Sample records for chloroprene

  1. Inhalation developmental toxicology studies: Developmental toxicity of chloroprene vapors in New Zealand white rabbits. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Mast, T.J.; Evanoff, J.J.; Westerberg, R.B.; Rommereim, R.L.; Weigel, R.J.


    Chloroprene, 2-chloro-1,3-butadiene, is a colorless liquid with a pungent ethereal odor that is primarily used as an intermediate in the manufacture of neoprene rubber, and has been used as such since about 1930. This study addressed the potential for chloroprene to cause developmental toxicity in New Zealand white rabbits following gestational exposure to 0, 10, 40, or 175 ppm chloroprene vapors, 6h/dy, 7dy/wk. Each treatment group consisted of 15 artificially inseminated females exposed on 6 through 28 days of gestation (dg). Body weights were obtained throughout the study period, and uterine and fetal body weights were obtained at sacrifice on 29 dg. Implants were enumerated and their status recorded and live fetuses were examined for gross, visceral, skeletal, and soft-tissue craniofacial defects. There were no overt signs of maternal toxicity and the change in maternal body weight over the course of the study was not affected. Exposure of pregnant rabbits to chloroprene vapors on 6-28 dg had no effect on the number of implantation, the mean percent of live pups per litter, or on the incidence of resorptions per litter. The incidence of fetal malformations was not increased by exposure to chloroprene. Results of this study indicate that gestational exposure of New Zealand white rabbits to 10, 40, or 175 ppm chloroprene did not result in observable toxicity to either the dam or the offspring.

  2. Chronic inhalation toxicity and carcinogenicity studies on β-chloroprene in rats and hamsters

    NARCIS (Netherlands)

    Trochimowicz, H.J.; Löser, E.; Feron, V.J.; Clary, J.J.; Valentine, R.


    Three groups of 100 Wistar rats and Syrian golden hamsters of each sex were exposed by inhalation to 0, 10, or 50 ppm (v/v) β-chloroprene for 6 h/day, 5 days a week for up to 24 and 18 too, respectively. To maintain the chemical integrity of this highly reactive material in the exposure chambers, β-

  3. Epidemiologic evidence for chloroprene carcinogenicity: review of study quality and its application to risk assessment. (United States)

    Bukowski, John Arthur


    This article evaluates the quality and weight of evidence associated with epidemiologic studies of cancer among occupational cohorts exposed to chloroprene. The focus is on liver, lung, and lymphohematopoietic cancers, which had been increased in early studies. Literature searches identified eight morbidity/mortality studies covering seven chloroprene-exposed cohorts from six countries. These studies were summarized and their quality was assessed using the 10 criteria suggested by the U.S. Environmental Protection Agency. The limitations within this literature (primarily the early studies) included crude exposure assessment, incomplete follow-up, uncertain baseline rates, and uncontrolled confounding by factors such as smoking, drinking, and co-exposure to benzene and vinyl chloride. Four cohorts were studied by the same group of investigators, who reported no overall increased associations for any cancers. This four-cohort study was by far the most rigorous, having the most comprehensive exposure assessment and follow-up and the most detailed documentation. This study also contained the two largest cohorts, including an American cohort from Louisville, Kentucky, that ranked at or near the top for each of the 10 quality criteria. There was evidence of a strong healthy worker effect in the four-cohort study, which could have hidden small excess risks. Small increased risks were suggested by internal or company-specific analyses, but these were most likely caused by uncontrolled confounding and low baseline rates. Overall, the weight of evidence does not support any substantial link between chloroprene exposure and cancer, but inconsistencies and a lack of control for major confounders preclude drawing firmer conclusions.

  4. Three-dimensional modeling of chloroprene rubber surface topography upon composition

    Energy Technology Data Exchange (ETDEWEB)

    Žukienė, Kristina, E-mail: [Department of Clothing and Polymer Products Technology, Kaunas University of Technology, Studentu St. 56, LT-51424 Kaunas (Lithuania); Jankauskaitė, Virginija [Department of Clothing and Polymer Products Technology, Kaunas University of Technology, Studentu St. 56, LT-51424 Kaunas (Lithuania); Petraitienė, Stase [Department of Applied Mathematics, Kaunas University of Technology, Studentu 50, LT-51368 Kaunas (Lithuania)


    In this study the effect of polymer blend composition on the surface roughness has been investigated and simulated. Three-dimensional modeling of chloroprene rubber film surface upon piperylene-styrene copolymer content was conducted. The efficiency of various surface roughness modeling methods, including Monte Carlo, surface growth and proposed method, named as parabolas, were compared. The required parameters for modeling were obtained from atomic force microscopy topographical images of polymer films surface. It was shown that experimental and modeled surfaces have the same correlation function. The quantitative comparison of function parameters was made. It was determined that novel parabolas method is suitable for three-dimensional polymer blends surface roughness description.


    ABSTRACTbeta-Chloroprene (2-chloro-1,3-butadiene, CD) which is used in the synthesis of polychloroprene, caused significant incidences of several tumor types in B6C3F1 mice and Fischer rats, but not in Wistar rats or Syrian hamsters. This project investigates the relevance o...

