Promoted biodegradation behavior of poly(L-lactic acid) in seawater conditions through blending amorphous polyhydroxyalkanoate

This study investigates the biodegradation behavior of a blend of poly(L-lactic acid) (PLLA) and amorphous polyhydroxyalkanoate (aPHA) (50:50 wt%) under seawater conditions for 12 weeks at 30 °C. The results revealed that the inclusion of aPHA in the blend enhanced the biodegradation of PLLA. The average molecular weight analysis indicated that the blend underwent homogeneous degradation primarily through exo-chain scission. Morphological changes observed via scanning electron microscopy demonstrated that aPHA first underwent decomposition in the blend, creating channels within PLLA that enhanced water and microorganism contact and promoted PLLA hydrolysis. The release of low-molecular-weight acids from the aPHA decomposition further facilitated PLLA hydrolysis.

The graph depicts fluctuations in the weight-average molecular weight of PLLA, the PLLA/aPHA blend, and aPHA throughout the biodegradation period under seawater conditions.