the effect of amount and size of crumb rubber on the thermal properties of gypsum materials. Gypsum is replaced by four different percentage of crumb rubber: 10, 20, 30 and 40% by weight of gypsum and two sizes of crumb rubber (#30, #10_20 to make eight rubberized gypsum specimens. The prepared specimens were tested for thermal conductivity using an apparatus specially designed and constructed for this purpose. The experimental program was concluded by proposing an empirical equation to predict the thermal conductivity of rubberized gypsum board. Results indicated better thermal performance of the gypsum board due to the addition of crumb rubber. Thermal conductivity of the rubberized gypsum was 18-38% lower than the ordinary gypsum. It is concluded that thermal conductivity of rubberized gypsum decreases with the increase of crumb rubber regardless the size of the rubber and that thermal conductivity of mixtures contained 40% of rubber was about 38% lower than conventional mixture when crumb rubber #10_20 was added, while the thermal conductivity reduced by 22% when crumb rubber #30 was added. The study suggested for future work to investigate the effect of air voids size and ratio on the thermal conductivity of rubberized gypsum.

  4. Study on heat under dynamic loading of rubber

    Directory of Open Access Journals (Sweden)

    T. I. Igumenova

    2016-01-01

    Full Text Available A number of studies on heat buildup in tire rubber surface scan method samples using a thermal imaging camera. Investigated the exothermic chemical reaction mechanical destruction rubber when loading designs permanent cyclic stretching with deformation of the working zone 50%. Percentage of deformation of the working zone was chosen on the basis of the actual data on the stretch-compression zone "Rusk" tires, which is the maximum level difference of deformation during run-in. Experiment plan provided for periodic relaxation samples of at least 72 hours for more accurate simulation of operation process of structural products. Created and processed data on temperature changes in samples for bar and line profile for rubber compounds with the introduction of nanomodificator (fullerene-containing technical carbon in comparison with the control sample without him. The data obtained reflect the nature of heat depending on the composition of the compound. Identified common patterns of thermal nature of physicochemical process mechanical destruction rubbers. For rubber with nanomodifikatorom there has been an increase in the temperature interval reaction from a minimum to a maximum 2 degrees that is also linked to the rise in the average temperature of the reaction on the histogram also at 2-3 degrees of deformation under the same conditions and the level of cyclic loading. However, the temperature in the control sample that is associated with the beginning of the formation of hardened rubber structures, economies of Mallinza-Petrikeeva, occurs with delay twice compared with modified Fullerenes. Measurement of physic-mechanical indicators selected in the course of testing of samples showed the beginning of formation of structure with increased strength of samples in the sample temperature zone that corresponds to the thermal effect of èndotermičeskomu recombination reactions of macromolecules.

  5. Devulcanization of ground tire rubber: Physical and chemical changes after different microwave exposure times

    Directory of Open Access Journals (Sweden)

    P. S. Garcia

    2015-11-01

    Full Text Available Microwave devulcanization is known to be a promising and an efficient rubber recycling method which makes possible for the rubber to regain its fluidity, and makes it capable of being remolded and revulcanized. The focus of this work is to understand the physical and chemical changes that occur in the ground tire rubber after different microwave exposure periods. For this purpose chemical, thermal, rheological and morphological analyses were performed on the tire rubber, which contains natural rubber (NR and styrene-butadiene rubber (SBR as polymeric material. The results showed that the microwave treatment promoted the breaking of sulfur cross-links and consequently increased the rubber fluidity. However, long periods of exposure led to degradation and modification of some properties. At nanoscale, the deformation of the devulcanized NR domain under stress was observed, and the morphology obtained appears to be a droplet dispersion morphology. The most exposed samples presented only one glass transition temperature, and from this it was concluded that the treatment may have played an important role in the compatibilization of the elastomeric blend. Based on the results, it is required to control the microwave exposure time and polymeric degradation in order to achieve a regenerated rubber with satisfactory properties.

  6. USE OF CRUMB RUBBER FROM USED CAR TIRES IN MINERAL ASPHALT MIXES

    Directory of Open Access Journals (Sweden)

    Andrzej Plewa

    2014-11-01

    Full Text Available With the development of the automotive industry the disposal of used tires is constantly growing problem. Storage of waste rubber is associated with a very long period of decomposition of rubber in the natural conditions. Simultaneously new technologies are developed every year, which in the future may significantly promote recycling of this type of materials. The crumb rubbery modification of the road bitumen is the one of the environmentally safe solutions of rubbery decomposition. Improvement of resistance of the crumb rubbery modification of the road asphalt mixtures is the very important ecological aspect of the future. The article presents the results of research on the fatigue life resistance of asphalt concretes AC16P and AC22P with asphalt-rubber binders. The above analyses have been based on the results of tests of fatigue life of mineral-rubber-asphalt mixes determined by the method of prismatic four-point bending (4PB-PR. Mineral-rubber -asphalt mixes have been diversified according to the amount of the additive of rubber fines in asphalt-rubber binder. On the basis of the test results have been proven improvements functional properties mineral-rubber-asphalt mixes compared with mineral-asphalt mixes with unmodified asphalt.

  7. Characteristics of rubber used in seismic isolation by digital and thermal image analysis

    Science.gov (United States)

    Lewangamage, Chamindalal S.; Abe, Masato; Fujino, Yozo; Yoshida, Junji

    2002-06-01

    The use of seismic isolation rubber bearings in bridges and buildings provides a very effective passive method to suppress hazard from earthquake-induced vibration. Carbons filled natural rubber and high damping rubber (HDR) are smart civil engineering materials especially used in those bearings. This study is to develop algorithms for large strain field measurements in rubber material by image analysis and to experimentally investigate temperature dependency on rubber behavior under cyclic loadings by thermal image analysis. A correlation-based template-matching algorithm is developed in displacement field measurements in continua so that a large strain field can be measured. Possible unrealistic displacement vectors present in measured displacement fields are eliminated by new algorithm in which the deformation should satisfy the continuity condition. The algorithms are successfully employed in strain field measurement of rubber materials reported here as experimental verification. Local deformational characteristics of rubber were also studied; results are shown by the analysis. Finally, a failure criterion was proposed for the rubber. The use of infrared thermographs to measure temperature field is described. This paper will discuss its application in HDR temperature field measurements under cyclic loadings. In HDR, various changes of properties were investigated with respect to the frequencies of loadings and its body temperature; results are shown by the analysis.

  8. Through the Technology Lens: The Expansion of Rubber and its Implications in Montane Mainland Southeast Asia

    Directory of Open Access Journals (Sweden)

    Jefferson Fox

    2014-01-01

    Full Text Available 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 growing areas of Laos, Cambodia, Myanmar, northeast Thailand, and northwest Vietnam. By critically assessing the impacts of this expansion of rubber and clarifying the relationship between tools and technologies, the paper suggests that the widespread adoption of rubber as a technology leads to loss of natural and agricultural biodiversity; greater use of surface and groundwater supplies; increased use of pesticides, fertilisers, and other chemicals; higher exposure to market booms and busts for smallholders and investors; and for some farmers, the loss of their land to industrial plantations on which they may become labourers. The paper argues that if state authorities recognise the double-edged nature of rubber as a technology, they can act to try to limit its damaging effects through polices that recognise secure tenure and encourage small-scale, diversified agroforestry systems.

  9. Effect of Deodorant Strains on the Dynamic Mechanical Properties of Natural Rubber%除臭菌株对 NR 动态力学性能的影响

    Institute of Scientific and Technical Information of China (English)

    丁丽; 程盛华

    2014-01-01

    Using RPA2000 rubber process analyzer ,the dynamic mechanical properties of NR ob‐tained by different coagulation was analyzed .The results showed that no significant effects of strain C5 on the dynamic mechanical properties of NR ,and C5-containing biological coagulation rubber had better processing performance and elastic recovery capability than that of biological coagulation rubber and acid coagulation rubber .%采用RPA2000橡胶加工分析仪,分析了不同凝固方式获得的NR的动态力学性能。结果发现,除臭菌株C5对生物凝固胶的动态力学性能无不良影响,且加有除臭菌株C5的生物凝固胶块具有比生物凝固和酸凝固更好的加工性能和回弹性。

  10. 割胶制度对天然橡胶胶乳成份及橡胶性能影响的研究进展%Research Progress of Components and Properties of Natural Rubber Latex on Tapping System

    Institute of Scientific and Technical Information of China (English)

    廖小雪; 吴翠; 廖双泉; 陈荣凤

    2011-01-01

    Tapping system of rubber trees were summarized in this paper.Effect of physiological conditions of the rubber tree, non-rubber component of latex, concentration of latex, performance of colloid latex and performance of rubber film on different tapping systems were introduced.Characteristic of low frequency new tapping system and high frequency old tapping system was analyzed, which was helpful to the further study about reform of tapping system.%概述了国内外割胶制度,介绍了不同割胶制度对橡胶树生理、胶乳非胶成份、胶乳浓度、橡胶胶乳胶体性能及胶乳胶膜性能的影响,对比分析了低频新割制与高频旧割制的特点,对割胶制度改革的推进具有一定的指导意义.

  11. Structural determination of ethylene-propylene-diene rubber (EPDM) containing high degree of controlled long-chain branching

    DEFF Research Database (Denmark)

    Mitra, Susanta; Jørgensen, Mikkel; Pedersen, Walther Batsberg;

    2009-01-01

    This work highlights an attempt to characterize the degree and nature of long-chain branching (LCB) in an unknown sample of ethylene-propylene-diene rubber (EPDM). Two EPDM rubbers selected for this study were comparable in comonomer compositions but significantly different with respect to molar ...

  12. Application of gamma irradiation for incorporation of rubber powder in the formulations of acrylonitrile-butadiene rubber (NBR)

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-07-01

    Full text: Polymeric materials do not decompose easily, disposal of waste polymers is a major environmental problem of global character. Recycling is an economical alternative and environmentally recommended for polymers consumed and discarded by society. As regards the rubber in object, its natural decomposition is much slower due to their highly crosslinked, in three-dimensional networks, structures which makes it an infusible and insoluble material. Moreover, these three dimensional structures entails several problems for their recovery and reprocessing. The aim of this paper was to study the behavior of NBR rubber recycle. It was used rubber powder from industry. The powder was irradiated in master-batch composition and used directly in classical formulations for rubber vulcanization. The master-batch processed was irradiated at doses of 50, 100 and 150kGy in {sup 60}Co source at 5 kGy s{sup -1} rate, at room temperature. Gamma radiation created active sites during devulcanization that promoted further integration of the rubber powder in formulations for commercial use. The processes were compared and their products were characterized by analytical methods of the physical properties such as tensile strength and elongation. The greatest change in the properties of polymeric materials by exposure to ionizing radiation resulted mainly of two main reactions occurring in the polymer molecule: chains scission (degradation) and crosslinking. Although these two processes occur simultaneously in all the polymers, the predominance of one or other effect depends mainly of the chemical structure of each polymer, and the irradiation conditions. In the results was observed the behavior of nitrile rubber under different doses and radiation improvement of the mechanical properties. (author)

  13. 纳米微晶纤维素替代炭黑补强天然橡胶%Reinforcement of Natural Rubber with Nanocrystalline Cellulose as a Substitution for Carbon Black

    Institute of Scientific and Technical Information of China (English)

    古菊; 林路; 罗远芳; 贾德民

    2012-01-01

    采用纳米微晶纤维素(NCC)部分替代炭黑,制备了天然橡胶/纳米微晶纤维素/炭黑复合材料(NP/NCC/CB),研究了NCC对NR/CB复合材料性能的影响.结果表明,NCC提高了CB补强NR的扯断伸长率,并保持在500%以上,永久变形下降至30%以下,且NP/NCC/CB的拉伸强度和撕裂强度基本保持或略优于NR/CB,硬度则基本保持不变;NCC替代炭黑的量为5 phr~ 20 phr时,材料仍能保持良好的耐磨耗性能;NCC替代炭黑的量低于15 phr时,材料的抗曲挠龟裂性能得到改善;NCC的加入还改善了材料的热空气老化性能,降低了材料的压缩疲劳生热,当NCC取代CB的量为10phr时,复合材料的生热达到最低值13.0℃.%Natural rubber/nanocrystalline cellulose/carbon black (NR/NCC/CB) composite was prepared by using NCC as a partial substitution for CB, and the effect of NCC on the properties of NR/CB composite was investigated. The results show that (1) with the addition of NCC, the elongation at break of NR/CB composite increases to more than 500% , while the permanent set decreases to less than 30% ; (2) both the tensile strength and the tear strength of NR/NCC/CB composite are similar or superior to those of NR/CB composite, while the hardness keeps unchanged; (3) the abrasion resistance of the composite keeps well when the NCC substitution rate for CB ranges from 5 to 20phr; (4) the flex cracking resistance of the composite improves when the NCC substitution rate is less than 15phr; (5) the addition of NCC improves the thermal oxidative aging property and reduces the heat buildup due to dynamic compression; and (6) the temperature of heat buildup reaches its minimum value of 13.0℃ when the NCC substitution rate is 10phr.

