微孔塑料气泡成核的聚合物刷子模型

摘要

气泡成核是微孔塑料连续挤出成型中的关键步骤之一,但现有的成核理论大都是以经典成核理论为基础的,而经典成核理论虽然给出了临界气泡核及成核速率的计算公式,但并没有考虑到聚合物的物性参数,并且不能计算临界气泡核半径的具体数值,所以其应用有很大的局限性.文章从聚合物刷子模型出发建立气泡成核的刷子模型,从而得出临界气泡核半径的计算公式,并分析温度、压力、聚合物分子量等对临界气泡核半径的影响.%Nucleation is one of the key stages during producing microcellular plastics, the radius of critical nucleus is the main factors for deciding the radius of bubbles of product, nu-cleus density also decides the bubble density. The nucleation theories existing are based on classicnucleation theory mostly, classicnucleation theory has given the calculation formulae of critical nucleus and nucleus density, but it does not consider the physical speciality of pol-ymer and can't calculate the certain numerical value, so it is restricted in application. This paper will construct the nodel of brushes for nucleation of microcellular plastics from the model of polymer brushes, giving the calculation formulae of critical nucleus radius, and ana-lyxing the influence of temperature, pressure and polymer molecular weight on critical nucle-us radius.