Study On Preparation And Properties Of New Biobased Composite Materials

In recent years,with the depletion of energy and increasingly serious environmental pollution,people gradually enhance the awareness of environmental and ecological protection.The traditional plastic packaging materials are made with oil and added some harmful chemical substances.Because the traditional packaging materials are not biodegradable,if they are discharged into the nature,they will cause resource waste and environment pollution.Therefore,the natural resource with harmless to human was chosen to prepare green and biodegradable packaging materials in this study.After enhancing and antibacterial treatment,the new type composite had the good mechanical property and certain antibacterial property.As the main influence factors to the mechanical properties of composites,the forming condition,enhancing fiber status,and additive species and content were studied.In the onion skin,there are a large number of antibacterial substances,which was considered as the antibacterial agent to improve the antibacterial property of prepared new composites.Experimental results showed that the onion had the good film forming property.Under 105? molding temperature and 25 min drying time,the tensile strength of pure onion film was 28.43 MPa,and the elongation at break was 0.977%.The tussah silk as the enhancing fiber can greatly improve the mechanical properties of the composites.The results showed that the best conditions of forming composite material was 105?.The best drying time was 25 min.The best tussah silk fiber's length was 1mm.The best fiber content was 10% and the beating time was 8min.At this time,the tensile strength and elongation could be improved to 48.80 MPa and 1.15%,respectively.Additives can further increase the mechanical properties of the composites.When the CMC contention in the composite was 0.6%,sodium alginate contention was0.4%,agar concentration was 1.5%,glycerol contention was 0.4%,it was found that the composite had best mechanical properties.The tensile strength was 57.65 MPa,and the fracture elongation was 1.86%.The flavonoids in onion skin can increase the antibacterial property of the composite.The flavonoids were extracted from onion skins by ethanol extraction,ultrasonic extraction and supercritical CO2 extraction method in this paper.The results showed that the best extraction method is super critical CO2 method.The best conditions were extraction temperature 40?,extraction pressure 30 MPa,extraction time1.5h,the entrainment rate 0.4ml/min,the extraction rate of flavonoids was 7.89.The antibacterial activity of flavonoids was studied in the paper.The extracted flavonoids were finished to composite materials.The antibacterial properties of materials on Escherichia coli and Staphylococcus were tested and compared.The results showed that this bio-based composite had a certain antibacterial activity,and the antibacterial activity of E.coli was better than that of Staphylococcus aureus.