  14. 天然橡胶基凹凸棒土纳米复合材料制备及性能研究%Study on Preparation and Properties of Attapulgite Reinforced Natural Rubber Nanocomposites

    Institute of Scientific and Technical Information of China (English)

    赵国璋; 施利毅; 卓靖; 冯欣; 丁鹏; 付继芳

    2011-01-01

    采用机械共混法制备了天然橡胶(NR)基凹凸棒土(AT)纳米复合材料,研究了复合材料的微观结构、力学性能及硫化特性,探讨了AT补强NR的机理.结果表明,改性后的AT能在NR基体中达到均匀分散并形成良好的聚合物-填料界面,显示出优异的补强效果.AT不但在胶料硫化过程中充当了交联点,而且在试样拉伸过程中沿拉伸方向取向,起了诱导结晶的作用.复合材料的拉伸结晶行为与填料量及填料粒子表面交联点数量有关.改性剂不同导致胶料交联行为存在差异,从而影响复合材料的拉伸结晶及应力-应变行为.改性及胶料混炼未破坏AT的层链结构.%Attapulgite (AT) reinforced natural rubber (NR) nanocomposites were prepared by mechanical compounding. The microstructures, mechanical properties and curing characteristics of the nanocomposites were investigated. The reinforcement mechanism of AT in NR was clarified. The results show that the modified AT exhibited outstanding reinforcement due to its homogeneous dispersion in the NR matrix and the strong polymer-filler interactions. AT needles not only act as crosslink points during the vulcanization, but also orient along the stretch direction and thus induce crystallization when the samples were stretched. The strain-induced crystallization of the nanocomposites is associated with the filler loading and the crosslink density on the surfaces of AT needles. Different modifiers result in different crosslinking characteristics, and affect the strain-induced crystallization and stress-stain behaviors of the nanocomposites. The layer-chain structure of AT is not influenced by the modification and mechanical compounding.

  15. Standardization of radiation vulcanized natural rubber latex

    International Nuclear Information System (INIS)

    Standards for concentrated latex used in the preparation of irradiated latex, standard irradiation conditions, further treatment of irradiated latex, level of prevulcanization and its estimation, film preparation and testing procedures are discussed in this paper. (author)

  16. Improved rubber nanofillers

    Energy Technology Data Exchange (ETDEWEB)

    Boyle, T. J.

    2012-03-01

    During this task, Silane functionalized TiO2 and HK3Ti4O4(SiO4)3 were sent to Goodyear (GY) for testing. These materials were characterized based on their interaction with the model elastomer, squalene. The Van der Waals interactions and Hamaker Constants for ZnO particles in squalene and rubber materials were characterized and it was determined that a 10-20 nm spacing was necessary between primary filler particles to maintain a stable nanocomposite. Contact angle measurements on the ZnO and ZnO-silane materials indicated that the solvent should wet the particles, and solvophobic attractions should not be present. These studies showed that the surface modification with sulfosilane coupling agents was successful, and high levels of dispersion of the particles remained possible. Further, a novel surface charging phenomenon where negative surface charging is developed in the squalene environment was observed and corroborated by measurements of particle size and of the surface modified materials in squalene. This impacts the dispersion of the particles according to the traditional colloidal interpretation of electrostatic repulsive forces between particles. Additionally, thin nanocomposite fibers were developed using electrospinning. The size and shape of the oxides did not change during the electrospinning process, although the shape of the fiber and the distribution of the particles, particularly for ZnO, was not ideal. There was an obvious increase in elastic modulus and hardness from the addition of the oxides, but differentiating the oxides, and particularly the surfactants, was difficult. The A-1289 lead to the greatest dispersion of the filler particles, while the A-1589 and the NXT produced clustered particle aggregates. This agrees with previous study of these materials in low molecular weight squalene solvent studies reported earlier. The behavior of the nanoparticle ZnO and the microparticle silica is different as well, with the ZnO being contained within

  17. HbNIN2, a cytosolic alkaline/neutral-invertase, is responsible for sucrose catabolism in rubber-producing laticifers of Hevea brasiliensis (para rubber tree).

    Science.gov (United States)

    Liu, Shujin; Lan, Jixian; Zhou, Binhui; Qin, Yunxia; Zhou, Yihua; Xiao, Xiaohu; Yang, Jianghua; Gou, Jiqing; Qi, Jiyan; Huang, Yacheng; Tang, Chaorong

    2015-04-01

    In Hevea brasiliensis, an alkaline/neutral invertase (A/N-Inv) is responsible for sucrose catabolism in latex (essentially the cytoplasm of rubber-producing laticifers, the source of natural rubber) and implicated in rubber yield. However, neither the gene encoding this enzyme nor its molecular and biochemical properties have been well documented. Three Hevea A/N-Inv genes, namely HbNIN1, 2 and 3, were first cloned and characterized in planta and in Escherichia coli. Cellular localizations of HbNIN2 mRNA and protein were probed. From latex, active A/N-Inv proteins were purified, identified, and explored for enzymatic properties. HbNIN2 was identified as the major A/N-Inv gene functioning in latex based on its functionality in E. coli, its latex-predominant expression, the conspicuous localization of its mRNA and protein in the laticifers, and its expressional correlation with rubber yield. An active A/N-Inv protein was partially purified from latex, and determined as HbNIN2. The enhancement of HbNIN2 enzymatic activity by pyridoxal is peculiar to A/N-Invs in other plants. We conclude that HbNIN2, a cytosolic A/N-Inv, is responsible for sucrose catabolism in rubber laticifers. The results contribute to the studies of sucrose catabolism in plants as a whole and natural rubber synthesis in particular. PMID:25581169

  18. Analisa Kadar Nitrogen Dalam Crumb Rubber Mutu Sir 20 Dan Crumb Rubber Mutu Sir 3 Metode Kjeldhal

    OpenAIRE

    Singarimbun, William Prodis

    2011-01-01

    Was done compare analysis titrates nitrogen in rubber SIR 20 by rubber SIR 3 at PT. Bridgestone Sumatra Rubber Estate Dolok Melangir, where does analysis need is done to know rubber rate compare SIR 20 by rubber SIR 30. Compare analysis so effective is done in determine top-grade crumb rubber quality bases classification among SIR'S quality 20 by SIR'S qualities 3. Parameter that is utilized is know to titrate greater or smaller nitrogen bases Standart Indonesian Rubber (SIR) already been det...

  19. Reproducibility of sterilized rubber impressions.

    Science.gov (United States)

    Abdelaziz, Khalid M; Hassan, Ahmed M; Hodges, J S

    2004-01-01

    Impressions, dentures and other dental appliances may be contaminated with oral micro-flora or other organisms of varying pathogenicity from patient's saliva and blood. Several approaches have been tried to control the transmission of infectious organisms via dental impressions and because disinfection is less effective and has several drawbacks for impression characterization, several sterilization methods have been suggested. This study evaluated the reproducibility of rubber impressions after sterilization by different methods. Dimensional accuracy and wettability of two rubber impression materials (vinyl polysiloxane and polyether) were evaluated after sterilization by each of three well-known methods (immersion in 2% glutaraldehyde for 10 h, autoclaving and microwave radiation). Non-sterilized impressions served as control. The effect of the tray material on impression accuracy and the effect of topical surfactant on the wettability were also evaluated. One-way ANOVA with Dunnett's method was used for statistical analysis. All sterilizing methods reduced the reproducibility of rubber impressions, although not always significantly. Microwave sterilization had a small effect on both accuracy and wettability. The greater effects of the other methods could usually be overcome by using ceramic trays and by spraying impression surfaces with surfactant before pouring the gypsum mix. There was one exception: glutaraldehyde still degraded dimensional accuracy even with ceramic trays and surfactant. We conclude that a) sterilization of rubber impressions made on acrylic trays was usually associated with a degree of dimensional change; b) microwave energy seems to be a suitable technique for sterilizing rubber impressions; c) topical surfactant application helped restore wettability of sterilized impressions. PMID:15798825

  20. Factors Influencing the Quality of Natural Rubber Produced Experimenlally with Bio--coagulation%生物凝固法天然橡胶试生产的质量因素分析

    Institute of Scientific and Technical Information of China (English)

    曹海燕; 阮林光

    2012-01-01

    We took a trial rubber production by the method of bio-coagulation. Comparing six performances from two kinds of the rubber. We find that storage periods will affect the Po and PRI of the rubber. We also analyze and discuss the reason of affecting the bio-coagulation liquid and latex solidification. The result shows that six performances of bio-coagulation are good. Its Po is higher than the Po of formic acid. And the PRI of the two kinds of the rubber is similar. So, by the theoretical calculation, the charge of the bio-coagulation is cheaper with 41 --43.5 yuan per ton than that of the formic acid%对生物凝固法进行试生产,对比研究2种胶的6项性能,贮存时间对天然橡胶Po和PRI值的影响,并对影响生物凝固液及胶乳凝固效果的因素进行分析与讨论。结果表明:生物凝固胶的6项性能较好,生物凝固胶的Po值比甲酸凝固胶的Po值高,两种胶的PRI值较相似。从理论计算可看出,生物凝固直接费用比甲酸凝固直接费用每吨干胶可节约41~43.5元。

  1. Modelling of damage initiation mechanism in rubber sheet composites under the static loading

    OpenAIRE

    Da Silva Botelho, T; N. Isac; E. Bayraktar

    2007-01-01

    Purpose: Modelling – Finite Element Analysis (FEA) of the damage initiation mechanisms in thin rubber sheet composites were carried out under static solicitation at room temperature. Natural rubber vulcanised and reinforced by carbon, NR is used in this study.Design/methodology/approach: Experimental results were compared with that of the Finite Element Analysis (FEA). Damage mechanism has been described with a threshold criterion to identify the tearing resistance, characteristic energy for ...

  2. USE OF CRUMB RUBBER FROM USED CAR TIRES IN MINERAL ASPHALT MIXES

    OpenAIRE

    Andrzej Plewa

    2014-01-01

    With the development of the automotive industry the disposal of used tires is constantly growing problem. Storage of waste rubber is associated with a very long period of decomposition of rubber in the natural conditions. Simultaneously new technologies are developed every year, which in the future may significantly promote recycling of this type of materials. The crumb rubbery modification of the road bitumen is the one of the environmentally safe solutions of rubbery decomposition. Improvem...

  3. Pyrolysis of rubber gloves in integral pyrolysis test plant

    International Nuclear Information System (INIS)

    Previously, pyrolysis of rubber gloves in laboratory study was described. In order to visualize the practical application of rubber gloves pyrolysis in terms of treating rubber gloves in medical waste, a new test plant was designed and constructed. The semi-continuous test plant was designed to accommodate rubber gloves that were not cut or shredded. The test plant has a capacity of 2kg/ hr and employed auxiliary fuel instead of the conventional electrical power for heating. The concept was based on moving bed reactor, but additional feature of sand jacket feature was also introduced in the design. Pyrolysis of the gloves was conducted at three temperatures, namely 350 degree Celsius, 400 degree Celsius and 450 degree Celsius. Oxygen presents inside of the reactor due to the combined effect of imperfect sealing and suction effect. This study addresses the performance of this test plant covering the time temperature profile, gas evolution profile and product yield. Comparison between the yield of the liquid, gas and char pyrolyzate was made against the laboratory study. It was found that the oil yield was less than the one obtained from bench scale study. Water formation was more pronounced. The presence of the oxygen also altered the tail gas composition but eliminate the sticky nature of solid residue, making it easier to handle. The chemical composition of the oil was determined and the main compounds in the oil were esters and phtalic acid. (author)

  4. De novo assembly and transcriptome analysis of the rubber tree (Hevea brasiliensis and SNP markers development for rubber biosynthesis pathways.

