Synthesis and characterization of ABS resin using in situ transferring from emulsion to suspension polymerization

A novel approach based on an emulsion in situ suspension polymerization process for synthesizing poly(acrylonitrile-butadiene-styrene) (ABS) resin is reported. Experimental results show that the reaction system can be transformed from an emulsion state to a suspension polymerization state steadily with the content of polybutadiene (PB) in the range 0-15 wt% in ABS resin. When PB is replaced by poly(styrene-co-butadiene) with the content of rubber particles being kept below 20 wt%, the emulsion system can be easily transferred to the suspension polymerization state through a process of latex coagulation in the forward direction, which means that the emulsion solution was dripped slowly into the suspension reaction system in the presence of coagulating agent. The dispersion status of the rubber particles in the ABS resin was studied using transmission electron microscopy, which indicated that the rubber particles were in a dispersed state in a continuous matrix of poly(styrene-co-acrylonitrile) when the content of rubber particles was below 20 wt%. The mechanical properties of the ABS resins obtained are as follows: elongation at break, 9.4-45.7%; yield tensile strength, 35.1-42.2 MPa; impact strength, 98.2-116.3 J m(-1). (c) 2006 Society of Chemical Industry.