Abstract
It is shown for the first time that mutual transesterification between carbochain polyesters (polymethyl methacrylate) and heterochain polyesters may be used for synthesizing graft copolymers. The graft copolymers obtained from polymethyl methacrylate and crystalline polyesters are crystalline have high softening temperatures. The grafting of amorphous polyesters yields amorphous graft copolymers. An increase in the number of graft side chains is accompanied by a decrease in intrinsic viscosity of the copolymer and by a rise in value of the Huggins constant. The decrease in the intrinsic viscosity is not the result of a degradation process, since polymethyl methacrylate may be regenerated by methanolysis of the graft copolymers. The intrinsic viscosity of the regenerated polymethyl methacrylate is equal to that of the initial polymer. Graft copolymers from polymethyl methacrylate and heterochain polyesters possess a lower tensile strength and higher ultimate elongation than polymethyl methacrylate. It was also established that on heating mixtures of methyl methacrylate and ฯโhydroxyacids in the presence of a catalyst graft copolymers form by simultaneous polymerization, polycondensation, and mutual transesterification reactions. Some correlations in this process and the properties of the resultant graft copolymers have been studied.