  6. Interaction of Chloroprene and Nitrile- Butadiene Rubber with Lubricating Greases and Base Oils

    Institute of Scientific and Technical Information of China (English)


    The present communication addresses compatibility of two synthetic rubber types, chloroprene and nitrilebutadiene ones, with a number of base oils of petroleum origin and lubricating greases produced thereof. Four base oils,including three naphthenic products with varying degrees of refining and one paraffinic product,were compared with each other in terms of their effect on the rubbers. Degenerative changes occurring in the rubbers on contact with the oils and greases were studied using accelerated ageing tests. Alterations in rubber parameters, such as hardness, weight and glass transition temperature, caused by interaction with oil were monitored. The main physicochemical mechanisms standing behind the changes observed in the rubber properties were found to be (i) migration of plasticizer from rubber into the oil phase, (ii) absorption of oil by rubber,and (iii) oxidation of rubber. An increase in glass transition temperature (Tg) of rubber aged in a base oil or grease was considered as an indirect indication that the plasticizer had migrated out of rubber;the plasticizer accumulation in the oil phase being directly confirmed by gas chromatography. In order to suppress the plasticizer migration, oil additivation with dioctyl adipate (DOA), a common plasticizer used in rubber formulations, was attempted. However, the BOA-additivated oils, while reducing plasticizer migration, were found to cause more swelling than the original oils in the case of chloroprene rubber. As an alternative, replacement of BOA by an alkylated aryl phosphate in nitrile- butadiene rubber formulations was considered, but it did not solve the problem either.The results of this study suggest conclusively that the type of rubber, the plasticizer, and the base oil are all the crucial parameters that should be considered when matching rubber with oil in real- life applications. Interaction of rubber with base oils and with greases produced thereof is largely controlled by (i) solvency of the

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

    Directory of Open Access Journals (Sweden)

    Khalil Ahmed


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

  8. 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)


    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.

  9. Compression Tests of the Rectangular Plain Chloroprene Rubber Bearings in Salty Frozen Condition%盐冻条件下矩形氯丁橡胶支座受压性能试验

    Institute of Scientific and Technical Information of China (English)

    沈小俊; 陈伯奎; 高飞; 谢应爽; 郑怡; 马良


    为了研究矩形氯丁橡胶支座在盐冻条件下的各项力学性能指标变化,将矩形氯丁橡胶支座分别进行20,40,60,80 d盐冻处理,并采用压力试验机对其进行轴心受压试验,研究盐冻对矩形氯丁橡胶支座的承载力、极限抗压强度、竖向刚度、抗压弹性模量的影响.试验结果表明:在盐冻条件下,矩形氯丁橡胶支座更易发生脆性破坏,弹性阶段缩短,发生钢板外露、裂缝、层状破坏等现象更严重;承载力、极限抗压强度、竖向刚度、抗压弹性模量随盐冻程度的加深而逐渐降低.采用最小二乘法对试验结果进行回归得到盐冻条件下矩形氯丁橡胶支座50 a抗压强度及抗压弹性模量衰减曲线和衰减模型,统计分析表明衰减曲线和衰减模型符合实际情况.%In order to do the research on the change of the mechanical indexes of the rectangular plain chloroprene rubber bearings,the rectangular plain chloroprene rubber bearings were processed under salty frozen condition for 20,40,60 and 80 days.Moreover,the axial compression tests were also carried out by pressure testing machine.The effect of the salt-frost on bearing capacity,ultimate compressive strength,vertical stiffness,and compressive elastic modulus of the rectangular plain chloroprene rubber bearings was also studied.The results showed that in salty frozen condition,brittle fracture of the plain chloroprene rubber bearings was easier to appear; the elastic stage was shorten and the phenomenon of steel plate exposure,cracks and layered destruction were more serious; the bearing capacities,ultimate compressive strength,vertical stiffness,and elastic modulus of compression decreased with the deepening of the salty frozen degree.The attenuation curve of compressive strength and compressive elastic modulus and the attenuation model were acquired in 50 years by regression analysis with the least square method.The statistical analysis result shows that the


    Institute of Scientific and Technical Information of China (English)

    任庆海; 马养民; 张天福


    杜仲胶作为热塑性材料具有优异的低温可塑加工性和优良的耐水、耐寒、耐酸碱、高绝缘等特性,同时还具有高阻尼性,并且利用其高阻尼性可制作隔音设备与减震材料.作者将杜仲胶与氯丁橡胶共混,加入发泡剂,制备了具有良好吸声和隔音性能的杜仲胶/氯丁橡胶复合材料,并研究了复合材料各组分的最佳配比、发泡剂的最佳用量及其硫化特性.%Gutta-percha as low-temperature thermoplastic materials has excellent processing of plastic, excellent water resistance, cold resistance, acid and alkali resistance, high insulation and high damping.Gutta-percha can be used for insulation and damping materials due to its high damping of the system.In this paper, gutta-percha and chloroprene rubber were blended, and foaming agent was added into composite.Meanwhile, we studied the optimum proportion of the composite, the optimum amount of foaming agent and the curing characteristics of the composite.

  11. Point mutations of K-ras and H-ras genes in forestomach neoplasms from control B6C3F1 mice and following exposure to 1,3-butadiene, isoprene or chloroprene for up to 2-years. (United States)

    Sills, R C; Hong, H L; Boorman, G A; Devereux, T R; Melnick, R L


    1,3 Butadiene (BD), isoprene (IP) and chloroprene (CP) are structural analogs. There were significantly increased incidences of forestomach neoplasms in B6C3F1 mice exposed to BD, IP or CP by inhalation for up to 2-years. The present study was designed to characterize genetic alterations in K- and H-ras proto-oncogenes in a total of 52 spontaneous and chemically induced forestomach neoplasms. ras mutations were identified by restriction fragment length polymorphism, single strand conformational polymorphism analysis, and cycle sequencing of PCR-amplified DNA isolated from paraffin-embedded forestomach neoplasms. A higher frequency of K- and H-ras mutations was identified in BD-, IP- and CP-induced forestomach neoplasms (83, 70 and 57%, respectively, or combined 31/41, 76%) when compared to spontaneous forestomach neoplasms (4/11, 36%). Also a high frequency of H-ras codon 61 CAA-->CTA transversions (10/41, 24%) was detected in chemically induced forestomach neoplasms, but none were present in the spontaneous forestomach neoplasms examined. Furthermore, an increased frequency (treated 13/41, 32% versus untreated 1/11, 9%) of GGC-->CGC transversion at K-ras codon 13 was seen in BD-, and IP-induced forestomach neoplasms, similar to the predominant K-ras mutation pattern observed in BD-induced mouse lung neoplasms. These data suggest that the epoxide intermediates of the structurally related chemicals (BD, IP, and CP) may cause DNA damage in K-ras and H-ras proto-oncogenes of B6C3F1 mice following inhalation exposure and that mutational activation of these genes may be critical events in the pathogenesis of forestomach neoplasms induced in the B6C3F1 mouse.