    Directory of Open Access Journals (Sweden)

    Camila Campos Mantello

    Full Text Available Hevea brasiliensis (Willd. Ex Adr. Juss. Muell.-Arg. is the primary source of natural rubber that is native to the Amazon rainforest. The singular properties of natural rubber make it superior to and competitive with synthetic rubber for use in several applications. Here, we performed RNA sequencing (RNA-seq of H. brasiliensis bark on the Illumina GAIIx platform, which generated 179,326,804 raw reads on the Illumina GAIIx platform. A total of 50,384 contigs that were over 400 bp in size were obtained and subjected to further analyses. A similarity search against the non-redundant (nr protein database returned 32,018 (63% positive BLASTx hits. The transcriptome analysis was annotated using the clusters of orthologous groups (COG, gene ontology (GO, Kyoto Encyclopedia of Genes and Genomes (KEGG, and Pfam databases. A search for putative molecular marker was performed to identify simple sequence repeats (SSRs and single nucleotide polymorphisms (SNPs. In total, 17,927 SSRs and 404,114 SNPs were detected. Finally, we selected sequences that were identified as belonging to the mevalonate (MVA and 2-C-methyl-D-erythritol 4-phosphate (MEP pathways, which are involved in rubber biosynthesis, to validate the SNP markers. A total of 78 SNPs were validated in 36 genotypes of H. brasiliensis. This new dataset represents a powerful information source for rubber tree bark genes and will be an important tool for the development of microsatellites and SNP markers for use in future genetic analyses such as genetic linkage mapping, quantitative trait loci identification, investigations of linkage disequilibrium and marker-assisted selection.

  5. Standard Test Method for Application and Analysis of Natural Rubber Latex Concentrate (Centrifuged or Creamed,Ammonia Pr%浓缩天然胶乳(氨保存离心或膏化)检测方法标准应用解析

    Institute of Scientific and Technical Information of China (English)

    李开鹏

    2011-01-01

    天然胶乳为防止因微生物、酶的作用而凝固、腐败,常加入氨和其他稳定剂来保存,为了便于运输和加工常采用离心和膏化2种方式,将胶乳浓缩至固含量60%以上称为浓缩天然胶乳。现行有效的国家标准GB/T8299-2008《浓缩天然胶乳氨保存离心或膏化胶乳规格》对浓缩天然胶乳这一重要产品进行了技术界定,对该标准的应用解析可以确保加工原材料的科学有效,保证生产加工制品的产品质量及规范胶乳行业行为提供技术支撑。%Natural rubber latex is an important process for raw materials of industrial product.Adding ammonia and other stabilizer can prevent the natural rubber latex by microorganisms,enzymes and solidification,leading to latex corruption.To facilitate the transp

  6. Damage initiation mechanism in rubber sheet composites during the static loading

    Directory of Open Access Journals (Sweden)

    N. Isac

    2007-01-01

    Full Text Available Purpose: Mechanical behaviour and damage initiation 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.

  7. Modified rubberized stone matrix asphalt for Nineveh roads

    Institute of Scientific and Technical Information of China (English)

    Al-Hadidy AI; TAN Yi-qiu

    2008-01-01

    To evaluate the effects of Crumb Rubber Modifiers (CRMS) on basic engineering properties (i. e.Marshall, tensile strength, and compressive strength) of stone matrix asphalt mixtures, the ASTM testing and procedures were employed. Results of the evaluation were used to quantify the effect of CRM source and CRM content on engineering properties at testing temperatures of 25℃and 60℃. Statistical models were developed, which represent the nature of effects on performance-related properties of stone matrix asphalt mixtures.

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

    OpenAIRE

    Young-Doo Kwon; Seong-Hwa Jun; Ji-Min Song

    2015-01-01

    Most machines and instruments constantly require elastomeric materials like rubber for the purposes of shock absorption, noise attenuation, and sealing. The material properties and accurate lifetime prediction of rubber are closely related to the quality of machines, especially their durability and reliability. The properties of rubber-like elastomers are influenced by ambient conditions, such as temperature, environment, and mechanical load. Moreover, the initial properties of rubber gaskets...

  9. Thermomechanical characterisation of cellular rubber

    Science.gov (United States)

    Seibert, H.; Scheffer, T.; Diebels, S.

    2016-09-01

    This contribution discusses an experimental possibility to characterise a cellular rubber in terms of the influence of multiaxiality, rate dependency under environmental temperature and its behaviour under hydrostatic pressure. In this context, a mixed open and closed cell rubber based on an ethylene propylene diene monomer is investigated exemplarily. The present article intends to give a general idea of the characterisation method and the considerable effects of this special type of material. The main focus lies on the experimental procedure and the used testing devices in combination with the analysis methods such as true three-dimensional digital image correlation. The structural compressibility is taken into account by an approach for a material model using the Theory of Porous Media with additional temperature dependence.

  10. Rubber friction: comparison of theory with experiment.

    Science.gov (United States)

    Lorenz, B; Persson, B N J; Dieluweit, S; Tada, T

    2011-12-01

    We have measured the friction force acting on a rubber block slid on a concrete surface. We used both unfilled and filled (with carbon black) styrene butadiene (SB) rubber and have varied the temperature from -10 °C to 100 °C and the sliding velocity from 1 μm/s to 1000 μm/s. We find that the experimental data at different temperatures can be shifted into a smooth master-curve, using the temperature-frequency shifting factors obtained from measurements of the bulk viscoelastic modulus. The experimental data has been analyzed using a theory which takes into account the contributions to the friction from both the substrate asperity-induced viscoelastic deformations of the rubber, and from shearing the area of real contact. For filled SB rubber the frictional shear stress σ(f) in the area of real contact results mainly from the energy dissipation at the opening crack on the exit side of the rubber-asperity contact regions. For unfilled rubber we instead attribute σ(f) to shearing of a thin rubber smear film, which is deposited on the concrete surface during run in. We observe very different rubber wear processes for filled and unfilled SB rubber, which is consistent with the different frictional processes. Thus, the wear of filled SB rubber results in micrometer-sized rubber particles which accumulate as dry dust, which is easily removed by blowing air on the concrete surface. This wear process seams to occur at a steady rate. For unfilled rubber a smear film forms on the concrete surface, which cannot be removed even using a high-pressure air stream. In this case the wear rate appears to slow down after some run in time period. PMID:22139094

  11. Investigation of cement based composites made with recycled rubber aggregate

    Directory of Open Access Journals (Sweden)

    Jevtić Dragica Lj.

    2012-01-01

    Full Text Available The results of experimental investigations performed on cement based composites made with addition of recycled rubber as a partial replacement of natural river aggregate are presented in this paper. Different properties of cement based mortar were analyzed, both in fresh and in hardened state. Tested properties in the fresh state included: density, consistency and volume of entrained air. In the hardened state, the following properties were tested: density, mechanical properties (compressive and flexural strength, modulus of elasticity, adhesion to concrete substrate, water absorption, freeze-thaw resistance and ultrasonic pulse velocity. The obtained results indicate that recycled rubber can be successfully applied as a partial replacement of natural river aggregate in cement based composites, in accordance with the sustainable development concept. The investigation showed that physical-mechanical properties of cementituous composites depend to a great extent on the percentage of replacement of natural river aggregate with recycled rubber, especially when the density, strength, adhesion and freeze-thaw resistance are concerned. The best results were obtained in the freeze-thaw resistance of such composites.

  12. CAN POLITICIANS SPEED UP LONG-TERM TECHNOLOGICAL CHANGE? SOME INSIGHTS FROM A COMPARISON OF THE GERMAN AND US-AMERICAN SYNTHETIC RUBBER PROGRAMS BEFORE, DURING AND AFTER WORLD WAR II

    Directory of Open Access Journals (Sweden)

    Jochen Streb

    2003-01-01

    Full Text Available I investigated the effect of government demand on firms’ innovation activities comparing the German and American synthetic rubber industries before, during and after World War II. I obtained three main results. 1. Because of the low price of natural rubber, price and sales guarantees were needed to motivate firms to produce the synthetic rubber BUNA S. 2. Facing fixed prices I.G. Farben improved their efficiency more than the American firms working under cost plus contracts. 3. The patent sharing agreement of the American synthetic rubber program caused firms to hold back advanced synthetic rubber inventions.

  13. Behavior of asphalt-rubber hot mixes obtained with high crumb rubber contents

    OpenAIRE

    Dantas Neto, Silvrano A.; Farias, Márcio Muniz de; Pais, Jorge C.; Pereira, Paulo A. A.; Santos, Luís Picado

    2003-01-01

    This paper shows the results of a study about the mechanical behavior of dense graded asphalt-rubber hot mixes (grading envelope C of DNER-ES 313/97) prepared with two different types of asphalt-rubber binders. These asphalt-rubber binders were obtained with penetration grade asphalt (AC 50/70) mixed with 21% and 25% of crumb rubber in weight. The rubber was recycled from unserviceable tires using the ambient grinding process. Hot mixes made with the conventional binder AC 5...

  14. Influence of crumb rubber and digestion time on the asphalt rubber binders

    OpenAIRE

    Neto, Silvrano Adonias Dantas; Farias, Márcio Muniz de; Pais, Jorge C.; Pereira, Paulo A. A.; Sousa, Jorge B.

    2006-01-01

    This paper shows the results of a study about the mechanical behavior of dense graded asphalt-rubber hot mixes prepared with two different types of asphalt-rubber binders. These asphalt-rubber binders were obtained with penetration grade asphalt (AC 50/70) mixed with 21% and 25% of crumb rubber in weight. The rubber was recycled from unserviceable tires using the ambient grinding process. Hot mixes made with the conventional binder AC 50/70 were also studied for comparison. The...

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

    Directory of Open Access Journals (Sweden)

    Banić Milan S.

    2012-01-01

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

  16. 75 FR 38119 - Polychloroprene Rubber From Japan

    Science.gov (United States)

    2010-07-01

    ... from Japan (38 FR 33593). Following five-year reviews by the Department of Commerce (``Commerce'') and... imports of polychloroprene rubber from Japan (64 FR 47765, September 1, 1999). Following second five-year... antidumping duty finding on imports of polychloroprene rubber from Japan (70 FR 44893). The Commission is...

  17. 75 FR 57980 - Polychloroprene Rubber From Japan

    Science.gov (United States)

    2010-09-23

    ... interested parties did not participate in this sunset review * * *.'' (75 FR 51981). Accordingly, pursuant to... COMMISSION Polychloroprene Rubber From Japan AGENCY: United States International Trade Commission. ACTION... whether revocation of the antidumping duty finding on polychloroprene rubber from Japan would be likely...

  18. Better Tomorrow of China Rubber Chemicals Industry

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    I. Development of China Rubber Chemicals Industry During the "11th Five-Year Plan" period, China rubber Chemicals industry fully implemented the development guideline of "Adhering to science and technology development, developing green chemistry with environmental protection, safety and energy conservation as the core, and building enterprise and world brands". With the great support of the state,

  19. Biorefinery of proteins from rubber plantation residues

    NARCIS (Netherlands)

    Widyarani, R.

    2016-01-01

    Biorefinery of rubber tree side streams could add economic value and income for farmers, who already grow the trees for latex production. The objective of this research was to design a process for the recovery of proteinaceous fractions from rubber tree. The aimed applications were expected to be su

  20. Exploratory Study of Rubber Seed Shell as Partial Coarse Aggregate Replacement in Concrete

    Directory of Open Access Journals (Sweden)

    K. Muthusamy

    2014-02-01

    Full Text Available 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 concrete making. Total of five mixes consisting various content of crushed rubber seed shell as partial coarse aggregate replacement ranging from 0, 5, 10, 15 and 20%, respectively were prepared in form of cubes. All the specimens were water cured before tested at 7 and 28 days. The workability test, compressive strength test and flexural strength test of the mixes was conducted in accordance to MS26 Part 1: Section 2, BSEN 12390 and ASTM 293-79 respectively. Generally, workability, compressive strength and flexural strength decrease with the increase in the crushed rubber seed shell replacement level. However, mix consisting around 10% of crushed rubber seed shell is suitable for the application in concrete work.

