NOVEL COPOLYESTERS CONTAINING NAPHTHALENE STRUCTURES .3. POLY(ALKYLENE NAPHTHALATE TEREPHTHALATE)

Copolyesters containing rigid segment (naphthalene and benzene) and fl exible segment (aliphatic diol) structures were synthesized from bis(h ydroxyalkyl)terephthalate and bis(hydroxyalkyl)naphthalate in various molar ratios. Copolyesters having intrinsic viscosities of 0.52-0.69 d L/g were obtained by the melt polycondensation in the presence of meta llic catalysts. The effects of reaction temperature and time on the fo rmation of copolyesters were investigated in order to obtain an optimu m condition for copolyester manufacturing. Most copolyesters have bett er solubilities than poly(ethylene naphthalate) (PEN) and poly(ethylen e terephthalate) (PET) in various solvents. The effect of molar ratio of starting monomers on the thermal properties of the resulting copoly esters was also investigated by the differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). Glass transition tempera tures of copolyesters from xyethyl)terephthalate/bis(hydroxyethyl)naph thalate were in the range of 70.7-115.2 degrees C, and temperatures fo r 10% weight loss in nitrogen were all above 426 degrees C. Another se ries of copolyesters from the xybutyl)terephthalate/bis(hydroxybutyl)n aphthalate system have T-g in the range of 51-66 degrees C, and 10% we ight loss in nitrogen of over 419 degrees C. (C) 1997 Elsevier Science Ltd.