Synthesis and characterization of impact modifier PB-g-(SAN-co-Si) with core-shell structure

A new macromolecular modifier polybutadiene-grafting styrene/acrylonitrile/silicon tetracopolymer (PB-g-(SAN-co-Si))was synthesized by grafting styrene(St), acrylonitrile(An) and methacryloxypropyltrimethoxysilane (KH-570) onto polybutadiene(PB) latex particles via seeded emulsion polymerization technique. The tetracopolymer was characterized by transmission electron microscopy(TEM), Fourier transformation infrared spectrum (FT-IR) and grafting efficiency of St-An copolymer(SAN). TEM study indicates that latex particles obtained have a regular core-shell structure with a diameter of 300nm. FT-IR spectrum shows that KH-570 is chemically bonded onto the PB chains. SAN can be grafted on PB chains by both radical polymerization and hydrolysis/condensation of KH-570 and consequently grafting efficiency of SAN is enhanced significantly by KH-570.