Biological Enzymatic Hydrolysis—Single Screw Co-Extrusion Treatment to Improve the Mechanical Properties of Biodegradable Straw Fiber Mulching Films

Biodegradable agricultural films manufactured with straw serve as a viable substitute for plastic films, effectively addressing the issue of white pollution. However, existing biodegradable straw fiber films exhibit insufficient mechanical properties, primarily characterized by their susceptibility to fracture damage. To address this issue, a novel method for the preparation of film raw materials was proposed, which employs the synergistic treatment of bioenzymes and a single screw extruder, with the aim of enhancing the mechanical properties of the film. The method begins with the application of microbial agents to pretreat the straw, for improving its fiber morphology and inducing beneficial physicochemical structural changes. Subsequently, single screw extrusion technology is employed to further enhance the quality of the straw fibers and the mechanical performance of the film. The bio-mechanical pulp produced with this method demonstrated an increase in the crystallinity index (CrI) from 50.33% to 60.78%, while the degree of polymerization (DP) decreased from 866.51 to 749.60. Furthermore, the tensile strength, tear strength, and burst strength of the fiber covering film increased by 35.74%, 16.22%, and 11.65%, respectively, which meet the mechanical durability requirements for farmland mulching. This research effectively mitigates agricultural white pollution by converting agricultural waste straw into biodegradable mulch film, which promotes the recycling of straw resources. This study presents a novel method with significant potential application value for the production of bio-pulping in the paper industry.