Structure of poly[(ethylene glycol)‐(diethylene glycol) terephthalate] as determined by chemical degradation

The influence of preliminary thermal treatment and diethylene glycol (DEG) content on the rate of degradation, DEG amount in the degradation products, WAXS, relative viscosity, and density of the understructed poly(ethylene terephthalate) (PET) is studied upon aminolysis with hydrazine hydrate at 60 and 85°C. The results indicate that (i) the aminolysis is a two‐stage process, corresponding to the degradation of the amorphous and crystalline regions and (ii) the phase boundary is not sharp. A model is proposed, describing the comonomer distribution in the semicrystalline copolyesters. The comonomer units are concentrated mainly in the amorphous regions. The effect of degradation conditions like temperature, concentration, duration, particle size, deposition of low molecular products on the polymer surface, etc. is also discussed.