Preparation of graft copolymers by the reaction of primary amine‐terminated polystyrene with copolymers containing β‐isocyanatoethyl methacrylate

A variety of polymers containing pendant isocyanate groups was prepared by the copolymerization of small amounts of β‐isocyanatoethyl methacrylate. Polystyrenes prepared by sodium amide initiation in liquid ammonia at −33°C. were characterized and shown to contain one terminal primary amine group per polymer chain. Approximately equivalent amounts (by functional group) were reacted in a dry inert solvent, generally at room temperature for one to two days. Graft copolymers were formed in high efficiency; this was conclusively shown for graft copolymers of poly(methyl methacrylate)‐polystyrene by disappearance of titratable amine groups, extraction of the graft copolymer with diethyl ether, ultraviolet analysis of the product, and agreement between calculated and actual number‐average molecular weight. The preparative method allows control of the length of the backbone and number of attached polystyrene side chains; the complete structure of the graft copolymer is known, including the number and length of side chains.