Preparation Of Bamboo Fiber And Study On Its Reinforced Epoxy Resin Composite

China is extremely rich in bamboo（Bambusa emeiensis）resources,Bambusa emeiensis fiber and plastics blend composite materials with high specific strength,high specific modulus,light quality and environmental friendly and many other advantages,suitable for automotive,machinery,building materials,decoration and other fields,has a broad application and development prospects.Carry out the preparation of bamboo fiber and composite materials research,to play China’s bamboo fiber resource advantages,and vigorously promote the advantages of forestry resources to Product advantages,enhance the technical level of the forest industry and promote the development of the rural economy is of great significance.But,at present our country bamboo fiber and plastic composite materials research and development there are still some problems,including traditional bamboo plastic composite reinforced phase for the bamboo powder instead of long fiber,usually can’t play a role of long fiber enhancement,as well as sinocalamus affinis fiber preparation of serious pollution,low drying efficiency,poor fiber dispersion and low mechanical strength of composites.In this thesis,the preparation and reinforcement of the epoxy resin composite from the bamboo（Bambusa emeiensis）fibers were studied.Chemical pretreatment is studied through orthogonal test sinocalamus affinis fiber preparation technology conditions,inspected the pretreatment temperature,holding time,dosage of Na OH dosage and Na₂SO₃ after four factors on the yield of bamboo pretreatment,combing the influence of yield and sulfonic group content,determined the chemical pretreatment,the optimal process for the pretreatment temperature 130℃,holding time 2h,2%Na OH dosage,Na₂SO₃ dosage of 10%.The pretreatment and carding yields of the bamboo fibers prepared by chemical pretreatment were 89.54%and 42.98%respectively,the COD of the cooking waste liquid was22700mg/L,the length of the bamboo fibers was 36.7mm,the diameter was 0.285mm,the tensile strength was 407MPa,and the elastic modulus was 27.7GPa.The process conditions for the preparation of bamboo fibers by hydrothermal pretreatment were investigated,and the effects of pretreatment temperature and holding time on the pretreatment yield,carding yield and fiber tensile strength of bamboo pieces were investigated to determine the optimal process for the hydrothermal pretreatment with a holding time of 2h and a pretreatment temperature of 150°C.The results of the hydrothermal pretreatment were presented.The yield after pretreatment and carding was 90.46%and 49.58%,respectively.The COD value of the cooking waste liquid was 6900 mg/L,the length of bamboo fiber was46.88mm,the diameter was 0.228mm,the tensile strength was 310MPa,and the elastic modulus was 14.7GPa.XRD analysis shows that the relative crystallinity of chemical pretreatment is 59.31%,and that of hydrothermal pretreatment is 57.89%.The relative crystallinity of chemical pretreatment is slightly higher than that of hydrothermal pretreatment.Chemical pretreatment fiber color bright,hydrothermal pretreatment color dark yellow;The mechanical properties of bamboo fiber prepared by hydrothermal pretreatment were slightly lower than those prepared by chemical pretreatment,but the yield of bamboo fiber prepared by hydrothermal pretreatment was higher,and the COD value of cooking waste liquid was lower.No chemicals were needed to prepare bamboo fiber by hydrothermal pretreatment,which reduced the difficulty of sewage treatment.From the Angle of utilization rate and environmental protection,the hydrothermal method is more advantageous.The characteristics of bamboo fiber by collision drying were studied,and the effects of drying air temperature,air velocity,mass flow rate of bamboo fiber and initial moisture content of bamboo fiber on the morphology,strength and dispersion of bamboo fiber were discussed.Collision drying can not only improve the heat and mass transfer effect of bamboo fiber in the drying process,but also use the shear generated between hot air flow and wet bamboo fiber and the shear generated by collision between wet bamboo fiber to disperse bamboo fiber and prevent the bamboo fiber from flocculating into groups after drying and losing water.The main factors affecting the drying of bamboo fiber are air temperature,air velocity,mass flow rate and initial moisture content.Under the premise of ensuring fiber quality,a higher drying air temperature can be selected to enhance the drying rate of bamboo fiber,and the drying air velocity can be increased as far as possible to improve the drying rate.It is necessary to control the mass flow rate and initial moisture content of bamboo fiber well,so as to meet the requirements of drying rate and dispersibility of bamboo fiber.Considering the drying rate of bamboo fiber,the strength of bamboo fiber after drying,and the morphology and dispersity of bamboo fiber,the appropriate technological parameters for the collision drying mode are the air flow temperature of collision drying at 80℃,the air flow speed of 27.59m/s,the mass flow rate of fiber 0.9kg/h,and the initial moisture content of fiber 70%.Under the optimum conditions of collision current drying,the moisture content of bamboo fiber drops to26.88%,which is suitable for the subsequent requirements of dryness of bamboo fiber carding machine.The length of bamboo fiber is 45.86mm,and the tensile strength is 288MPa.The mechanical properties,dynamic thermomechanical properties and thermal stability of bamboo fiber reinforced epoxy resin composite prepared by chemical and hydrothermal methods were studied,and the optimal dosage of bamboo fiber and silane coupling agent was optimized.When the dosage of bamboo fiber is 40%,the dosage of coupling agent was 2%,the mechanical properties of composite materials,chemical preparation of bamboo fiber reinforced epoxy resin composite materials tensile strength,bending strength,impact strength is 51.42 MPa,89.11MPa,19.58 MPa,the hydrothermal preparation of bamboo fiber composite materials tensile strength,bending strength and impact strength of 48.04MPa,83.91 MPa,17.08 MPa.DMA,TG,SEM profile observation and other characterization methods were used to compare the performance characteristics of chemical bamboo fiber and hydrothermal bamboo fiber reinforced epoxy resin composite before and after modification.The coupling agent modifies the composite material to improve the energy storage modulus,reduce the loss modulus and loss factor of the composite material,improve the thermal stability of the composite material,the composite material is more tightly bound,the interface adhesion is stronger,so as to improve the mechanical properties of the composite material.The properties of bamboo fiber reinforced epoxy resin composite prepared by hydrothermal method are slightly lower than those prepared by chemical method.However,considering factors such as bamboo utilization rate and environmental protection,bamboo fiber reinforced epoxy resin composite prepared by hydrothermal method has a more promising development prospect.