development and co-continuity in reactive blends of poly(isobutylene-co-

p-methylstyrene) (BIMSM) and polyamide (PA) containing different amounts

of plasticizer without vulcanization is examined. The interfacial

reaction was found to be effective in dispersing blend components down

to 50–80 nm fine droplets and to produce high amounts, about 46%, of the

interfacial graft copolymer. This copolymer amount can be even higher,

up to 57%, in a plasticized blend. The reaction between the elastomer

and PA shifts the percolation thresholds and overall continuity

development to higher concentrations, but no effect can be observed on

the concentration region of dual-phase continuity. It is found that the

dominant factor in controlling the dispersion of higher amounts of BIMSM

elastomer into the PA phase is the extent of reaction between BIMSM and

PA.