  1. A computational study of adhesion between rubber and metal sulfides at rubber–brass interface

    International Nuclear Information System (INIS)

    Highlights: • An atomic level model for brass–rubber interactions has been presented. • The main adhesion force has been tracked to the rubber sulfur–brass zinc or brass copper interaction. • The model gives new understanding of the adhesion and can be used for further developments of the system. - Abstract: Computational study at level of density functional theory has been carried out in order to investigate the adhesion between rubber and brass plated steel cord, which has high importance in tire manufacturing. Adsorption of natural rubber based adsorbate models has been studied on zinc sulfide, ZnS(1 1 0), and copper sulfide, Cu2S(1 1 1) and CuS(0 0 1), surfaces as the corresponding phases are formed in adhesive interlayer during rubber vulcanization. Saturated hydrocarbons exhibited weak interactions, whereas unsaturated hydrocarbons and sulfur-containing adsorbates interacted with the metal atoms of sulfide surfaces more strongly. Sulfur-containing adsorbates interacted with ZnS(1 1 0) surface stronger than unsaturated hydrocarbons, whereras both Cu2S(1 1 1) and CuS(0 0 1) surfaces showed opposite adsorption preference as unsaturated hydrocarbons adsorbed stronger than sulfur-containing adsorbates. The different interaction strength order can play role in rubber–brass adhesion with different relative sulfide concentrations. Moreover, Cu2S(1 1 1) surface exhibits higher adsorption energies than CuS(0 0 1) surface, possibly indicating dominant role of Cu2S in the adhesion between rubber and brass

  2. 橡胶沥青的改性机理%Rubber asphalt modification mechanism

    Institute of Scientific and Technical Information of China (English)

    王笑风; 曹荣吉

    2011-01-01

    In light of the complexity of rubber asphalt modification mechanism, such means as scanning electron microscopy, infrared spectroscopy, differential thermal analysis, microscopic structure analysis, component analysis were adopted to study the components of the asphalt before and after modifying, and chemical analysis of rubber powder are adopted to study the modification mechanism of asphalt rubber blending system. The results indicate that the swollen rubber powder is mutually-adhered to form a network structure, and the matrix asphalt changes from homogeneous body into a two-phase continuous blending structure system constituted by rubber powder and asphalt; physical swelling dominates the system, accompanied by a little chemical reaction and with the prolongation of time, the chemical reaction becomes more obvious; the swollen rubber powder forms damping effects to improve the viscosity of rubber asphalt. The modification of asphalt comes from two aspects: firstly, the network structure formed by swollen rubber powder; secondly, the modification of the asphalt composition resulting from rubber powder desulphurization degradation. The natural rubber has better performance in modifying asphalt than synthetic rubber. 4 tabs, 9 figs. 12 refs.%针对橡胶沥青改性机理的复杂性,采用扫描电镜、红外光谱、差热分析、微观结构分析、组分分析及胶粉化学分析等方法,研究了橡胶沥青混溶体系的改性机理.结果表明:胶粉溶胀后互相粘连,形成网络结构,基质沥青由匀质体变成了胶粉和沥青构成的两相连续共混结构体系;胶粉与基质沥青间以物理溶胀为主,但存在弱化学反应,且随时间延长,化学反应越明显;溶胀胶粉形成阻尼作用,提高了橡胶沥青粘度;沥青的改性源于溶胀胶粉构成的网络结构和胶粉脱硫降解对沥青组分的改善作用;天然橡胶对沥青的改性效果优于合成橡胶.

  3. Fracture resistance of rubbers with MWCNT, organoclay, silica and carbon black fillers as assessed by the J-integral: Effects of rubber type and filler concentration

    Directory of Open Access Journals (Sweden)

    T. Ricco

    2012-07-01

    Full Text Available The fracture resistance of different rubbers containing various nanofillers, such as multiwall carbon nanotube (MWCNT, organoclay, silica and carbon black (CB, was determined by the J-integral making use of the single edge notched tensile loaded (SEN-T single specimen approach. The elastomeric matrices were natural (NR, ethylene propylene diene (EPDM and hydrogenated nitrile rubbers (HNBR. Moreover, the strain softening (Payne effect of selected rubbers with 30 part per hundred rubber (phr filler content was also investigated by dynamic mechanical thermal analysis (DMTA in shear mode. DMTA results indicated that the Payne effect follows the ranking: MWCNT(fibrous > organoclay(platy > silica(spherical. J-resistance (JR curves were constructed by plotting the J value as a function of the crack tip opening displacement (CTOD*, monitored during loading. CTOD* = 0.1 mm was considered as crack initiation threshold and thus assigned to the critical value JIc. JIc increased with increasing filler loading, whereby MWCNT outperformed both silica and CB. On the other hand, JIc did not change with filler loading for the NR/organoclay systems that was traced to straininduced crystallization effect in NR. The tearing modulus (TJ also increased with increasing filler loading. The related increase strongly depended on both rubber and filler types. Nonetheless, the most prominent improvement in TJ among the fillers studied was noticed for the fibrous MWCNT.

  4. Viscoelastic behavior and reinforcement mechanism in rubber nanocomposites in the vicinity of spherical nanoparticles.

    Science.gov (United States)

    Bindu, P; Thomas, Sabu

    2013-10-17

    The viscoelastic behavior and reinforcement mechanism of nano ZnO reinforced natural rubber (NR) nanocomposites were investigated in this study. Dynamic mechanical analysis was performed to investigate the nature of the constrained polymer region in NR-nano ZnO nanocomposites, and the constrained polymer region is responsible for the reinforcement mechanism. The viscoelastic and tensile properties of NR nanocomposites were investigated with respect to the effect of nanofiller loading. All the nanocomposites showed a significant increase in storage modulus in the glassy and rubbery regions, the shift of the tan δ peak to the higher temperature region, and the lowering of the tan δ peak intensity compared to neat NR. The enhancement in the modulus is related to the weight % of the added nano ZnO as well as the volume of the constrained rubber chains in the proximity of ZnO nanoparticles. The study of the constrained volume of the polymer indicates that the structure of the nanocomposite possesses a moderately strong interfacial interaction between rubber chains and ZnO nanoparticles. The type of rubber-nanofiller interaction strongly influences the amount and modulus of the constrained region and contributes to the enhancement in the storage modulus of the resulting nanocomposites. The volume fraction of the constrained region of the NR nanocomposites was found to have good linear correlation with the weight % of nano ZnO. It was also understood that there should exist an optimum cross-linking density for a certain nanofiller reinforced rubber system, as well as partial physical adsorption of macromolecular rubber chains on the nanofiller surface. An optimum nanofiller loading is necessary for moderately strong rubber-nanofiller interaction and hence for the enhancement in the mechanical properties of the NR nanocomposites. A core-shell morphology model and constrained polymer model have been proposed to explain the constrained polymer chains in the NR-nano Zn

  5. History of Rubber and Its Use

    Science.gov (United States)

    Müller, Ingo; Strehlow, Peter

    Despite its spectacular properties rubber was not much good for anything before the latter part of the 19th century. To be sure the Aztecs had used it to make balls for their ceremonial ball games - or so we are told. But those games died along with the Aztec culture in the 16th century and there is no record of other useful applications until the late 18th century. But then, after that, rubber took off in a small way. After the American inventor Samuel Peal had obtained a patent in 1791 for the production of rubber-coated watertight textiles, the Scottish chemist Charles Macintosh (1766-1843) used such textiles for making rain-coats, and Thomas Hancock (1786-1865) produced rubber boots. At that time it was not really appropriate to speak of a rubber industry. What little material the evil-smelling workshops in New York and London needed, could be satisfied with the import of 30 tons of Caoutchouc1 annually - extracted from the sap of the tree Hevea brasiliensis - and most of that went for making erasers. Indeed, it had been reported by the English minister and scientist Joseph Priestley (1733-1804) that pieces of rubber are well-suited to rub out (sic!) pencil marks. Even today there is nothing better for the purpose and rubber became the English word for Caoutchouc.

  6. Zinc Leaching from Tire Crumb Rubber

    Science.gov (United States)

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

    2010-12-01

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

  7. Polypropylene–rubber blends: 2. The effect of the rubber content on the deformation and impact behaviour

    NARCIS (Netherlands)

    Wal, van der A.; Nijhof, R.; Gaymans, R.J.

    1999-01-01

    The effect of the rubber content on the deformation and impact behaviour of polypropylene–EPDM rubber blends is studied. The blends are made on a twin screw extruder. The rubber content ranged from 0 to 40 vol.%. The tensile modulus and the yield stress decrease linearly with increasing rubber conte

  8. Applicability of Landsat TM data for inventorying and monitoring of rubber (Hevea brasiliensis) plantations in Selangor, Malaysia: Linkages to policies

    Science.gov (United States)

    Suratman, Mohd Nazip

    2003-06-01

    Rubber tree (Hevea brasiliensis (Wild ex Adr. De Juss) Muell Arg.) plantations in Malaysia are important sources of natural rubber and wood products. Effective management and appropriate policy for these resources require reliable information on resource dynamics and forecasts of resource availability. The need for inventories and monitoring systems prompted this research into utilising ground information and satellite imagery for developing methods for forest plantation inventory. Monitoring procedures were developed using three dates of Landsat Thematic Mapper (TM) imagery. The specific objectives of the research were: (1) to develop an effective method for inventorying rubber tree plantations using an appropriate combination of satellite imagery and ground sampling in the State of Selangor, Malaysia; (2) to demonstrate the application of a Landsat TM-based rubber volume model in an extended area of rubber plantations south of Kuala Lumpur (KL), Malaysia; (3) to develop an operational methodology for monitoring land use/cover change, with a primary focus on rubber plantations; and (4) to identify relationships between the primary drivers of resource change and policies, and examine the evidence of policies---rubber area change linkages in the study area. Reasonably accurate predictions of the volume, age, and area of rubber plantations were obtained from Landsat TM data. The use of supervised image classification and an image segmentation approach for rubber volume model application showed better performance for volume prediction than a combined land use/cover and rubber volume classification technique, thus providing a useful tool for displaying rubber stand volume within segments or spatial units across the landscape. The combined use of a time series of Landsat TM imagery, modified postclassification change detection, and geographic information system (GIS) techniques made it possible to produce land use/cover change matrices and rubber area change information

  9. Analysis of rubber supply in Sri Lanka

    Energy Technology Data Exchange (ETDEWEB)

    Hartley, M.J.; Nerlove, M.; Peters, R.K. Jr.

    1987-11-01

    An analysis of the supply response for perennial crops is undertaken for rubber in Sir Lanka, focusing on the uprooting-replanting decision and disaggregating the typical reduced-form supply response equation into several structural relationships. This approach is compared and contrasted with Dowling's analysis of supply response for rubber in Thailand, which is based upon a sophisticated reduced-form supply function developed by Wickens and Greenfield for Brazilian coffee. Because the uprooting-replanting decision is central to understanding rubber supply response in Sri Lanka and for other perennial crops where replanting activities dominate new planting, the standard approaches do not adequately capture supply response.

  10. Fatigue life of automotive rubber jounce bumper

    Energy Technology Data Exchange (ETDEWEB)

    Sidhu, R S [Automotive Engineering Unit, Institute of Advanced Technology, University Putra Malaysia, 43400, UPM Serdang, Selangor (Malaysia); Ali, Aidy, E-mail: aidy@eng.upm.edu.my [Department of Mechanical and Manufacturing Engineering, Faculty of Engineering, Universiti Putra Malaysia, 43400 UPM, Serdang Selangor (Malaysia)

    2010-05-15

    It is evident that most rubber components in the automotive industry are subjected to repetitive loading. Vigorous research is needed towards improving the safety and reliability of the components. The study was done on an automotive rubber jounce bumper with a rubber hardness of 60 IRHD. The test was conducted in displacement-controlled environment under compressive load. The existing models by Kim, Harbour, Woo and Li were adopted to predict the fatigue life. The experimental results show strong similarities with the predicted models.

  11. Material Model Research on Rubber Vibration Isolators

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A viscohyperelastic constitutive model is proposed to describe the mechanical behaviour of vibration isolation rubber under broad-band vibration. This constitutive model comprises two parts: a component with three parameters to characterize the hyperelastic static properties of rubber materials,and the other component incorporating two relaxation time parameters, corresponding to high and low strain rates, respectively, to describe the dynamic response under vibration and impact loadings. Based on this proposed constitutive model, a series of experiments were performed on two types of rubber materials over a wide strain rate range. The results predicted from this model are in good agreement with the experimental data.

  12. Effect of crumb rubber origin on asphalt rubber hot mix laboratory performance

    OpenAIRE

    Pais, Jorge C.; Sousa, Jorge B.; Saim, Rachid; Pereira, Paulo A. A.

    2001-01-01

    Asphalt rubber traditionally has been produced with crumb rubber coming from an ambient grinding process and mostly from car tires. With this product and the binders used in Arizona and California the specifications currently present in ASTM D 6114 have been established. Nowadays relatively new types of crumb rubber are available in the markets namely those that have been produced by cryogenic methods and can then be reprocessed if desired by a further ambient step such as through a crack...

