Synthesis And Properties Of Bio-Oil Based Epoxy Curing Agent And Toughening Agent

Epoxy resin is a widely used thermosetting materials,modified epoxy resin related auxiliary with renewable resources is the trend of today's epoxy resin industry development.In this paper,a series of modified epoxy resin which can subsitute complete or partially petro-based products was synthiesd by different kinds of bio-based oil,such as cashew nut shell oil,tung oil and dimer fatty acid,and the properties was studied.A novel Mannich base(MBCDE)derived from cardanol diethers(CDE)was synthesized as both toughener and curing agent for epoxy resins.The chemical structure was confirmed by FT-IR and 1H-NMR.The cure behaviors of MBCDE cured with diglycidyl ether of bisphenol A(DGEBA)was studied by differential scanning calorimetry(DSC).Thermal stability,tensile and dynamic mechanical properties of the cured epoxies were also investigated.Phase separation of MBCED/DGEBA ocurred during the curing process was further studied by scanning electron microscopy(SEM),Soxhlet extraction and FT-IR.N-Aminoethylpiperazine(AEP)was chose as a contrast to investigate the toughening properties of MBCDE in the study.The morphology of the cured MBCDE/DGEBA consisted of globular cavities dispersed in continuous epoxy matrix,the cavities markedly improved the impact strength of the cured resin.The DSC result indicated that for MBCDE/DGEBA system,the exothermic peak temperature is at 101.8°C.The higher exothermic peak temperature indicated that MBCDE has a lower reactivity towards the epoxy resin.The weight loss of cured MBCDE/DGEBA at the first stage was mainly resulted from the weight loss of dispersed phase in the epoxy matrix.A novel cardanol-based cyclic carbonate epoxy curing agent(CAC)was synthesized from cardanol cyclic carbonate and triethylenetetramine.In comparison,a phenalkamine with a similar structure was also prepared.The chemical structures were confirmed by Fourier transform infrared(FT-IR).The cure behaviors of diglycidyl ether of bisphenol A(DGEBA)with these two curing agents was studied by differential scanning calorimetry(DSC),thermal properties,mechanical properties of the cured epoxies were also investigated.The result indicated that the curing reactivity,thermal stability and mechanical properties of CAC was very closed to phenalkamine.A novel dimerized acid carbonate(DAC)toughening curing agent was synthesis from dimerized acid and CO2.The chemical structures were confirmed by Fourier transform infrared(FT-IR)and 1H-NMR.A series of epoxy cured materials curing by different ratio of E-51 and DAC with diethylenetriamine.The mechanical properties and thermal properties of thecured epoxies were investigated.The result indicated that thetoughness of epoxies was increased and the epoxies have a good thermal stability.With the ratio of DAC increase,the elongation at break was improve from the 3.64% to7.35%,impact strength was improve from 4.981 kJ/m2 to 19.054 kJ/m2,but the Tg was slightly decreased.A novel flame retardant epoxy curing agent(DOPO-TOMAH)based on tung acid-maleic anhydride was successed synthesized.The tung acid-maleic anhydride(TOMAH)was firstly synthesized from tung acid and maleic anhydride,then DOPO-TOMAH was synthesized by adding different molar ratios of 9,10-dihydro-9-oxa-10-phosphaphenanthren-10-oxide(DOPO)to TOMAH via Michael addition reaction.In comparison,a methyl eleostearate maleic anhydride adduct with a similar structure was also prepared.The chemical structures were confirmed by Fourier transform infrared(FT-IR).The results showed that the tensile strength of curing materials gradually decreased with an increase of DOPO reacted content,and the hardness,glass transition temperature and flame retardant performance gradually increased with an increase of DOPO reactant;Thermogravimetric analysis showed that all the prepared cured epoxy materials owned good thermal stability,the heating initial decomposition temperatures were all above 350?.With the ratio of DOPO increase to 50%,the LOI of epoxy materials was 27,it was belong to the flame retardant materials.