| Epoxy resin has played an important role in adhesives,coatings,electrical engineering and other field because of its excellent adhesion,mechanical strength,corrosion resistance.However,it is difficult to apply in some technology fields due to its poor toughness.In general,the traditional toughening agents for epoxy resin are some elastomers or nanoparticles for toughening the epoxy resin.However,the raw materials of these toughening agents were made from petroleum and other non-renewable resources,which has the limited effect on the toughening of epoxy resin.Therefore,it is a necessary to find an efficiency toughening agent for the epoxy resin.In this manuscript,using 1,3-propylene glycol,1,4-butanediol,succinic anhydride,sebacic acid,maleic anhydride,itaconic acid and polyethylene glycol,we prepared two kinds of aliphatic polyester with different molecular structures by melting polycondensation.After the process of emulsification,irradiation crosslinking and spray drying,three kinds of biodegradable irradiation crosslinking polyester elastomer particles?BEP?,named as BEPA,BEPB and BEPC,were prepared.The BEP has a small particle size,large surface area,large number of hydroxyl groups on the surface and good elasticity.Therefore,as a novel polyester elastomer particles,BEP can be used as an excellent toughening agent for epoxy resin.According to the curing kinetics parameters of the epoxy resin?E-51?/BEP mixture,we concluded that the BEP can decrease the reaction activation energy of cured E-51.With the same loadings of BEP,the BEPA which has a smallest particle size and lots of hydroxyl groups has decreased the reaction activation energy of E-51—BEP curing system obviously?33%?.The curing reaction orders of E-51 and E-51—BEP mixture were first-order.The reaction rate constants of the E-51/BEP composites are higher than that of cured E-51 in the temperature range of 0°C-60.8°C.The FT-IR test confirmed that the BEP accelerated the curing reaction speed of E-51.The BEP improve the mechanical property and thermostability of epoxy resin.With the same loadings of BEP,the toughness of E-51/BEP composites is higer than that of E-44/BEP composites.The BEPB with a large particle size and lots of hydroxyl groups can toughnening the E-51/BEP composites significantly.Compared with the elongation at break of the cured E-51,the elongation at break of E-51 containing 6phr BEPB increased 237%while the impact strength increased 58.28%,and the storage modulus decreased obviously.The mechanism of BEP toughening E-51 is crack branch and termination mechanism according to the fracture surface morphology of E-51/BEP composites.The loss factors of E-51/BEPB composites and E-51/BEPC composites are higher than that of cured E-51 at 0°C-50°C,meaning that the BEP has the effect on enhancing the damping properties of the E-51/BEP composites obviously.The BEPA and BEPB with lots of hydroxyl groups can improve the thermostabiliy of E-51/BEP obviously.The temperature of 5%decomposition of E-51/BEPA66 and E-51/BEPB66 composites increased 6.93°C and 6°C respectively than that of cured E-51. |
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