Investigation In Preparation And Properties Of Bamboo Powder/Starch Foam Composites

Starch-based foam composite is degradable by being prepared withstarch as matrix, modified with additives as plasticizer, compatilizer,foamer and processed by extrusion, injection or baking foaming. On theone hand, the starch-based foam composite has good biodegradation toreplace non-biodegradable foamed plastic especially EPS, so it makesfor relieving the problems of white pollution and oil shortage; On theother hand, it is helpful to improve the added value of starch and addagricultural economic benefits; However, there are some commonproblems of the starch-based foam composite, such as poorcompatibility and water resistance, cells with uniform distribution andlow expansion rate and rebound rate. Therefore, performance ofstarch-based foam composite is still not as good as EPS and limits itswide application in the market. If we can get breakthrough the aboveproblems, it will bring hope for its application in the market.In the bamboo power/starch foam composites（PFRSP） wereprepared with starch as matrix, strengthened by bamboo power,modified with additives as plasticizer, compatilizer, foamer andprocessed by injection foaming. Firstly, starch was plasticized byglycerol/DOP to explore the plasticizing mechanism; PVA was used toresearch interface mechanism of fiber/starch composite; The influence ofglycerol/DOP、fiber、PVA content and temperature on the melt rheologywas researched. Secondly, it was investigated that glycerol/DOP、bamboo power、foamer、PVA content and extrusion molding processparameters (extrusion temperature, extrusion pressure, extrusionfrequency) effected in composites’ apparent density, expansionraterebound rate, degradability, melt rheology and cell expansion.The results showed that:(1) When mass ratio of glycerol and DOPwas10to1and their mass content was30%of starch, starch wasplasticized best, and its tensile strength increased by1.5times; WhenPVA content was12%, it could improve interface compatibility of eachcomponent best, and its tensile strength increased to the maximum15.4 MPa.(2) Melt shear viscosity was reducing with the increase of shearrate which was called as "shear thinned behavior"; When shear rate wasthe same, with increase of mixed plasticizer and foamer content, theshear viscosity were decreasing. However, with increase of bamboo fiber,shear viscosity was increasing; Shear viscosity was decreasing firstlywith the rise of temperature, then increasing; Shear viscosity wasincreasing firstly with the rise of PVA content, then decreasing.(3)Rebound rate was rising increasing of mixed plasticizer, fiber andfoamer content, then reducing; Apparent density was decreasing withincrease of mixed plasticizer, bamboo powder, foamer content andextrusion process parameters, then increasing; Expansion rate was raisedwith increase of mixed plasticizer, fiber, foamer content and theextrusion process parameters, then reducing;(4) The weight loss ratewas increasing with time whose mixed plasticizer content was30%,fiber content20%, its degradation rate was the most appropriate amongall.（5）Water absorption increased with increasing foamer content, thendecreasing; Water absorption of FFRSP with3%content of AC/ZnO wasrespectively71.8%;(6) The cell size was more moderate with uniformerdistribution, and its numbers were more, when foamed composite wasproduced with30%mixed plasticizer,20%bamboo power,3%foamer,and its extrusion temperature, pressure, rate was respectively140℃,70MPa and11g/s.