DSC and X-ray studies on side-chain crystallization of comb-like polymers - Fluorinated n-alkyl acrylate and methacrylate polymers

Thermal properties of acrylate and methacrylate monomers containing long-fluorocarbon chains (H(CF2)(n)CH2OCOCH=CH2, (F(n)A) and H(CF2)(n)CH2OCOC(CH3)=CH2, (F(n)MA), where n = 6, 8, 10) and their comb-like polymers have been investigated by differential scanning calorimeter (DSC) and X-ray diffraction. The comb-like polymers (PF(10)A and PF(10)MA) with sufficiently long-fluorocarbon chains showed a simple melting and crystallizing behavior. For the fusion of PF(10)A in 1st heating, enthalpy change Delta H-f was 18 kJ mol(-1) and entropy change Delta S-f was 45 J K-1 mol(-1), while for PF(10)MA the values Delta H-f and Delta S-f were 5.3 kJ mol(-1) and 14 J K-1 mol(-1) respectively. Melted PF(8)A crystallized slowly, whereas PF,MA with same fluorocarbon chain and also both of PF(6)A and PF(6)MA with shorter fluorocarbon chains can hardly crystallize by the aggregation of side-chains. Effects of the length of side-chain and the flexibility of main chain on the side-chain crystallization of comb-like polymers are clear. Crystallization process of the methacrylate monomers was sensitively affected by the scanning rate of DSC measurement and the length of fluorocarbon chains.