  13. Efeito do óleo de linhaça e do óleo de amendoim sobre a vulcanização da borracha natural (NR. parte II: modelo detalhado Effect of linseed oil and peanut oil upon natural rubber (NR vulcanization. part II: detailed model

    Directory of Open Access Journals (Sweden)

    Alexandre Bezerra

    2013-01-01

    Full Text Available O efeito da substituição total ou parcial do ácido esteárico por óleos vegetais de linhaça e amendoim foi investigado em composições de borracha natural (NR. Um sistema de vulcanização convencional foi escolhido e os estudos cinéticos foram conduzidos nas temperaturas de 160 ºC, 170 ºC e 180 ºC. O modelo cinético detalhado permitiu estudar os diferentes estágios da vulcanização e verificar que na etapa de formação do precursor de ligações cruzadas (A → B houve diferenças significativas entre o ácido esteárico e os óleos vegetais. Tal resultado foi devido à presença expressiva de ácidos graxos insaturados na composição química dos óleos de linhaça e de amendoim (principalmente, os ácidos oléico e linolênico, o que facilitou a ocorrência de reações laterais inesperadas e, consequentemente, diminuiu o rendimento final de ligações cruzadas nos vulcanizados.The effect of the total or partial replacement of stearic acid with vegetable oils of linseed and peanut has been investigated in natural rubber (NR compositions. A conventional vulcanization system has been chosen and kinetic studies have been done in the temperatures of 160 ºC, 170 ºC and 180 ºC. The detailed kinetic model has allowed studying the different stages of vulcanization and verifying that in the formation of the crosslink precursor (A → B there were significant differences between stearic acid and the vegetable oils. This result has been attributed to the high concentration of unsaturated fat acids in the chemical composition of the vegetable oils (mainly, oleic and linolenic acids, which allowed unexpected side reactions and, consequently, diminished the final yield of crosslinking in the vulcanizates.

  14. SNP identification from RNA sequencing and linkage map construction of rubber tree for anchoring the draft genome.

    Directory of Open Access Journals (Sweden)

    Jeremy R Shearman

    Full Text Available Hevea brasiliensis, or rubber tree, is an important crop species that accounts for the majority of natural latex production. The rubber tree nuclear genome consists of 18 chromosomes and is roughly 2.15 Gb. The current rubber tree reference genome assembly consists of 1,150,326 scaffolds ranging from 200 to 531,465 bp and totalling 1.1 Gb. Only 143 scaffolds, totalling 7.6 Mb, have been placed into linkage groups. We have performed RNA-seq on 6 varieties of rubber tree to identify SNPs and InDels and used this information to perform target sequence enrichment and high throughput sequencing to genotype a set of SNPs in 149 rubber tree offspring from a cross between RRIM 600 and RRII 105 rubber tree varieties. We used this information to generate a linkage map allowing for the anchoring of 24,424 contigs from 3,009 scaffolds, totalling 115 Mb or 10.4% of the published sequence, into 18 linkage groups. Each linkage group contains between 319 and 1367 SNPs, or 60 to 194 non-redundant marker positions, and ranges from 156 to 336 cM in length. This linkage map includes 20,143 of the 69,300 predicted genes from rubber tree and will be useful for mapping studies and improving the reference genome assembly.

  15. Technology of Rubber Cryogenic Grinding%橡胶低温粉碎技术综述

    Institute of Scientific and Technical Information of China (English)

    杜琳琳

    2012-01-01

    随着我国经济的发展和汽车工业的兴起,橡胶消耗量及废旧轮胎产量正逐年上升。我国每年70%以上的天然橡胶和40%以上的合成橡胶需依赖进口,回收废旧橡胶生产胶粉,既可以作为橡胶原料的补充,又可以缓解"黑色污染"引发的环境问题。介绍了废旧橡胶回收利用方式,提出低温粉碎法是生产精细胶粉的发展方向。通过对液氮冷冻粉碎法、空气冷冻粉碎法和LNG冷能低温粉碎法的比较,提出直接或间接利用LNG冷能低温粉碎生产胶粉,可以降低胶粉生产成本,带动废旧橡胶循环利用产业发展。%With the development of economic and the automobile industry in China,rubber consumption and waste tire production are increasing every year.In China,more than 70 % natural rubber and more than 40 % synthetic rubber need to rely on importing every year.Recycling of waste rubber and producing rubber powder can not only as a complement of rubber raw materials,but also alleviate the environmental problems caused by the "black pollution".It was introduced the way to recycle waste rubber,and indicated that freeze grinding was the developing direction in fine rubber powder production.By comparing freeze grinding in liquid nitrogen,air freeze grinding and LNG cold cryogenic,it was pointed that by direct or indirect using of LNG cold energy to produce rubber powder by cryogenic grinding,the powder production costs can be lower,and it can also drive waste rubber recycling industry development.

  16. Oils and rubber from arid land plants

    Science.gov (United States)

    Johnson, J. D.; Hinman, C. W.

    1980-05-01

    In this article the economic development potentials of Cucurbita species (buffalo gourd and others), Simmondsia chinensis (jojoba), Euphorbia lathyris (gopher plant), and Parthenium argentatum (guayule) are discussed. All of these plants may become important sources of oils or rubber.

  17. Radiation stability of plastics and rubbers

    International Nuclear Information System (INIS)

    Physical radiation effects of #betta# particles, #betta#-radiation, x rays and accelerated electrons on thermosets, thermoplastics and rubbers are charted. Modifications to the information due to composition, shape and environment are noted. (U.K.)

  18. Rubber smallholders' flexibility No windfall, no crisis

    OpenAIRE

    Penot, E.,; F. Ruf

    2001-01-01

    A few decades ago rubber was one of the first tree crops to be characterized by a spectacular breakthrough, the production of new, highly productive clonal material. With regard to rubber, the adoption of clonal planting materials led to a spectacular improvement in labour-productivity and revenues. It requires also different cropping patterns during immature period. An increase in return to labour costs is usually the first priority of smallholders. As this adoption of clones by smallholders...

  19. THERMAL CONDUCTIVITY OF RUBBERIZED GYPSUM BOARD

    OpenAIRE

    Taher Abu-Lebdeh; Ellie Fini; Ashraf Fadiel

    2014-01-01

    The disposal of scrap tires is a challenging task and hence an innovative solution to meet these challenges is needed. Extensive work has been done on the utilization of waste tires in a variety of applications in asphalt pavements and concrete. However, previous investigations focus only on the mechanical properties of the rubberized materials, but few on the thermal performance. This is especially true for rubberized gypsum. Limited or no experimental data on the thermal performance of rubb...

  20. Use of Recycled Tire Rubber in Concrete

    OpenAIRE

    ECT Team, Purdue

    2007-01-01

    More than 250 million scrap tires weighing more than 3 million tons are generated each year in the United States. This is considered as one of the major environmental challenges facing municipalities around the world because waste rubber is not easily biodegradable even after a long period of landfill treatment. One of the solutions suggested is the use of tire rubber particles as additives in cement-based materials. Experiments under the laboratory environments commonly presented that the us...

  1. Draft genome sequence of the rubber tree Hevea brasiliensis

    OpenAIRE

    Rahman Ahmad Yamin Abdul; Usharraj Abhilash O; Misra Biswapriya B; Thottathil Gincy P; Jayasekaran Kandakumar; Feng Yun; Hou Shaobin; Ong Su Yean; Ng Fui Ling; Lee Ling Sze; Tan Hock Siew; Sakaff Muhd Khairul Luqman Muhd; Teh Beng Soon; Khoo Bee; Badai Siti Suriawati

    2013-01-01

    Abstract Background Hevea brasiliensis, a member of the Euphorbiaceae family, is the major commercial source of natural rubber (NR). NR is a latex polymer with high elasticity, flexibility, and resilience that has played a critical role in the world economy since 1876. Results Here, we report the draft genome sequence of H. brasiliensis. The assembly spans ~1.1 Gb of the estimated 2.15 Gb haploid genome. Overall, ~78% of the genome was identified as repetitive DNA. Gene prediction shows 68,95...

  2. Radiation processing of natural polymer in Malaysia

    International Nuclear Information System (INIS)

    Research on radiation processing of natural polymer has been carried out by Nuclear Malaysia since 10 years ago. The progress of the research is at various stages. Radiation processing of sago hydrogel has been commercialized. Meanwhile ago film for packaging is at the pilot scale trial. Palm oil products are ready to be further developed for commercialization with any interested industrial partner. On the other hand, some new materials are being developed based on natural rubber such as liquid natural as compatibilizer, natural rubber thermoplastic nanoclay composites and natural rubber magnetic nano particles composites. (author)

  3. Preferential localizations of super-conductive carbon black in natural rubber compounds and their effects on the electromagnetic properties of materials%天然橡胶共混物中超导电炭黑的偏聚及其对电磁性能的影响∗

    Institute of Scientific and Technical Information of China (English)

    赵鹏飞; 宋喜梅; 吕臻; 罗勇悦; 陶金龙; 何东宁; 龚伟; 张智; 彭政

    2015-01-01

    Super-conductive carbon black (SCCB)was incorporated into natural rubber (NR),epoxidized natural rubber (ENR)and their bend (NR/ENR)to fabricate electromagnetic interference shielding composites via tow-roll mixing.The influences of SCCB contents and matrices nature on the microstructures and electromag-netic properties were systematically investigated.As the results shown,the conductivity and electromagnetic in-terference shielding effectiveness (EMI SE)of all composites gradually increased with the increasing of SCCB contents,presenting obvious percolation behavior and absorption-dominated shielding mechanism.Due to the polarity difference-induced preferential localization of SCCB in NR/ENR blend,the SCCB/NR/ENR showed the greatest improvements in electromagnetic properties,i.e.lowest percolation threshold of 2.1 1vol% (4.0wt%), highest EMI SE of 5.33 dB.Also,the relation between electromagnetic properties and SCCB connectivity was discussed.%采用机械共混法,在天然橡胶(NR)、环氧化天然橡胶(ENR)及其1∶1的共混物(NR/ENR)中添加超导电炭黑(SCCB),制备电磁屏蔽橡胶复合材料,研究了 SCCB 含量和基体极性差异对复合材料结构和电磁性能的影响.结果表明,随着 SCCB 含量增加,复合材料导电率(σ)和电磁屏蔽效能(EMI SE)逐渐增大,σ和 EMI SE 变化符合基于填料浓度的“逾渗”行为,并呈现以吸收为主导的电磁屏蔽机制;由于 NR 与ENR 极性差异诱导的 SCCB 选择性分布,SCCB/NR/ENR 复合材料具有最优的电磁性能,即最低的逾渗值(2.11%(体积分数))和最高的 EMI SE(5.33 dB).此外,还讨论了电磁性能与 SCCB 联通性之间的关系.

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

    NARCIS (Netherlands)

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

    2001-01-01

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

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

    NARCIS (Netherlands)

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

    1997-01-01

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

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

    Science.gov (United States)

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

    2016-07-01

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

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

    Directory of Open Access Journals (Sweden)

    D. A. Baeta

    2009-03-01

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

  8. Effects of preparation process on performance of rubber modified asphalt

    Science.gov (United States)

    Liu, Hanbing; Luo, Guobao; Wang, Xianqiang; Jiao, Yubo

    2015-06-01

    The rational utilization of waste rubber tire is essential for the environmental protection. Utilizing rubber particles to modify asphalt can not only improve asphalt performance, but also help the recycling of waste materials. Considering the effect of different preparation process parameters on the performance of rubber modified asphalt, this paper analyzes the effects of the shear temperature, shear time and shear rate on the performance of rubber modified asphalt, and provided a reference for its preparation.

  9. INVESTIGATION OF ASPHALT PAVEMENT WITH ADDED CRUMB RUBBER

    OpenAIRE

    Mandula, Jan; Olexa, Tomaš; Holubka, Mariya; Salaiova, Brigita

    2014-01-01

    Waste tires must be recycled in environmentally safe ways that meet civil engineering concerns while fulfilling standards for construction materials. Used tires can be processed into rubber powders with particle sizes of 0–2 mm, a suitable fine aggregate for mixing into road pavements. We tested asphalt mixtures with rubber added using the dry method, comparing their properties with a traditional mixture. We tested asphalt–rubber mixtures with rubber incorporated at either ambient temperature...

  10. Use of scrap rubber in asphalt pavement surfaces

    Science.gov (United States)

    Eaton, Robert A.; Roberts, Richard J.; Blackburn, Robert R.

    1991-12-01

    Scrap tire rubber was mixed into an asphalt concrete wearing course to study the effect of ice disbonding from the pavement surface under traffic. Rubber contents of 0, 3, 6, and 12 percent by weight were studied. Initial laboratory ice disbonding test results led to the development of a new paving material, Chunk Rubber Asphalt Concrete (CRAC), that uses larger pieces of rubber in a much denser asphalt concrete mix. Strength values doubled and ice disbonding performance was enhanced.

