Toughness enhancement of polyamide 12 with natural rubber via non-reactive and reactive compatibilions

Abstract

This research work studied toughness enhancement of polyamide12 (Nylon12) by adding natural rubber (NR) via melt blending process. Copolymers of polystyrene/natural rubber (PS/NR) and polystyrene/maleated natural rubber (PS/MNR) were used as non-reactive and reactive compatibilizes, respectively. The result revealed that the non-reactive compatibilizer improved the compatibility between Nylon12 and NR via physical linkage, leading to a good dispersion of NR domains in Nylon12 matrix and the enhancement of impact energy by a factor of 3. The reactive compatibilizer was then used to increase the interfacial adhesion between Nylon12 and NR via chemical linkage. However, different mixing procedures of PS/ MNR copolymer as well as maleic anhydride loading affected to crosslinked NR (gel) content and MA grafting efficiency. The result showed that PS/MNR copolymer prepared by two-step mixing and low MA loading had a lower gel content and a higher MA grafting efficiency. The reactive compatibilizer with various contents also affected to the properties of Nylon12/NR blend. The formation of succinimide linkages via imidization reaction at Nylon12/NR interfaces caused an increase of shear viscosity and a reduction of extrudate swell viscosity ration approached to 1 with increasing PS/MNR content up to 7 phr. Rubber particle appeared to be spherical with diameter and interparticle distance less than 0.5 and 0.3 µm. respectively. The compatibilized blends showed the enhancement of mechanical properties impact energy Increased by a factor of 5.