Study On Preparation And Properties Of Biodegradable Composite Of Straw Fiber/PPC

Poly(propylene carbonate)(PPC) is a biodegradable material used carbon dioxide as the main raw material.Its development and application can avoid the traditional polyme r material pollution to the environment because of its completely biodegradability.Some main drawbacks of PPC restrict its progress,which include poor toughness,Iow melting t emperature and high production costs.A kind of composite.made of plant fiber and PPC, can improve the weakness of PPC and expand the application range.Straw fiber is chea p,readily available.biodegradable, renewable resource.Straw fiber/PPC composite can red uce costs andimprove the performance of PPC materials.In this paper,straw and rice root is used as raw material to prepare the straw fiber and rice root cellulose by microwave assisted hydrolysis,and the optimum process conditions are discussed.Then the above product is used as raw material to prepare straw microcrystalline cellulose and rice root microcrystalline cellulose by microwave assisted acid hydrolysis.Straw microcrystalline cellulose,rice root microcrystalline cellulose and straw fiber raw material is respectively filled in PPC to prepare composite materials.The effects on the mechanical properties of different fillers in PPC-based composites were investigated.And the rheological performance and interface features of PPC-based composites was analyzed and studied.The results show that:compared with traditional extraction of cellulose sodium chlorite method and microwave method, using the way of microwave-assisted oxidation of NaOH-H2O2hydrolysis preparation of rice root cellulose and traw cellulosetraw cellulose are simple procedure,shorter time,by-product of no pollution,high yield,maximum extraction rate of91.8%.Preparation of microcrystalline cellulose by microwave maintain the chemical properties of straw fiber,the type of the structure of cellulose I.surface of microcrystalline cellulose showed more regular rod-like structure and neat arrangement. With the increase of the content of straw fiber,the fluidity of PPC based composite material is poor,mechanical properties are improved significantly and the softening point becomes higher, notch-impact toughness of Straw fiber after alkali treatment is much higher than that of untreatment.The SEM of cross section displays that the interface structure of different types of materials are different and the compatibility between alkali-treated fiber and PPC becomes poor.The study of thesis provides a theoretical basis and experimental test data to support for further development of biodegradable materials as well as modification of PPC resin and provides a direction of straw utilization.