  12. Research on Wearability of nano-Attapulgite/Chloroprene Rubber Composites%纳米凹凸棒土/氯丁橡胶复合材料耐磨性的研究

    Institute of Scientific and Technical Information of China (English)

    宋帅帅; 姚亮; 吴友平


    Attapulgite(AT)/chloroprene rubber(CR) composites was prepared by using mechnical mixing technology,and effects of AT content, modifier kinds and content and curing systems on wear-ability of the composites were discussed,and the surface morphology of Akron abrasion of the composites having the different modifiers was observed, too. The results showed that the wearability of the composites was the best when the amount of AT was 30 phr; Modifier KH —550 was an effective coupling agent in increasing the wearability of the composites,and the optimal content was 3% of AT content; The wearability was different by using different curing systems. The wearability of the composites was the best when curing agents MgO/ZnO/DCP mass ratio was 4/5/1.%采用机械共混法制备了凹凸棒土(AT)/氯丁橡胶(CR)纳米复合材料,探讨了AT用量、改性剂种类及用量和硫化剂体系等对复合材料耐磨性能的影响,还观察了使用不同改性剂制备的复合材料阿克隆磨耗表面形态.结果表明,AT用量为30份时复合材料耐磨性最好;改性剂KH-550能显著提高硫化胶耐磨性,其最佳用量为AT用量的3%;硫化体系不同时复合材料的耐磨性有所不同,采用MgO/ZnO/DCP(质量比为4/5/1)并用硫化体系时复合材料耐磨性最好.

  13. 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)



    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.

  14. Physical properties of blended and vulcanizednitrile-butadiene rubber/chloroprene rubber%共混硫化丁腈橡胶-氯丁橡胶的物理性能

    Institute of Scientific and Technical Information of China (English)



    将丁腈橡胶(NBR)和氯丁橡胶(CR)按不同质量分数共混并硫化,研究了硫化橡胶在自然环境、热空气老化、热油老化等条件下的物理性能,并测定了硫化橡胶与镀铜钢丝的粘合性能.结果表明,随着 CR 质量分数的增大,混炼胶的焦烧时间逐渐缩短.经热空气老化后,NBR 的硬度增加幅度比 CR 的硬度增加幅度大,拉断强度降低幅度则比 CR 的小得多.此外,NBR 的耐油性能优于 CR.就物理性能以及与镀铜钢丝的粘合性能而言,单一 NBR 和单一 CR 优于共混 NBR/CR.%Nitrile-butadiene rubber (NBR)and chloroprene rubber (CR)were blended at differ-ent mass fractions and vulcanized,followed by aging at various conditions.The physical prop-erties of the vulcanized rubbers aged at ambient condition as well as in hot air and hot oil were determined,and their adhesion to Cu-coated steel wires was measured as well.Results indicate that,with the increase of the mass fraction of CR,the scorch time of the gross rubber tends to decline gradually.After being aged in hot air,the hardness of vulcanized NBR tends to rise more noticeably than that of vulcanized CR,while the tensile strength of the vulcanized NBR reduces at a much less extent than that of the vulcanized CR.Moreover,vulcanized NBR exhib-its better resistance against oil than vulcanized CR,while mono NBR and mono CR are advan-tageous over blended NBR/CR in terms of the physical properties and adhesion to Cu-coated steel wire.

  15. 阻燃氯丁橡胶的无焰燃烧与阻燃性能%Flameless combustion and flame retardant properties of retardant chloroprene rubber

    Institute of Scientific and Technical Information of China (English)

    李森; 李洪成; 周兵; 李荣勋


    将十溴二苯乙烷(DBDPE)、成碳剂(CTJ)、化学膨胀剂(IFR)复配阻燃氯丁橡胶,利用氧指数(LOI)和锥形量热仪(CONE)探讨了十溴二苯乙烷与CTJ、IFR复配阻燃氯丁橡胶的协同效应,通过扫描电镜研究表征样品的断面形貌.结果表明,当三者共用15份,且DBDPE∶CTJ∶IFR比例为7∶2∶6时,阻燃CR体系的无焰燃烧时间为7 s,同时LOI达到了40%,热释放速率只有纯CR的11.4%,生烟速率为纯CR的30.8%,表现出一定的协同作用;从样品燃烧后的断面扫描电镜照片看出,兼有了物理成炭和化学成炭的优点,提高了阻燃性能.

  16. Coordinating Support of Fuels and Lubricant Research and Development (R&D) 2. Delivery Order 0002: Handbook of Aviation Fuel Properties - 2004 Third Edition (United States)


    oxygen while the second, a higher temperature pyrolysis process, is independent of oxygen. With stable hydrocarbons, deoxygenation greatly reduces low...Recommended for Use in Turbine Fuels Low Density Polyethylene (LDPE) Ethylene Propylene Dimer (EPDM) Chloroprene Styrene Butadiene ( SBR ) Isobutylene...Recommended for Use with Aviation Gasoline Fuels Low Density Polyethylene (LDPE) Chloroprene Styrene Butadiene ( SBR ) Ethylene Propylene Dimer (EPDM

  17. 硝酸腐蚀条件下公路桥梁氯丁橡胶支座抗剪试验%Shearing Tests of Plain Chloroprene Rubber Bearings of Highway Bridge under Acid Corrosion Condition