  11. 推广胶园生物覆盖,促进橡胶产业持续发展%Demonstration on Biologic Mulching in Rubber Plantain to Promote the Sustainable Development of Rubber Industry

    Institute of Scientific and Technical Information of China (English)

    冯育辉; 何维景; 符锡照

    2011-01-01

    With the development of science and technology as well as developing and strengthening forever of natural rubber industry in state farm recently, there are more attentions to the biologic mulching in rubber plantain, which improves greatly construction of ecological environment and promotes medium and little seedlings of rubber fast growing, which influences on bigger and stronger and consistent development of rubber industry, while making great achievements for rubber industry in Guangdong state farm, and even China. In the current 3 years, the technique of stylosanthes planted in rubber plantain is extended, which has made certain economic, social and ecological benefits.%近年来,随着科学技术的发展和农垦天然橡胶产业的不断发展壮大,人们对胶园种植生物覆盖作物越来越重视,胶园种植生物覆盖作物大大改善生态环境建设,促进橡胶中小苗的速生快长,直接影响到橡胶产业的做大做强及持续发展。广东农垦近3年来推广胶园种植柱花草技术,取得了一定的经济、社会和生态效益。

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

    Energy Technology Data Exchange (ETDEWEB)

    Kiyan, Ludmila de Ysasa Pozzo

    2014-07-01

    The natural decomposition of rubber is a very slow process due to its three-dimensional network formed by vulcanized crosslinked structures becoming extremely difficult to reprocess this material. The present work aims to study the application of gamma irradiation as devulcanization process for material reuse/recycling. The interactions of elastomers with ionizing radiation of a gamma source were investigated and the changes in physicochemical properties of the materials were evaluated. Formulations of NBR (acrylonitrile - butadiene) and EPDM (ethylene - propylene - diene terpolymer) from the rubber industry were crosslinked by conventional sulfur-based mixing. Master - batch was processed with rubber powder (industrial waste) and virgin rubber. The raw material (master batch) was irradiated in {sup 60}Co source at doses of 50, 100, 150 kGy and dose rate of 5 kGy h{sup -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)

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

    Directory of Open Access Journals (Sweden)

    Young-Doo Kwon

    2015-01-01

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

  14. [Contemporary state of work conditions and occupational morbidity of workers engaged into rubber, mechanical rubber and tire industries].

    Science.gov (United States)

    Stepanov, E G; Galiullina, É F; Samsonov, V M; Kudriavtsev, V P; Davletgareeva, G R; Shakirova, É D; Khasanov, B G; Buliakov, R T; Kamilov, R F; Shakirov, D F

    2014-01-01

    Based on analysis of materials provided by occupational safety department PC "UZEMiK" and JSC "Kauchuk", the authors evaluate contemporary work conditions and occupational morbidity in workers engaged into rubber, mechanical rubber and tyre industries. PMID:25335420

  15. Investigations on cementitious composites based on rubber particle waste additions

    Directory of Open Access Journals (Sweden)

    Glaucio Laun Nacif

    2013-04-01

    Full Text Available The amount of waste rubber has gradually increased over recent years because of over-growing use of rubber products. The disposal of waste rubber has caused serious environmental problems. The incorporation of recycled materials into cementitious composites is a feasible alternative that has gained ground in civil construction. The performance of such materials is much affected not only by the rubber addition, but also the particle size which has been controversially reported in the literature. In order to investigate the single effect of rubber particles into cement based materials, rubber cementitious composites were prepared with no silica particle additions. A full factorial design has been conducted to assess the influence of the rubber particle size (0.84/0.58 mm and 0.28/0.18 mm; mass fraction used (5, 15 and 30%; and water/cement ratio (0.35 and 0.50 on the physic-mechanical properties of the composites. The materials were characterized through apparent density, porosity, compressive strength, flexural strength, modulus of elasticity and microstructural analysis. The interactions of rubber particle size, rubber fraction and water/cement ratio affected significantly the density and compressive strength of the composites. The apparent porosity was influenced mainly by the rubber particle size. The flexural strength was affected by the main factors and the modulus of elasticity was affected by the interaction factors rubber particle size and fraction, and rubber fraction and w/c ratio.

  16. The Properties of Sulfur Rubber Concrete (SRC)

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The mix designs and specimen preparation for the dry process and wet process of sulfur rubber concrete (SRC) were investigated.The compressive strength, corrosion-resistance and toughness were studied and discussed.The results show that SRC is corrosion-resistanct.Although the compressive strength of SRC decreases with increasing rubber content, the toughness increases instead.Adding micro-filler will improve the compressive strength of SRC. There is a threshold value for the sulfur content, at which the compressive strength and the work ability of SRC reach an optimum balanc e.The bond between rubber particles and surrounding sulfur is strong due to the vulcanization process that generates cross-links through S-C bonds.

  17. Mapping tropical forests and rubber plantations on Hainan Island using PALSAR and multi-temporal Landsat data

    Science.gov (United States)

    Dong, J.; Chen, B.; Xiao, X.; Li, X.; Kou, W.; Wu, Z.

    2015-12-01

    Updated and accurate maps for tropical forests and plantations such as natural rubber (Hevea brasiliensis) are of vital importance for ecological study and optimal forest management practices. However, the existing optical-based efforts are limited by the coverage of clouds and shadows, which is prevent in the tropical regions. In this study, we combined PALSAR 25-m mosaic and 30-m multi-temporal Landsat (TM/ETM+) images to map tropical forests and rubber plantation in Hainan Island, China. Based on PALSAR imagery and maximum NDVI, we first identified tropical forests in 2010 using a decision tree algorithm. The resultant forest map has high accuracy (producer/user accuracy > 96%) and can serve as a reliable base map for rubber plantation mapping. Deciduous rubber plantation subsequently extracted from the PALSAR/Landsat-based forest map according to its high NDVI in peak growing season, and low LSWI during the rapid defoliation and foliation stage. The rubber map had good accuracy when validated by ground truth-based Region of Interests (ROIs) and three farm-scale land use maps. This study has clearly demonstrated the advantage of integrating PALSAR and Landsat images and phenology-based algorithm to map tropical forests and rubber plantation.

  18. Hydrological eco-service of rubber plantations in Hainan Island and its effect on local economic development

    Institute of Scientific and Technical Information of China (English)

    JIANG Ju-sheng; WANG Ru-song

    2003-01-01

    The impacts of economic forest on global environmental change(GEC) are one of the hot issues in environmental study. Based on the 3-year observation data and 40-year climate data, GEC and analysis of the hydrological dynamic characteristics of rubber plantations and estimate of the water balance in the rubber plantations in Hainan Island were made. The results showed that the rainfall intercepted by the canopy of the plantations accounted for 11.45% of the annual rainfall, the total runoff for 23.71%, the total evaporation and transpiration for 63.24%, the soil moisture storage for 1.6%. Analysis of the 40-year rainfall data in the 19 counties of Hainan Island during 1951-1990 showed that the large-scale substitution of the natural vegetation with the rubber plantations had no significant effect on the local rainfall in Hainan Island. The main reasons are (1) 80% of the rainfall in Hainan is brought by typhoons; (2) the proportion of 11.6% rubber plantations in total forest coverage in Hainan is not enough to influence the local rainfall in Hainan Island; and (3) although the rubber plantation is artificial vegetation, it has the similar function to the tropical rain forest. Analysis of the total water resource and total GDP of Hainan in 1997 showed that the economic benefit resulted from the water resource was 1.0 RMBYuan/m3. The value of hydrological of the rubber plantation in Hainan was 113.9 million RMB Yuan/a when compared with the tropical rain forest. The paper reaches conclusion that the hydrological eco-service function of rubber plantation has been enhanced after transformed from natural vegetation, which includes the natural service and powerful social service.

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

    Science.gov (United States)

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

    2001-01-01

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

  20. DURABILITY OF GREEN CONCRETE WITH TERNARY CEMENTITIOUS SYSTEM CONTAINING RECYCLED AGGREGATE CONCRETE AND TIRE RUBBER WASTES

    Directory of Open Access Journals (Sweden)

    MAJID MATOUQ ASSAS

    2016-06-01

    Full Text Available All over the world billions of tires are being discarded and buried representing a serious ecological threat. Up to now a small part is recycled and millions of tires are just stockpiled, landfilled or buried. This paper presents results about the properties and the durability of green concrete contains recycled concrete as a coarse aggregate with partial replacement of sand by tire rubber wastes for pavement use. Ternary cementious system, Silica fume, Fly ash and Cement Kiln Dust are used as partial replacement of cement by weight. Each one replaced 10% of cement weight to give a total replacement of 30%. The durability performance was assessed by means of water absorption, chloride ion permeability at 28 and 90 days, and resistance to sulphuric acid attack at 1, 7, 14 and 28 days. Also to the compression behaviors for the tested specimens at 7, 14, 28 and 90 days were detected. The results show the existence of ternary cementitious system, silica fly ash and Cement Kiln Dust minimizes the strength loss associated to the use of rubber waste. In this way, up to 10% rubber content and 30% ternary cementious system an adequate strength class value (30 MPa, as required for a wide range of common structural uses, can be reached both through natural aggregate concrete and recycled aggregate concrete. Results also show that, it is possible to use rubber waste up to 15% and still maintain a high resistance to acid attack. The mixes with 10%silica fume, 10% fly ash and 10% Cement Kiln Dust show a higher resistance to sulphuric acid attack than the reference mix independently of the rubber waste content. The mixes with rubber waste and ternary cementious system was a lower resistance to sulphuric acid attack than the reference mix.

  1. 黏土及界面剂对乳液插层法天然橡胶纳米复合材料结构与性能的影响%Influence of clay and interfacial agent on structure and properties of natural rubber nanocomposites by emulsion intercalation

    Institute of Scientific and Technical Information of China (English)

    郑云; 项可璐; 张立群; 吴友平

    2011-01-01

    采用乳液插层法制备了黏土/天然橡胶(NR)纳米复合材料,考察了蒙脱土(MMT)、累托石(REC)2种黏土和用界面剂等量替代NR的方式对复合材料微观结构及性能的影响.结果表明,在2种纳米复合材料中,大部分MMT和REC均以纳米片层结构分散在橡胶基体中,与REC片层相比,MMT片层边界模糊且稍微有些弯曲,且层间距变化较大,所填充复合材料的Payne效应更明显.与MMT/NR纳米复合材料相比,REC/NR纳米复合材料的硫化时间稍长,定伸应力、拉伸强度和撕裂强度较高,耐磨耗性能和抗湿滑性较好,抗切割性能下降,抗拉伸疲劳性基本相当;用界面剂等量替代NR时,复合材料的物理机械性能、耐磨性和抗湿滑性得到明显提高.%Clay/natural rubber ( NR) nanocomposites were prepared by emulsion intercalation. The effects of montmorillonite ( MMT) and rectorite ( REC ) and equivalent replacement of NR with interfacial agent on the microstrucure and properties of clay/NR nanocomposites were investigated. The results showed that most of the MMT and REC dispersed as nano-layer in the rubber matrix. The MMT had the blurred and slightly bent edges which was different from REC, and the layer space changed more than that of REC, besides, the Payne effect of MMT/NR nanocomposites was stronger. Compared with MMT/NR nanocomposites, the REC/NR nanocomposites exhibited long curing time; high modulus , tensile strength, tear strength; good skid resistance and abrasion resistance, but the cutting resistance decreased, and the tensile fatigue resistance of both fillers was almost the same. When the equivalent amount of NR was replaced with interfacial agent, the mechanical properties, abrasion resistance and wet skid resistance of the nanocomposites improved obviously.

  2. The Dynamic Characteristics of Silicone Rubber Isolator

    Institute of Scientific and Technical Information of China (English)

    YU Lianjiang; LIU Suling; YE Linming; HUANG Guangsu; XU Yuntao

    2012-01-01

    The dynamic stiffness and the specific damping energy,as well as the vibration response characteristics of a silicone rubber isolator were researched.The results of the vibration test showed that the silicone rubber isolator was excellent in the performance of vibration control.The dynamic stiffness and the damping characteristics were non-linear.From the comparison between experimental results and simulation analysis,the displacement transmissibility characteristics of the isolator were obtained.As a result,the dynamic characteristics of the isolator could be accurately described by the quadratic type non-linear terms at small amplitude.

  3. Asphalt rubber mixtures in Portugal: fatigue resistance

    OpenAIRE

    Miranda, Henrique; Batista, Fátima; Neves, José; Antunes, Maria de Lurdes; Fonseca, Paulo

    2009-01-01

    This paper presents a study concerning the fatigue behaviour of asphalt mixtures with bitumen modified with high content of crumb rubber used in Portugal. For assessing the fatigue behaviour of this type of mixtures, four asphalt mixtures with high content of crumb rubber were used: two field bituminous mixtures – an open-graded and a gap-graded – both with granite aggregates; and two laboratory manufactured bituminous mixtures – an open-graded mixture with granite aggregates and a gap-graded...

