Maximizing of the functionalization degree of acrylonitrile-butadiene-styrene (ABS) with maleic anhydride through the incorporation of the Sn(Oct) 2 catalyst

Abstract

The grafting of functional groups onto polymers in the molten state presents challenges related to low efficiency and the occurrence of side reactions. The use of complementary additives to maximize the degree of functionalization is essential. In this study, the functionalization of acrylonitrile-butadiene-styrene (ABS) with maleic anhydride (MA) was investigated, using dicumyl peroxide (DCP) as an initiator and different concentrations of the catalyst tin (II) 2-ethylhexanoate (Sn(Oct)₂), ranging from 1 to 5 parts per hundred resin (phr). The formulations were processed in a torque rheometer, and the effects of the catalyst on the grafting degree, rheology, thermal stability, and surface wettability were evaluated. FTIR and titration analyses confirmed the incorporation of MA, with the formulation containing 1 phr of Sn(Oct)₂ being the most efficient (4.35% by FTIR and 4.71% by titration). The ABS/MA/DCP/Sn(Oct)₂ (1 phr) formulation also resulted in higher complex viscosity, lower melt flow index (MFI), and increased hydrophilicity. The ABS/MA/DCP/Sn(Oct)₂ (1 phr) formulation also resulted in higher complex viscosity, lower melt flow index (MFI), and increased hydrophilicity compared to pure ABS. Higher concentrations of Sn(Oct)₂ reduced the grafting degree and thermal stability, indicating the occurrence of side reactions. Thus, the controlled addition of 1 phr of Sn(Oct)₂ demonstrated to be an effective strategy to maximize MA grafting onto ABS, providing potential for use in reactive compatibilization of polymer blends, composites, and nanocomposites.