Chain extension of polyester typed bio-based polymer

Hydroxyl-terminated and carboxyl-terminated prepolymers of bio-based polyester were synthesized from propylene glycol, butanediol, se-bacic acid, succinic acid, itaconic acid. Using tri-phenyl phosphate (TPP) as a chain extender, the effects of the temperature of chain-extending reaction, the mass fraction of TPP added to the system and different relative molecular masses of prepolymer on chain-extending reaction were studied. The results showed that the appropriate condition for chain-extending reaction was the number-average molecular weight of prepolymer 1.0x10(4), the mass fraction of TPP 15% and the chain-extending temperature 180 degree C. Under this condition, the number-average molecular weight of chain-extending polymer reached 4.8 x 10(4). Fourier transform-infrared spectroscopy confirmed the occurrence of chain-extending reaction. The differential scanning calorimetry data indicated that after the chain-extending reaction, glass transition temperature increased and melting temperature decreased com