Copolymers of methyl methacrylate and fluoroalkyl methacrylates: Effects of fluoroalkyl groups on the thermal and optical properties of the copolymers

Abstract

Fluoroalkyl methacrylates, 2,2,2‐trifluoroethyl methacrylate (1), hexafluoroisopropyl methacrylate (2), 1,1,1,3,3,3‐hexafluoro‐2‐methyl‐2‐propyl methacrylate (3), and perfluoro t‐butyl methacrylate (4) were synthesized. Homopolymers and copolymers of these fluoroalkyl methacrylates with methyl methacrylate (MMA) were prepared and characterized. With the exception of the copolymers of MMA and 2,2,2‐trifluoroethyl methacrylate (1), the glass transition temperatures (Tgs) of the copolymers were found to deviate positively from the Gordon‐Taylor equation. The positive deviation from the Gordon‐Taylor equation could be accounted for by the dipole–dipole intrachain interaction between the methyl ester group and the fluoroalkyl ester group of the monomer units. These Tg values of the copolymers were found to fit with the Schneider equation. The fitting parameters in the Schneider equation were calculated, and R2 values, the coefficients of determination, were almost 1.0. The refractive indices of the copolymers, measured at 532, 633, and 839 nm wavelengths, were lower than that of PMMA and showed a linear relationship with monomer composition in the copolymers. 2 and MMA have a tendency to polymerize in an alternating uniform monomer composition, resulting in less light scattering. This result suggests that the copolymer prepared with an equal molar ratio of 2 and MMA may have useful properties with applications in optical devices. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4748–4755, 2008

Mechanical and thermal properties of perfluoroalkyl ethyl methacrylate–methyl methacrylate statistical copolymers synthesized in supercritical carbon dioxide

“…Thus, the Y mod and the T g values of the copolymer reduced (Figs. 4 and 7) in a similar trend with the data reported in references [9,30,34,39,51]. In addition, the relationship between the Y mod and the T g values of the copolymer is shown in Fig.…”

“…In this table, it is realized that the increase of the perfluoroalkyl ethyl methacrylate content in the copolymers caused a decrease in the T g values due to the increase in the number of -CF 2 -group in the CF 3 (CF 2 ) x -side chain. In the literature, T g value of PMMA homopolymer was reported to be 105 8C [30] and T g value of the poly(perfluoroalkyl ethyl methacrylate) homopolymer having x = 5 were reported as 21.2 [48], 49.1 [6] and 52 8C [11] and T g value was found to be 90.8 8C when x = 0 [6]. We determined T g = 40 8C for Zonyl-TM homopolymer which was synthesized in the heterogeneous CO 2 medium and this value was within the range of T g values reported in the literature.…”

“…The curve show positive deviation when monomer 1 which has the lower T g is the dominant composition and negative deviation when monomer 2 which has the higher T g is the dominant composition [28]. Zhou et al, synthesized the fluorinated alkyl methacrylate copolymers consisting of monomers containing different number of -CF 3 end group and methyl methacrylate, and they indicated that the presence of the bulky CF 3 -containing groups caused a positive deviation from the Gordon-Taylor equation due to the dipole-dipole interaction between the CF 3 (CF 2 ) n CH 2 CH 2 O-and the C5 5O groups [30]. When 2,2,2-trifluoroethyl methacrylate containing only one -CF 3 group was used in the copolymer, then it had a good fit with the GordonTaylor equation, however when perfluoro t-butyl methacrylate containing three -CF 3 groups was used in the copolymer, then it had a positive deviation from the Gordon-Taylor equation [30,31].…”

“…Zhou et al, synthesized the fluorinated alkyl methacrylate copolymers consisting of monomers containing different number of -CF 3 end group and methyl methacrylate, and they indicated that the presence of the bulky CF 3 -containing groups caused a positive deviation from the Gordon-Taylor equation due to the dipole-dipole interaction between the CF 3 (CF 2 ) n CH 2 CH 2 O-and the C5 5O groups [30]. When 2,2,2-trifluoroethyl methacrylate containing only one -CF 3 group was used in the copolymer, then it had a good fit with the GordonTaylor equation, however when perfluoro t-butyl methacrylate containing three -CF 3 groups was used in the copolymer, then it had a positive deviation from the Gordon-Taylor equation [30,31]. The free volume of the copolymers can be measured by the positron annihilation lifetime spectroscopy (PALS) as reported in the literature [21,[32][33][34][35][36].…”

Hydrophobic methacrylic copolymers containing azobenzene moieties

“…They have high thermal stability, low moisture absorption, weather resistance, low refractive index and high transparency [5,6]. Fluorinated acrylates and methacrylates exhibit all these properties with the advantage of being soluble in common organic solvents and easily synthesized.…”