Preparation Of Organic Functionalized Magnesium Hydroxide Curing Agent And Study On Properties Of Intrinsic Flame Retardant Epoxy Resin

Epoxy resin（EP）is a kind of high performance thermosetting polymer material.Because of its good bonding strength,thermal stability,chemical resistance,excellent mechanical properties and easy processability.It is widely used in coatings,electronic appliances,transportation and other fields.However,epoxy resin materials are flammable,which greatly limits their application in fields that require high flame retardancy.Therefore,improving the flame retardancy of EP materials is one of the important ways to expand the application of epoxy resin.In this thesis,an organic functional magnesium hydroxide curing agent with flame retardant was prepared,and the curing reaction occurred with epoxy resin to form an intrinsic organic-inorganic hybrid flame-retardant EP material.The specific research contents were as follows:1.A novel organic functional curing agent（DMMH）was prepared from maleic acid（MA）,magnesium hydroxide（MH）and 9,10-dihydro-9-oxa-10-phosphate phenanthrene-10-oxide（DOPO）as raw materials.Then the intrinsic halogen-free flame retardant epoxy resin was prepared by using DMMH as co-curing agent of diethylenetriamine（DETA）.The morphology and structure of curing agent DMMH and intrinsic halogen-free flame retardant epoxy resin were characterized by Fourier transform infrared spectroscopy（FTIR）,X-ray photoelectron spectroscopy（XPS）,nuclear magnetic resonance（NMR）and scanning electron microscopy（SEM）.The flame retardancy of intrinsic flame retardant epoxy resin was investigated by cone calorimetry,horizontal vertical combustion（UL-94）and limiting oxygen index test（LOI）,and its flame retardant mechanism was studied.The mechanical properties of the materials were investigated by electronic universal testing machine.The results showed that the peak heat release rate（p HRR）,smoke release rate（SPR）and carbon dioxide generation rate（CO₂P）of the intrinsic epoxy resin prepared by adding 1.7 wt%DMMH and 5.3 wt%APP were reduced by 54.5%,43.6%and 53.2%,respectively.The flexural modulus and flexural strength of the material with 7 wt%DMMH were the best,which increased by 47.1%and 35.1%,respectively.2.Using tris（2-hydroxyethyl）isocyanurate（THEIC）,phosphoric acid（PA）,magnesium hydroxide and melamine（MEL）as raw materials,a functional magnesium hydroxide curing agent（TPM-MEL）was prepared by esterification and neutralization reaction,and then used as a co-curing agent of diethylenetriamine to prepare intrinsic flame retardant epoxy resin.The morphology and structure of TPM-MEL and intrinsic epoxy resin were characterized by FTIR,XPS and SEM.The flame retardancy and mechanical properties of intrinsic epoxy resin were investigated.The results showed that the p HRR,SPR and carbon monoxide generation rate（COP）of the intrinsic epoxy resin prepared by adding 20 wt%TPM-MEL decreased by69.0%,66.3%and 64.8%,respectively.Its flexural modulus and flexural strength increased by 125%and 51.4%,respectively.3.An organic-inorganic hybrid curing agent（DTM-MEL）was prepared from diethylenetriamine pentamethylene phosphoric acid（DTPMPA）,MH and MEL as raw materials.Then DTM-MEL and epoxy monomer were cured to prepare intrinsic flame-retardant epoxy resin material.The morphology and structure of DTM-MEL and epoxy resin were characterized by FTIR,XPS and SEM.The flame retardancy and mechanical properties of epoxy resin were investigated.The results showed that the p HRR,SPR and CO₂P of the intrinsic epoxy resin prepared by adding 20 wt%DTM-MEL were reduced by 69.9%,57.5%and 71.7%,respectively.Its flexural modulus and flexural strength increased by 145%and 89.2%,respectively.