Enhancement Of Interfacial Adhesion Between Bamboo Fiber And Thermoplastic Polymer By Calcium Carbonate Deposition In Situ On Bamboo Fiber

Bamboo fiber reinforced thermoplastic polymer composites(referred to as bamboo plastic composites in this thesis)receives wide attention with economic value and market development,because of its lightweight(energy saving),low cost(economical),excellent mechanical properties and environmentally friendly(good for human health).However,the incompatibility between bamboo fiber and polymer has seriously restricted its development and application,and how to improve the interfacial bonding strength of bamboo plastic composites is a hot research topic in the field of bamboo processing and utilization.By the impregnation modification technology of calcium carbonate(CaCO3)in situ,interfacial bonding between bamboo fibers and thermoplastic polymer was improved;the bamboo fiber preparation process were determined;the effect of the technique on properties of single bamboo fibers was studied;bamboo plastic composites were obtained by different molding processes;the enhancement mechanism on the interface of bamboo plastic composites was studied by micro performance test and thermodynamic performance analysis and the feasibility of this modification technology in the practical application of bamboo plastic composites was discussed.The main conclusions are as follows:(1)The performance of single bamboo fibers prepared by different methods of segregation differences with hydrogen peroxide and acetic acid method more suitable for fiber cell surface morphology,and dissolving bamboo pulp is more suitable for large scale system on bamboo plastic composite material preparation and characterization.(2)Contact angles of single plant fiber by optical method and mechanical method were not significant(P>0.05)with the linear coefficient of determination 0.812,and the effect of isolation methods on contact angle is not significant.(3)CaCO3 inorganic particles were successfully deposited in situ on the surface of bamboo fibers by this modification technology,and inorganic particles showed typical calcite and vaterite crystal morphology with nanometer and submicron level.Surface roughness of single bamboo fibers were reduced significantly,and the tensile strength and modulus of single bamboo fibers increased by 19.48%and 12.21%,respectively.(4)Mechanical properties and the interfacial bonding strength of bamboo plastic composites by different molding preparation process reinforced with treated fibers improved.The mechanical performance of bamboo plastic composites was optimized with calcium carbonate content of 1.35%,and the bending strength,impact strength and tensile strength were increased by 14.16%,60.02%and 19.21%respectively,which played a role in strengthening and toughening.(5)By this modification technology,the surface energy of dissolving bamboo pulp fiber decreased within the range of 35-50 mJ/m2,and especially the polar part and the alkali component decreased significantly.The theory limit of adhesion work of treated fibers in the case of complete wetting is 80mN/m from the isolines of adhesive work and wetting envelope.(6)The interface performance parameters A of dissolving bamboo pulp fiber and matrix could reflect the temperature with the state of the composite interface,and the interfacial property of the composites was improved by this modification technology,and the external resistance of the composites was enhanced.When the amount of calcium carbonate was 1.35%,the interfacial interaction parameter B of the bamboo plastic composites plate was the maximum value of 3.12,and the interfacial strength was the highest.(7)At 50? and 100? rubber glassy state,the dependence of storage modulus of bamboo plastic composites on test frequency increased with the increased Calcium Carbonate content.The glass transition temperature increased with the increase of the content of calcium carbonate.(8)The mechanical properties of bamboo plastic composites were better,as the content of dissolving bamboo pulp was 30%.The tensile fracture surface topography of bamboo plastic composites had significant fractal characteristics with the fractal dimension 2.0632?2.1155,and the coefficients of determination were greater than 0.99.The fractal characteristics of tensile fracture surface topography could be to effectively reflect the macro mechanical properties,and the percentage error of fitting function is less than 10%.