Phase Transition And Side-Chain Crystallization Of Poly(Methyl Vinyl Ether-Alt-Maleic Anhydride)-G-Alkyl Alcohol Comb-Like Polymers

A series of poly(methyl vinyl ether-alt-maleic anhydride)-g-alkyl alcohol (PVEM -Cn) comb-like polymers were synthesized by a simple esterification reaction between poly(methyl vinyl ether-alt-maleic anhydride) and n-alkyl alcohol with n = 14-26. Thermal property, side-chain crystallization, and phase transition behavior of PVEM-Cn comb-like polymers were investigated by H-1 NMR,DSC, variable-temperature X-ray scattering and FTIR, as well as solid-state C-13 CP/MAS NMR. Obvious side-chain crystallization behavior from the pended side chains onto the PVEM backbone is well confirmed. With the side-chain length increasing from 14 to 26, phase transition temperature and melting enthalpy both increase from 30.1 to 79.4 degrees C and from 17.1 to 55.0 kJ/mol, respectively, and the crystallizable carbon atoms (N-c) also vary from N-c = 5.6 to 17.7 accordingly. Regular trans conformation state first transforming into irregular trans conformational disordered one and then to gauche state is well demonstrated, and the chain packing manners of orthorhombic and hexagonal show a size-dependent phenomenon. Comparison of the phase transition behavior and chain packing structure for the single-component and the two-component polymer backbone comb-like polymers is approached. And, the influence of chemical junction on the side-chain crystallization behavior is also discussed from the aspect of molecular chain packing and crystallization behavior.