MICROSTRUCTURES AND SEQUENCE DISTRIBUTIONS IN POLYDIENES

The sequence distribution of polydienes is studied both theoretically and experimentally. The expressions for sequence length distribution, the probability functions for monads and dyads are derived from solving a set of kinetic differential equations on the condition of constant monomer concentration [M]. The microstructure data of polybutadiene generated by anion and Ziegler-Natta catalyst at low conversion or in the case of constant [M] show that our theory mentioned above is correct, i. e. as in the case of batch reactor, there is also an unsteady stage during the initial period of polymerization for the system of constant [M] when the sequence structures of the product vary with reaction time; then the polymerization arrives at the steady stage when the microstructures become unchanging.     

聚双烯烃的近程结构

本文首先求解单体浓度恒定条件下的动力学微分方程组,得到各种不同结构的序列分布函数的表达式,从而给出一元组和二元组的概率函数。当低转化率时或单体浓度不变时,由阴离子方法和稀土催化合成的聚丁二烯的实验数据表明:上述理论是正确的,即在恒定单体浓度的双烯烃聚合反应的初期,和变浓体系一样,存在着一个非稳态阶段,这时产物的结构随反应时间而变化;然后才逐渐进入聚合反应的稳态阶段,此时产物的微观结构趋于恒定。