STEREOREGULARITY OF VARIOUS POLYACRYLATES OBTAINED FROM GRAFT-COPOLYMERS ONTO STARCH

C-13 nuclear magnetic resonance spectra of poly(methyl acrylate) (PMA), poly(ethyl acrylate) (PEA) and poly(butyl acrylate) (PBA), obtained from graft copolymers onto amylose or amylopectin, have been studied. The spectra of the polymers were recorded with a 75 MHz spectrometer and were analysed by triad, tetrad, pentad or hexad placements. All of them follow Bernoullian statistics, with an isotactic parameter of 0.51, 0.44 and 0.43 for PMA, PEA and PBA respectively. By comparison with other values found in the literature it can be asserted that the presence of the carbohydrate has no effect on the tacticity of the grafted polymer.