Polymer Engineering Faculty Research

Effect of the Ionic Aggregation on the Crystallization Behavior of Polyethylene Part of Ionomer.

Robert Weiss, The University of Akron


The influence of ionic interaction on the melt-crystallization behavior of the ethylene ionomer was studied using modulated DSC (MDSCTM), wide angle X-ray scattering (XRD) and hot stage microscopy. The kinetics of the crystallization process of the ionomer was evaluated using isothermal differential scanning calorimetry (iso-DSC). Wide-angle X-ray scattering was used to examine the d spacing of poly(ethylene) part. The crystallinity of the poly(ethylene) part of ionomer measured from XRD is found to be 24%, which is comparable to that obtained from MDSCTM. Small-angle X-ray scattering (SAXS) results show that the clusters and multiplets exist in the ionomer, and the cluster is about 127L. The kinetics of crystallization process obtained using Avrami equation shows that the crystallization process is fundamentally similar to poly(ethylene) as it goes through nucleation and propagation stages of the crystals. However, the morphology of the crystal appears to be different and influenced by clusters (platelike and/or needle-shaped) as evident from Avrami constant. This is different from the poly(ethylene) (which is spherulitic in nature) due to polar cluster and hydrophobic PE melt interaction.