ABSTRACT:The thermal behavior of mixtures of bis(4-maleimidophenyl) (A) with bis(4-isomaleimidophenyl)methane (C) and their mixture with 4,4Ј-diaminodiphenyl methane (D) were investigated by differential scanning calorimetry. The study of the binary system A/C in different proportions led us to determine an eutectic mixture at a molar fraction of C in the range of 0.7-0.9. The ternary ACD mixtures showed themselves able to participate in three principal reactions: polyaddition, ring-opening addition, and homopolymerization. In each mixture studied the addition of diamine changed the melting point and maximum polymerization temperatures in the sense of a general decrease. The properties of the networks were studied by thermal analysis and through evaluation of water absorption.

The effect of the polyethyleneglycol (PEG) content on the properties of the ethyleneglycol terephthalate (EGT)=polyethyleneglycol terephthalate (PEGT) copolymers has been studied. The PEG content varied over a wide range (5À70% PEG). To obtain information on the solubility and on the thermal properties, the following methods: turbidimetry, differential scanning calorimetry (DSC), thermogravimetry and differential thermogravimetry (TG, DTG) have been used. The turbidimetric characteristics are dependent on composition copolymers. The incorporation of increasing amount of PEG 4000 in EGT=PEGT copolymers has a pronounced effect on the properties: increases viscosity and solubility of copolymers, decreased glass transition, cold crystallization and melting temperatures and also decreased crystallization and melting heat. These changes are desirable for better processing of these copolymers comparatively with PET in products with higher elasticity and hydrophilicity. It must be take into account, however, that above 20 wt% PEG the copolymers the thermal stability is significantly affected.