Comparison of bound rubber and swelling in silicone rubber/silica mixes and in silicone rubber vulcanizates

Unextracted polymer and liquid absorption values have been determined on unvulcanized silicone rubber/silica mixes and on unfilled silicone rubber vulcanizates, for comparison of the two different types of three-dimensional structure which must exist. In both types, the amount of rubber extracted on immersion in liquid is dependent on the expansion of the respective network but only in the former is the amount dependent on the method of extraction; this is attributed to interaction between filler and rubber continuing as a result of immersion. Even at equilibrium, the amount of unextracted polymer can be greater than that of bound rubber. In some mixes, liquid absorption is substantially constant during extraction of considerable amounts of soluble rubber. This is attributed, in the presence of filler, to a dependence of the absorption on the previously postulated interparticular rubber which, in turn, is dependent on the mean distance between filler particles. Although unextracted polymer is also dependent on that mean distance, it is proposed that this is a secondary effect of network expansion by the absorbed liquid. As some published values of bound rubber have undoubtedly been of unextracted polymer, these results help to explain published differences of opinion on the value of bound rubber for investigation of filler reinforcement phenomena.     

溶剂法制备天然橡胶结合胶的研究

结合胶是未硫化的混炼胶中不能被其良溶剂溶解的那部分橡胶。用化学溶剂法制备结合胶具有药品用量小、实验过程操作简单,重现性好等优点。通过讨论橡胶加入量、炭黑用量、反应时间、静置时间等因素,确定了溶剂法制备结合胶的最佳工艺参数,并与混炼法制备的结合胶进行了性能对比。结果表明,橡胶在甲苯溶液中的质量浓度约为0.02g/mL、橡胶和炭黑的质量比为2∶1、反应时间为14h、静置时间为72h的工艺参数下,可以制得高质量结合胶。混炼法制备的结合胶的质量比溶剂法制备的结合胶的质量大。但是其具有与溶剂法结合胶相同的抽提温度曲线,在结合胶的实验研究中,可以用溶剂法代替混炼法。     

A molecular explanation for the origin of bound rubber in carbon black filled rubber compounds

Some of the theories that have been developed to explain the origin of bound rubber are critically reviewed and discussed with respect to published data. Theories for carbon black filled compounds and for silica–silicone rubber mixtures are considered; the phenomena involved are likely to be very different, with clear chemical aspects for the latter systems. A common feature emerges, however, from these theories: the area of the polymer–filler interaction site, which is generally considered as a fitting parameter in most approaches. This article concentrates on this aspect and suggests that, with respect to recent findings about the very surface of carbon black particles, an explanation for bound rubber can be offered that considers strong topological constraints exerted by the filler surface on rubber segments. Calculations of interaction site area made with experimental data give values close to a fraction of the half-lateral surface of the structural unit representative of the rubber considered. It follows that the bound rubber variation during storage can now be understood by considering a slow replacement of short rubber chains initially adsorbed on filler particles by larger ones, as demonstrated by calculated data. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 2257–2268, 1997     

Studies on natural rubber bound para-phenylenediamine antioxidants in NBR

Para-phenylenediamine (PD) was chemically attached to depolymerized natural rubber by a photochemical reaction. The rubber bound PD was characterized by TLC, ¹H-NMR, IR, and TGA. The efficiency and permanence of the bound PD were compared with conventional antioxidants in NBR vulcanizates. The rubber bound PD was found to be less volatile and more resistant to water and oil extraction. The vulcanizates showed improved aging resistance in comparison to vulcanizates containing conventional antioxidants. The liquid rubber bound antioxidant reduces the amount of plasticizer required for compounding. © 1995 John Wiley & Sons, Inc.     

New oligomer‐bound antioxidants in natural rubber/polybutadiene rubber and natural rubber/styrene–butadiene rubber blends

New paraphenylene diamine antioxidants were prepared. The efficiency and permanence of these oligomer‐bound paraphenylene diamines were compared with those of conventional amine‐type antioxidants in elastomer blends such as natural rubber/styrene–butadiene rubber and natural rubber/polybutadiene rubber. These oligomer‐bound antioxidants showed improved aging resistance and ozone resistance in comparison with the blends containing conventional antioxidants. The liquid oligomer‐bound paraphenylene diamine could replace the plasticizer required for compounding. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 437–443, 2004     

Polymer/particulate filler interaction—the bound rubber phenomena

In Part I, after an historical note on the subject of bound rubber, the experimental determination of bound rubber and the many factors affecting the value, in the case of the organic rubber/carbon black and silicone rubber/silica systems, are reviewed. Mention is made of the relation between swelling index and bound rubber and, in Part II, the accuracy and significance of bound rubber values are appraised.Some experimental work on the natural rubber/fine particle black system is described in Part III; this assesses qualitatively the rigidity of swollen jellies of the (unvulcanized) mixtures and shows how it is not correlated with either bound rubber or solvent content. Other experiments lead to the conclusion that the uptake of solvents of different solubility parameters compares with that of a pure gum vulcanisate, indicating no significant or substantial change in the solubility parameter of the rubber on becoming insolubilized. Results are reported on bound rubber determinations in solutions of rubber and it is suggested that these provide a method of arriving at the true bound rubber value. The discussion which forms Part IV suggests how the two structures, postulated recently as present in polymer/filler systems, might be further analysed to explain the phenomena.     

