Modification of partially carboxymethylated cotton via crafting with acrylic acid and styrene using gamma radiation

摘要

AbstractPartially carboxymethylated cottons (PCMC) having 15.549, 27.409, and 46.834 meq COOH/100 g cellulose as well as untreated cotton and alkali‐treated cotton, which was prepared in an analogous manner to PCMC but, in the absence of monochloroacetic acid, were graft‐copolymerized with either acrylic acid or styrene using gamma radiation under different conditions. Moisture regain and dyeing properties of the copolymers so obtained were investigated. It was found that the graft yeld increases by increasing monomer concentration and radiation dose irrespective of the monomer or substrate used. Using water/methanol mixtures as polymerization media are advantageous for grafting of styrene onto the substrates in question. The graft yields of PCMCs are much lower than those of unmodified and alkali‐treated cottons when they were grafted with acrylic acid. In case of styrene on the other hand, the graft yields for PCMCs are higher than the corresponding yields obtained with the unmodified and alkali‐treated cottons. Poly(acrylic acid)–PCMC graft copolymers show much higher moisture regain than PCMCs particulary when the carboxylic groups of the graft were in the sodium form. The opposite holds true for polystyrene–PCMC graft copolymers which exhibit much lower moisture regain as compared with PCMCs. The color strength of PCMC dyed with direct or reactive dyes decreases significantly after being copolymerized with poly(acrylic acid) prior to dyeing. On the other hand, this copolymerization improves the affinity of PCMCs for the basic dye and brings about perceptible shade. Polystyrene–PCMC graft copolymers acquire higher color strength than the PCMC when dyed with direct, disperse, and basic dyes but lower color strength upon dyeing with the reactive dye. Also reported were the moisture regain and dyeability of unmodified and alkali‐treated cotton before and after copolymerization with acrylic acid or styre