Epoxy−Polycarbonate Blends Catalyzed by a Tertiary Amine. 1. Mechanism of Transesterification and Cyclization

Abstract

In the Bisphenol A base polycarbonate−Bisphenol A base epoxy blend system, the carbonate group can react with epoxide in the presence of a tertiary amine. The transesterification reactions convert the original aromatic/aromatic carbonate of PC to aromatic/aliphatic and aliphatic/aliphatic carbonates. IR spectroscopy shows an unknown major structure formed during the later stages of the transesterification reaction. The unknown structure was investigated by a model reaction using diphenyl carbonate and phenyl glycidyl ether leading to the formation of 4-(phenoxymethyl)-1,3-dioxolan-2-one (PMD), which has been identified by IR, UV, 1H NMR, 13C NMR, and mass spectroscopy. The mechanism of forming the cyclic carbonate is proposed to proceed through a zwitterion and a nucleophile attack of the aromatic/aliphatic or the aliphatic/aliphatic carbonate group.

Spontaneous Growth and Chemical Reduction Ability of Ge Nanoparticles

“…4a shows UV-vis absorbance spectra of 2,5-dichlorophenol after reacting with fresh Ge NPs. It exhibits that as dechlorination proceeded, Cl atoms, as typical auxochromes, broke away from benzene rings, leading to a decline in absorbance of the three representative absorption bands of 2,5-chlorinated sodium phenolate, together with an obvious blue shift, especially for B band or fine-structure band located at 300 nm of benzene52. As shown in Fig.…”

High-Tg, Low-Dielectric Epoxy Thermosets Derived from Methacrylate-Containing Polyimides

“…1 H-NMR (DMSO-d 6 ): 7.0-8.4 ppm (Ar-H); 5.8 and 6.2 ppm (-C=CH 2 ); 1.9 and 1.6 ppm (CH 3 ). 31 P-NMR (DMSO-d 6 ): 36.5 ppm. IR: 1780 and 1720 cm −1 (imide), 1238 cm −1 (P=O), 1370 cm −1 (C-N-C), 1105 cm −1 (Ar-O-C), 950 cm −1 (-C=C-H).…”

Fourier transform infrared analysis of polycarbonate/epoxy mixtures cured with an aromatic amine

“…A detailed review and discussion of amine-epoxide reactions has been given in several books and After a clear solution of PC/EPON 828 was obtained either by an SB or an MB method, 27 articles. 31,35 -44 In principle, primary amines react with epoxide groups, producing secondary parts of DDM, previously melted at 90-100ЊC, was added to the solution.…”

“…Epikote᭨ have been several articles concerning modifica-828 was mixed with PC using methylene chloride tion of epoxies with polycarbonate (PC). [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] The as a cosolvent; after solvent removal, the mixture primary object of these endeavors is to increase was then cured with DETA. The authors conthe fracture toughness of originally brittle epoxcluded that the blend was miscible and the fracies, especially highly crosslinked, high glass tranture toughness, K IC , was increased somewhat by sition temperature (T g ) epoxies.…”

“…No mechanical properties were reported. Li et al 27 studied the chemical reactions in the diaminodiphenyl methane (DDM) at 80ЊC for 6 h followed by 3 h at 150ЊC. It was found that the epoxy/PC blends with a tertiary amine catalyst.…”