Polymer crystallization in the presence of 'sticky' additives

摘要

The effect of "sticky" additives (viz., those that have attractive interactions with the polymer) onpolymer crystallization, has been investigated by dynamic Monte Carlo (DMC) simulations.Additive-polymer attractive interactions result in a slowing down of the polymer chain diffusivity inthe melt state. Our results show that with increasing additive stickiness, polymer crystallinitydecreases monotonically, and thinner crystallites form, viz., crystallization is inhibited by thepresence of sticky additives. Unusually, the observed "specific heat" peak at the phase transitionshows nonmonotonic behavior with additive stickiness, and exhibits a maximum for intermediatevalues of additive stickiness. While the origins of this unexpected behavior are not clear, we showthat it correlates with a large interchange between crystalline and amorphous states of themonomers, in the vicinity of the additives. At this intermediate additive stickiness, we also find thatcrystallization follows a qualitatively different route—crystallinity shows a non-Avrami-likeevolution, unlike the case at low or high additive stickiness.