Copolymerization of itaconic anhydride and styrene, determination of reactivity ratios

The copolymerization of itaconic anhydride and styrene has been studied and ther1‐r2values determined. In benzener1= 0.78,r2= 0.015; in tetrahydrofuranr10.60, =r2, 0.10. One possible explanation of the definite positive deviation from constant values in the different solvents has been advanced; it is based on the fact that the copolymer precipitates from benzene as formed. In all cases ther1,r2product is in the order of 0.01 to 0.06 and indicates that the copolymer is highly alternating in structure. Excellent agreement has been obtained between values of copolymer compositions by analysis and values predicted by copolymer theory based on the copolymer equation. Copolymers of molecular weights in the order of 50,000 to 150,000 (determined by light scattering) were prepared. The rate of copolymerization was about twenty times faster in benzene than in tetrahydrofuran.