| Due to their strong bonding strength,chemical resistances,excellent electrical performance and other good features,currently epoxy resins are intensively used across a wide range of fields,where they act as fiber-reinforced materials,adhesives,high-performance coatings,and encapsulating materials.However,epoxy resins cannot work when used alone.When it’s formulated with a curing agent to produce the a three-dimensional network structure,it can bring the properties into full play.In this thesis,H12DMA and 4,4’-bis(chloromethyl)biphenyl were used to synthesize two epoxy curing agents.Nuclear magnetic resonance spectroscopy(NMR)、Fourier transform infrared spectroscopy(FTIR),differential scanning calorimetry(DSC),and Thermogravimetric analysis(TGA)were used to characterize the samples of Bis-Triazine and BPN curing agents,epoxy resin curing systems and powder coatings.The main results are as follows,1.A new Bis-Triazine compound was first synthesized by using by H12DMA,and its chemical structure was characterized by ’H NMR and 13C NMR.DSC and TGA were used to analyze the epoxy resin curing system consisting of bistriazine compounds.It was found that the Bis-Triazine compound had low curing activity.Therefore,the accelerating agent 2-methylimidazole(2MI)was used to optimize for the curing system.It was found that the curing speed of the curing system was accelerated and the curing temperature was significantly reduced.In addition,the prepared Bis-Triazine molecules could form a supramolecular compound through hydrogen bond assisted self-assembly between molecules and had a unique Tg like polymer materials.2.Using biphenyl dibenzyl chloride as raw material to produce a biphenyl novolac resin(BPN)with good heat resistance.By using a thermogravimetric analyzer(TGA),it was found that the temperature of BPN at 50%weight loss was 500 ℃.The DSC and TGA curves were used to study,compare and evaluate the thermodynamic properties,curing process and heat-resistance of cured products of using the mentioned two polymer curing agents.Finally,BPN with high reactivity,good heat resistance,and low water absorption was selected as curing agent for epoxy powder coating.3.Thermogravimetric analysis(TGA)、cathodic disbondment、peeling and adhesion tests were used to study the curing performance of epoxy powder coating cured by BPN.The residual amount was 10%at 600℃,the adhesion level reached the level 1 according to the CJ/T 120-2016 criterion.Moreover,by adding the promoter 2MI,it was found that the peeling resistance and heat resistance of the coating were improved and the residual amount at 600℃increased to 22%. |
