Some aspects of graft polymerization of vinyl monomers onto cellulose with the use of tetravalent cerium. V

Abstract

Abstract The presence of occluded air lowers the ceric consumption between the beginning and end of the reaction time, decreases the grafting parameters, and increases the copper number. Grafting reactions carried out in presence of organic solvents show parameters that are lower than those obtained when the reactions are carried out in water. Solvents with high chain‐transfer constants cause a marked decrease in the yield relative to the solvents of low chain‐transfer constants. Conversion percentages are similarly influenced. However, the donor alcohols enhance polymer formation with the acceptor monomers; this is attributed to the ability of ceric salt solution to oxidize alcohol and hence initiate polymerization reaction. Scavenging of the free radicals by certain alcohols and competition between alcohol and cellulose for the ceric consumption are responsible for the low grafting yields achieved. The order of reactivity of monomers may change when solvents are used; it follows the relative differences in the chaintransfer constant of solvent with the different monomers. Pseudografting and complex formation, when they occur, interfere with the results achieved.