Application of a new pH-metric Method to the Kinetic study of copolymerization of polysaccharides Fucan N1 with PMMA in presence of Cerium Ce+4 .

Abstract

The copolymerization of a Poly-Acrylic PMMA with polysaccharide, Fucan N1 and Dextran T70,in presence of a ceric salt used as initiator in acidic medium ,was carried out under the following conditions : Fucan N1=0,5 g ; [CAN ] = 3,6.10 -3 M , [HNO 3 ] = 0,2M ; temperature =40°C with a relative ratio between the initiator and the monomer , initiator/monomer =1/10. Besides a pH study of the reaction medium , an infrared spectroscopy (IR) proved the appropriatness of these best conditions of synthesis , and this by showing the presence of a characteristic peak of the carbonyl grouping situated at 1733cm -1 for the copolymer Fucan PMMA in respect to the individual PMMA spectra and Fucan N1. In addition , a 13 C NMR study has been conducted on the copolymer. A viscosimetry study of two Fucan fractions was performed in aqueous medium (H 2 0), and also of the obtained copolymer in DMSO. An outcome of this work allows for us the suggestion of a plausible reaction mechanism , of which the copolymerization rate -Rp-is first order dependant to the monomer concentration, and to the square -concentration of both the initiator and the polysaccharide .