Reinforced chloroprene rubber by in situ generated silica particles: Evidence of bound rubber on the silica surface

Nano silica is generated in situ inside the uncrosslinked chloroprene rubber (CR) by the sol‐gel reaction of tetraethoxysilane (TEOS). This results in appreciable improvement in mechanical properties of the CR composites at relatively low filler content. Furthermore, exploitation of reactive organosilanes, γ‐aminopropyltrimethoxysilane (γ‐APS) in particular, in the silica synthesis process facilitates growing of spherical silica particles with a size distribution in the range of 20‐50 nm. The silica particles are found to be uniformly dispersed and they do not suffer from filler‐filler interaction. Additionally, it is observed that the silica particles are coated by silane and rubber chains together which are popularly known as bound rubber. The existence of the bound rubber on silica surface has been supported by the detailed investigations with transmission electron microscopy (TEM), energy filtered transmission electron microscopy (EFTEM) and energy dispersive X‐ray spectroscopy (EDAX). The interaction between rubber and silica, via bi‐functionality of the γ‐APS, has been explored by detailed FTIR studies. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43717.     

提高硅橡胶密封材料粘结性和耐温性的途径

介绍了提高双组分室温硫化硅橡胶密封材料粘结性能和耐温性能的途径,重点阐述了采用硅氮聚合物作为双组分室温硫化硅橡胶密封材料的硫化体系,可有效消除硅橡胶端基引发的解扣式降解,使硅橡胶密封材料具有更高的热稳定性。有效提高了粘结性能和耐温性能。其粘结强度可由未处理硅酸酯硫化体系的0.43 MPa提高到2.35 MPa。     

自动凯氏定氮法测定丁腈橡胶中结合丙烯腈含量

采用自动凯氏定氮法测定丁腈橡胶(NBR)中结合丙烯腈含量,研究了催化剂组成、试样的消解温度和消解时间对测定结果的影响,考察了方法的精密度和准确性,并与现行的SH/T 1157—1997方法进行了对比。结果表明,采用硫酸钾和硫酸铜混合催化剂(二者质量比为8∶1)消解试样时,最佳消解温度为420℃、消解时间为2 h,方法的标准差为0.110%~0.215%,2次重复测定结果的绝对差不大于重复性限0.35%或0.45%。该方法与SH/T 1157—1997测定结果差值为0.27%~0.43%,小于规定值,方法的准确性高;与SH/T 1157—1997方法相比,该方法可同时消解的试样数从2个提高到10~20个,蒸馏时间由60 min缩短到5~10 min。     

结合橡胶对SBR/BR并用胶界面相互作用的影响

通过对采用不同结合橡胶控制工艺制备的SBR/BR并用胶进行界面相互作用分析,研究结合橡胶对SBR/BR并用胶界面相互作用的影响。结果表明,采用SBR控制结合橡胶工艺可以形成更多的结合橡胶,使填料得以均匀分散;采用分子链柔顺性较好的BR控制结合橡胶,有利于提高两相通过填料形成的相互作用,从而提高并用胶体系相容性。     

低结合苯乙烯含量溶聚丁苯橡胶的制备及性能

以四氢糠醚(THFA)为结构调节剂合成了结合苯乙烯质量分数为15％的溶聚丁苯橡胶(SSBR),考察了结构调节剂THFA的用量、聚合温度对微观结构、耐低温性能、门尼黏度及拉伸强度的影响.结果表明,玻璃化转变温度(Tg)随结合苯乙烯质量分数的增加呈线性增加;随THFA用量的增加,1,2-结构质量分数增大,Tg随着THFA用...     

中结合苯乙烯含量丁苯橡胶在轮胎中的应用研究

考察了采用中结合苯乙烯含量丁苯橡胶SBR1756制备轮胎的流变性能、老化性能、抗湿滑性能、滚动阻力以及耐磨耗性能,并与SBR1723N制备的轮胎性能进行了对比。研究结果表明,采用SBR1756制备的轮胎抗湿滑性能和耐磨耗性能优于采用SBR1723N制备的轮胎,两者的滚动阻力相当。     

Effect of bound rubber on characteristics of highly filled styrene–butadiene rubber compounds with different types of carbon black

Viscosity and cure time of a filled rubber compound having an accelerated sulfur cure system are affected by types and contents of the rubber and the filler as well as of the curatives. Bound rubber content is used as level of the reinforcement. Influence of bound rubber on viscosity and cure time of a rubber compound was studied using highly filled styrene–butadiene rubber compounds with carbon black having different structures. The bound rubber content increases with increase of the carbon black content and also increases as the carbon black structure is developed. The Mooney viscosity increases linearly with increase of the bound rubber content irrespective of the carbon black structure when the primary particle size of carbon black is nearly the same. The Mooney scorch time decreases linearly with increase of the bound rubber content irrespective of the carbon black structure. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1001–1006, 2004     

