CELLULOSE METHACRYLATE - SYNTHESIS AND LIQUID-CRYSTALLINE BEHAVIOR OFSOLUTIONS AND GELS

A new derivative of cellulose was synthesized by reaction of the polym er dissolved in dimethylacetamide (DMAc)/5% LiCl and methacryloyl chlo ride. The control of the molar ratio between the reagents and the temp erature permits one to obtain a specific degree of substitution (DS). Cellulose methacrylate (CEMA) is a semirigid polymer with a persistenc e length which decreases as the DS increases. Consequently, the polyme r concentration Cp at which the anisotropic phase becomes stable gets higher as the DS increases. CEMA solutions gellify when irradiated by UV, due to the crosslinking reaction of lateral double bonds. Swelling in DMAc/5% LiCl and water depends on the CEMA concentration and irrad iation time. The first appearance of optical anisotropy may be observe d at a polymer critical concentration which is always lower than the C b of the uncrosslinked polymer. (C) 1998 Elsevier Science Ltd. All rig hts reserved.