THE EFFECT OF CERTAIN PROCESSING VARIABLES ON THE FORM-II TO FORM-I PHASE-TRANSFORMATION IN POLYBUTENE-1

Density and wide angle x-ray scattering techniques were used to study the form II to form I phase transformation in polybutene-1. The influence of deformation by cold rolling, orientation produced by melt processing (film blowing), and certain additives blended with the homopolymer on the phase transformation behavior were examined. A new technique based on a combination of wide angle X-ray diffraction and density measurements was devised to determine the relative fractions of form I, form II, and amorphous phases present. The mechanical blending of polypropylene with polybutene-1 was found to accelerate the form II to form I phase transformation, while another additive (1-naphtylacetamide) known to be a good nucleating agent for crystallization of polybutene-1 did not increase the rate of phase transformation when added at concentration levels needed to nucleate crystallization from the melt.