An experimental investigation of crystallization rates for deformed polybutene-1 melts and characterization of the resulting morphology

A deformation dilatometer was designed and built for the purpose of investigating crystallization rates in deformed polymer melts. A sliding plate arrangement is used to apply stepwise shear strains to supercooled polybutene-1 melts which are isothermally crystallized at 90 and 95 deg C. The results show that stepwise shear causes oriented crystallization when shear rates are sufficiently high. Nucleation rates dramatically increase as induction times vary from several minutes (quiescent crystallization) to less than a second. Wide angle X ray scattering confirmed crystalline orientation and indicated that the form 2 form 1 transformation rate had increased. No evidence was found for residual strains in completely crystallized samples.