中结合苯乙烯含量丁苯橡胶聚合影响因素研究

在传统丁苯橡胶聚合的基础上研究了中结合苯乙烯含量的丁苯橡胶基础胶乳聚合过程中3个最重要影响因素——单体配比、引发剂和调节剂含量对聚合过程的影响,从而确定中结合苯乙烯含量的丁苯橡胶基础胶乳聚合过程中三者的配方用量分别为:丁二烯/苯乙烯单体质量比64/36~60/40,引发剂用量0.06~0.08份,调节剂用量0.15~0.16份。     

Stabilization of nigeria natural (havea) rubber with bound antioxidant added as masterbatch

Nigeria natural rubber concentrates in a newly synthesized antioxidant were added as conventional additives for normal natural rubber. The natural weathering, thermal and photooxidative protective performance of the adduct were examined by measurement of the carbonyl index and induction periods. From the results obtained, it is concluded that the addition of this new antioxidant in the form of masterbatch appears to be a better practical way of incorporating it into natural rubber simply by dilution of natural rubber. The bound stabilizers were found to be resistant to leaching.     

溶剂法制备碳纳米管结合胶及其微观结构的研究

利用溶剂法制备碳纳米管结合胶,确定了制备高质量碳纳米管结合胶的实验参数：橡胶／甲苯溶液的质量浓度为0．020g／mL,橡胶与碳纳米管的质量比为4：1,反应时间为7h。用扫描探针显微镜对天然橡胶、碳纳米管及其结合胶的微观形貌进行研究,得到了碳纳米管结合胶的清晰结构。碳纳米管结合胶的结构为天然橡胶分子在定向紧密排列的碳纳米管的两侧沿着纳米管的表面与碳纳米管结合形成环状的闭合结构,随着纳米管管径的增大,结合胶的结构趋向于炭黑结合胶的结构。     

橡胶轮胎摩擦理论与数值化发展前景

轮胎摩擦是关系汽车安全行驶的重要力学行为,汽车的操纵稳定性主要来自轮胎-路面间的摩擦力,对轮胎的研究具有重要的意义.大量的研究表明,轮胎的摩擦系数不仅与摩擦表面材料性能有关,而且与载荷、表面形态、相对滑动速度、环境因素有关,所有这些影响因素都不是线性的关系.从不同的角度详细地阐述了轮胎的研究进展情况,并通过对相关研究成果的分析,指出了下一步研究方向.     

结合丙烯腈量对丁腈橡胶/炭黑硫化胶热降解性能的影响

采用热失重分析法和差示扫描量热法研究了结合丙烯腈量对丁腈橡胶/炭黑硫化胶热降解性能及热降解活化能的影响。结果表明,在降解反应初期首先发生交联环化反应,然后发生断链降解反应。交联反应放出的热量随结合丙烯腈量的增加而降低,最大放热峰温受结合丙烯腈量的影响不大。断链降解过程分为2个阶段,分别受结合丙烯腈量和丁二烯单元含量的影响。初期断链降解受腈基含量影响较大,腈基起到催化和加速降解的作用;430℃以上的失重行为与丁二烯单元的含量有关;494℃以上的降解受丁腈橡胶成炭性质的影响。不同结合丙烯腈量的丁腈橡胶/炭黑硫化胶的降解活化能趋近。     

高结合苯乙烯含量且均匀无规分布的溶聚丁苯橡胶的合成(英文)

采用负离子活性聚合的方法,以正丁基锂为引发剂、环己烷为溶剂、四氢呋喃为极性调节剂、叔戊醇钾为无规化剂,合成了结合苯乙烯质量分数为40%且均匀无规分布、1,2-结构质量分数为35%~40%的溶聚丁苯橡胶;考察了四氢呋喃用量和叔戊醇钾用量对产物的苯乙烯无规分布均匀性、1,2-结构含量等的影响。结果表明,四氢呋喃只能使苯乙烯-丁二烯无规共聚,苯乙烯的均匀无规分布主要受叔戊醇钾加入量的影响;当四氢呋喃和叔戊醇钾与正丁基锂的摩尔比分别为50和15.33×10-3时,在整个大分子链的增长过程中结合苯乙烯含量都保持在设计值附近,表明苯乙烯在大分子链上基本为均匀无规分布;四氢呋喃对于产物1,2-结构含量的调节起主要作用,而叔戊醇钾基本无影响,二者对产物的相对分子质量及其分布和共聚组成基本无影响。     

基于分形理论的橡胶复合材料磨耗表面形貌表征

利用橡胶高温磨耗试验机,进行不同温度、角度、负荷及路面条件下的高温磨耗试验,获得具有不同形貌的橡胶磨耗试样。借助3D测量显微镜采集橡胶试样表面形貌图像并进行表征,对橡胶表面磨耗形貌图像进行黑白二值化处理,利用分形理论建立多重分形谱分析模型,定量分析不同试验条件下橡胶试样表面磨耗形貌,定性描述表面磨耗形貌分布特点。研究结果表明,橡胶复合材料磨耗表面形貌具有明显的分形特征,橡胶磨耗性能(磨耗量)随着温度、角度、负荷和路面粗糙度增大而增大。