Propylene/1-butene polymer alloys were prepared by in-situ slurry polymerization with spherical supported Ziegler-Natta catalyst and the technology of monomer composition switching method. Combining the kinetic model of propylene/1-butene copolymerization and the material balance

a reactor model with the monomer composition switching was developed by the moment method. The model parameters were fitted according to the real-time consumption rate of propylene obtained from experiments. The polymerization reactivity

the product's composition and their changes with switching frequency of monomer composition were simulated. The results show that the model can well describe the polymerization rate at different stages

the catalyst activity

the total content of 1-butene in the alloy

and the contents of random copolymer and “block” copolymer at various switching frequencies. It has been revealed also that the pulse feed of propylene in the copolymerization process is conducive to increasing the monomer diffusion to the active center

thereby increasing the polymerization rate and polymerization activity.