Browsing by Author "Chuang, HR"

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Siloxane- and imide-modified epoxy resin cured with siloxane-containing dianhydride
(2005-10-01)
Li, HT
;
Lin, MS
;
Chuang, HR
;
Wang, MW
;
應用化學系
Hydrosilylation of nadic anhydride by tetramethyldisiloxane yielded 5,5'-(1, 1,3,3-tetramethyl- 1, 1,3,3-disiloxanediayl)-bisnorborane-2,3-dicarboxylic anhydride (I), which further reacted with 4-aminophenol to form N,N'-bis(4-hydroxyphenyl)5,5'-(1,1,3,3-tetramethyl-1,1,3,3-disiloxanediallyl)-binorborane-2,3-dicarboximide(II) reacted with epichlorohydrin to form siloxane- and imide-modified epoxy (i.e. N,N'-diglycidylether-bis-(4-phenyl)-5,5'-(1,1,3,3-tetramethyl-1,1,3,3disloxanediallyl)-bis-norborane-2,3-dicarboximide (III) (Scheme 1). Various equivalent ratios of III/I for 1/1, 1/0.8 and Bisphenol F epoxy (830LVP DIC Co.)/I for 1/1, 1/0.8 were prepared and cured to produce four crosslinked materials. Thermal and dynamic mechanical properties were measured with TMA and DMA. Kinetic analysis was studied with dynamic DSC, which revealed a relatively lower curing activation energy of III/I systems, because the tertiary amine on the imide group catalyzed the curing reaction. III/I system also indicated moderate Tg, storage modulus but higher loss modulus as compared with Bisphenol F epoxy/I systems. These phenomena were interpreted by the fact that the siloxane group in III toughened the crosslinked materials. In addition, photos of SEM, carbon-mapping-SEM, oxygen-mapping SEM and siloxane-mapping-SEM indicated all homogeneity of these materials.
Synthesis, properties and pyrolysis of siloxane- and imide-modified epoxy resin cured with siloxane-containing dianhydride
(2005-10-01)
Li, HT
;
Chuang, HR
;
Wang, MW
;
Lin, MS
;
應用化學系
Hydrosilylation of nadic anhydride with tetramethyl disiloxane yielded 5,5'-(1,1,3,3-tetramethyl disiloxane-1,3-diyl)-bis-norborane-2,3-dicarboxylic anhydride (1), which further reacted with 4-aminophenol to give N,N'-bis(4-hydroxyphenyl)-5,5'-bis-(1,1,3,3-tetramethyl disiloxane-1,3-diyl)-bisnorborane-2,3-dicarboximide (II). Epoxidation of II with excess epichlorohydrin formed a siloxane-and imide-modified epoxy oligomer (ie diglycidyl ether of N,N'-bis(4-hydroxyphenyl)-5,5'-bis(1,1,3,3-tetramethyl disiloxane-1,3-diyl)-bis-norborane-2,3-dicarboximide) (III). Equivalent ratios of IIIII of 1/1 and 1/0.8 were prepared and cured to produce crosslinked materials. Thermal mechanical and dynamic mechanical properties were investigated by TMA and DMA, respectively. It was noted that each of these two materials showed a glass transition temperature (T-g) higher than 160 degrees C with moderate moduli. The thermal degradation kinetics was studied with dynamic thermogravimetric analysis (TGA) and the estimated apparent activation energies were 111.4 kJ mol(-1) (in N-2), 117.1 kJ mol(-1) (in air) for III/I = 1/0.8, and 149.2 kJ mol(-1) (in N-2), 147.6 kJ mol(-1) (in air) for III/I = 1/1. The white flaky residue of the TGA char was confirmed to be silicon dioxide, which formed a barrier at the surface of the polymer matrix and, in part, accounted for the unique heat resistance of this material. (c) 2005 Society of Chemical Industry.