A method for obtaining high modulus polyethylene from the melt: The influence of crystal nucleation

A method is presented by which polyethylene filaments of exceptionally high modulus (500–1000 kbar) can be prepared from flowing melts. The method relies on the formation of fibrous crystals which are directly flow–induced, but are present in sufficiently small quantities not to block the flow of the melt. If the rest of the still uncrystallized material is induced to crystallize onto these fibers, which then serve as nuclei, under enhanced hydrostatic pressure, the ultrahigh moduli are obtained. In addition to their relevance to mechanical behavior these observations point to some novel aspects of crystal nucleation by fibrous substrates and to the way such nucleation can influence the modulus.