The Optimization Experimentation Of Processing Parameter Of The Biodegradable Material Prepared By Straw

China is a large agricultural nation. Annual production of crops straw is about700million tons, ranking first in the world. Wheat, corn and rice, three crops straw accounts for about84%of total crops straw in China. However, the largest percentage of wheat straw can reach30%. It is known that the straw utilization is about33%recently in China. There are approximately400million tons of unused straw resources each year in the country, and most of which are untreated. The straw treated by technology are only2.6%,so that the potential of comprehensive utilization is very great. Therefore, straw is selected as raw material in preparation of biodegradable materials research subject, which have an important practical significance including alleviate oil resources crisis, the environment protection and the solution to the problem of "agriculture, countryside and farmers". In this study, cutting fraction single-screw extrusion machines was adopted to extrude the wheat straw, and biodegradable composite was prepared by the method of molding forming. Meanwhile, the orthogonal experiment scheme L9(34) and range analysis test was selected to investigate the impact of pretreatment parameters on the mechanical properties of compos, five levels of four factors was adopted to carry on Orthogonal rotation combination of experimental design. And regression analysis method was selected to explore the impact of the molding parameters on the mechanical properties of the composites, which laid the foundation for the application of straw preparation of biodegradable material.In this paper straw and starch were respectively as the main ingredient and adhesive to make the biodegradable composites. Through the study of screw extrusion pretreatment test and compression molding experiment, the main conclusions were obtained as follows:1) Straw was extruded by single-screw extruder. It was shown that the basic law about the particle size distribution of the nine materials was similar. fiber of10mesh to16mesh accounted for35%to50%, fiber of30mesh to70mesh accounted for20%to30%, fiber of16mesh to30mesh accounted for about20%.2) It can be concluded by screw extrusion pretreatment process parameters that, when the material moisture content was50%, sleeve initial temperature was100℃,and screw speed was80r/min, mechanical properties of composites was the best.3) The upper and lower mold temperature were controlled respectively, which contributed to the stripping of the composite. The composite firstly separated from the lower mold of low temperature 4) Molding process parameters of higher flexural strength of composite optimal were:Upper and lower mold temperature were respectively144℃and134℃; rubber ratio was1.23:1; the pressure was74kN; when the dwell time was3.55min, the maximum of the bending strength was37.1MPa.5)Molding process parameters of higher stretching strength of composite optimal were:Upper and lower mold temperature were respectively144℃and134℃; rubber ratio was1.21:1; the pressure was80kN; when the dwell time was3.95min, the maximum of the stretching strength was14.9MPa.6) Degradation of performance of the composite material of straw has been investigated. Soil landfill method was selected to decompose sample. It was shown that white fungus appeared in the sample in30days. With the time went by, white fungus and the area of corrosion were growing until break down. Simple lost weight to50%after degradation in60days. Blisters method was selected to decompose sample. It was shown that simple completely broke and large-size fibers decomposed into tiny fine fibers. Simple lost weight to53%after degradation in60days.