Photodegradation of composites based on polylactide and polybutylene adipate terephtalate

Degradation of polylactide (PLA)— polybutylene adipate terephthalate (PBAT) mixtures under the action of UV radiation (λ= 254 and 365 nm) was investigated. It is established that polybutylene adipate terephthalate slows down the PLA degradation without changing its mechanism. After photodegradation, the PLA glass transition temperature shifts to higher values, while its melting point decreases by 3.6–5.0 °C (λ = 254 nm). The crystallinity degree of PLA is reduced by no more than 5% after exposure to UV radiation at both wavelengths. After UV radiation at both wavelengths, intensities of characteristic IR bands of both components change substantially. The mechanical properties of mixtures of all studied compositions deteriorate after irradiation with light with λ = 254 nm for 50 h, and more significant deterioration is observed for samples with a predominance of PLA.