Preparation And Characterization Of Transparent Wood,Transparent Jute Fiber And Transparent Coir Fiber-Epoxy Resin Composite

Transparent biomass material is a new type of composite material with high strength and high transmittance,which is impregnated with resin under the condition of maintaining the original cellulose skeleton of biomass material.In this paper,wood,coir fibers and jute fibers were delignified and then impregnated by epoxy resin.The transparent biomass materials were studied in terms of transmittance test,haze test,tensile test and impact test.In this paper,sodium chlorite(NaClO2,2%wt)and hydrogen peroxide(H2O2,5 mol/L)were used to remove lignin and then vacuum impregnated with epoxy resin to prepare transparent biomass materials.However.different biomass materials require different preparation processes.According to the experimental analysis of delignification process of two kinds of biomass raw materials,the best delignification process of each material was obtained,and epoxy resin was impregnated.Finally,the transparent biomass materials were tested,and the differences and advantages between the three materials were compared,which laid the foundation for large-scale production of transparent biomass materials.The balsa wood has the smallest density and contains more space inside,which is easier to remove lignin and impregnate resin.There are many extractive in Paulownia(8.9%),hence it needs to be impregnated in sodium hydroxide(NaOH)to removal extractive and open the blocked pits.The density of basswood is 0.49 g/cm3,which causes lignin difficult to remove,but its tensile property is good.Besides the influence of tree species,the thickness has a great influence on transparent wood.The thicker the wood is,the greater the difficulty of removing lignin.The properties of transparent wood combined with the same direction are closer to the original transparent wood.However,the transmission of transparent wood combined with the cross direction is lower than original transparent wood.But its tensile property upright to the grain has been greatly improved.The results showed that the properties of transparent coir were different with different coir content.The increase of coir content in transparent coir composites will lead to the increase of water absorption and swelling rate of the composites,which may lead to the warpage of the composites.Therefore,the addition of delignified coir should not be too high.The transmittance of transparent coir composites decreases with the increase of the addition of delignified coir.The transmittance of transparent 5%wt coir is the highest,which can reach 71%.The mechanical properties of transparent jute fiber are much stronger than that of coconut fiber,and the anisotropy of transparent jute fiber is not as obvious as that of wood.Transparent jute fiber is a transparent biomass material suitable for mass production because of its smaller size limitation and less warpage.Comparing several transparent bio-materials,transparent balsa wood has the best transmittance and less energy consumption,but its mechanical properties are weak.Transparent basswood has the best mechanical properties,but because of its high density,the process of lignin removal is time-consuming.Coir and jute fibers are more convenient to remove lignin,but they have no structure like wood.It is necessary to use braiding method to improve their mechanical properties.The test of transparent jute fibers also proves that the mechanical properties of bio-fibers can be improved by braiding before transparency,and the tensile strength of the transparent jute fibers is similar to that of transparent balsa wood.