EFFECT OF CROSS-LINKING AGENTS ON THE STRUCTURE AND PROPERTIES OF POLYURETHANE MILLABLE ELASTOMER COMPOSITES

A study of the effect of crosslinking agents on the structure and properties of the millable polyurethane (PU) elastomer is reported here. Effects of the conventionally used dicumyl peroxide (DCP) and tolylene diisocyanate dimer (TDID) on the curing characteristics, mechanical properties, and relative thermal stabilities of the PU composites have been compared. Use of X-ray diffraction as a supportive evidence helps in understanding the nature of crosslinking. The mixture of DCP and TDID is also evaluated as crosslinking agents. A dramatic improvement in the mechanical properties and thermal stability is observed because of the mixed type of crosslinking obtained by the combined use of DCP and TDID. Effect of carbon black loading shows an increase in the mechanical strength with a decrease in the elongation. The results obtained from various properties measurements have been satisfactorily explained with a general model of crosslinking.