Chemical interactions in blends of bisphenol A polycarbonate with tetraglycidyl-4,4'-diaminodiphenylmethane epoxy

Abstract

The physical and chemical interactions existing between the two blend components, tetraglycidyl-4,4'-diaminodiphenylmethane (TGDDM) and Bisphenol A polycarbonate (PC), were investigated by differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM). The homogeneous phase behavior, which was found to exist not only in the heated binary blends of TGDDM/PC with no curing agents but also in amine-cured blends, is believed to be a result of these special chemical links developed between the TGDDM epoxy and linear PC polymer molecules. Mechanisms of chemical reactions and the resulting links between these two components upon heating of the TGDDM/PC blends (in the absence of any curing agents) have been proposed and proven by experimental results.

Molecular Architecture and Morphology Homogenization of Polycarbonate-Crosslinked Epoxy Resins

“…6,1997 groups of the PC polymer chains in the heated TGDDM/PC. 2 Usually, the secondary hydroxyl groups in epoxy pre-exist or can be generated from ring-opening homo-polymerization of epoxides at high temperatures. 2· 13·14 In this fashion, the fragmented PC (i.e., PC chain scission at the carbonate 0-¢ linkage) segments are exchanged with the hydroxyl hydrogen or the epoxide groups of epoxy.…”

“…An earlier study on probing the mechanism of exchange reactions has pointed out that when PC is present in great excess to epoxy, the chain exchange reactions may be limited to a lesser extent when PC as the epoxy (TGDDM) becomes the limiting species. 2 The physical differences between the extracted solute and leached solid samples have been previously studied using DSC to determine the Tg. 12 Both the Tg's of the leached solid portion and the corresponding parent epoxy/PC sample have been found to increase with heating time at I 77°C.…”

“…Studies have shown that mixtures of tetraglycidyl diaminodiphenyl sulfone (TGDDM)/bisphenol-A polycarbonate (PC) mixtures of various compositions cured with an aromatic amine (4,4'-diamino diphenyl sulfone, DDS) lead to a crosslinked network with rare homogeneity.1 A continuing FT-IR study 2 demonstrates that by excluding DDS and using only TGDDM and PC as a simplified model, chemical transreactions take place between the carbonyl in PC and the epoxide group in TGDDM acting as a tertiary amine auto-catalyst. The unheated TGDDM/PC liquid mixtures contain all <f>-0-CO-O-</> linkages characteristic of the original unreacted PC chains; nevertheless, the structure of the transreacted solids contains ¢---carbonate-</> and/or C---carbonate-C linkages, where symbols "</>" and "C" adjacent to the carbonate group indicate the phenyl or aliphatic chain, respectively.…”

Hydrogen-bond interactions between poly[(ethyl acrylate)-co-(acrylic acid)] and polycyanate derived from bisphenol A dicyanate

“…Miscible blends of highly cross-linked networks and linear polymers are even more rare. One example illustrating a homogeneous blend of thermoset and linear polymer is the blend of tetraglycidyl-4,49-diaminodiphenylmethane (TGDDM) epoxy and bisphenol A polycarbonate (PC) 1) : However, the abnormal miscibility between these two components is due to the chemical reactions of the hydroxyl groups generated from cleavages of the carbonate linkages in PC and the TGDDM epoxy at elevated temperatures.…”

Diffusion-controlled reaction mechanisms during cure in polycarbonate-modified epoxy networks

“…Chemical exchange reactions and interactions have been found to occur between PC and DGEBA, 3,4 or between PC and TGDDM. 5 Fur-one has been reported for the amine-cured tem is transformed from a liquid/rubbery state to a glassy state. Generally, formation of macromo-TGDDM-PC system, and the n-th order kinetics have been shown to be good up to near the vitrifilecular networks is accompanied by a considerable rise in the T g of the reacting system.…”