Study On Properties Of Starch-Based Biomass Composites

Traditional plastic packaging waste has become "white pollution",owing to its refractory nature,and it has also led an appearance that the shorta of petroleum resources.People are aware of the importance of protecting the environment and saving energy.Ask for higher requirements in composite materials.Under the theme of green development,composite materials are gradually moving toward renewable,degradable and green environmental protection.Biomass composite materials that consist of crop waste and starch have the advantages of renewable and degradable.Completely environmentally friendly materials constitute one of the effective ways to effectively solve white pollution at this stage.Therefore,it is of profound significance to carry out in-depth research on straw/starch biomass composites.In this paper,Four starches(cassava starch,potato starch,wheat starch,corn starch)are used as the matrix,and four plant fibers are used as filling materials(wheat straw fiber,rice straw fiber,wheat hull fiber,rice husk fiber).Plasticizer(formamide,ethylene glycol,glycerol,formamideðylene glycol,formamide&glycerol,ethylene glycol&glycerol),adding water-resistant polymer material natural rubber(3%,5%,10%,15%),a fully degradable biomass composite was prepared by compression molding.The mechanical and hygroscopic properties of rice husk fiber and different starch matrix,different plant fiber and tapioca starch were compared and analyzed.The effects of natural rubber content and single/composite plasticization on the performance of rice husk/cassava starch composites were studied.The main conclusions are as follows:(1)Comparison of different starch matrix(cassava starch,potato starch,wheat starch,corn starch)biomass composites showed C=O stretching vibration of rice husk/cassava starch composite in 1634 cm-1 amide-CONH2 The peak is strong,and it can form hydrogen bonds with the-OH of cellulose husk fiber and hemicellulose.The interface between cassava starch and rice husk fiber is better.The mechanical properties are better,tensile strength,flexural strength and flexural modulus.The impact strength was 6.7MPa,13.69 MPa,653.45 MPa,and 9.93 kJ/m2,respectively.However,due to the high amylopectin content of tapioca starch,the hydrophobic properties of the composites were poor.(2)Comparing the performance of natural rubber rice husk/cassava starch with different addition amount,the performance of the rice husk/cassava starch biomass composite with 10%addition is superior,the hydrophobic property is good,the tensile strength,bending strength,The flexural modulus,impact strength and moisture absorption rate are 10.69 MPa,13.52 MPa,1563.78 MPa,2.03 kJ/m2,22%,respectively,and the moisture absorption rate is 0%,3%,5%,15%of the composite material added with natural rubber content.The reduction of 46.96%,38.4%,26%,28%,10%natural rubber composite material has a flat tensile section and a good interface.(3)Comparison of rice husk/cassava starch with different plasticizers(formamide,ethylene glycol,glycerol,formamideðylene glycol,formamide&glycerol,ethylene glycol&glycerol)The properties of the composite materials show that the mechanical properties of the single plasticized glycerin plasticized composites are the best,but the glycerol plasticized composites have the highest moisture absorption rate,and the ethylene glycol plasticized composites have the lowest moisture absorption rate,but the mechanical properties are the same.Poor,formamide plasticized composites have moderate properties.The mechanical properties of formamide&glycerol composite plasticized composites are excellent.The tensile strength,impact strength,flexural strength and flexural modulus are 6.69 MPa,10.64 kJ/m2,14.12 MPa and 1067.23 MPa,respectively,but due to glycerol and The formamide contains higher hydrophilic functional groups,which leads to higher moisture absorption rate of the composite.The formamideðylene glycol composite plasticized composite has better hydrophobic properties,but its mechanical properties are small.By comparing the properties of the composites plasticized by the six plasticizers,the mechanical properties of the single plasticized composite of formamide are 7%to 31%lower than that of the plasticized composite composite of formamide and glycerol.The hygroscopicity of plasticized composites is 35%smaller than that of formamideðylene glycol.So formamide is used as a high-quality plasticizer.(4)Research on different plant fiber/cassava starch biomass composites showed that the tensile strength,impact strength,flexural strength and flexural modulus of wheat straw/cassava starch biomass composites were the best,8.77MPa and 3.23 respectively.kJ/m2,8.79MPa,1491.89MPa,and the lowest equilibrium moisture absorption rate is 25.1%;the wheat straw fiber reinforced cassava starch composite material has better interface quality,no obvious gap,and the wheat straw and cassava starch matrix have better binding;The main absorption peaks of the four kinds of plant fiber composites have obvious peak difference at 3300-3500cm-1.The wheat straw/cassava starch composite has a small amplitude and the band shifts to low frequency,indicating wheat straw/cassava starch composite.The hydrogen bond formed inside is strong,so that the matrix and the fiber have a good interfacial bonding force,so it can be concluded that the wheat straw fiber reinforced tapioca starch(formamide is a plasticizer,10wt%natural rubber),the composite material the best performance.