Molecular weight distribution (MWD) and short chain branching distribution (SCBD) play a decisive role in the performance of linear low-density polyethylene (LLDPE). A model based on a non-standard polymerization reaction scheme is developed for ethylene/α-olefin gas phase copolymerization in a fluidized bed reactor. Experimental MWD and SCBD are simultaneously deconvoluted. The results obtained by this simultaneous deconvolution method are physically more relevant. Reduction of parameters and parameter estimability analysis are conducted to screen parameters to obtain a subset for reliable parameter estimation. The model based on the estimated parameters yields MWD and SCBD which are in good agreement with experimental ones for several LLDPE grades obtained from a pilot-scale gas phase polymerization process. The non-standard polymerization reaction scheme depicts well the “comonomer effect” - activation of dormant ethylene species.

分子量分布（MWD）和短链支化分布（SCBD）对线性低密度聚乙烯（LLDPE）的性能起着决定性的作用。建立了基于非标准聚合反应方案的乙烯/α-烯烃气相共聚在流化床反应器中的模型。实验 MWD 和 SCBD 同时解卷积。通过这种同时反卷积方法获得的结果在物理上更具相关性。进行参数约简和参数可估计性分析以筛选参数以获得可靠参数估计的子集。基于估计参数的模型产生的 MWD 和 SCBD 与从中试规模气相聚合过程中获得的几种 LLDPE 等级的实验结果非常一致。