CHARACTERIZATION OF CROSS-LINKING OF RANDOM POLYMER NETWORK BY RHEOLOGICAL AND EQUILIBRIUM SWELLING DATA

The transesterification reaction in the molten state of ester groups o f ethylene vinyl acetate (EVA) copolymers and ethylene acrylic ester ( EMA) copolymers has been used to crosslink the chains of this polymeri c system. The relative EVA copolymers (or EMA copolymers) concentratio n dependence of the network formation by co-crosslinking of EVA/EMA mi scible blends has been assessed. EVA/EMA networks were characterized b y swelling experiments, theological measurements, and determination of the extent of the reaction through a chromatographic technique. All r esults can be compared in a master curve. The influence of the polydis persity and the microstructure of EVA and EMA samples was put in evide nce. On the other hand, a scaling law (v2 similar to M(c)(-3/5)) was o bserved in agreement with predictions of the Flory-Rhener expression. (C) 1994 John Wiley and Sons, Inc.