Role of Metastable Phases in Polymer Crystallization; Early Stages of Crystal Growth

In this chapter we have addressed issues concerning crystallization of flexible polymers from melt. We have described several examples where crystallization proceeds via a transient phase before a thermodynamically stable phase intervenes. With several examples it has been shown that transient state of a phase strongly depends on the crystal size. A phase that is thermodynamically stable during the initial stages of crystallization becomes metastable with crystal growth. Taking linear polyethylene as an example, it is shown that crystal size can be controlled during polymerization, thus the phase behavior. These findings have implications in polymer processing like sintering of intractable ultra high molecular weight polyethylene