Acid effects in the styrene comonomer technique for radiation grafting to wool

Graft polymerization onto wool fibre for improved functionality

“…The maximum grafting of 38% was observed at the reaction temperature of 60°C and a decrease in grafting occurred at a higher temperature probably due to the accelerated termination process (Chandel and Misra 1977). The catalysing effect of mineral acid for the grafting process has also been reported by other researchers Garnett 1973, Garnett andKenyon 1977) using benzoyl peroxide as an initiator, Chandel et al, grafted polystyrene onto the wool. A mixture of acidic acidpyridine was also used as a pH modifier.…”

“…Nevertheless, this technique is not applicable to other monomers, particularly acrylates, because the high amount of copolymer formation occurs and prevents the successful wool grafting. Garnett et al showed that if styrene is used as one of the monomers in the mixture, then it is possible to achieve wool grafting using a simultaneous irradiation method (Garnett and Kenyon 1977). Therefore, incorporation of styrene, for example, with ethyl acrylate results in a successful grafting with a minimum formation of unwanted homopolymer.…”

“…Therefore, incorporation of styrene, for example, with ethyl acrylate results in a successful grafting with a minimum formation of unwanted homopolymer. In addition, at high ratios of ethyl acrylate/styrene of 5 to 1 (w/w), the graft was mainly (87%) consisting of ethyl acrylate (Garnett and Kenyon 1977). If styrene is not present in the mixture, the homopolymerization of ethyl acrylate would be dominant or virtually no copolymerization can occur (acrylonitrile).…”

In Textiles

“…Inclusion of styrene as a comonomer in the MMA solution decreases the homopolymer formation signifi cantly, leading to higher grafting yields. A similar comonomer technique using styrene as the comonomer with the EA monomer has been studied earlier for radiation -induced graft copolymerization onto wool to effectively reduce homopolymer formation [51] . Such enhancement of grafting in the presence of the additives is important, as the required grafting level can be achieved at a reduced dose of radiation.…”

Hydrophilic/hydrophobic character of grafted cellulose

“…Styrene, by decreasing k p in the solution, reduces homopolymerization reaction and consequently decreases its competition process with graft polymerization (monomer-cellulose reaction) (Garnett and Kenyon, 1977).…”