Cure kinetics and physical properties of poly(dicyclopentadiene/5-ethylidene-2-norbornene) initiated by different Grubbs' catalysts

Abstract

Cure kinetics of endo-dicyclopentadiene (DCPD)/5-ethylidene-2-norbornene (ENB) blends with 1^st and 2^nd generation Grubbs' catalysts were characterized using dynamic differential scanning calorimetry. The results of the analysis revealed that the reactions with both Grubbs' catalysts were greatly accelerated by adding ENB. However, a strong dependence was observed on the fractional conversion and the type of catalyst used. The addition of ENB and different Grubbs' catalysts was found to have significant effects on gel fraction and crosslinking density of the resulting polymers. Although the modulus and maximum stress of the resulting polymers were observed to decrease slightly, tensile tests showed that the yielding strain and tensile toughness were enhanced with ENB loading. The glass transition temperature and thermal stability of the polymers with both catalysts decreased with increasing ENB loading. The effects of the different Grubbs' catalysts on cure kinetics and various physical properties are discussed in detail.