Nanomechanics Characterization Of Fibrous Materials And Performance Study Of Banana Fiber Hybrid Composites

As one of the most abundant natural macromolecular compounds in the world,natural fibers has good prospect because of many advantages such as renewable,excellent performance,biodegradability,lower costs,etc.This is of great significance for solving the current protectionof forest resources,improving the ecological environment.High-performance hybrid fibre composites were produced which were made up of coir fiber,banana stem fiber and rice straw,taking advantage of different physical and mechanical performance of natural fibre.This will improve the use efficient of abundant biomass wastes resources.Performance analysis and overall evaluation of fibers and hybrid fiber composites were studied through experiments,comparative method and simulation,including mechanical property and micromorphology,chemical components,combustion perform ance,Reliability.This would change traditional production processes of coir fiberboard and straw board.This could increase the application range and utilization efficiency of biomass wastes resources,improving reliability and decreasing quality costs of composites.Firstly micro mechanical properties of coir fiber and banana stem fiber,rice straw were studied.Hybrid fiber composites including CB fibreboards and TB fibreboards were produced and the performances of them were tested and discussed through nanoindentation technique and mechanical test,SEM,FTIR,TG,cone calorimeter.Performance of hybrid fiber composites was improved by adding nano-silica dispersion and was characterized by testing.Reliability of hybrid fiber composites was analyzed in different working conditions with second-order second-moment method and method of response surface.Forecasting analysis of the mechanical properties of hybrid fiber composites was undertook by using the curve-fitting method.The main contents of this paper were as follows:(1)Specimens of coir fiber and banana fiber,rice straw embedded in epoxy resin have been determined with a nano-indenter using to explore the mechanical properties and observed the morphology under a microscope.The results of the test have shown that there were many differences on the property of cell wall.The longitudinal elastic modulus and hardness of the cell wall were higher than transverse elastic modulus and hardness of them.The two kinds of modulus of elasticity and hardness were compared with each other and regression analysis was carried out with a combination of the principle of nanoindentor,constituents of cell wall(cellulose,hemicellulose,lignin)and microfibril angle.Indentation depth and deformation of indentation were discussed by the statistical analysis.(2)Firstly the technology for banana fiberboard manufacturing was studied and the technological parameters,such as hot-pressing temperature,hot-pressing time,resin content were designed.Technology factors have effects on the properties of the hybrid composites through orthogonal test.So the optimum parameters were acquired.Based on this,hybridfiber composites were prepared by way of mixing banana stem fiber with coir,rice straw.This improved the mechanical properties of coir fiberboard and straw board such as the bending properties and stiffness.Mass ratios of fiber and density,fiber length have effect on the property of hybrid fiber composites through dynamic and static mechanical properties.Physical and mechanical characteristics of composites were proceed to conduct analysis through chemical characterization methods.Specific surface area of fibers have important effects on resin content and TS of composite panel,Morphological micro structure and the weight loss characters of fiberboards,chemical reaction in the hot-pressing of the panel were respectively revealed through the analysis of SEM and FTIR,TG.(3)MOR and MOE,IB of hybrid fiber composites were improved and TS was decreased by adding nano-silica dispersion in PF under the same production process.The cause of improving mechanical property was studied by means of FTIR,SEM.The bonding strengths of resin adhesive increased after blending PF and nanometer silica because of abundant unsaturated bonds on the surface of them.Thermostability of hybrid fiber nanocomposites has been discussed by means of TG.The effect of on combustion performance of hybrid fiber nanocomposites including thermal release property,mass ratio,fire behaviors was studied by cone calorimeter.The significance effect on smoke of hybrid fiber composites including releasing characteristics was also studied.(4)The security of hybrid fiber composites was analyzed under concentrated load or distributed load with three different working conditions.Maximum bending strength and maximum deflection of hybrid fiber composites would take as maximum resistance under bearing strength limit state.Reliability index and failure probability of composites were computed by using second order moment method and response surface methodology.The results have shown that size and mechanical properties(MOR and MOE)of the materials,span have effect on safereliability.Safereliability of CB particleboards was calculated by reliability modules of finite element software.Results showed that safereliability would be influenced by the size(width and thickness)and external load,MOE,span of the materials at varying degree.(5)Predictability of the mechanical properties of hybrid fiber composites were undertook by using the curve-fitting method of matlab.The most accurate predictive model was confirmed through comparison between the predicted and actual values,quadratic trinomial for CB hybrid fiber composites(MOR and IB)and TB hybrid fiber composites(IB),cubical quadrinomial for TB hybrid fiber composites(MOR)and dynamic mechanical properties(Ep and Ef)of the two kinds of composites.The prediction model was set up by using the RBF function of SVM and was much predictive as well.The main work of the paper includes nano-mechanical properties of fibrous materials,analysis of hybrid fiber composites and a series of chemical characterization,nano silica dispersion improving performance of composites,eventually reliability and predictability of hybrid fiber composites.These would provide a scientific basis in applying to the furniture and construction and decoration.