Preparation Of Functionalized Magnesium-based Curing Agent And Intrinsic Flame Retardant Epoxy Resin

Epoxy resin（EP）has great potential in chemical coatings,adhesives,integrated circuit boards,electronic packaging and advanced composites due to its satisfactory adhesion,chemical and electrical resistance,mechanical and dielectric properties.However,EP’s flammability and large smoke emissions after combustion greatly limit its application in areas where fire safety requirements are strict.In order to improve the flame retardant performance of EP,functionalized flame retardant was designed and prepared in this study,and intrinsic flame retardant epoxy resin was prepared on this basis,as follows:1.The intermediate prepared by the reaction of phytic acid（PA）and piperazine（Pi）was used to modify magnesium hydroxide（MH）,and the product obtained was reacted with melamine（MEL）to obtain a new multifunctional magnesium-based flame retardant curing agent（PPM-MEL）.The chemical structure of PPM-MEL was investigated by FTIR and XPS.The surface morphology of PPM-MEL was characterised by SEM.The thermal stability of the intrinsic flame retardant EP was assessed by thermogravimetric analysis（TG）.The flame retardant properties of the intrinsic flame retardant EP were investigated.And the mechanical properties of the intrinsic flame retardant EP were examined.The results showed that the p HRR of the intrinsic flame retardant EP produced by adding 20 wt%PPM-MEL decreased by 70.2%,the p SPR by 63.0%,and the p COPR and p CO₂PR by 57.1%and 68.9%,respectively,compared to the pure EP.the LOI results were significantly improved by up to 25.4%and the UL-94 rating reached V-0.The flexural modulus and flexural strength were increased by 117.5%and 138.2%,respectively.2.A new magnesium-based curing agent with phosphorus and nitrogen,HTM-MEL,was prepared by a two-step reaction using hexamethylene diamine tetra-methylene-phosphonic acid（HDTMPA）,MH and MEL as raw materials.The chemical structure of HTM-MEL was investigated by FTIR and XPS.The surface morphology of HTM-MEL was characterised by SEM.The thermal stability of the intrinsic flame retardant EP was assessed by thermogravimetric analysis（TG）.The flame retardant properties of the intrinsic flame retardant EP were investigated.And the mechanical properties of the intrinsic flame retardant EP were examined.The results show that the LOI value of this flame retardant EP with 5 wt%HTM-MEL and 15 wt%APP reached 33.7%and passed UL-94 test V-0.p SPR,p COPR and p CO₂PR were reduced by 74.9%,67.9% and 77.7% respectively compared to pure EP.Their flexural modulus and flexural strength were increased by 55.0%and 88.0%respectively.3.Using 2-hydroxyphosphonoacetic acid（HPAA）and MH as raw materials,a new magnesium-based curing agent HMH was synthesised using a neutralisation reaction.HMH was added to EP using a curing reaction to produce the intrinsic flame retardant EP.The chemical structure of HMH was characterised using FTIR and XPS.The surface morphology of HMH was characterised using SEM.The thermal stability of the intrinsic flame retardant EP was assessed by thermogravimetric analysis（TG）.The mechanical properties of the present flame retardant EP were investigated.The results show that the LOI value of this flame retardant EP is 26.7%with the addition of 15 wt%HMH and 5wt%APP compared to pure EP,and the UL-94 test achieves a V-1 rating.Compared to pure EP,its p COPR and p CO₂PR were reduced by 56.7% and 66.6% respectively.