The influence of aliphatic low molar mass polyesters on crystallization ofpoly(ethylene terephthalate)

Several poly(1,4-butylene sebacate) (SBT) with low molar mass were synthesi zed, and their number:average molar masses were determined by vapor phase o smometer (VPO). Thermogravimetric analysis (TGA) indicated that they displa y a good thermal stability, The measurement of solution viscosity of poly(e thylene terephthalate) (PET) certified that the addition of SET leads to an only small decrease in molar mass of PET in the case of higher molar mass SBT. The compatibility of PET with SET was studied by scanning electron mic roscope (SEM); higher molar mass SBT shows a larger tendency towards phase separation. The influence on crystallization of PET was investigated using differential scanning calorimetry (DSC). It was revealed that SET significa ntly accelerates the crystallization rate of PET at low temperature and als o enhances the crystallization rate of PET at high temperature.