On the internal morphologies of high-modulus polyethylene and polypropylene fibres

摘要

High modulus polyethylene fibres, both meltand gel-spun, contain the same longitudinal density deficientregions, revealed by permanganic etching, as were found inspecimens of the same fibres after treatment by the Leedshigh temperature compaction process. For these materials anew model of fibre structure is proposed, which develops as aconsequence of nucleation on an extended network ofentangled molecules permeating the fibres. Subsequentgrowth into spaces between the network will encounterstresses due to the contraction on crystallization leading todistributed density deficient regions of high free volume.Each of the four commercial PE fibres examined differs fromthe others in its characteristic outline and the details of itsinternal substructure. The structure of commercialpolypropylene fibres is also compared.