Effect of γ-radiation on the thermal and mechanical properties of a commercial poly(butylene adipate-co-terephthalate)

Abstract

Background: Poly(butylene adipate-co-terephthalate) (PBAT) has attracted wide interest as a biodegradable polymer. However, its use is restricted in certain applications due to its low melting point. Results: PBAT was treated using γ-radiation. The radiation features were analyzed using Soxhlet extraction, and the ratio of chain scission and crosslinking and gelation dose were determined using the classical Charlesby-Pinner equation. The results showed that PBAT is a radiation-crosslinkable polymer. The degree of crosslinking increased with increasing radiation dose; the relation between sol fraction and dose followed the Charlesby-Pinner equation. Differential scanning calorimetry analyses showed that the melting temperature (Tm) and the heat of fusion (ΔHm) of PBAT exhibited almost no change in the first scan. The second scan, however, showed a decrease in Tm and ΔHm. The glass transition temperature of irradiated PBAT increased with increasing radiation dose. The weight loss of control and irradiated PBAT resulting from thermal degradation was a one-step process. Moreover, the tensile strength and elongation at break decreased with an increase in radiation dose. However, the Young's modulus and stress at yield were not greatly affected by γ-radiation. Conclusion: PBAT can be crosslinked using γ-radiation. The crosslinking efficiency is relatively low. The thermal and mechanical properties of PBAT are affected by γ-radiation. © 2009 Society of Chemical Industry.