DSC and X-ray studies on side-chain crystallization of comb-like polymers

Abstract

Thermal properties of acrylate and methacrylate monomers containing long-fluorocarbon chains (H(CF 2 ) n CH 2 OCOCH=CH 2 , (F n A) and H(CF 2 ) n CH 2 OCOC(CH 3 )=CH 2 , (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 ΔH f was 18 kJ mol -1 and entropy change ΔS f was 45 J K -1 mol -1 , while for PF 10 MA the values ΔH f and ΔS f were 5.3 kJ mol -1 and 14 J K -1 mol -1 , respectively. Melted PF 8 A crystallized slowly, whereas PF 8 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.