Processing Condition And Performance Research Of Wheat Straw Based Compound Packing Materials

In this paper, wheat straw was fibrillated by twin-screw extruder after alkaline spray treatment, then starch was added such as adhesives. Material was prepared for performance test by hot-pressing methods after mixing with extruding machine. Choose the suitable technological conditions to make the molded part and test its packaging applicability. Experimental research of alkali amount and processing temperature and time on the material properties. Additive type and dosage of the influence of material properties-Extrusion processing temperature on the material properties and moulding process conditions on the influence of material properties.Experiment chooses dilute treatment and alkali amount choice1%,2%and4%three points. Wheat straw was treated under room-temperature for16hours. Then using co-rotating twin screw extruder which screw diameter is60mm and length-diameter ratio is15. Defibering under the condition of120℃and75r/min. Back whorl through twin-screw extruder was used to increase the defibering effects. Use BAUER fiber classifier to analysis the defibering effects.Through the experiments of moulding after the mechanics properties of relief after testing shows, the fiber materials has certain mechanical strength without any addition. And when NaOH dosage of2%, composite materials tensile strength value is8.25MPa. When the amount of1%NaOH, composite bending strength and impact strength are16MPa and about5KJ/m2respectively.To improve the mechanics properties of fiber materials, starch material was added as adhesives. Starch in different forms (starch, self-made pre-gelatinizied starch and starch paste) and different amount (10%,20%, and30%) was sprayed on fibers, then through the twin-screw extruder to make starch produce adhesive performance. The mechanics properties testing shows the self-made pre-gelatinizied starch and starch paste can make better performance compared with crude starch effect. Meanwhile, material with starch addition does not get good improve, even have the downward trend.For the composite performance is improved, the cation starch and wood powder as additive, and its performance. Results showed that in other under the same conditions, when additives is20%, the content of the rubber wood to join the mechanical properties of composite is best. The tensile strength of the average9.53Mpa, bending strength to average for21.28Mpa. But the cation starch and wood powder has timeliness, if use undeserved will make serious reduce material properties.The reasonable technological parameters set helps improve the mechanical properties of composite materials. Therefore the experiment of extrusion processing temperature and hot-pressing process conditions were studied. The results show that when the extrusion temperature for120℃, composite materials can achieve good mechanical properties. When holding time, with temperatures5min in120℃, the pressure for3MPa conditions, the sample can obtain better mechanical strength.The compound material was applied in package industry, instead of wood packaging material.