Conditions and Mechanism of Curing of some Ester-Imide Oligoiners

摘要

Ester-imide oligomers obtained by melt copolycondensalion of tris(2-hydroxy-ethyl)isocianurale, ethylene glycoleopenlylglycol, diaminodiphenilmethane. trimellitic anhydride, and dimethylterephthalate were cured by heating. The curing conditions and mechanism were established by TG. Superposed TG curves of uncured and cured compounds, normalized to unity, show that curing produces an increase of heal resistance within the temperature range 250-350℃. This is assigned to the increase of chain length, supposition supported by DSC curves, which show higher glass transition temperatures for the cured materials. IR, DTA, DSC, and gas chromatography emphasized the reactions respousible for chain length increase and reaction steps. Attenuation of absorption bands of hydrroxyl or hydroxyl and methyl groups suggests that curing occurs by elimination of water and glycols. Thus, molecular weights increase about 40 times and oligomers transform into polymers.