Study of molecular weight and chain branching architectures of natural rubber

The origin of the unique bimodal molecular weight distribution (MWD) of natural rubber (NR) has been controversial up to now. Studying the connection between particle size and molecular weight (MW) might be a key approach to revealing the mystery of NR architectures. In this study, through constructing NR models as objectives and employing gel‐permeation chromatography coupled to a viscosity detector as well as a multiangle laser light scattering detector (GPC‐DP‐MALLS), we have acquired branching parameters for NR from solid experiments and data fitting. It is found that small rubber particles (SRPs) and large rubber particles (LRPs) jointly construct the unique bimodal MWD of NR. SRPs with low branching numbers (Bn) and branching frequency (λ) are believed to be composed of almost linear rubber molecules having no chain‐end groups to be branched. In contrast, LRPs transform their MWD curve into a clear bimodal peak after transesterification and possess high Bn. Meanwhile, the formation of branch points in LRP by hydrogen bonding and ionic linkages has been clearly confirmed. Thus, a clear and exact structure of NR has been revealed for the first time. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci, 2016.     

中国合成橡胶工业现状

介绍了中国合成橡胶工业的生产消费现状、生产技术开发现状及其发展前景。     

UV treatment of synthetic styrene-butadiene-styrene rubber

The effectiveness of the treatment with ultraviolet light (UV) on several polymeric surfaces has previously been established. In this study, a low pressure mercury vapour lamp was used as a source of UV radiation for the surface treatment of a difficult-to-bond block styrenebutadiene-styrene rubber (S6), the treatment time ranging from 10 s to 30 min. The UV-treated S6 rubber surfaces were characterized by contact angle measurements (ethylene glycol, 25°C), ATR-IR spectroscopy, XPS, Scanning Electron Microscopy (SEM), and Atomic Force Microscopy (AFM). T-peel tests on UV-treated S6 rubber/polyurethane (PU) adhesive/ leather joints (before and after ageing) were carried out to quantify adhesion strengths. The UV treatment of S6 rubber produced improved wettability, the formation of C—O, C=O and COO^- moieties, and ablation (removal of a thin rubber layer from the surface). The extent of these modifications increased with increasing treatment time. The extended UV treatment produced greater surface modifications, as well as the incorporation of nitrogen moieties at the surface. Furthermore, noticeable ablation of S6 rubber surface occurred. Peel strength values increased with increased treatment time of UV treatment of S6 rubber. Also, with increasing treatment time, the adhesive joints showed different loci of failure: adhesional failure for the as-received and 2 min-UV treated S6 rubber/polyurethane adhesive/leather joints changed to mixed failure (cohesive in the treated S6 rubber + adhesional failure) for the 30 min-UV treated S6 rubber/polyurethane adhesive/leather joint.     

Surface modification of synthetic vulcanized rubber

Surface modifications produced by treatments (mainly halogenation) of synthetic vulcanized styrene-butadiene rubber (SBR) leading to increased adhesion properties with polyurethane adhesives have been studied. T-peel tests, scanning electron microscopy (SEM), advancing contact angle measurements, infra-red (IR) spectroscopy, X-ray photoelectron spectroscopy (XPS) and differential scanning calorimetry (DSC) were used to analyze the nature of surface modifications produced in the rubber. Although some surface heterogeneities were created, physical treatments (ultrasonic cleaning, solvent wiping, abrasion) did not noticeably increase the adhesion strength because certain abhesive substances (e.g. zinc stearate, paraffin wax) cannot be removed from the rubber surface by such treatments. Chemical treatment (chlorination) was carried out using ethyl acetate solutions of trichloroisocyanuric acid (TCI) (1,3,5-trichloro-1,3,5-triazine-2,4,6-trione). Chlorination of SBR with trichloroisocyanuric acid produced a significant improvement in T-peel strength, due to the contribution of mechanical (surface roughness, microcracks), thermodynamical (increase of polar contribution to the surface energy) and chemical (removal of abhesive substances, creation of polar groups) rubber surface modifications. The strong adhesion between the chlorinated SBR surface and the polyurethane adhesive was due to the presence of oxidized species of >C=O, -C-OH and -COR type. Chlorination of SBR is a fast reaction which needs only a small concentration of chlorination agent (< 1 wt% TCI/ethyl acetate) to produce high adhesion levels. An increased amount of TCI facilitated the chlorination reaction progressing from the exterior to the internal rubber bulk; however, although a thicker layer of chlorinated rubber created no further increase in adhesion strength was obtained.     

