OPENING AND ADDITION MODES IN PROPAGATION DURING RADICAL POLYMERIZATION OF FUMARIC AND MALEIC DERIVATIVES

Polymers of bis(trimethylsilyl) fumarate, di-tert-amyl fumarate, and m ethyl tert-amyl fumarate were prepared by radical polymerization at 60 or 120 degrees C. The polymers were converted into poly(dimethyl fuma rate) via thermolysis or hydrolysis and subsequent methylation to dete rmine the tacticity using C-13-NMR spectroscopy. The probabilities of meso addition (P-m) were revealed to be 0.66 (60 degrees C) for the bi s(trimethylsilyl) ester, 0.60 (60 degrees C) and 0.52 (120 degrees C) for the di-tert-amyl ester, and 0.54 (60 and 120 degrees C) for the me thyl tert-amyl ester. From the temperature dependence of the P-m value s, the differences in activation enthalpies and entropies for the meso and raceme additions were evaluated. The microstructure of poly(dimet hyl fumarate) derived from poly(maleic anhydride) was also examined. T he opening and addition modes in propagation of the fumaric and maleic derivatives were discussed based on the results obtained in the prese nt and previous work.