SYNTHESIS, REACTIVITY RATIOS, AND SOLUTION BEHAVIOR OF VINYLPYRROLIDONE-CO-MONOALKYL ITACONATE AND VINYLPYRROLIDONE-CO-DIALKYL ITACONATE COPOLYMERS

Copolymers containing vinylpyrrolidone and mono and dialkyl itaconate units with different length in the side chains were synthesized and ch aracterized. Copolymers of vinylpyrrolidone with three different compo sitions of monomethyl, monoethyl, monopropyl, monoamyl, dimethyl, diet hyl, dipropyl, and diamyl itaconate were obtained by radical polymeriz ation. The reactivity ratios was estimated by using the classical Fine man-Ross and Kelen Tudos procedures. These parameters were also estima ted using a computer program based on nonlinear minimization algorithm , starting from the values of r(1) and r(2) obtained by the linear pro cedures. The copolymers can be considered as random. Fractionation of the copolymers were achieved by fractional precipitation. Fractions we re characterized by viscometry and light scattering measurements. The unperturbed dimensions were determined using the Stockmayer-Fixman met hod. Higher rigidity indexes and characteristic ratios are observed in copolymers containing diitaconate units than that with monoitaconate moieties. The dependence of the glass transition temperature T-g with copolymer composition and its correlation with the chain stiffness is also analyzed.