Effect of maturation on the bulk viscosity and molecular chain length of cuplump natural rubber

The effects of the maturation and storage of naturally coagulated latex, generally termed cuplumps, on some bulk rheological properties and on parameters characterizing the macromolecular chain length were investigated for natural rubbers of different clonal typologies. The sensitivity of the clonal material to the degradative effects of cuplump maturation increased with the level of tree energetic metabolism, with the most metabolically active plant materials (e.g., PB 235) being most sensitive, whereas the less active clone PB 217 was less sensitive. A definite relationship evolves between Hevea tree metabolism and the stability of the structure of the biosynthesized rubber. The results presented here highlight at a macromolecular level the effects of maturation previously demonstrated on bulk processing parameters. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 703–708, 2002     

橡胶配方的模糊综合评判

采用模糊综合评判方法对橡胶方进行整体评价,并引入信息效用函数构造权重集和综合评价模型,可得到配方和的优劣顺序。办 胎面胶配方实例表明,此方法可较好地解决多性能指标的橡胶配方综合评价问题。     

离子液体在合成橡胶中的应用

综述了离子液体在合成橡胶的合成和加工中的应用,着重总结了其作为加工助剂和填料改性剂的应用,展望了其今后的发展方向。     

合成橡胶常压氢化及产物性能

简介了合成橡胶的３种常压氢化方法：（１）用水溶性Ｗｉｌｋｉｎｓｏｎ催化剂在常压氢下使合成胶所合成胸乳在常压与氢化。指出第３种方法最有发展前景,用此方法除了可制备氢化度高的丁腈胶乳外,不可制备具有热塑性弹性体性质的氢化丁苯胶乳及氢化聚丁二烯胶乳;最后二者不经硫化即可用于制备老化的浸渍制品、涂料、粘接剂、复合垫片等。     

离子液体在合成橡胶中的应用研究进展

综述了离子液体在合成橡胶的加氢反应、硫化和填料改性等方面的应用,着重总结了其在碳纳米颗粒和无机纳米颗粒填料改性中的应用。     

国内合成橡胶生产技术

评述了中国石油化工集团公司各企业的合成橡胶生产技术,分析了存在的问题和差距,提出了今后发展的建议。     

Natural rubber and its synthetic analogue, polyisoprene rubber, production prospects

One of the main features characterizing the contemporary level of civilization is the universal use of motor transport. Over the past 15 years, global production of cars has increased by more than one and a half, exceeding 80 million vehicles per year. The tire industry has been developing at the corresponding rate.     

合成二氧化硅对硅橡胶性能的影响

介绍了合成二氧化硅及硅橡胶的结构性质，探究了二氧化硅的结构性质对硅橡胶补强性能的影响，指出了二氧化硅颗粒的大小、形态、聚结状态、表面性质和与高分子硅氧烷之间的相互作用是影响二氧化硅对硅橡胶补强性能的最主要的因素，并用实验对硅橡胶的硬度、拉伸强度、300％定伸应力、扯断伸长率、撕裂强度、压缩永久变形等物理性能进行测定，结果表明：BET比表面积180～200m^2／g，孔隙度（吸油量）为3.0～3.2mL／g，平均粒径为8～10岬的沉淀法白炭黑对硅橡胶具有很好的补强效果。     

中国石油天然气股份有限公司合成橡胶工业发展建议

综述了国内外合成橡胶工业现状，指出了我国合成橡胶工业与国外相比存在的差距，提出了中国石油天然气股份有限公司（以下简称“中油股份公司”）合成橡胶工业发展建议。     

近两年我国合成橡胶产量

胶种 2003年 2002年 同比/%聚丁二烯橡胶 39.37 33.75 16.65丁苯橡胶 40.80 35.69 14.32 其中溶聚丁苯 0.94 - -丁腈橡胶 1.69 1.63 3.60SB S 22.44     

2009年国内合成橡胶产业回顾及展望

回顾了2009年我国合成橡胶的产能、产量、进口量、表观消费量以及丁二烯的供应状况,介绍了民营企业在合成橡胶领域的投资建设情况,并对2010年国内合成橡胶发展趋势进行了展望。     

2020年中国合成橡胶行业重大新闻

1战疫情,稳生产,合成橡胶企业攻坚克难,行业发展逆势上扬2020年新冠肺炎疫情肆虐,中国合成橡胶企业全面贯彻疫情防控要求,落实“六稳六保”任务,攻坚克难,努力克服疫情带来的不利影响。经过不懈努力,2020年全行业产量、消费量、利润率等相关经济指标较去年同期均逆势上扬,助力国内经济复苏,全面提振市场信心。