Modification Of Epoxy Resin With Poly(Propylene Glycol Diglycidyl Ether) And Polyethersulfone

Epoxy resin curing products have excellent comprehensive properties,and are widely used in various fields of national life.However,the defects of brittle fracture and poor toughness limit its application in high-end fields,so it needs to be toughened in practical using.Common modification methods usually reduce the thermal and mechanical properties of the castables,and the modification cost is relatively high.In order to overcome these shortcomings,PPGDGE and PES are selected to toughen the epoxy resin in this paper.PPGDGE with molecular weight of 420,1000 and 2000 were selected to modify the epoxy resin.The results of mechanical properties test showed that when the content of PPGDGE-1000 was 15 wt%,the comprehensive mechanical properties were the best.It could effectively improve the toughness of the castables without affecting the tensile properties and bending properties.Compared with the E51/DDS system,the impact strength of PPGDGE-1000(15 wt%)/E51/DDS system was increased by 79%.The viscosity test showed that the addition of PPGDGE with different molecular weight could effectively reduce the viscosity of the system at low temperature,but had little effect on the viscosity of the high temperature.Gel time test showed that the addition of PPGDGE with different molecular weight could properly prolong the gel time of the system under different addition amounts.The non-isothermal DSC test of PPGDGE-1000(15 wt%)/E51/DDS system showed that the addition of PPGDGE-1000 could reduce the activation energy of the system,and the S,B(m,n)model could be used for fitting.The isothermal DSC test showed that the addition of PPGDGE-1000 did not change the reaction mechanism of the system,and the Kamal model could be used to fit the experimental results.Based on the PPGDGE-1000(15 wt%)/E51/DDS system,different amounts of PES were added for further modification.The test results showed that the mechanical properties of the castables could be further improved by adding PES.When the addition of PES was 6 wt%,the tensile strength,flexural strength and impact strength of the castables reached the maximum.Compared with PPGDGE-1000(15 wt%)/E51/ DDS system and E51/DDS system,the impact strength was increased by 47.4% and 164.4%,respectively.Rheological analysis was carried out on the optimal system of mechanical properties.Viscosity tests showed that the viscosity of the system increased with the addition of PES.When the temperature was low,the melting of PES had a great influence on the isothermal viscosity of the system.Gel time test showed that the addition of PES prolonged the gelation time of the system,but the higher the temperature,the weaker the effect.DSC test showed that the addition of PES did not change the autocatalytic curing mechanism of the system..The composite materials were prepared with E51/DDS system,PPGDGE-1000(15wt%)/E51/DDS system and PES(6 wt%)/PPGDGE-1000(15 wt%)/E51/DDS system.The fiber content test showed that the molding process had good process stability and could effectively control the fiber content.The mechanical test showed that the comprehensive mechanical properties of the PES(6 wt%)/PPGDGE-1000(15 wt%)/E51/DDS system were the best.Water absorption test showed that the addition of PPGDGE-1000 and PES could reduce the water absorption.The water absorption of PES(6 wt%)/PPGDGE-1000(15wt%)/E51/DDS system was the least,and its ten-day water absorption was only 15.3%.