Functionalization of slow-release fertilizers and “passive predation microplastics” mechanism for polylactic acid composites

Abstract

The large-scale use of nonrenewable plastic mulch has resulted in serious agricultural health pollution. Biobased plastic materials with degradable properties offer attractive sustainable alternatives, but the shortcomings of their properties are slow degradation and extremely monofunctional, making their full-scale promotion still challenging. This work proposes a novel functionalized strategy for the multifunctionality empowerment of bio-based PLA materials for environmental protection and crop yield enhancement. This strategy relies on the effective combination of amine-modified lignin hybrid filler (L-U) and PLA matrix, which generates a hydrogen bonding network that can effectively synergize to improve crystalline ability and mechanical properties of PLA. In addition, L-U can effectively increase the PLA matrix degradation sites and improve its hydrophilicity to enhance its degradation properties further. In agricultural mulch, the functionalized materials (PLU) have high water insulation, biodegradability, and excellent slow release of nutrients, which can effectively improve the utilization of fertilizers and reduce the dependence of industrial fertilizers in agricultural systems. In addition, the “passive predation” mode of plants on bio-based polyester-based micron-sized microplastics was explored, which can better understand the adsorption characteristics of biopolyester-based micron-sized microplastics on plants, thus reducing the potential risk to food yield, quality, and safety.