of 4-methoxyphenylacetica cid, and 2-hydroxyethylmethacrylateH, , prepared by free-radical polymerization in solution at low conversion, were analysed by 1H (300MHz) and 13C (75.5MHz) nuclear magnetic resonance spectroscopy, in terms of sequence distribution and stereochemistry of monomeric units along the copolymer chains. The concentration of M- and H-centred sequences was determined experimentally from the analysis of the ~-CH 3 resonance signals of M and H units, which gave a relatively complex pattern assigned to M and H centred triads with specific composition and stereochemical configuration. The carbonyl carbon group of M and H gave resonance signals with different chemical shift sensitive to sequences of tactic pentads, independently of the chemical composition. The experimental results were in fairly good agreement with those calculated statistically, taking into consideration the terminal copolymerization model and Bernoullian distribution of stereoregularity, with the statistical parameters Pij and Pu determined from the reactivity ratios rM= 1.49 and rn=0.61 and the stereochemical parameters a~M=0.27, ann=0.21 and o-* : O'MH = O'HM : 0.30
Посилання на статтю:
Microstructural analysis of copolymers of hydroxyethylmethacrylate and methacrylic esters of biomedical interest by n.m.r. spectroscopy / Alberto Gallardo and Julio San Roman // Polymer. – 1994. – Vol 35. – P. 2501-2509.