INTERCHAIN CROSS-LINKING BETWEEN NBR AND THIOKOL RUBBER AND ITS EFFECT ON PROCESSABILITY AND STRUCTURE-PROPERTY RELATIONS OF BLENDS

The rheological behaviour of NBR and Thiokol rubber has been studied a t different shear rates throughout the entire composition range. Prehe ating of the blends has pronounced effects on the blend properties of the NBR/Thiokol rubber blend, compared with those of the blend produce d from the corresponding pre-blends without heating. Interchain crossl inking is observed in the preheated blends, which gives rise to the im proved blend properties as oil and ozone resistance. The blend ratio a nd the shear rate have predominant effects on the rheological behaviou r of the preheated blends due to microgel formation. From the physical properties'' it seems that 80:20 NBR:Thiokol rubber is the optimum ra tio for useful application.