Synthesis and thermal properties of poly(methyl methacrylate)-graft-(cellobiosylamine-C15)

Model experiments for synthesis of a comb-shaped copolymer with cellulose side-chains were performed with cellobiose derivatives. A novel cellobiose monomer, N-(15-methacryloyloxypentadecanoyl)-2,3,6-tri-O-acetyl-4-O-(2,3,4,6-tetra-O-acetyl-β-d-glucopyranosyl)-β-d-glucopyranosylamine (2) was prepared from heptaacetylcellobiosyl- amine. Homopolymerization of cellobiose monomer 2 and copolymerization of monomer 2 with methyl methacrylate (MMA) were performed using 2,2′-azobis(isobutyronitrile) (AIBN) as an initiator to obtain homopolymers 3-i (i = 1–4) and copolymers 3-i (i = 5–7), poly(methyl methacrylate)-graft-(heptaacetylcellobiosylamine-C15). The size exclusion chromatography—multi-angle laser light scattering (SEC-MALS) measurements revealed that comb-shaped homopolymers 3-i (i = 1–4) had more compact structures compared to copolymers 3-i (i = 5–7) at the same elution volume. Selective deacetylation of polymers 3-i (i = 1–7) gave novel cellobiose polymers 4-i (i = 1–7), poly(methyl methacrylate)-graft-(cellobiosylamine-C15). The amide linkages between cellobiose moiety and long-chain alkyl group, and the ester linkages between PMMA main-chain and long-chain alkyl group remained after deprotection.

The differential scanning calorimetry (DSC) measurements revealed that the T _gs of the polymers 4-i (i = 1, 5, 6, 7) increased with increasing cellobiose composition in the polymers. It was indicated that cellobiose moieties of polymers 4-i (i = 1, 5, 6, 7) reduced the mobility of PMMA main-chain.