THERMAL GRAFT-COPOLYMERIZATION OF 4-VINYL PYRIDINE ONTO ETHYL CELLULOSE IN HOMOGENEOUS MEDIA .1. INFLUENCE OF AMMONIUM PERSULFATE

Graft copolymerization of 4-vinyl pyridine(4-VP) onto ethyl cellulose (EC) using ammonium persulfate (APS) as free radical initiator was studied in the toluene: DMSO (4:1 v/v) solvent system. The weight conversion, grafting percentage and grafting efficiency were determined as functions of the polymerization temperature and of the concentration of monomer, ethyl cellulose and initiator. The homopolymerization of 4-VP in the presence of APS was also investigated. The graft copolymers were characterized by thin layer chromatography, IR spectroscopy, nuclear magnetic resonance and intrinsic viscosity measurements. The highest rate of propagation of graft copolymerization of 4-VP onto EC in the presence of APS observed was 0.06 %/min. A suitable mechanism of grafting reaction is discussed.