Thermogravimetric analysis and thermal ageing of crosslinked nitrile rubber/poly(ethylene-co-vinyl acetate) blends

The thermal behaviour of nitrile rubber (NBR)/poly(ethylene-co-vinyl acetat e) (EVA) blends was studied by thermogravimetry. The effects of blend ratio , different crosslinking systems (sulphur, peroxide and mixed), various fil lers (silica, clay and carbon black) and filler loading on the thermal prop erties were evaluated. It was found that the initial decomposition temperat ure increased with the addition of NBR to EVA. Among the various crosslinki ng systems studied, the peroxide cured system showed the highest initial de composition temperature. This is associated with the high bond dissociation energy of C-C linkages. The addition of fillers improved the thermal stabi lity of the blend. The mass loss at different temperatures and activation e nergy of degradation were also studied. The thermal ageing of these blends was carried out at 50 and 100 degreesC for 72 h. It was seen that the prope rties are not affected by the mild ageing condition. Also, the peroxide cur ed system was found to exhibit better retention in properties, than other c rosslinking systems.