    Institute of Scientific and Technical Information of China (English)

    司月华; 王桂玲; 刘铭


    本研究将氯丁橡胶支座完全浸泡在pH为4.5的硝酸溶液中,对5组试件分别浸泡20d、40d、60d、80d、100d,将浸泡试件与标准件进行抗剪试验,将腐蚀试件与标准件的抗剪承载力、极限抗剪强度、水平等效刚度、抗剪弹性模量的数据进行对比分析,结果表明,氯丁橡胶支座在硝酸溶液浸泡后,其抗剪弹性阶段明显缩短,破坏程度更严重;从数据分析得,浸泡天数越多,其抗剪承载力、极限抗剪强度、抗剪弹性模量越小.%The neoprene bearings are completely soaked in nitric acid solution with pH=4.5, the five groups of speci-mens are soaked respectively for 20 d, 40 d, 60 d, 80 d, 80 d, thesoaked specimen andstandard partsare arried out with shear test.The data of shear bearing capacity,ultimate shear strength, equivalent stiffness and shear modulus of elasticity for the corrosion specimens are compared and analyzed with thoseof standard parts.The results show that af-ter soaking in nitric acid solution,neoprene bearing has significantly reduced shear elastic stage, and more serious damage. From the data analysis, it can be obtained that the more days it is soaked, itsshear bearing capacity, ultimate shear strength, shear elastic modulus become smaller .

  18. Compression Tests of Plain Chloroprene Rubber Bearings of Highway Bridge under Acid Corrosion Condition%硝酸腐蚀条件下公路桥梁板式氯丁橡胶支座受压试验

    Institute of Scientific and Technical Information of China (English)

    张延年; 司月华; 张军; 刘圣杰; 郑怡


    目的 研究硝酸腐蚀条件下公路桥梁板式氯丁橡胶支座受压性能的变化规律.方法 采用pH =4.5的硝酸溶液对公路桥梁板式氯丁橡胶支座进行20 d、40d、60 d、80 d、100 d的全浸泡处理,利用5 000 kN的压力试验机进行轴心受压试验,从承载力、极限抗压强度、抗压弹性模量、竖向刚度对腐蚀试件与标准件进行对比分析.结果 经硝酸腐蚀后,氯丁橡胶支座的抗压弹性阶段变短,且破坏更加严重;其承载力、极限抗压强度、抗压弹性模量随处理天数的增加而逐渐下降.结论 采用最小二乘法对使用0 ~50年后的橡胶支座的抗压强度和弹性模量进行分析,其衰减函数及衰减曲线大致符合指数函数的变化规律.%This paper studies compression performance change rules of highway bridge slab neoprene bearing under acid corrosion conditions.Do the full immersion treatment of 20 d,40 d,60 d,80 d,100 d on highway bridge slab neoprene bearing using pH =4.5 nitric acid solution,use 5 000 kN pressure tester for axial compression experiments,and compare the corrosion specimen to standard parts form analyzing bearing capacity,ultimate compressive strength,compressive elastic modulus,the vertical stiffness and so on.The experiment results show that the compressive elastic stage of neoprene bearings becomes shorter and the damage is more serious after the acid corrosion;Its bearing capacity,ultimate compressive strength,compressive elastic modulus gradually decline along with the processing days increasing.Analyze compressive strength and elastic modulus of the rubber bearing which are used for 0 ~ 50 years by using the least square method,its attenuation formula and decay curve are broadly in line with the changing rule of the exponential function.

  19. 船用电缆用低烟低卤阻燃氯丁橡皮护套研究%Research on the formulation of the low smoke and low halogen chloroprene rubber sheathing compound for shipboard cable

    Institute of Scientific and Technical Information of China (English)




  20. JNS-1改性氯丁胶乳水泥砂浆在碱厂的应用%Application of JNS-1 Modified Chloroprene Latex Cement Mortar in the Soda Plant

    Institute of Scientific and Technical Information of China (English)

    刘锋; 丛志栋; 张宪军; 王旭东; 王永飞



  1. Influence of Ultrasonic Vibrations on the Static Friction Characteristics of a Rubber/Aluminum Couple

    Institute of Scientific and Technical Information of China (English)

    程廷海; 高焓; 包钢


    A novel ultrasonic vibration approach is introduced into a chloroprene rubber/aluminum friction couple for improving the static friction properties betwesn rubber and metal.Compared to the test results without vibrations,the static friction force of a chloroprene rubber/aluminum couple decreases observably,leading to the ultimate displacement of rubber.The values of the static friction force and ultimate displacement can be ultimately reduced to 23.1% and 50% of those without ultrasonic vibrations,respectively.%A novel ultrasonic vibration approach is introduced into a chioroprene rubber/aluminum friction couple for improving the static friction properties between rubber and metal. Compared to the test results without vibrations, the static friction force of a chioroprene rubber/aluminum couple decreases observably, leading to the ultimate displacement of rubber. The values of the static friction force and ultimate displacement can be ultimately reduced to 23.1% and 50% of those without ultrasonic vibrations, respectively.

