Natural Degradation Behavior of Poly(lactic acid) Nanocomposite Films and the Adsorption Behavior of Degraded Products on Cu(II).

In this study, the degradation behavior of poly(lactic acid) nanocomposite films (PLA/Hec-g@PS) under extreme natural environments was investigated, and the degraded PLA based films were applied to adsorb Cu(II). During the early and midstages of degradation, the surface roughness and crack propagation rate of PLA/Hec-g@PS films were significantly lower than those of PLA films. This could be due to the fact that Hec-g@PS enhanced the interaction forces between C-O-C + CH and C═O in the PLA chains, thereby mitigating the degradation of PLA. Neural network predictions indicated that the molecular weight of PLA films decreased to 30% after 1344 days, whereas PLA/Hec-g@PS films reached the same reduction in 1451 days, extending the lifespan of PLA by 1.08 times. The environmental impact of PLA/Hec-g@PS was further assessed by their adsorption behavior toward Cu(II). It was found that PLA films adsorbed 244.51 μg/g of Cu(II), while PLA/Hec-g@PS films adsorbed 372.63 μg/g of Cu(II). The isotherm adsorption model showed that the maximum adsorption capacities () of PLA and PLA/Hec-g@PS were 326.60 μg/g and 441.51 μg/g, respectively. This improvement offers PLA based films new possibilities for applications in wastewater treatment and soil remediation.