Investigation on the Thermal and Crystallization Behavior of High Density Polyethylene/Acrylonitrile Butadiene Rubber Blends and Their Composites

The properties of a blend containing a crystallizable component depend largely on the extent of crystallinity and the crystallization behavior of that component in presence of the other. Here, the semi crystalline high density polyethylene (HDPE) is blended with the amorphous elastomer, acrylonitrile butadiene rubber (nitrile rubber or NBR) and we focus mainly on the crystallinity of HDPE/NBR immiscible blends and its variation in the presence of compatibilizer and filler. The effect of blend ratio, compatibilizer concentration, dynamic vulcanization, and filler incorporation were carefully evaluated from the crystallinity measurements using differential scanning calorimeter and the basic aim of this work lies in tuning these conditions. This study allows the elucidation of the influence of crosslink density in regulating the crystallinity of thermoplastic elastomer blends. The scanning electron micrographs provide blend morphology from which the reduced domain size and the influence of NBR particles as heterogeneous nuclei for crystallization are evidenced especially at 5% compatibilizer concentration. The crystallinity of blends was observed to be high at 30 phr carbon black filler addition. Finally, the thermal stability of blends and their composites are also addressed and correlated with the crystallization effect. POLYM. ENG. SCI., 55:1203-1210, 2015. (c) 2014 Society of Plastics Engineers