The Preparation, Structure And Properties Of Poly (Vinyl Alcohol)/Starch Biodegradable Composite Materials

PVA/starch composite is a kind of very potential biodegradablematerials in environment protection filed and cost field. However,PVA/starch composite has some disadventages such as be difficult to hotprocessing, poor water resistance and degradation period long, so it willaffect its application range.This paper studied on the property, structure and preparation ofbiodegradable PVA/starch composites. The main subjects are: ModifiedPVA film and spline were prepared with glycerol/diethanolamine/sorbitolcompound plasticizers using physical modification and chemicalmodification mothod, then the best plasticizing process was exploed thoughthe research of PVA plasticizing mechanism; PVA/starch composite waspreparaed by melt blending mechod, the optimal components ratio of starchand plasticizers in PVA/starch composite was obtained by the analysis ofinterface morphology and mechanical properties, and PVA/starchcomposite has good biodegradability and excellent water resistance; Usingcitric acid and sodium carbonate as compound foaming agent, PVA/starchfoam material with high-ratio of foaming was preprared by double screwextrusion process though the analysis of sodium carbonate content andsilica content and the study of double screw processing technology.The results show that: PVA was plasticizing effectively by usingglycerol/diethanolam-ine/sorbitol as compound plasticizers and integratingphysical modification and chemical modification mothod successfully, andthe hot melting behavior and rheological properties were improved.PVA/starch composite was prepared after mixing the plasticizing PVA andplasticizing starch, and it has better mechanical properties and interfacialcompatibility. With the increase of plasticizers, water resistance ofcomposite was improved, in order to expand the application scope ofcomposite. When the citric acid content is5wt%, the foaming ratio ofPVA/starch composite all can be improved by increasing the sodiumcarbonate content and silica content. When the dosage of sodium carbonateis6wt%, the dosage of nanometer silica is5wt%, processing temperature is145℃and the host frequency is9HZ, the bubble holes of PVA/starchfoam material are evenly distributed, the quantity is more, the shape is neat.