Mechanical Activationg Strengthened Solid Phase Reaction To Synthetise Cassava Less Acetic Ester And The Preparation Of All Fiber Composite Materials

Guangxi is the biggest eassava production area in China,accounting for around 70%of the national cassava output.Lots of waste lees from producing cassava starch and alcohol is producted,which would be resulting in numberous biomass waste,causing environmental pollution.Thus,efficient utilize of cassava lees are favourable choice to meet the need of increasing value of cassava products.Moreover,efficient utilize of cassava lees can reduce environmental pollution.owing to the renewability biodegradability of cassava lees.Therefore,the development and application of cassava lees will product high economic benefit and social benefit.All fiber Composite(AFCM)is a kind of new material that will be green protection and resource recycling of environment.Based on varieties low-cost plant fiber(such as wood powder,sisal,bamboo,straw and plant fruit fiber),the cellulose composite material is prepared by extrusion or mixing molding after being chemical modified to improve thermoplastic of cellulose.This article discussed the preparation and applitation of all fiber composites research based on the rich lees residue in Guangxi.The main research contents and results are as follows:Cassava lees acetate was synthesized by MA-strengthened solid phase reaction using a self-designed stirring ball mill as reactor.The effects of reaction temperature,reaction time,reagent quality ratio and dosages of catalyst,were investigated by using the degree of the weight rate(W)of cassava lees acetate as evaluating parameter,respectively.The results indicated that the optimized conditions for producing cassava lees acetate by MA-strengthened solid phase reaction were:10.00g of cassava lees:percentage of catalyst(ZnCl2)to cassava lees was 30%,quality ratio of cassava lees and esterifying agent(acetic anhydride)was 3:1,reaction temperature was 80 ?,reaction time was 2.0 h.Under these reaction conditions,the weight rate of cassava lees acetate was 96.8%.The difference weight rate of esterified products activation degree showed that with the increasing weight gain rate,the degree of products activation got higher,as well as the hydrophobic.The particle morphology,functional groups,crystal structure,thermal stability of the cassava lees acetate were characterized by SEM,FT-IR,XRD and DSC,respectively.FT-IR analysis showed that esterified products of esterhad an absorption peak at 1740 cm-1,and it suggested a generation of cassava lees esterified products in solid phase reaction;The results of SEM showed that the cellulose in cassava lees did not appear sheaflike structure,but gradually broken into small particles.The difference weight gain rate(such as 28.8%,47.4%,96.8%)of cassava lees acetate products' X-ray diffraction crystallinity index were 42.88%,42.75%,18.03%,respectively,rendered a crystal modification of cellulose I.It is proven an increased of amorphous;The results of DSC analysis showed a glass transition temoerature of the esterification product.The results of DSC also crarified that with the increase of weight gain rate,the glass transition temperature got lower.Based on cassava lees esterification products as raw materials,all fiber composite materials was prepared under directly hot pressing.The influence of hot pressing temperature and time,Pressure and different weight gain rate were studied on the mechanical properties of fiber composites to find out the best formula of the all fiber composite materials.The results showed that:under a condition of the weight gain rate of 96.8%of the esterified product as raw materials,pressing temperature 120 ?,the pressure 8 MPa,hot pressing time 5min,the all fiber composites had better mechanical property.The flexural strength was 16.118 MPa,the flexural modulus was 1.945 GPa,the tensile strength was 4.811 MPa,the elongation at break was 0.491%.The water resistance,resistance to environmental temperature,water vapor stability,acid and alkaline application properties of all fiber composite material were studied,and the results showed that:the higher of weight gain rate results in the lower of bibulous rate;all fiber composite laterial properties was best stability in the room temperature,too low or too high temperature would both reduced the mechanical property of all fiber composite materials;when all fiber composite materials was tested in the water vapor,with the place time was prolonged,the impact on the mechanical properties was stronger;all fiber composite material would decreased mechanical property in acid and alkali atmosphere,and alkaline atmosphere had more effect to the mechanical properties.