  2. Evaluation of an artificial intelligence program for estimating occupational exposures. (United States)

    Johnston, Karen L; Phillips, Margaret L; Esmen, Nurtan A; Hall, Thomas A


    Estimation and Assessment of Substance Exposure (EASE) is an artificial intelligence program developed by UK's Health and Safety Executive to assess exposure. EASE computes estimated airborne concentrations based on a substance's vapor pressure and the types of controls in the work area. Though EASE is intended only to make broad predictions of exposure from occupational environments, some occupational hygienists might attempt to use EASE for individual exposure characterizations. This study investigated whether EASE would accurately predict actual sampling results from a chemical manufacturing process. Personal breathing zone time-weighted average (TWA) monitoring data for two volatile organic chemicals--a common solvent (toluene) and a specialty monomer (chloroprene)--present in this manufacturing process were compared to EASE-generated estimates. EASE-estimated concentrations for specific tasks were weighted by task durations reported in the monitoring record to yield TWA estimates from EASE that could be directly compared to the measured TWA data. Two hundred and six chloroprene and toluene full-shift personal samples were selected from eight areas of this manufacturing process. The Spearman correlation between EASE TWA estimates and measured TWA values was 0.55 for chloroprene and 0.44 for toluene, indicating moderate predictive values for both compounds. For toluene, the interquartile range of EASE estimates at least partially overlapped the interquartile range of the measured data distributions in all process areas. The interquartile range of EASE estimates for chloroprene fell above the interquartile range of the measured data distributions in one process area, partially overlapped the third quartile of the measured data in five process areas and fell within the interquartile range in two process areas. EASE is not a substitute for actual exposure monitoring. However, EASE can be used in conditions that cannot otherwise be sampled and in preliminary

  3. Study on NR/CR Blends Technology%NR/CR并用胶共混性能研究

    Institute of Scientific and Technical Information of China (English)

    黄庆; 白健


    Natural rubber and chloroprene rubber blends technology was developed and the effect of ratio between NR/CR on the property of the rubber was studied. The results showed that natural rubber and chloroprene rubber blends has the better mechanical properties. With more natural rubber in composition, the blend cures fast, and the flame resistance and weather aging performances of the rubber are poor,while with more chloroprene rubber in composition solvent resistance and flame resistance of the rubber are better.%研究了天然橡胶和氯丁橡胶的共混工艺,并研究了NR/CR二者之间并用比例对并用胶性能的影响.结果显示,天然橡胶和氯丁橡胶分别加填料混炼均匀后再共混在一起,共混胶的各项物理力学性能较好,并用胶组成中,天然橡胶比重大时,硫化速度较快,但耐天候老化及阻燃性差.氯丁橡胶比重大时,耐溶剂性和阻燃性较好.

  4. Degradation mechanisms of organic rubber and glass flake/vinyl ester linings in flue gas desulphurization plants

    Energy Technology Data Exchange (ETDEWEB)

    Weber, R. [Allianz-Centre for Technology GmbH, Ismaning (Germany)


    In recent years, there have been reports in numerous publications about damage to rubber and glass flake coatings in flue gas desulphurization plants. The pattern of damage has been described and attempts have frequently been made to determine and explain the cause of the damage. Oxidation/hydrolytic changes were generally observed as the damage mechanisms. In addition, blistering occurs in both the chloroprene coatings in the absorbers and in the glass flake coatings in clean gas ducts. This blistering may be considered as the end of the useful life and leads to cost-intensive and time-intensive repair and restoration measures. The present state of knowledge suggests that the blistering is mainly due to osmotic processes preceded by permeation processes and with permeation processes superimposed on them. Among other things, the reports describe the permeation behaviour of water and other flue gas constituents; the blistering in chloroprene rubber coatings and glass flake coatings is explained by means of the knowledge gained. (au) 16 refs.

  5. A new role for glutathione: protection of vitamin B12 from depletion by xenobiotics. (United States)

    Watson, William P; Munter, Tony; Golding, Bernard T


    NADPH in microsomes reduces the hydroxocob(III)alamin form of vitamin B12 to cob(II)alamin and the supernucleophilic cob(I)alamin, which are both highly reactive toward xenobiotic epoxides formed by mammalian metabolism of dienes such as the industrially important chemicals chloroprene and 1,3-butadiene. With styrene, the metabolically formed styrene oxide is reactive toward cob(I)alamin but not cob(II)alamin. Such reactions in humans could lead to vitamin B12 deficiency, which is implicated in pernicious anemia, cancer, and degenerative diseases. However, glutathione inhibits the reduction of hydroxocob(III)alamin by formation of the 1:1 complex glutathionylcobalamin. This blocks reactions of the cobalamins with metabolically formed epoxides. The interaction between glutathione and vitamin B12 could protect against diseases related to vitamin B12 depletion.

  6. Inferring Alcoholism SNPs and Regulatory Chemical Compounds Based on Ensemble Bayesian Network. (United States)

    Chen, Huan; Sun, Jiatong; Jiang, Hong; Wang, Xianyue; Wu, Lingxiang; Wu, Wei; Wang, Qh


    The disturbance of consciousness is one of the most common symptoms of those have alcoholism and may cause disability and mortality. Previous studies indicated that several single nucleotide polymorphisms (SNP) increase the susceptibility of alcoholism. In this study, we utilized the Ensemble Bayesian Network (EBN) method to identify causal SNPs of alcoholism based on the verified GAW14 data. Thirteen out of eighteen SNPs directly connected with alcoholism were found concordance with potential risk regions of alcoholism in OMIM database. As a number of SNPs were found contributing to alteration on gene expression, known as expression quantitative trait loci (eQTLs), we further sought to identify chemical compounds acting as regulators of alcoholism genes captured by causal SNPs. Chloroprene and valproic acid were identified as the expression regulators for genes C11orf66 and SALL3 which were captured by alcoholism SNPs, respectively.

