Journal of Applied Polymer Science, Vol.79, No.1, 159-165, 2001
P[CF3(CF2)(5)CH(2)MA-co-MMA] and P[CF3(CF2)(5)CH(2)MA-co-BA] copolymers: Reactivity ratios and surface properties
This study aimed at reducing the surface energy of coatings by copolymerization of commonly used monomers with fluorine-containing monomers. Copolymers of 1,1-dihydroperfluoroheptyl methacrylate (FHMA) and methyl methacrylate (MMA) or butyl acrylate (BA) are prepared by low-conversion polymerization in solution. Using H-1-NMR data and nonlinear least-squares data fitting, reactivity ratios of these systems at 80 degreesC are determined to be r(FHMA) = 1.31, r(MMA) = 0.76, and r(FHMA) = 3.15, r(BA) = 0.38, respectively. We assume that the penultimate unit effect plays an important role in these systems. Introduction of the perfluoroalkyl side chain lowers the polymer surface energy significantly; copolymers of MMA and FHMA show a reduction in total surface energy of about 50% at a content of 15 mol % FHMA as compared with pure PMMA. The attainable reduction in surface energy is much larger than with, for example, Teflon. This is due to the preferential adsorption of the -CF3 groups of the fluoroalkyl side chain, if compared to that of the -CF2- groups of Teflon.
Keywords:reactivity ratios;nonlinear least-squares data fitting;perfluoroalkyl side chain;copolymers;surface energy