Straight-chain segment length distributions in UHMWPE reactor powders of different morphological types

A series of reactor powders of ultrahigh molecular weight polyethylene obtained using supported and unsupported Ziegler catalysts were Studied with the help of low-frequency Raman spectroscopy. This experimental technique allows one to calculate the length distribution of straight-chain segments (SCS) in a polymer sample without differing between the SCS localized in either crystalline or amorphous regions of the sample. A comparison of the scanning electron microscopy images of powders with their SCS distributions showed that the samples with pronounced fibrous morphology exhibit bimodal distribution functions, while the granular morphological pattern yields Unimodal SCS length distributions.