Effect of UV-induced crosslink network structure on the properties of polylactic acid/polybutylene adipate terephthalate blend

Over the past few decades, biobased polylactic acid (PLA) has emerged as the most promising option to replace some of the fossil-based and nonbiodegradable polymers due to environmental concerns. In this study, a flexible polymer, polybutylene adipate terephthalate (PBAT) was blended with PLA to improve the toughness and flexibility of PLA, and the PLA/PBAT blend was further UV-induced to form crosslink structure. The results show that the flexibility and toughness of PLA could be significantly enhanced when PBAT was introduced, and the compatibility of PLA and PBAT could be enhanced by the development of a crosslink structure. Especially, the elongation at break and unnotched impact strength of ABT-UV30 (PLA/PBAT/triallyisocyanurate (TAIC) exposed to ultraviolet (UV) light for 30 min) was increased to 3.9 and 8.4 times of neat PLA. The glass transition temperature (Tg) of PLA was increased from 63.4 to 72.9 degrees C as the radiation duration was prolonged to 60 min. The melting point temperature of PBAT was also increased gradually until it eventually coincided with that of PLA. The thermalgravimetric analyzer thermograms show that a moderate amount of UV radiation can improve the thermal stability of the sample while an excessive amount of UV radiation can reduce the degradation temperature.