Monte Carlo Simulations Of Semi-Batch Mode In Hyperbranched System Of AB_g Type

Hyperbranched polymer is a kind of macromolecule with special structure,which is widely used in chemistry,biology and industry production.In order to simulate the effect of semi-batch mode,a set of differential kinetic equations based on the growth of polymers are given,it should be noted that the unequal reactivity and cyclization of system are not taken into account.The size distribution function of hyperbranched polymers formed in two types of polymerization systems are obtained by the method of Monte Carlo simulation,where one of the two types of polymerization system is AB_g type,and the other system is AB_g(10)B _f.Moreover,the number-and weight-average molecular weights as well as polydispersity index are further presented.In these two types of polymerization systems,the effects of different semi-batch modes on the average properties of polymers are discussed.In this dissertation,the various conditions in the AB_g systems are discussed to provide some useful clues for the hyperbranched polymers in the relevant experiments and chemical production.There are four chapters in the dissertation as following:Chapter 1:The development of hyperbranched polymers and the semi-batch reactions are summarized.In detail,the AB_g hyperbranched polymerization system are outlined from recent experiments,theories and simulations.Meanwhile,the study of semi-batch process in polymerization is mainly introduced.Chapter 2:Monte Carlo simulations of semi-batch mode in hyperbranched system of AB_g type.The feeding ways of equal feeding and compensatory feeding are obtained by the method of Monte Carlo simulation.The effects of the feeding batches,conversions and functionality of the monomer on the weight-average molecular weight and polydispersity index of system are mainly discussed.As a result,it is found that these factors play an important role in the structures of hyperbranched polymers.Chapter 3:Monte Carlo simulations of semi-batch mode in hyperbranched system of AB_g type with B_f.The size distribution functions of two types of hyperbranched polymers with and without a core are obtained by the method of Monte Carlo simulation based on the differential kinetic equations for describing the growth of hyperbranched polymers.In detail,the effects of the feeding ways,feeding batches,total conversion,the molar ratio of monomers to cores,and functionality of the monomer and core on the weight-average degree and the polydispersity index of polymerization are mainly discussed,which is hoped that some useful clues can be provided for regulating the structure of the hyperbranched polymers in the relevant experiments.Chapter 4:Summary and prospect.The chapters in the dissertation are summarized,and the development prospect of the related fields are briefly described.