Copolymers of 4-adamantylphenyl methacrylate derivatives with methyl methacrylate and styrene

Three 4-(I-adamantyl)phenyl methacrylate monomers were synthesized from 4-( l-adamantyl)phenol derivatives which were obtained by Friedel-Crafts alkyla tion of phenol, 2-methylphenol and 2,6-dimethylphenol with 1-bromoadamantan e. Characterization of the monomers by IR, H-1 and C-13 NMR, GC and element al analysis confirmed structures and purities. Copolymers of these new mono mers with styrene were synthesized using free radical techniques. One serie s of 4-(1-adamantyl)phenyl methacrylate was also prepared with methyl metha crylate (MMA). Copolymer compositions were evaluated by H-1 and C-13 soluti on NMR, and with FTIR. Reactivity ratios were estimated to have values of r (1) = 0.22 and r(2) = 1.51 for styrene and 4-(1-adamantyl)phenyl methacryla te copolymers; r(1) = 0.31 and r(2) = 2.44 for styrene and 2-methyl-4-(1-ad amantyl)phenyl methacrylate; and r(1) = 0.97 and r(2) = 0 for styrene and 4 -(1-adamantyl)-2,6-dimethylphenyl methacrylate copolymers (J Polym Sci A 3 (1965) 369-87, J Macromol Sci Rev C4 (1970) 281). All homo- and copolymers were characterized using DSC and TGA to determine copolymer composition eff ects on T-g and thermal stability. The estimated T-g for the homopolymer of 4-(l-adamantyl)phenyl methacrylate was 253 degreesC and the onset of decom position was 250 degreesC in nitrogen. The homopolymer of 2-methyl-4-(1-ada mantyl)phenyl methacrylate had a T-g of 250 degreesC which was at the onset of decomposition in nitrogen. The homopolymer of 4-(1-adamantyl)-2,6-dimet hylphenyl methacrylate could not be obtained by free-radical polymerization . 4-(Adamantyl)phenyl methacrylate was incorporated into styrene copolymers at 1-30 mol% and gave T-g increases of cs. 5-60 degreesC over that of poly styrene, respectively. Incorporation of this monomer into MMA copolymers (0 .75-35 mol%) resulted in T-g increases of ca. 6-70 degreesC over that of po ly(methyl methacylate). (C) 2001 Elsevier Science Ltd. All rights reserved.