Reactive Compatibilization of Polyisoprene/Polydimethylsiloxane Interfaces

The immiscible blends of polydimethylsiloxane (PDMS) and polyisoprene (PI) were reactively compatibilized by means of multifunctional reactive compounds capable of forming crosslinked copolymers at the interface. Interfacial chemical reaction was occurred between aminefunctional PDMS and maleic anhydride-functional PI. Droplet-matrix blends of PI/PDMS with different reactive compatibilizer loadings were examined by optical microscopy and rheometry.The PI-continuous blends show double emulsion morphology including drop clusters and some drops with apparently rough interfaces. In contrast, PDMS-continuous blends displayed double emulsion with round drops that do not appear to aggregate. The rheological properties are alsoasymmetric: The PI-continuous blend showed gel-like behavior in oscillatory experiments, high viscosity and strong viscosity overshoots in creep experiments, all of which are likely attributable to drop clustering, whereas PDMS-continuous blends showed liquid-like behavior,and low viscosity due to drops coalescence. We consider that the observed morphological and rheological asymmetry is attributable to the asymmetry of the compatibilizer architecture on the two sides of the interface