聚乳酸水热全量解聚特性研究OA

This study investigates the degradation behavior of polylactic acid(PLA)plastic tableware and pure PLA un-der specific hydrothermal conditions(190℃).The physical and chemical changes in PLA before and after hydrothermal treatment were characterized using multiple analytical techniques,including mass loss measurements,scanning electron microscopy,high-performance liquid chromatography,and Fourier-transform infrared spectroscopy(FTIR).The kinet-ics of lactic acid generation and the evolution of macrostructure during hydrothermal depolymerization were systematically analyzed.Results indicated that solid-phase degradation of PLA reached completion(100%).The presence of lactic ac-id in solution significantly accelerated the hydrolysis of PLA without compromising the final lactic acid conversion yield(>90%).In contrast,common additives in PLA tableware,such as talc,cellulose,and other formulation compo-nents,moderately enhanced the initial hydrolysis rate but ultimately suppressed the lactic acid conversion efficiency.No-tably,polyethylene glycol exhibited a strong inhibitory effect on PLA hydrolysis.FTIR analysis revealed that hydrolysis proceeded primarily through cleavage of ester bonds,generating terminal—OH and—COOH groups.Consequently,the concentration of degradation products containing hydroxyl groups increased markedly,whereas the abundance of car-bonyl-containing species remained largely unchanged.