T. Nagabhushanam

Graft Copolymerization of Acrylic Monomers onto Biopolymers. Part I. Grafting of Poly(butyl Acrylate) onto Gelatin

Abstract Gelatin was graft copolymerized with poly(butyl acrylate) using potassium peroxy disulfate in aqueous medium. Effects of temperature, time, monomer concentration, and backbone concentration were studied. The percent grafting was found to increase initially and then decreased in all cases. Infrared, viscosity, and thermal analysis were carried out on the graft copolymers, and the mechanism of the graft copolymerization reaction was discussed.

Polymerization of methyl methacrylate in the presence of molecular oxygen - a kinetic study

Abstract Methyl methacrylate was polymerized in aqueous medium initiated by a copper(II)-ascorbic acidoxygen system at 40°C and a kinetic study of the reaction is presented. The rate of polymerization, Rp showed an increase, constancy and then a decrease with increase in the [Cu2+]. The order with respect to [Cu2+] was 0.5 in the rate increase region. The order in monomer concentration changed gradually from 1.0 to 2.0 with increase in [Cu2+]. Rp became independent of ascorbic acid (AA) concentration and oxygen concentration at high concentrations. These results indicate that termination by mutual interaction of chain radicals predominates at low [Cu2+] while termination was exclusively by metal ions at high [Cu2+]. Rp was also observed to increase with temperature and ionic strength and to K p K t 1 2 value was calculated and compared with literature values. Chain lengths were determined by viscometry for the polymers obtained under various experimental conditions.

Oxygen promoted radical polymerization of acrylonitrile in aqueous nitric acid. A kinetic study

The polymerization of acrylonitrile (AN) initiated by oxygen-ascorbic acid (AA)-ferric ion system was studied in dil. HNO3 at 40°. The rate of polymerization, Rp, was found gravimetrically. In the [Fe3+] range, (2–5 × 10−5 M, Rp was proportional to [AN]1.5 ± 0.05, [O2]0.5 ± 0.02 [AA]0 and [Fe3+]0; for [Fe3+] = (5–30) × 10−5 M, it was proportional to [AN]1.8 ± 0.05, [O2]0.6 ± 0.02, [AA]0 and [Fe3+]−0.9 ± 0.05. A plausible reaction scheme is proposed and rate law presented to explain these results. Rp increased with ionic strength and [HNO3] (up to ∼0.25 M). An initial rate increase with temperature followed by a decrease was noticed. Chain lengths of the polymers were determined viscometrically.