SOME EFFECTS OF IRRADIATION ON PROPERTIES OF FILLED PVC COMPOUNDS

Compounds based on poly(vinyl chloride) (PVC), and containing CaCO3 fi ller and trifunctional acrylic crosslinking agent have been crosslinke d by exposure to gamma-rays at dosages to 70 kGy. The crosslinking age nt was found to be essential for crosslinking to proceed, only minor s ensitivity to the irradiation having been found in compounds omitting the chemical. The presence of filler somewhat inhibits crosslink effec tiveness, as measured by solvent uptake data. Elastic moduli and elong ations at rupture respond to crosslinking processes, the latter being particularly sensitive to the effects of irradiation. The presence of filler was found to raise modulus, while ductilities of compounds were greater than expected, owing to adhesion at polymer/filler interfaces . Favorable acid/base interaction forces appear responsible for the ef fect. The reduced sensitivity of filled PVC compounds to gamma-ray exp osure is attributed to polymer immobilization, the consequence of stro ng interfacial bonding with the filler.