Studies on graft copolymerization onto cellulose derivatives. XXIX. Photo‐induced graft copolymerization of methyl methacrylate onto chitin and oxychitin

Abstract

SynopsisGraft copolymerization of methyl methacrylate (MMA) onto chitin and oxidized chitin was carried out by a noncatalytic photo-induced and a photo-sensitized method. The isolation method of grafted chains without a decrease in their degree of polymerization (DP) by sulfuric acid hydrolysis and the effects of some factors on the conversion and the grafted chain length have been studied.In case of the photo-induced graft copolymerization, if a small amount of dimethylformaldehyde (DMF) is added in the polymerization system, the induction period is shortened and the degree of grafting and the apparent number of grafted chains increase. The degree of grafting and the apparent number of grafted chains of the oxidized chitin containing a small amount of C=O groups are greater than those of the untreated chitin, but a further increase in C=O groups decreases these values.In the presence of this two species of the chitin samples, the polymerization reaction was carried out as functions of monomer and chitin concentrations. From these results, the mechanisms of the photo-induced graft copolymerization were discussed. It is also clear that the conversion and the apparent number of grafted chains by the noncatalytic photo-induced method are generally larger than those by the photo-sensitized method, and the grafting activity with hydrogen peroxide (HPO) is higher than that with azobisisobutyronitrile (AIBN).

Preparation of Chitin/Polystyrene Hybrid Materials by Efficient Graft Copolymerization Based on Mercaptochitin

“…Though graft copolymerization onto chitin has not been studied extensively, some initiation methods for vinyl monomers have been reported: cerium(IV), − tributylborane, γ-ray, and UV …”

From Chitin to Chitosan

“…This proves that water can permeate into chitin for solvating, which damages the hydrogen bonds between chitin molecules and increases the diffusivity of styrene, so that the reaction becomes easier [96]. Methyl methylacrylate grafts chitin or chitin oxide when they are irradiated by a low-pressure mercury lamp [98]. Differently, chitosan film can be grafted without solvent, but only trace homopolymers of styrene can be formed.…”

Synthesis of Chitosan-<i>graft</i>-Poly(vinyl ether) as a Thermoresponsive Water-Soluble Chitosan

“…In fact, their properties can be altered not only by the degree of substitution but also by the molecular weight and functions of the graft chain. However, the structure of general branched grafting polymers is usually unknown because their molecular weights cannot be easily controlled, thereby leading to a broad molecular weight distribution [2,3,[12][13][14][15][16][17]. Furthermore, since the solubility of chitin/chitosan is low, the grafting reaction must be performed in a heterogeneous system, and so the degree of substitution (DS) and reproducibility tend to be poor;…”