DYNAMIC-MECHANICAL PROPERTIES OF AN IONIC ELASTOMER BASED ON CARBOXYLATED NITRILE RUBBER - EFFECT OF CALCIUM-CARBONATE AND CLAY

The dynamic mechanical analyses of moulded samples of carboxylated nit rile rubber (XNBR) in the presence of zinc oxide show occurrence of a biphasic structure in both unfilled and filled compositions; two trans itions appear in elastic modulus (E') and loss tan delta with temperat ure, The low temperature transition is believed to be due to the T-g o f the XNBR matrix and the high temperature transition is believed to b e due to the hard phase of the ionic aggregates of zinc carboxylic aci d salt. Incorporation of a filler like calcium carbonate and clay affe cts the dynamic mechanical properties, particularly the high temperatu re transition; the effect is more pronounced in the clay filled compos ition.