Novel copolyesters containing naphthalene structures .3. Poly(alkylene naphthalate terephthalate)

摘要

Copolyesters containing rigid segment (naphthalene and benzene) and flexible segment (aliphatic diol) structures were synthesized from bis(hydroxyalkyl)terephthalate and bis(hydroxyalkyl)naphthalate in various molar ratios. Copolyesters having intrinsic viscosities of 0.52-0.69 dL/g were obtained by the melt polycondensation in the presence of metallic catalysts. The effects of reaction temperature and time on the formation of copolyesters were investigated in order to obtain an optimum condition for copolyester manufacturing. Most copolyesters have better solubilities than poly(ethylene naphthalate) (PEN) and poly(ethylene terephthalate) (PET) in various solvents. The effect of molar ratio of starting monomers on the thermal properties of the resulting copolyesters was also investigated by the differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). Glass transition temperatures of copolyesters from bis(hydroxyethyl)terephthalate/bis(hydroxyethyl)naphthalate were in the range of 70.7-115.2 degrees C, and temperatures for 10% weight loss in nitrogen were all above 426 degrees C. Another series of copolyesters from the bis(hydroxybutyl)terephthalate/bis(hydroxybutyl)naphthalate system have T-g in the range of 51-66 degrees C, and 10% weight loss in nitrogen of over 419 degrees C. (C) 1997 Elsevier Science Ltd.