INFLUENCE OF OXIDIZED CARBON-BLACK ON THE DEGREE OF CURE IN POLYBUTADIENE CROSS-LINKED BY HIGH-PRESSURE VULCANIZATION

The influence of oxidised and graphitised carbon black on the degree o f crosslinking has been investigated for two different crosslinking sy stems: peroxide and high pressure vulcanisation (HPV), The latter incl udes also high temperature, but not any vulcanisation chemicals. It wa s found that peroxide yielded lower degrees of crosslinking when oxidi sed carbon black was used while HPV polybutadienes showed the opposite behaviour. It is suggested that strong polymer - carbon black interac tions are evolved in HPV, increasing the apparent crosslink density as measured by swelling.