Comb-shaped graft copolymers with cellulose side-chains prepared via click chemistry

Comb-shaped copolymers with cellobiose acetate or cellulose triacetate (CTA) side-chains, PPMA-g-(CTA2-C15) and PPMA-g-(CTA13-C15), were prepared by grafting N-(15-azidopentadecanoyl)-2,3,6-tri-O-acetyl-4-O-(2,3,4,6-tetra-O-acetyl-β-d-glucopyranosyl)-β-d-glucopyranosylamine (CTA2-C15-N3) and N-(15-azidopentadecanoyl)-tri-O-acetyl-β-cellulosylamine (CTA13-C15-N3, number average degree of polymerization (DPn) = 13) onto poly(2-propyn-1-yl methacrylate) (PPMA, weight average degree of polymerization (DPw, X + Y = 5.59 × 102)) via “click chemistry”. The copolymers were characterized by 1H, 13C and two-dimensional NMR and size exclusion chromatography–multi-angle laser light scattering (SEC–MALS) measurements. The numbers of CTA side-chains (X) of PPMA-g-(CTA2-C15) and PPMA-g-(CTA13-C15) were calculated as 4.03 × 102 and 2.45 × 102, respectively. Copolymers with cellulosic side-chains, PPMA-g-(CELL2-C15) and PPMA-g-(CELL13-C15), were successfully obtained after deacetylation of PPMA-g-(CTA2-C15) and PPMA-g-(CTA13-C15), respectively. X-ray diffraction measurements revealed that PPMA-g-(CELL13-C15) showed crystalline pattern of cellulose II, which is believed to have anti-parallel orientation.