Modification Of Linseed Oil And Its Application In Bio-based Plasticizer

Linseed is widely grown in China,and its product linseed oil(flax oil)is a kind of fat rich in unsaturated fatty acids and has broad application prospects.In this paper,linseed oil is used as a raw material to carry out research on both technical applications and food production.On the one hand,the catalyst is used to catalyze the solvent-free epoxidation of linseed oil to produce epoxy linseed oil and thermal polymerization of maleic anhydride to form epoxy resin Polymers are bio-based plasticizers.On the other hand,it uses self-produced lipase to hydrolyze linseed oil to separate and purify high value-added product linolenic acid.This subject uses linseed oil which is rich in unsaturated fatty acids as raw materials,and uses a solvent-free cell catalysis method of epoxy linseed oil.The cell catalysis comes from Candida sp.99-125,The body has good tolerance to hydrogen peroxide,and has been found to have strong esterification activity and weak hydrolysis activity,which greatly reduces the occurrence of side reaction hydrolysis during the reaction process.The epoxy effect of different enzymes,the optimization of the conditions of bacterial epoxidation,and the epoxy effect of the bacteria on different types of fats and oils were studied.The optimal conditions for the epoxy process of linseed oil were:one-time addition of enzymes,the amount of enzymes was 30%,the amount of hydrogen peroxide added is the molar ratio of hydrogen peroxide to double bonds in linseed oil is 1:1,the flow rate of hydrogen peroxide is 1 ml/h,the amount of added oleic acid is 2.5 m%,the reaction temperature is 25?,the reaction time is 12 h.Under this condition,the linseed oil has an epoxy conversion rate of 72.5%and an epoxy value of 8.7(complete epoxy value of 12).The most important factor influencing factors is the reaction temperature.After synthesizing epoxidized linseed oil,epoxy linseed oil and maleic anhydride are polymerized to form oligomers.By optimizing the amount of maleic anhydride added,sample oligomers with different reaction time and reaction temperature are synthesized.Gel chromatography was used to test the molecular weight of the polymer.Among them,the optimal addition amount of maleic anhydride is 3%,and the molecular weight of the synthetic polymer ranges from 1000 to 9000.The synthetic bio-based plasticizer is mixed with PVC in different proportions,and the application of thermal properties such as thermal stability and thermogravimetric analysis(TG),mechanical properties such as Shore hardness,compatibility,tensile properties,thermomechanical properties analysis(DMA)characterizes the performance of oligomers as plasticizers.Based on the comprehensive evaluation indicators,40 phr was selected as the optimal amount of plasticizer.Through the characterization of various thermal and mechanical properties,it was verified that the performance of the synthetic plasticizer is similar to that of different types of plasticizers on the market.The indicators are better than the performance of certain plasticizers on the market.After hydrolysis of linseed oil,the fatty acid composition is 50%linolenic acid,20%oleic acid,20%linoleic acid,and 10%saturated fatty acid,which is separated and purified for high added value of linolenic acid.The difficulty lies in the separation of linolenic acid,linoleic acid,and oleic acid.The three fatty acids are octadecadienoic acid,dienoic acid,and monoenoic acid,each with a double bond,a difference in molecular weight of 2,and a freezing point of 10?Within.According to these characteristics,the four methods of molecular distillation,chromatography,urea inclusion method and freezing crystallization method were verified.After testing the existing separation methods,the best method is preferably chromatography.After immobilizing the silver ion silica gel,the molar ratio of silver ion to double bond is 1:1,the activation time of silver silica gel is 12 h,and the eluent is 2%,5%and 7%acetone-n-hexane solutions,the highest purity of linolenic acid reaches 100%,and the total recovery of linolenic acid with a purity of more than 80%is 82%.