Effect of epoxidised liquid natural rubber on nitrile/butadiene rubber based mixes

Epoxidised liquid natural rubber (ELNR) constitutes a new family of polymer s chemically derived from natural rubber. It is a highly viscous rubber of low molar mass generally used as plasticiser or processing aid, especially during processing of natural rubber and styrene/butadiene rubber stocks. The effect of incorporating this polymer rather than a standard plasticiser in a nitrile/butadiene rubber based mix has been investigated. The retenti on in mechanical properties following air and oil aging of the vulcanisates was also studied. Satisfactory processability of compounded stocks, mechan ical properties, and aging resistance was maintained following incorporatio n of ELNR into nitrile/butadiene rubber formulations even at the lowest pla sticiser concentrations. The improvement in aging behaviour was more pronou nced when 25 mol-% ELNR was used at concentrations above 15 pphr.