在稀土体系催化下的丁二烯聚合动力学

本文应用键谷勤聚合动力学公式进行动力学研究。求出了活性中心数目,有关的动力学常数和聚合速度方程(R_p=k_p[C~*][M])并着重研究了聚合物活性链性质。 在链引发阶段,发现20℃和50℃聚合,属于迅速引发类型,在0℃时则是缓慢引发类型。聚合过程中,存在明显的链转移反应。Al(i-C_4H_9)_3是主要的链转移剂。在50℃聚合时,有活性中心失活现象发生,并表明其为双基终止。

KINETICS OF BUTADIENE POLYMERIZATION IN THE PRESENCE OF Ln(naph)3-Al(i-C4H9)3-Al(i-C4H9)2Cl CATALYST SYSTEM

Based on the kinetic equations of polymerization proposed by T. Kagiya. a kinetic study on the polymerization of butadiene in hydrogenated gasoline with Ln (naph),-Al(i-C4H9)?Al(i-C4H9)2 Cl catalyst has been carried out.It was found that the rate of propagation is first order with respect to the concentration of both active center and monomer. Thus, the equation of the polymerization rate can be described as Rp=kp [C*] [M].In addition, the nature of the chain, such as chain initiation, transfer and termination were also examined.The initiation step is considered to be instantaneous at 20℃ and 50℃, but slow down at 0℃. The ratio of the rate constant of chain transfer reaction of alkyla-luminum compound to the rate constant of chain propagation is close to 1/90.The decrease in polymerization rate should be ascribed to the deactivation of the active centers at higher temperateure (e.g., 50℃). The termination reaction is shown to be a bimolecular process.