Study On Preparation And Performance Improvement Of Different Plant Leaf/Gelatin Biomass Composite Materials

With the improvement of people’s living standards,the use of non-degradable plastic products such as disposable tableware and plastic bags has increased,and the resulting"white pollution"has become more and more serious.Last year,the state issued the"Regarding Further Strengthening of Plastic Pollution Control"Opinions",in the future,the use of disposable plastic straws,plastic packaging and tableware in the catering takeaway industry will be completely prohibited,so the research on substitutes for disposable plastics is of great significance to my country’s environmental protection.In this paper,plant leaves and biological glue are used to prepare biomass composite materials to replace disposable plastic products.Three plant leaves(lotus leaves,banana leaves,and bamboo leaves)and gelatin are selected,and moisture barriers(glycerin,tagatose,glycerin)are added.&Tagatose),add polyurethane,prepare plant leaf/gelatin biomass composite material through compression molding process,use orthogonal experiment method to determine the best molding process parameters,compare and analyze the mechanical properties and moisture absorption of the composite material prepared by three plant leaf gelatin Performance,contact angle and other properties,and studied the effects of moisture barrier and polyurethane on the properties of Ruo bamboo leaf/gelatin composites.The main conclusions are as follows:(1)Through orthogonal experiment method L9(3~4),with tensile strength and impact strength as optimized parameters,the optimal process parameters for molding lotus leaf/gelatin composites are determined as follows:molding temperature 80℃,molding pressure 10MPa,molding pressure time 40min.(2)According to the analysis of the fiber composition of the three plant leaves,lotus leaf,banana leaf,and Ruozhu leaves,Ruozhu leaves have the highest cellulose content.Comparing the properties of the three plant leaf raw materials,it can be seen that the tensile strength and maximum shear force of Ruo bamboo leaves are the highest,respectively 25.50MPa and 7.33N;Ruo bamboo leaves have the lowest equilibrium moisture absorption rate,12.82%;Ruo bamboo leaves contain internal content.For obvious large-fiber tube bundles,Ruo bamboo leaves have the best mechanical properties;Ruo bamboo leaves have the highest onset temperature of thermal weight loss at 257°C,good high temperature resistance,and the smallest thermal weight loss rate of 60.09%.Comparing the properties of three kinds of plant leaves and gelatin to prepare composite materials,it can be seen that the tensile strength,impact strength,flexural strength and flexural modulus of the bamboo leaf/gelatin composite material are the highest,respectively 28.22MPa,22.29KJ/m2,40.32Mpa,5.21GPa;The surface of Indocalamus leaves is the smoothest and flat,without cracks and cavities.The interface between Indocalamus leaves and gelatin is better;the infrared spectrum curve of Indocalamus leaves/gelatin composite material has an absorption peak at wavenumber of 3400～3500cm-1.The strength is lower than that of the other two plant leaf composite materials,resulting in the lowest moisture absorption rate;the special groove structure on the surface of Indocalamus leaves maximizes the contact angle of Indocalamus leaves/gelatin composite materials.Using the principal component analysis method,the comprehensive score analysis of the biomass composite materials made from three plant leaves showed that the comprehensive score of Ruo bamboo leaves was the highest,the banana leaves were the second,and the lotus leaves were the lowest.(3)Comparing the performance of different moisture barriers(glycerin,tagatose,glycerin&tagatose)on the Indocalamus leaf/gelatin composite material,we can see that the tensile strength of adding moisture barrier is higher than that without adding moisture barrier.The strength is high,but the impact strength of the composite material with tagatose is reduced,the flexural strength of the composite material with glycerin,glycerin&tagatose is reduced,and the flexural modulus of the composite material with moisture barrier agent is higher than that of the non-added composite material.It should be low;the infrared spectrum hydroxyl absorption peak of the composite material with moisture barrier is weak,the moisture absorption is small during the moisture absorption experiment,and the equilibrium absorption rate is the lowest at 12.14%;the addition of moisture barrier increases the contact angle of the composite material,The contact angle of the composite material with glycerol added is 126°.(4)Comparing the performance of adding different content of polyurethane(0,5wt.%,10wt.%,15wt.%)Indocalamus leaf/gelatin composite material,it can be concluded that polyurethane can improve the tensile strength of Indocalamus leaf/gelatin composite material,Impact strength,flexural strength,when the polyurethane content is 10wt.%,the tensile strength is the maximum,44.84MPa,when the polyurethane content is 5wt.%,the impact strength and tensile strength are the maximum,respectively 28.72KJ/m2,62.40MPa.The high compactness of polyurethane leads to the improvement of the moisture barrier properties of the bamboo leaf/gelatin composite material.When the polyurethane content is 15wt.%,the equilibrium moisture absorption rate of the composite material is the smallest,which is9.01%;the effect of polyurethane on the composite material The surface hydrophobicity has a certain enhancement effect,and the enhancement effect does not differ significantly with the increase of the polyurethane content.When the polyurethane addition amount is 5wt.%,the contact angle is the largest,which is 127.3°;from the microstructure,it can be seen that the addition of polyurethane The surface of the composite material is smoother and flatter,which is conducive to better interface bonding inside the Indocalamus leaves.