  4. Removal Water Turbidity by Crumb Rubber Media

    OpenAIRE

    Abeer I. Alwared; Muna Yousif Abdul-Ahad; Abbas H. Sulaymon

    2014-01-01

    The removal of water turbidity by using crumb rubber filter was investigated .The present study was conducted to evaluate the effect of variation of influent water turbidity (10, 25 and 50 NTU), media size (0.6and 1.14mm), filtration rate (25, 45 and 65 l/hr) and bed depth (30 and 60 cm) on the performance of mono crumb rubber filter in response to the effluent filtered water turbidity and head loss development, and compare it with that of conventional sand filter. Results revealed that 25 l/...

  5. Influence of cerrado fragments in the distribution of mites in rubber tree crop

    International Nuclear Information System (INIS)

    The aim of this study was to verify whether fragments of cerrado influence the composition of the mite fauna on rubber trees. Five transects distant 50 m, being the first in the edge near the native areas and the last 200 m inside the crop, were established in each rubber tree crop in southern State of Mato Grosso. In each transect five plants were chosen, and seven leaves were collected from each plant. During one year, 25 quantitative samplings were conducted in two rubber tree crops. The lowest number of phytophagous mites occurred in the transect closer to the native vegetation, and the highest number, in the most distant from the native vegetation. The largest diversity was also observed in the transect closer to the neighboring vegetation. Ten species of predatory mites were also registered in neighboring native areas. These data suggest the movement of predatory mites from the native areas to the mono culture. These natural areas can possibly supply alternative food and habitat for natural enemies of phytophagous mites in the period of food scarceness in the rubber tree crop. The presence of native areas close to culture areas should be taken into account in the elaboration of programs of ecological management of pests. (author)

  6. Simulation work of fatigue life prediction of rubber automotive components

    Energy Technology Data Exchange (ETDEWEB)

    Samad, M S A [Automotive Engineering Unit, Institute of Advanced Technology, University Putra Malaysia, 43400, UPM Serdang, Selangor (Malaysia); Ali, Aidy, E-mail: aidy@eng.upm.edu.my [Department of Mechanical and Manufacturing Engineering, Faculty of Engineering, Universiti Putra Malaysia, 43400 UPM, Serdang Selangor (Malaysia)

    2010-05-15

    The usage of rubbers has always been so important, especially in automotive industries. Rubbers have a hyper elastic behaviour which is the ability to withstand very large strain without failure. The normal applications for rubbers are used for shock absorption, sound isolation and mounting. In this study, the predictions of fatigue life of an engine mount of rubber automotive components were presented. The finite element analysis was performed to predict the critical part and the strain output were incorporated into fatigue model for prediction. The predicted result shows agreement in term of failure location of rubber mount.

  7. Behaviour of asphalt rubber mixtures with different crumb rubber and asphalt binder sources

    OpenAIRE

    Fontes, Liseane P. T. L.; Pereira, Paulo A. A.; Pais, Jorge C.; Trichês, Glicério

    2006-01-01

    This study evaluates the performance in laboratory of gap graded mixture prepared with different crumb rubber types and different conventional grade asphalt binders. The asphalt rubbers were prepared via wet process (continuous blend) and their properties were measured through the current tests: (i) penetration;(ii) softening point: (iii) resilience; (iv) apparent viscosity using a Brookfield viscometer. The rheological properties for conventional asphalts were measured too, in order to evalu...

  8. Properties of asphalt-rubber binders related to characteristics of the incorporated crumb rubber

    OpenAIRE

    Dantas Neto, Silvrano A.; Farias, Márcio Muniz de; Pais, Jorge C.; Pereira, Paulo A. A.; Santos, Luís Picado

    2003-01-01

    The behavior of asphalt binders modified with recycled crumb rubber depends on several factors, such as: rubber contents and type, temperature and time employed during the digestion process. This paper shows the results of a series of tests performed on asphaltrubber produced via the wet process. The tests included standard penetration, softening point, Brookfield viscosity and resilience. The results show that the limiting variable in the digestion process is the Brookfield vi...

  9. Filled liquid silicone rubbers: Possibilities and challenges

    DEFF Research Database (Denmark)

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

    2014-01-01

    Liquid silicone rubbers (LSRs) have been shown to possess very favorable properties as dielectric electroactive polymers due to their very high breakdown strengths (up to 170 V/μm) combined with their fast response, relatively high tear strength, acceptable Young’s modulus as well as they can...

  10. Numerical modelling of rubber vibration isolators

    NARCIS (Netherlands)

    Beijers, Clemens A.J.; Boer, de André; Nilsson, A.; Boden, H.

    2003-01-01

    An important cause for interior noise in vehicles is structure-borne sound from the engine. The vibrations of the source (engine) are transmitted to the receiver structure (the vehicle) causing interior noise in the vehicle. For this reason the engine is supported by rubber isolators for passive iso

  11. NUTRITIVE VALUE OF RUBBER SEED (Hevea brasiliensis

    Directory of Open Access Journals (Sweden)

    Md. Emran HOSSAIN

    2016-01-01

    Full Text Available The study was undertaken to find out the chemical composition of rubber seeds (Hevea brasiliensis available in Bangladesh. Hevea brasiliensis seeds were collected directly from 200 rubber trees of the rubber garden in the Bandarban area under standard random sampling technique. Seeds were decorticated, ground and dried in hot air oven. Chemical analyses of the samples were carried out in triplicate for moisture, dry matter (DM, crude protein (CP, crude fiber (CF, nitrogen free extract (NFE, ether extract (EE and ash in the animal nutrition laboratory, Chittagong Veterinary and Animal Sciences University, Chittagong, Bangladesh. Metabolizable energy (ME was calculated mathematically by using standard mathematical formula. Results indicated that, decorticated Hevea brasiliensis seeds contained 85.7% DM, 26.1% CP, 43.0% CF, 13.8% NFE, 11.0% EE and 1.8% ash. ME contents in in the seeds was 2101.1 kcal/kg DM. Since, decorticated rubber seeds contained substantial amount of metabolizable energy and proximate components, therefore it could be assumed that, like other unconventional feeds, it might be a promising feed resource for livestock.

  12. Rubber Recycling: Chemistry, Processing, and Applications

    NARCIS (Netherlands)

    Myhre, M.; Saiwari, S.; Dierkes, W.K.; Noordermeer, J.W.M.

    2012-01-01

    For both environmental and economic reasons, there is broad interest in recycling rubber and in the continued development of recycling technologies. The use of postindustrial materials is a fairly well-established and documented business. Much effort over the past decade has been put into dealing wi

  13. Why Do Calculators Have Rubber Feet?

    Science.gov (United States)

    Heavers, Richard M.

    2007-01-01

    Our students like using the covers of their TI graphing calculators in an inquiry-based extension of a traditional exercise that challenges their preconceived ideas about friction. Biology major Fiona McGraw (Fig. 1) is obviously excited about the large coefficient of static friction ([mu][subscript s] = 1.3) for the four little rubber feet on her…

  14. Boron-Loaded Silicone Rubber Scintillators

    Energy Technology Data Exchange (ETDEWEB)

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

    2003-05-12

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

  15. Nature

    OpenAIRE

    Ferretti, Federico; Schmidt Di Friedberg, Marcella

    2012-01-01

    International audience From the ancient times to the present debates on nature and environment, the idea of Nature has been one of the main concepts which interested Geographers. This paper deals with the representations of this idea in the works of thinkers who played a major role in shaping modern Geography, with a special focus on the Mediterranean world. It aims to clarify how Nature was important in defining heuristic strategies of the geographical sciences and their explications of r...

  16. A Model of Appropriate Self-Adjustment of Farmers who Grow Para Rubber (Hevea brasiliensis in Northeast Thailand

    Directory of Open Access Journals (Sweden)

    Montri Srirajlao

    2010-01-01

    Full Text Available Problem statement: Para Rubber was an economic wood growing in Northeast Thailand playing economic and social role. The objectives of this research were to study: (1 the economic, social and cultural lifestyle and (2 the appropriate adjustment model of agriculturists or farmers growing Para Rubber in Northeast Thailand. Approach: The research area covered 6 provinces: Mahasarakam, Roi-ed, Khon Kaen, Nongkai, Udontani and Loei. The samples were selected by Purposive Sampling including: 90 experts, 60 practitioners and 60 general people. The instruments using for collecting data were: (1 The Interview Form, (2 The Observation Form, (3 Focus Group Discussion and (4 Workshop, investigated by Triangulation. Data were analyzed according to the specified objectives and presented in descriptive analysis. Results: The farmers' lifestyle in traditional period of Northeast Thailand was to earn their living from producing by themselves and sharing resources with each other including: rice farming, farm rice growing, vegetable garden growing, searching for natural food without cost wasting one's capital. When it was period of changing, the price of traditional industrial crop was lowered, the agriculturists began to grow Para Rubber instead since the promotion of governmental industrial section. For the economic, social and cultural changes, found that the agriculturists growing Para Rubber Plantation, had more revenue. But, the mechanism of market price and selling had stability was attached with political situation. For the pattern of adjustment of the agriculturists growing Para Rubber Plantation in Northeast Thailand, found that there was an adjustment in individual level for developing their self study by applying body of knowledge learned by experience of successful people by being employed in cutting Para Rubber in The Southern of Thailand as well as the academic support and selling to serve the need of farmers. Conclusion/Recommendations: Para Rubber

  17. Enhancement of flame retardancy of rubber matrix using nanofillers.

    Science.gov (United States)

    Cho, Baik Hwan; Hwang, In Ra; Lee, Youn-Sik; Jeong, Jong Myun; Son, Kae Jung; Nah, Changwoon

    2008-10-01

    Natural rubber (NR) nanocomposites filled with carbon nanotubes (CNT) and organoclay (O-MMT) were prepared by melt mixing, and their vulcanization, mechanical, thermal and flammability properties were characterized. The obtained results were compared with those of carbon black (CB) and pure NR composites. The incorporation of OC reduced drastically the cure times, when compared with CNT and CB-reinforced compounds. The addition of CNT increased considerably the difference between minimum and maximum torques compared with OC and CB-reinforced composites. The mechanical properties were improved by adding nanofillers of CNT and OC. The nanocomposites filled with OC and CNT showed lower peak heat release rate (PHRR) obtained from a cone calorimeter and corresponding reduced surface cracks of formed chars after burning. A slight synergistic effect was found for NR nanocomposite having equal amount of OC and CNT. PMID:19198489

  18. Dry ripened mortar with quarry waste and rubber powder from unserviceable tires

    Directory of Open Access Journals (Sweden)

    José Aparecido Canova

    2015-01-01

    Full Text Available Stone-quarry fines have been evaluated in mortar and concrete, but have presented drying shrinkage and consequently higher incidence of cracks than those with natural sand. This study compared the dry ripened mortar in two types of aggregates added of 8% rubber powder. It was used quicklime, artificial and natural sand in volumetric proportions of 1:6. Mixtures were oven-dried, received the cement, establishing the volumetric proportion of 1: 1.5:9. Inplastic state, we evaluated aspects such as consistence, air content, water retention and bleeding; whereas compressive strength, static deformation modulus and water absorption by capillarity was determined in hardened state. Cracking aspects were evaluated in substrate. As a result, the mortar with artificial sand showed higher increases in compressive strength, capillarity rate and cracking, and greater reductions in air content and bleeding. As for the rubber powder, exhibited a greater reduction in the cracking rate and capillarity was found.

  19. Mechanical Properties of Medium Density Fibreboard Composites Material Using Recycled Rubber and Coconut Coir

    Directory of Open Access Journals (Sweden)

    S. Mahzan

    2010-06-01

    Full Text Available Natural fibre reinforced composite has emerged as highly potential replacement for synthetic fibres. Various natural waste fibres have been adopted for various engineering applications. This paper investigates the mechanical properties of medium density fibreboard composites material fabricated using recycled rubber and coconut coir. The suitability of using recycled rubber and coconut coir as a raw material and polyurethane as a resin in the manufacturer of medium density fibreboard was also studied. The medium density fibreboards were fabricated at prescribed percentages of filler. The performance of composite was evaluated by its mechanical and physical properties. Experimental investigation indicated that the mechanical strength of medium density fibreboards such as modulus of rupture and modulus of elasticity increased with increasing board hardness. Overall, the results showed that medium density fibreboard had been produced with acceptable properties, thus providing alternatives to manufacturing and agricultures economic planning.

  20. Biodiesel Production from Rubber Seed Oil via Esterification Process

    Directory of Open Access Journals (Sweden)

    W Widayat

    2012-07-01

    Full Text Available One promise source of alternative energy is biodiesel from rubber seed oil, because the raw materials available in plentiful quantities and can be renewed. In addition, the rubber seed is still lack of utilization, and Indonesia is one of the largest rubbers producing country in the world. The objective of this research is to studied on biodiesel production by esterification process. Parameters used in this study are the ratio of catalyst and temperature and its influence on the characteristics of the resulting biodiesel product. Characterization of rubber seed include acid content number analysis, saponification numbers, density, viscosity, iodine number, type of free fatty acids and triglyceride oils. The results of analysis showed that rubber seed oil content obtained is 50.5%. The results of the GCMS analysis showed that a free fatty acid level in rubber seed is very high. Conversion into bio-diesel oil is obtained by at most 59.91% and lowest 48.24%.