  7. Pembuatan lem sintetik dan aplikasinya pada alas kaki

    Directory of Open Access Journals (Sweden)

    Arum Yuniari


    Full Text Available Footwear can be categorized as one of labour intensive and very superior export commodities, consequently the product quality must be maintained and be continually improved. The quality parameter of footwear is determined by the bonding strength between the uppers and the soles, it means that it depends on the adhesive applied. Soling system is widely applied in small and medium industries are cemented system used synthetic adhesive. Now, the adhesive was applied in the manufacturing of foot wear supported by binding of the soles and the uppers is easy to peel off because of the poor bonding strength. The aim of the research was to investigate a suitable synthetic adhesive formula to used in footwear manufacturing. In preparing of the adhesive formula, the effect of phenolic resin addition as tackifier were varies i.e 35, 45 and 55 phr using chloroprene rubber as raw material were observed. Synthetic adhesive compound was produce by two roll mill after that compound were dissolved in toluene with ratio 1 : 3. The prepared adhesive then was applied to manufacture footwear using cool press system. The soles used in the experiment were made of rubber and plastic material whereas the uppers made of either leather or artificial leather. The test result and data analysis showed that adhesive performed for the highest bonding strength as much as 1000 g/cm and decrease to lowest bonding strength after soaking in to water for 500 seconds one percent was obtained by the following formula that were : chloroprene rubber 100 phr, butylated hydroxyl toluene 2 phr, magnesium oxide 4 phr, zinc oxide 5 phr and phenolic resin 45 phr. The prepared formula performed a better bonding strength when it was compared with chloroperene rubber adhesive in market. The application of this prepared formula in making ladies shoes performed good bonding strength and accordance with the requierments of SNI 12-2942-1992 about Leather Pantopel Style Cemented System Ladies Shoes.

  8. 汽车用橡胶减震材料新型环保配方研究%Study on the Formula of new Environmental Protection Rubber Damping Material for Automobile

    Institute of Scientific and Technical Information of China (English)



    笔者研究了氯丁橡胶、三元乙丙橡胶共混胶:防老剂4020、防老剂RD、防老剂NBC,硫化促进剂TATD在橡胶减震材料中的应用,从经济环保的角度进行了新的配方设计,并进行了性能(邵尔A型硬度、拉伸强度、扯断伸长率、老化系数和耐久性)测试。通过对实验结果分析,确定氯丁橡胶、三元乙丙橡胶共混胶的在橡胶减震材料配方的壤佳比例及防老刑4020、防老荆RD、防老剂NBC的优化配伍比例。通过对比实验.结果表明:问等条件下,生产相同的橡胶减震材料产晶,使用硫化促进剂TATD的制品综合性能要优于使用硫化促进剂TMTD的制品.且用量少。%The author studied the application of chloroprene rubber, ethylene propylene diene monomer (EPDM) rubber blends, antioxidant 4020, antioxidant RD, antioxidant NBC and vulcanization accelerator TATD in the rubber damping material product, made the new formulation design from the economic and environmental protection angle, and tested properties (Shore A hardness, tensile strength, elongation at break, aging coeffcient and durability). The author through the analysis of experimental results, found out the best proportion of chloroprene rubber and EPDM rubber in the rubber damping material formula. The author also found out the optimized compatibility proportion of antioxidant 4020, anti0xidant RD and antioxidant NBC in the formula. By comparing the experimental results, the properties use vulcanization accelerator TATD were better than which use vulcanization accelerator TMTD in the same conditions producing rubber damping material. Also the used quantity was less.

  9. 氯丁橡胶的老化和寿命预测研究%Study on neoprene rubber aging and shelf-life predictions

    Institute of Scientific and Technical Information of China (English)

    王锋; 董玉华; 郭文娟; 丁晓东; 周琼


    The thermal oxidative aging properties of neoprene at 55 ℃ ,70 ℃ ,85 ℃, 100 ℃ were determined by using accelerated aging method at laboratory. The aging mechanism of chloroprene rubber was determined by IR: thermal aging on the C = C;85 ℃ ,100 ℃ the side groups Cl was away from the main chain. The relationship between properties and aging time of neoprene was established, and predicted at 25 ℃ neoprene storage life is twenty years.%通过对氯丁橡胶在55℃、70℃、85℃、100℃下热空气加速老化的实验,研究了氯丁橡胶的老化机理并进行了寿命预测.红外分析结果说明氯丁橡胶的老化机理为:热氧老化在C=C上进行;85℃、100℃侧基Cl脱离主链.以扯断伸长率为指标进行寿命预测,可知氯丁橡胶在本实验条件下的贮存寿命约为20 a.

  10. Occurence and implications of radiation dose-rate effects for material aging studies (United States)

    Gillen, Kenneth T.; Clough, Roger L.

    A number of commercial cable materials, including ethylene propylene rubber and crosslinked polyolefin insulations and chloroprene and chlorosulfonated polyethylene jackets have been radiation aged in air and nitrogen at radiation dose rates ranging from approximately 10 3 to 10 6{rad}/{hr}. Material degradation was followed using ultimate tensile properties (elongation and tensile strength), swelling measurements and infrared spectroscopy. The tensile results indicate that in air environments radiation dose rate effects are important for all four materials, with more mechanical damage occurring as the dose rate is lowered. These results are interpreted as coming from a competition between crosslinking and oxidative scission in which scission becomes more important as the dose rate is lowered. The swelling results offer direct evidence in support of this interpretation. In addition the infrared results show increased carbonyl content at lower dose rates, also indicative of increased oxidation. The conclusions of this study have important implications for the qualification of elastomeric materials for nuclear applications, since they clearly indicate that the mechanism of degradation is quite different (and the amount usually more severe) under low dose rate exposures compared to the mechanism occurring under the high dose rate exposures normally utilized for stimulating the natural aging.

