Test Characterization And Exploration Of Nano-composite Flame-retardant Epoxy Resin Materials

Optical epoxy resin(EP)has been widely used in many fields,such as lens,encapsulating agent,antireflective layer and infrared imaging,because of its wear resistance and low cost.However,optical epoxy resin is very easy to burn in the air,and it will produce a lot of toxic and harmful gases when burning,which is easy to cause fire and other safety accidents,threatening the safety of people's lives and property.However,at present,the flame retardant treatment of optical epoxy resin is often accompanied by the reduction or even disappearance of the transparency and refractive index of epoxy resin.Therefore,the preparation of optical flame retardant epoxy resin with excellent flame retardant properties,good transparency and refractive index has become a research hotspot.The research contents of this paper are as follows.A new multifunctional liquid colorless curing agent DPTA was prepared by diphenylphosphine chloride(DPPC)and tetraethylene pentamine(TEPA).~1H-NMR and FTIR showed that DPTA was successfully prepared.Then it was applied to epoxy resin to obtain cured epoxy resin DPTA-EP.The transparency test results show that the transmittance of DPTA-EP can reach 90%in the visible light range,with excellent transparency.The flame retardant test results show that the DPTA-EP prepared by adding only 15 wt%DPTA can pass the UL-94 V-0 test,and the limiting oxygen index(LOI)reaches 29.0%.Cone calorimetry results showed that compared with DPTA-EP,the peak heat release rate(PHRR)and total smoke production(TSP)of DPTA-EP decreased by43.1%and 58.8%,respectively,which further proved its excellent smoke suppression efficiency and flame retardancy.The study of flame retardant mechanism shows that the gas phase flame retardant is dominant in the combustion process of DPTA-EP system.At the same time,according to the mechanical properties test,compared with the reference sample DPTA-EP,the introduction of flame retardant groups in the system will not reduce its mechanical properties.The above results show that DPTA-EP has excellent flame retardancy and transparency.A kind of modified nano zinc sulfide(MZnS)was successfully prepared by mercaptoethanol(ME)and zinc acetate dihydrate.The results of FTIR,XRD and SEM showed that MZnS nanoparticles were successfully prepared.Then it was added to epoxy resin to obtain MZnS/EP.The transparency test results show that the epoxy cured MZnS/EP can achieve 90%high transmittance in the visible region.The refractive index test results showed that the refractive index of epoxy cured MZnS/EP was 1.697 when the mass fraction of MZnS was 32 wt%.The results of micro calorimetry(MCC)test shows that the peak heat release rate(PHRR)of MZnS/EP is reduced by 53.4%compared with the reference sample EP,and the FGR value is also greatly reduced,which indicates that MZnS/EP has excellent flame retardancy and fire safety.The above results show that the prepared epoxy resin MZnS/EP not only has excellent flame retardancy,but also has good refractive index and transparency.