Synthesis and Characterization of Novel Biodegradable Poly Copolymers

Novel biodegradable aliphatic polyesters, poly(butylene succinate-co-triethylene glycol succinate) (P(BS-co-TEGS)) and poly(butylene succinate) (PBS), were synthesized through a two-step procedure of esterification and polycondensation with succinic acid and 1, 4-butanediol/triethylene glycol as raw materials as well as tetrabutyl titanate and diphenylphosphinic acid as the co-catalysts. The chemical structure and molecular weight of the copolymers were characterized by 1H nuclear magnetic resonance (1H NMR) and gel permeation chromatography (GPC), respectively. In addition, thermal properties, crystal structure and mechanical properties were also analyzed with various techniques. P(BS-co-TEGS) exhibited more excellent mechanical properties than PBS, especially in elongation at break. Meanwhile, the crystal structure and thermal stability of the P(BS-co-TEGS) have hardly changed. The crystallinity of P (BS-co-TEGS) was lower than that of PBS and decreased with the increase of mole ratio of triethylene glycol. With the increase of TEGS unit molar composition, the melting point (Tm), crystallization temperatures (Tc) and heat of fusion (Δ Hm) of P(BS-co-TEGS) decreased, while glass transition temperature (Tg) increased.