  11. Adesivos poliméricos à base de SBR: influência de diferentes tipos de agentes promotores de adesão SBR-based polymeric adhesives: influence of different types of adhesion promoting agents

    Directory of Open Access Journals (Sweden)

    Mauro E. C. B. Pinto


    Full Text Available Neste trabalho, foi desenvolvido um novo adesivo não estrutural à base de copolímero de SBR com alto teor em estireno (SBR-53. O objetivo deste novo produto é avaliar a possibilidade de sua utilização no segmento moveleiro, em substituição ao adesivo de policloropreno (CR-M, cujo polímero-base é importado. Diferentes formulações de adesivos foram desenvolvidas, específicas para a indústria moveleira, e o desempenho do elastômero SBR-53 foi comparado ao dos elastômeros SBR-23 comercial (SBR tradicional - baixo teor de estireno e CR-M, quanto à estabilidade em solução, viscosidade e propriedades mecânicas.In this work a new non-structural adhesive based on a high styrene content SBR copolymer (SBR-53 was developed. This new product is intended to be used in the furniture segment, to replace the chloroprene rubber (CR-M adhesive, whose base polymer is imported. Different adhesive formulations were developed specifically for the furniture industry, and the performance of the elastomer SBR-53 was compared to that of commercial elastomers SBR-23 (low-styrene traditional SBR and CR-M, as for solution stability, viscosity and mechanical properties.

  12. Carcinogenicity and mechanistic insights on the behavior of epoxides and epoxide-forming chemicals. (United States)

    Melnick, Ronald L


    Many epoxides and their precursors are high production volume chemicals that have major uses in the polymer industry and as intermediates in the manufacture of other chemicals. Several of these chemicals were demonstrated to be carcinogenic in laboratory animal studies conducted by the Ramazzini Foundation (e.g., vinyl chloride, acrylonitrile, styrene, styrene oxide, and benzene) and by the National Toxicology Program (e.g., ethylene oxide, 1,3-butadiene, isoprene, chloroprene, acrylonitrile, glycidol, and benzene). The most common sites of tumor induction were lung, liver, harderian gland, and circulatory system in mice; Zymbal's gland and brain in rats; and mammary gland and forestomach in both species. Differences in cancer outcome among studies of epoxide chemicals may be related to differences in study design (e.g., dose, duration, and route of exposure; observation period; animal strains), as well as biological factors affecting target organ dosimetry of the DNA-reactive epoxide (toxicokinetics) and tissue response (toxicodynamics). N7-Alkylguanine, N1-alkyladenine, and cyclic etheno adducts, as well as K-ras and p53 mutations, have been detected in animals and/or workers exposed to several of these chemicals. The classifications of these chemical carcinogens by IARC and NTP are based on animal and human data and results of mechanistic studies. Reducing occupational and environmental exposures to these chemicals will certainly reduce human cancer risks.

  13. Effect of zinc oxide nanoparticles synthesized by a precipitation method on mechanical and morphological properties of the CR foam

    Indian Academy of Sciences (India)

    Rudeerat Suntako


    ZnO nanoparticles were synthesized by a precipitation method in aqueous media from zinc nitrate hexahydrate and sodium hydroxide. The synthesized ZnO nanoparticles exhibited a crystalline structure with hexagonal structure of the wurtzite. The morphology of the synthesized ZnO nanoparticles presented a spherical shape with the average primary size of 54.53 nm and the specific surface area of 20.28 m2 g−1. The effect of the synthesized ZnO nanoparticles by the precipitation method as a crosslinking agent for chloroprene rubber foam (CR foam) on cure characteristics, mechanical properties and morphologies was investigated. The aim of this study is to vary the synthesized ZnO nanoparticles’ level in the range of 0.5–5 parts per hundred parts of rubber (phr) compared with the conventional ZnO at 5 phr. The rheological characterization showed that the maximum torque (H), the minimum torque (L), the differential torque (H–L) and Mooney viscosity increased with the increase in synthesized ZnO nanoparticles’ content, whereas the optimum cure time (90) and scorch time (5) decreased. On the other hand, the mechanical properties such as hardness, tensile strength and specific gravity were improved. For CR foam, the results compared to the amount of conventional ZnO, only 60 wt% (3 phr) nano-ZnO was enough to obtain similar cure characteristics and mechanical properties. The synthesized ZnO nanoparticles showed the mechanical properties higher than conventional ZnO because of small particle size and large specific surface area which led to the increase in the degree of crosslinking.

  14. Permeation of 70% isopropyl alcohol through surgical gloves: comparison of the standard methods ASTM F739 and EN 374. (United States)

    Mäkelä, Erja A; Vainiotalo, Sinikka; Peltonen, Kimmo


    Standard test methods ASTM F739 and EN 374 were compared by assessing the permeation of 70% isopropyl alcohol (2-propanol) through seven brands of surgical gloves. The two standards differ in the flow rates of the collection medium and in the chemical permeation rate at which the breakthrough time (BTT) is detected, the EN detection level being 10 times higher than the permeation rate used by ASTM. In a departure from the EN standard method, a 4 h testing time was used instead of 8 h. All of the tested gloves were from the same manufacturer and were made from either natural rubber (NR) (six brands) or chloroprene rubber (CR) (one brand). Two of the NR glove brands were double layered. For the thin NR gloves (0.22, 0.28 and 0.27 mm) the permeation rates were higher throughout the tests with a flow rate of 474 ml/min (EN) of the collection medium (nitrogen) compared with the permeation rates obtained with a flow rate of 52 ml/min (ASTM). These resulted in BTTs of 4.6, 6.5 and 7.6 min (EN) and 4.8, 6.5 and 9.1 min (ASTM), respectively. No statistical difference could be observed between the BTT values obtained with the two standard methods for any of the thin gloves. Thus, although the ASTM standard has a lower criterion for the detection of permeation, it does not necessarily produce shorter BTTs. For the better barriers the methods yielded more equivalent permeation rate curves and thus the EN BTTs were longer than the ASTM BTTs: the EN results were 21, 80, 122 and >240 min compared with the ASTM results of 12, 32, 38 and 103 min for glove thicknesses of 0.37 (NR), 0.22 + 0.22 (double layered NR), 0.31 + 0.29 (double layered NR) and 0.19 mm (CR), respectively.

