Study On The Technics And Packaging Properties Of Waste Paper Fiber And Starch Composite Foaming Material

Starch-fiber composite foaming material is a new, environment-friendly product and it can replace EPS polystyrene foamed plastic in certain application range as cushioning material in packaging industry.In this paper, potato starch and paper fiber were used as the main raw material. The moisture content, amount of additives to the mixture was controlled to improve the performance. Mixture of the raw material was gelatinized in the first then compression moulded under designed temperature and pressure. The structure, density, mechanical and cushioning properties of foamed samples were tested and analyzed for the purpose of researching the influence to the foaming product caused by the ratio of raw material, mould processing technology and other factors.Following conclusions were obtained through the analysis:the density of starch foaming sample is0.16g/cm3, bending strength is3.6MPa when moisture content is60%, and the brittleness of these sample is high. The toughness of foaming product was enhanced when add PVA to the row material, at the same time the bearing capacity and buffer efficiency were improved, density was increased. The performance of products was not significantly different whether adding dry fiber or fiber pulp when material moisture content was more than70%. The fiber content has great influence on the internal structure of the sample. The major structure of the products is some cavities with continuous bubble walls when starch used as the main material, the fibers in the material enhance the mechanical properties but also affected the uniformity of the cavities. When the adding amount of fiber is greater than starch, three dimensional porous structure which made up by fibers became the main composition and was bonded by starch paste. These two representative structure models can absorbs energy when bear external force. With the increase of the fiber content the mechanical properties of the composite are improved obviously. The foaming products have good cushioning effect (minimum cushioning coefficient is2.71) under1010kPa stress when the mass ratio of fiber to starch is1.5:1.The thickness of the sample reached40mm. These samples were molded in a improved mould with high heat conducting efficiency with5-7min molding time and the mold temperature is about170℃. The apparent density of the cushioning sample is0.143g/cm3. The load capacity of the products is about650kPa, the minimum cushioning coefficient is under3.2.