Synthesis of acrylonitrile-butadiene-styrene copolymers through interface-initiated room-temperature polymerization

Acrylonitrile-butadiene-styrene (ABS) copolymers were synthesized in emulsions and silica-containing emulsion gels at 20, 40, and 60 degrees C. The room-temperature polymerization was achieved by decomposing 2,2 '-azobisisobutyronitrile (AIBN) at oil-water interfaces. The decomposition rate constants of the AIBN decomposed in bulk phases and at interfaces were measured for the first time. At room temperatures, the decomposition of AIBN primarily occurred at oil-water interfaces. At 60 degrees C, the decomposition of AIBN occurred both in bulk phases and at interfaces. In a dark environment without inert gas protection, the polymerizations in emulsions and emulsion gels were conducted at room temperatures successfully. The presence of fumed silica particles enhanced the interfacial initiation and the subsequent polymerization. In the presence of fumed silica, the polymerizations at 40 degrees C can be as fast as that conducted without silica at 60 degrees C. The molar mass of the ABS copolymers increased with decreased polymerization temperatures. The ABS copolymers with an ultra-high molar mass and narrow molar mass distribution were synthesized. The ABS copolymers with ultra-high molecular masses exhibit improved ductility and thermal properties without compromising Young's modulus and surface hardness. Interfacial initiation is an eco-friendly technique to produce high-performance polymer materials. AIBN initiators decomposed efficiently at the oil-water interface at room temperature. The interface-initiated room-temperature polymerization produced ductile ABS copolymer monoliths.