微观结构含量对稀土高顺式聚丁二烯性能的影响

Effects of Microstructure on Properties of Neodymium-based Cis Polybutadiene Rubber

采用羧酸钕催化剂体系催化丁二烯可控/活性配位聚合,制备了顺-1,4结构含量>98.0%的Nd-BR;采用膦酸酯钕催化剂体系催化丁二烯配位聚合制备了顺-1,4结构含量为94.9%的Nd-BR,并选择数均分子量(M_(n))及分子量分布指数(M_(w)/M_(n))接近但顺式结构含量不同的国外商业化产品进行对比,研究顺-1,4微观结构含量对其生胶及混炼胶加工性能、硫化胶物理机械性能及动态力学性能的影响.结果表明:当稀土高顺式聚丁二烯顺-1,4结构含量由94.9%逐渐升高至98.8%时,生胶强度逐渐提升,应力松弛速率逐渐加快,改善了生胶及混炼胶加工性能,与炭黑混炼效果更优,在提高炭黑结合胶含量的同时降低了Payne效应.少量顺式结构含量的提升可增强应变诱导结晶能力,从而可明显提升硫化胶拉伸强度和撕裂强度、耐磨性、耐刺扎性及耐屈挠裂口增长;降低轮胎滚动阻力的同时提高轮胎抗湿滑性,可以更好地平衡耐磨性、抗湿滑性及滚动阻力之间的矛盾,满足绿色轮胎“魔三角”的需求.顺式含量~98.5%的独特结构和合适的分子量分布(~2.8),赋予其优异的生胶加工性能、硫化胶物理机械性能及动态力学性能,适合于作为绿色轮胎橡胶原材料使用.

Neodymium-based polybutadiene rubber(Nd-BR)with cis-1,4 content>98.0%was prepared by neodymium carboxylate-based catalyst system and Nd-BR with cis-1,4 content of 94.9%was prepared by neodymium phosphonate-based catalyst system.Commercial products with similar molecular weight(M_(n))and molecular weight distribution(Mw/M_(n))while different cis-1,4 contents were selected for comparison.The effects of cis-1,4 configuration on properties of Nd-BRs with similar 1,2-configuration content,molecular weight and distribution were investigated.The characteristic stress relaxation time(τ)decreased obviously when the total content of 1,4-configuration(cis-1,4 and trans-1,4)is greater than 99%,and the cis-1,4 content increases from 94.9%to 98.8%,indicating the improvement of processability.The dispersion of carbon black in rubber and bound rubber content of Nd-BR composites were improved as well.The strain-induced crystallization capability was enhanced with the increase of a small amount of cis-1,4 content,which significantly improved the tensile strength,tear strength,wear resistance,puncture resistance and crack resistance.It is remarked that the rolling resistance and wet-skid resistance were increased with ultra-high cis-1,4 content of more than 98%.Nd-BR with ultrahigh cis-1,4 content of ca.98.5%and appropriate molecular weight distribution(ca.2.8)possessed excellent processing properties,mechanical properties and dynamic mechanical properties,which is suitable for the high-performance tires.