  1. On the response of rubbers at high strain rates.

    Energy Technology Data Exchange (ETDEWEB)

    Niemczura, Johnathan Greenberg (University of Texas-Austin)

    2010-02-01

    In this report, we examine the propagation of tensile waves of finite deformation in rubbers through experiments and analysis. Attention is focused on the propagation of one-dimensional dispersive and shock waves in strips of latex and nitrile rubber. Tensile wave propagation experiments were conducted at high strain-rates by holding one end fixed and displacing the other end at a constant velocity. A high-speed video camera was used to monitor the motion and to determine the evolution of strain and particle velocity in the rubber strips. Analysis of the response through the theory of finite waves and quantitative matching between the experimental observations and analytical predictions was used to determine an appropriate instantaneous elastic response for the rubbers. This analysis also yields the tensile shock adiabat for rubber. Dispersive waves as well as shock waves are also observed in free-retraction experiments; these are used to quantify hysteretic effects in rubber.

  2. Characterization of crumb rubber modified by gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-07-01

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

  3. CONCRETE-RUBBER TYRES USED IN BIKE PATH = CONCRETO COM BORRACHA DE PNEUS APLICADO EM CICLOVIA

    OpenAIRE

    José Franklin Moreira; Vanessa Rosa Pereira Fidelis; João Fernando Dias

    2014-01-01

    Automotive tires have indefinite decomposition in nature and represent great concern about the environmental impacts. The tires disposed of improperly can cause many problems to accumulate water and enhance the proliferation of disease vectors. When directed to landfills can cause instability due to massive voids generated between them. In the case of incineration generate particulate matter and toxic gases becoming a health risk. The constituents of tires as, rubber, nylon and steel may cons...

  4. MORPHOLOGY,INTERFACIAL INTERACTION AND PROPERTIES OF STYRENE-BUTADIENE RUBBER/MODIFIED HALLOYSITE NANOTUBE NANOCOMPOSITES

    Institute of Scientific and Technical Information of China (English)

    贾德民

    2009-01-01

    A natural nanotubular material,halloysite nanotubes(HNTs),was introduced to prepare styrene-butadiene rubber/modified halloysite nanotube(SBR/m-HNT) nanocomposites.Complex of resorcinol and hexamethylenetetramine (RH) was used as the interfacial modifier.The structure,morphology and mechanical properties of SBR/m-HNT nanocomposites,especially the interfacial interactions,were investigated.SEM and TEM observations showed that RH can not only facilitate the dispersion and orientation of HNTs in SBR matrix ...

  5. Synthetic rubbers prepared by lanthanide coordination catalysts

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    China is rich in rare earth resources. Rare earth elements, also named lanthanides, are number 58 to number 81 elements in the elemental periodic table. They have unique electronic structures and may form various coordination compounds. In the early 1960s, researchers at the Changchun Institute of Applied Chemistry, Chinese Academy of Sciences (CIAC) found the catalytic activities of lanthanide compounds in stereospecific polymerization of conjugated dienes, and published the first paper on this topic in 1964. On the basis of this finding, CIAC launched extensive research activities on lanthanide compounds as diene polymerization catalysts, from a series of fundamental research to the efforts of industrializing the rare earth catalyzed cis-1,4-polybutatine rubber and cis-1,4-polyisoprene rubber. This review aims to summarize the progress in this field in the past half century.

  6. Synthetic rubbers prepared by lanthanide coordination catalysts

    Institute of Scientific and Technical Information of China (English)

    CHEN WenQi; WANG FoSong

    2009-01-01

    China is rich in rare earth resources. Rare earth elements, also named Ianthanides, are number 58 to number 81 elements in the elemental periodic table. They have unique electronic structures and may form various coordination compounds. In the early 1960s, researchers at the Changchun Institute of Applied Chemistry, Chinese Academy of Sciences (CIAC) found the catalytic activities of lanthanide compounds in stereospecific polymerization of conjugated dienes, and published the first paper on this topic in 1964. On the basis of this finding, CIAC launched extensive research activities on lanthanide compounds as diene polymerization catalysts, from a series of fundamental research to the efforts of industrializing the rare earth catalyzed cis~(-1),4-polybutatine rubber and cis~(-1),4-polyisoprene rubber. This review aims to summarize the progress in this field in the past half century.

  7. Quantitative Electron Tomography of Rubber Composites

    International Nuclear Information System (INIS)

    Rubber composite materials have many applications, one example being tyre manufacture. The presence of a filler material in the composite (such as carbon black or silica) causes its mechanical properties to differ in several ways when compared to pure rubber such as viscoelastic behaviour (the Payne effect), increased tensile strength and improved wear resistance. To fully understand these properties, it is necessary to characterise how the filler material is organised on the nanoscale. Using composite materials representative of those found in tyres, this work illustrates the use of electron tomography and machine learning methods as tools to describe the percolation behaviour of the filler; in this case, we focus on the largest proportion of particles absorbed into one single object as a function of particle spacing

  8. Energy recycling of plastic and rubber wastes

    International Nuclear Information System (INIS)

    Major areas for applications of plastics and rubbers are building and construction, packaging, transportation, automobiles, furniture, house wares, appliances, electrical and electronics. Approximately 20% of all the plastics produced are utilized by the building and construction industry/sup (1-3)/. Categories of polymers mostly used in the above industries include poly (vinyl chloride), polypropylene, polyethylene, polystyrene phenolics, acrylics and urethanes. Tyres and tubes are almost exclusively made up of rubbers. One third of total consumption of plastics finds applications, like films, bottles and packaging, in food-products that have a maximum life-span of two years, after which these find way to waste dumps. As the polymer industry in Pakistan is set to grow very rapidly in the near future the increase in utilization of plastic products in synchronous with the advent of computers and information technology. About 0.60 Kg per capita of waste generated daily in Lahore /(7.14)/ contains considerable quantity of plastics. (AB)

  9. Properties of Waste Tire Rubber Powder

    Directory of Open Access Journals (Sweden)

    M. Bekhiti

    2014-08-01

    Full Text Available Scrap tires are abundant and alarming waste. The aggregates resulting from the crushing of the waste tires are more and more used in the field of civil engineering (geotechnical, hydraulic works, light concretes, asphaltic concretes, etc.. Depending on the type of the used tires, dimensions and possible separations and treatment, the physical and mechanical characteristics of these aggregates might change. Some physical, chemical and direct shear tests were performed on three gradation classes of waste tire rubber powder. The tests results were combined with data from previous studies to generate empirical relationships between cohesion, friction angle and particle size of waste tire powder rubber. A cubic (third order regression model seems to be more appropriate compared to linear and quadratic models.

  10. Use of rubber crumb for preparation of asphalt-concrete mixtures

    Directory of Open Access Journals (Sweden)

    Yerbol Tileuberdi

    2012-03-01

    Full Text Available In this article use of rubber crumb from spent tire for preparation of rubber-bitumen compounds is investigated. Then the rubber-bitumen compositions are used in composition of asphalt concrete mixes .

  11. Use of rubber crumb for preparation of asphalt-concrete mixtures

    OpenAIRE

    Yerbol Tileuberdi; S. Kozbakarova; Yerdos Ongarbayev; B. Tuleutaev; Zulkhair Mansurov

    2012-01-01

    In this article use of rubber crumb from spent tire for preparation of rubber-bitumen compounds is investigated. Then the rubber-bitumen compositions are used in composition of asphalt concrete mixes .

  12. Evaluating permanent deformation in asphalt rubber mixtures

    OpenAIRE

    Fontes, Liseane P. T. L.; Trichês, Glicério; Pais, Jorge C.; Pereira, Paulo A. A.

    2009-01-01

    Permanent deformation or rutting, one of the most important distresses inflexible pavements, has long been a problem in asphalt mixtures. Throughout the years, researchers have used different test methods lo estimate the performance of asphalt mixtures in relation to rutting. One of the alternatives to reduce permanent deformation in asphalt pavement layers is through the use of mixtures produced with asphalt rubber This work aims at comparing the performance of a conventional dense graded mi...

  13. Microstructural characterisation of rubber modified asphalt mixtures

    OpenAIRE

    Abdul Hassan, Norhidayah

    2013-01-01

    Research to improve the performance of asphalt mixtures through the addition of crumb rubber using the dry process has continued worldwide because of its potential as a recycling option for used tires. For decades, dry mixed rubberised asphalt mixtures have performed inconsistently in field trials and laboratory evaluations. However, current research has revealed that the performance of asphalt mixtures is highly dependent on the characteristics of its internal structure or phase constituents...

  14. Friction of Pneumatic Rubber Tyres on Snow

    Directory of Open Access Journals (Sweden)

    H. D. Sharma

    1967-10-01

    Full Text Available The paper describes a new apparatus for determination of the friction of pneumatic rubber tyres on snow at different loads for different inflation pressures. It is found that the friction decreases with increase of tyre size. It is also noted that the friction increases with decreasing the temperature below zero degree centigrade. Friction is found dependent on density and bearing capacity of snow. The results refer only to measurements at very slow speed.

  15. Impact resistance of concrete – using slit rubber from tyres

    OpenAIRE

    Coventry, Kathryn; Richardson, Alan; Diaz, Eli

    2015-01-01

    This paper examines recycled tyre rubber, which was machine cut into slits and these were added to Portland cement concrete mixes in different percentages, based on specimen volume. They were then tested to determine the impact performance of each mix in comparison to a plain non-rubberised mix. The results indicated that concrete samples containing recycled rubber, exhibited a loss in compressive strength when compared to the plain concrete mix, however, the rubber modified samples w...

  16. Comparison between asphalt rubber and conventional mixtures in overlay design

    OpenAIRE

    Fontes, Liseane P. T. L.; Trichês, Glicério; Pereira, Paulo A. A.; Pais, Jorge C.

    2008-01-01

    Asphalt modified with crumb rubber has been used to produce asphalt rubber mixtures for pavement overlays subjected to heavy loads and high temperatures. Under severe conditions, these mixtures are capable of resisting permanent deformations, having an extended fatigue life and resisting crack propagation in comparison to conventional ones. A laboratory research was conducted to determine the performance properties of overlays with asphalt rubber mixtures produced through wet processes using ...

  17. The improvement of pavement performance using asphalt rubber hot mixes

    OpenAIRE

    Pais, Jorge C.; Pereira, Paulo A. A.

    2007-01-01

    The need of a better pavement performance has led researchers to develop new road materials, mainly for the asphalt layers, where the modification of the asphalt is the main example. This modification usually forces the use of polymers and fibers and, more recently, the use of crumb rubber from ground tires, where the modified asphalt is known as asphalt rubber. This asphalt rubber used in asphalt mixtures produces a superior performance if compared to the asphalt mixtures with...

  18. Effect of base bitumen composition on asphalt rubber binder properties

    OpenAIRE

    Partl, M.N.; Ould-Henia, M.; Dumont, A.-G.

    2008-01-01

    The asphalt rubber blend properties are strongly related to its base components properties. The base bitumen composition is considered as a key factor influencing the final rheological properties of asphalt rubber binder. This paper describes results from a laboratory investigation of the interaction between crumb rubber and different composition bitumen according to the wet process. The bitumen composition is determined according to the SARA decomposition approac...

  19. Modification of Asphalt by the Use of Crumb Rubber

    OpenAIRE

    Shah Room; Muhammad Aleem; Muhammad Ahmad Rana; Umair Anwar Awan; Sajjad Ali

    2014-01-01

    Health aspects enforced to ponder a study on asphalt which incorporate rubber crumbs to increase strength and flexibility of asphalt. Disposal of waste tires is a menace and it’s a serious problem globally because it is not easily biodegradable as these tires consume large spaces, open burning cause serious problems. By the use of rubber tires, this scrap is utilized efficiently and reduces the cost of asphalt to produce economical system. The asphalt is absorbed by the rubber par...

  20. Laboratory Study on Properties of Rubber-Soils

    OpenAIRE

    Ahmed, Imtiaz

    1993-01-01

    The waste tire problem in the United States is of great magnitude and has far reaching environmental and economic implications. This study investigates the feasibility of using tire chips, alone and mixed with soils, as lightweight material in highway embankments . The report contains: synthesis of all available information and results from laboratory testing of tire chips, rubber-Ottawa sand, and rubber-Crosby till. It is found that rubber-sand with chip/mix ratios of 33% or less exhibits ex...