  15. 麻疯树籽油生物柴油-0#柴油混合燃料与橡胶、塑料的兼容性%Compatibility of rubbers and plastics in Jatropha curcas L. biodiesel-0#diesel blended fuels

    Institute of Scientific and Technical Information of China (English)

    张家栋; 尚琼; 鲁厚芳; 梁斌


    Biodiesel derived from transesterification of Jatropha curcas L. oil has a good application prospect as a renewable energy. To analyze and evaluate the compatibility of Jatropha curcas L. biodiesel and its blends of petroleum diesel with materials which were used in transportation,storage and application,interactions between eight materials (four types of rubbers and four types of plastics) and Jatropha curcas L. biodiesel-0#diesel were analyzed. The results showed that acid value and viscosity of fuels met national standards after immersion for 28-56 days. Fluorine rubber showed a good compatibility with the fuels,its weight and hardness changed a little,the increase rate of thickness was less than 18.00%,and the decrease rate of tensile strength was less than −22.00%. On the contrary,chloroprene rubber,EPDM rubber and butadiene acrylonitrile rubber were incompatible with the fuels for a long time. The changes of thickness and weight of four types of plastics were small,and their mechanical properties showed good stability.%  麻疯树籽油是制备生物柴油的优良原料油,由其制得的生物柴油具有良好的应用前景。为了分析和评价在运输、储存和使用过程中麻疯树籽油生物柴油与材料的相互影响,本文主要考察了4种橡胶和4种塑料分别与麻疯树籽油生物柴油-0#柴油混合燃料的相互作用及影响。试验结果表明:生物柴油混合燃料与材料接触28~56天后,其酸值和运动黏度仍满足国家标准要求;氟橡胶质量、硬度变化小,厚度的变化率小于18.00%,拉伸强度变化率小于−22.00%,有较好的耐甲酯性,而氯丁橡胶、三元乙丙橡胶及丁腈橡胶不能长期使用;生物柴油混合燃料对4种塑料厚度、质量的影响较小,其稳定性较好。

  16. Hand protection from ultraviolet exposure

    Energy Technology Data Exchange (ETDEWEB)

    Khazova, M.; O' Hagan, J.B. [Health Protection Agency, Radiation Protection Division, Chilton, Did cot (United Kingdom)


    Full text of publication follows: A number of industrial applications and public services involve exposure to ultraviolet radiation (U.V.R.) from a variety of lamps and lasers, for example, in forensic examination, biological trans-illuminators, dentistry, laser material processing, microelectronics, etc. The proposed European Union Directive on Optical Radiation would place specific requirements on employers to provide adequate safety measures to reduce exposure to U.V.R., including gloves for hand protection. The selection of gloves should be based on a risk assessment and on the performance characteristics of the gloves for the task. However, current International and national standards do not describe evaluation procedures of disposable gloves for hand protection against non-ionising radiation. A methodology for assessment of the UV protection level for disposable gloves and a simple measurement protocol are proposed, based on a common approach with UV protection by clothing and sunscreens. Glove Ultraviolet Protection Factor is defined as a time-scale increase in exposure permitted for the hand protected by a glove with respect to an unprotected hand. However, the wide variety of U.V.R. sources and the real-life conditions of glove use (stretching and wetting the surface by liquids) bring substantial challenges to the assessment method. Our study of {approx} 50 samples of widely used disposable gloves made of different materials (nitrile, vinyl, latex and chloroprene) showed that for all tested gloves a change in U.V.R. attenuation with stretching is characteristic for the type of glove material and can be included as a scaling factor in the definition of U.V.R. protection. Glove material has a bigger effect on U.V.R. protection level than variations in the glove thickness or its colour. The following approaches are suggested to overcome the problem of variable U.V.R. sources: - Worst case scenario minimal protection level, most restrictive case - Application

  17. Dynamic Mechanical Properties and Johnson-Cook Type Constitutive Equation of Wood Rubber Shock Absorber for Vehicle%车用木橡胶减震器动态力学性能及Johnson-Cook型本构方程

    Institute of Scientific and Technical Information of China (English)

    齐英杰; 孙奇; 马岩


    [Objective]The main purposes of this paper is to analyze the mechanical properties of wood rubber shock absorber for vehicle,to obtain the Johnson-Cook constitutive equation and to check out whether the equation can exactly describe the relationships of stress and strain for wood rubber shock absorber for vehicle. [Method]We select the small Xing’an mountain Korean pine (Pinus koraiensis) wood with the density of 0. 439 g cm -3 and moisture content of 12%, chloroprene rubber which has good elasticity,high bonding strength,flexible layer,resistant to impact and vibration is also used as experimental materials. Micrometer-level fiber forging machine is applied to process the dried red pine wood into wood fiber,then put these wood fiber into the kneading machine,and obtain the micro wood fiber with width of 1 -2 mm,length of 15 -30 mm. The specimens of wood rubber shock absorber for vehicle were prepared by several processes including the preparation,weighing,mixing,molding,holding pressure,unloading,and so on. Dynamic compression tests on the specimens of wood rubber shock absorber for vehicle are performed by using Split Hopkinson pressure bar,and get the curves at the strain rate of 1 250 s -1 ,1 500 s -1 and 1 750 s -1 ,respectively. Finally,using the experimental data and Origin software to ascertain the parameters of Johnson-Cook constitutive equation,then the Johnson-Cook constitutive equation,and the experimental curve and the curve fitted by the Johnson-Cook constitutive equation is established and compared,respectively.[Result]Theφ10 mm × 10 mm specimens of wood rubber shock absorber for vehicle were made, the stress and strain curves at the strain rate of 1 250 s -1 ,1 500 s -1 and 1 750 s -1 were obtained by dynamic compression tests,and the Johnson-Cook constitutive equation ( σ = [21 +0.329(ε)1.16]×[1 +0.148ln(·ε* )]) of wood rubber shock absorber for vehicle are successfully established. [Conclusion]By analyzing the stress and strain curves of