A copolyester hot melt adhesive was prepared by transesterification, esterificcation and polycondensation from dimethylterephthalate(DMT), dicarboxylic acid and dihydric alcohol. The influences of nucleating agents and crystallizing promoter on its crystallization kinetics was studied by measurement of depolarized light intensity with time. It was found that the complex additives composed of inorganic nucleating agent, organic agents and crystallization promoter could significantly accelerate the crystallization process of the copolyester due to the reduction of the activation energies of crystal nucleation and crystal growth.
It was demonstrated that some level of order exists in glassy poly(ethylene terephthalate) by depolarized light intensity(DLI) technique, but this order is different from that in crystalline PET. The degree of order in glassy PET decrease with increasing temperature between 288-343 K. The active energy of this transition is about 22 56 kJ/mol. The IR analysis indicated that this order relates to gauche structure of the ethyleneglycol fragments. The decrease of order with temperature comes from the increase of distance between the order segments.
