Properties of phosphorus-containing polybutylene succinate/polylactic acid composite film material and degradation process effects on physiological indexes of lettuce cultivation

Abstract

Phosphorus-containing polybutylene succinate (P-PBS) was prepared from the third monomer phenylphosphonic acid to improve the performance of biodegradable materials and endow plants with nutritional functions. The P-PBS/polylactic acid (PLA) composite was produced by blending P-PBS and PLA; its crystallization, thermodynamic, water vapor permeability, degradation, and plant nutrition properties were studied. Introducing phenylphosphoric acid destroyed the regularity of the PBS chain, decreased the crystallinity, and increased the polarity. With PLA, the composite crystallinity was further reduced. A certain intermolecular force combines P-PBS/PLA. When the P-PBS amount was 60%, the two-phase melting point was close, the two-phase compatibility was high, and the crystallinity was the lowest. Additionally, the molecular chain flexibility of the composite was the highest with the optimal thermal and mechanical properties. Furthermore, with 60% P-PBS, the composite material had the highest water vapor transmission rate for possessing the largest two-phase contact surface, which can be used as a mulching film. The composite was degraded in soil supernatant for 6 months, with a 60%–70% degradation rate. LC-MS identification revealed that the degradation products were succinic acid, butanediol, and phenylphosphonic acid oligomers, among which phosphorus-containing small molecules enhanced lettuce growth.