THE CROSS-LINKING OF ACRYLIC RUBBER IN THE PRESENCE OF GROUP-IIB METAL-OXIDES

Effects of group IIB metal oxides (viz., ZnO, CdO, and HgO) on ethylen e thiourea (ETU) accelerated the curing of acrylic rubber (ACM) have b een evaluated with a view to elucidate the cross-linking mechanism wit h special reference to the role of metal oxides. Best results are obta ined with CdO in the presence of ETU. ZnO - CdO or CdO - HgO blends pr ovide no synergism in the state and rate of cure. Formation of metal s ulfide and chloride during the cross-linking reaction has been confirm ed by XRD and XPS. Examination of FTIR spectra reveals that cross-link ing occurs at the C - Cl cure site of the acrylic polymer. Based on sp ectral and chemical analysis, a reaction mechanism has been put forwar d. (C) 1994 John Wiley & Sons, Inc.