Synthesis and characteristics of cellulose peroxides of the peracid type having a temperature-responsive function

The synthesis of cellulose peroxides of the peracid type having a temperature-responsive function was studied by using carboxymethyl cellulose (CMC) and acrylic acid (AA)-grafted cellulose, into which the temperature-responsive component, poly(N-isopropylacrylamide) poly(NIPAAm)], was introduced by a photografting method (λ > 300 nm). Dissolving pulp from softwoods was used as cellulose sample. NIPAAm-grafted CMC samples prepared by photografting with CMC peroxide exhibited a slightly larger temperature-responsive character than the samples prepared by photografting with xanthone photoinitiator, where the grafted CMC samples swelled and shrank in water at 5 °C and 60 °C, respectively. Ungrafted and NIPAAm-grafted CMC samples were subjected to peroxidation with hydrogen peroxide in the presence of methanesulfonic acid. About 90% of the initial amount of peroxide on the ungrafted CMC sample disappeared after thermal decomposition at 50 °C for 60 min. On the other hand, about 50% of the peroxide on the NIPAAm-grafted CMC sample remained stable under the same conditions. Peroxides on AA/NIPAAm-grafted samples, which were prepared by photografting of AA/NIPAAm binary monomers followed by peroxidation with hydrogen peroxide, were more stable towards thermal decomposition than those on NIPAAm-grafted samples.