Synthesis Of Magnesium-based Functional Inorganic Curing Agent And Application In Epoxy Resin

Epoxy resins are widely used in aerospace,construction industries and transportation because of their superior electrical,mechanical properties,suitable weather,thermal and chemical resistance.However,the poor flammability and mechanical properties have limited their further development and application in flame retardant field.As is well known,nearly all epoxy end-use products need reaction with a hardener,and the use of different hardeners may have different effects on the terminal properties of epoxy resins.Now,Multifunctional curing agent has greatly aroused interest by researchers.The main points of this thesis were summarized as follows:Chapter I:A series of different sizes of organophilic magnesium hydroxide（MH）were prepared based on magnesium hydroxide（MH）by neutralization reaction to carboxylic acid compounds（TMA,AA,PTA）.organophilic magnesium hydroxide can be grafted on epoxy resin by exothermic curing at the condition of N,N-dimethyl benzyl amine catalytic.The chemical structure,particle size,morphology,thermal stability and mechanic properties of the final products and organophilic magnesium hydroxide epoxy resin composites were investigated in detail with fourier-transform infrared spectra（FTIR）,X-ray power diffraction（XRD）,nanoparticleanalyzer,scanningelectronmicroscopy（SEM）,thermogravimetric analysis（TGA）,impact testing machine and microcomputer control electron universal testing machines.It turned out that,compared with EP-1,the impact strength,flexural strength and flexural modulus of EP₁-4 were increased by 39.4%,8%and 11.2%,respectively.The thermal stability of aromatic carboxylic acid（TMA,PTA）modified magnesium hydroxide epoxy resin is higher than aliphatic carboxylic acid（AA）modified magnesium hydroxide epoxy resin 6%.ChapterII:Anovelamino-functionalizedmagnesiumhydroxide（DETA-AA-MH）was prepared by amidation reaction of adipic acid（AA）and diethylenetriamine（DETA）basedonmagnesiumhydroxide（MH）.The DETA-AA-MH and intrinsic flame retardants composite were characterized by FT-IR,X-ray power diffraction（XRD）,nano particle analyzer,SEM,EDS,TGA,differential scanning calorimetry（DSC）,Limit Oxygen Index（LOI）,investigated the mechanic properties,flame retardant and burning residues of EP,confirmed the LOI of DGEBA/DETA-AA-MH higher than DGEBA/DETA 10.15%,DETA-AA-MH could promote the formation of a protective char layer during burning,compared with EP（7.39 wt%DETA）,the flexural strength,flexural modulus and impact strength of EP（15.97 wt%DETA-AA-MH）were efficiently increased by 669.70%,33.12%,228.57%,respectively.Chapter III:The a functional magnesium organic composite salt（FMOCS）were prepared by neutralizing reaction between PABA and MH.An efficient intrinsic flame retardants composite was prepared by curing epoxy resin with FMOCS and DETA.Curing behavior,thermal and flame-retardant properties of the cured epoxy resins were systematically investigated by FTIR,TGA,vertical burning test（UL-94）and LOI.It was found that flame retardancy and mechanical properties of the cured composite are significantly enhanced compared with DETA/EP.The LOI of the EP reached to 33%,which is much higher than the DETA/EP（19%）or its IFR composite（31%）in the optimal addition of ammonium polyphosphate（APP,18.69wt%）,pentaerythritol（PER,6.21 wt%）and FMOCS（3.50 wt%）.Furthermore,the mechanical properties of the composite material measurement results to imply that it can enhance tensile strength1（50%）and bending strength（88%）rather than DETA/EP,which were tested by impact testing machineand microcomputer control electron universal testing machines.