Study On Improving Cyanate Ester Resin With Nanometer Silica Particle

It is emergent to develop new radical resin used in composite material which hashigh performance in chemicophysics, mechnical and manufacturability. Cyanate EsterResin is a new potential resin meets these demands.Cyanate Ester Resin is a new kind of thermosetting resin; it keeps low and stabledielectric constant and dielectric loss within large scale of temperature and frequencyand has high thermal endurance and manufacturability etc. So it is broadly used infields such as aeronautics and astronautics, optical instrument. However, the default ofhigh crosslinking density, brittleness fatigue strength and impact toughness make itdifficult to meet the development of high-tech such as national defense industry. Anoptional method of using abio-nanometer particle to improve CE physical property tomeet the demand of various fields can be taken into account. This thesis aims atacquiring new cyanate ester resin which has high performance in mechanics, calorifics,dielectrics, and putting forward new methods on improving cyanate ester resin.In thesis, various specification silica (SiO₂) as abio-nanometer modifiers areused to improve performance of bisphenol-A cyanate resin through several methodssuch as direct addition, regular stir, ball-milling disperse and coupling agent processing.By studying property of compound reactivity, exploit improving technical process andcondition and various improving method under differ SiO₂ structure and modifieraddition. The results indicate that nanometer silica agglomeration is small fine andspread effectively under high shearing strength and optional coupling agentprocessing. Addition processing directly determines the spread of nanometer silica.High composite mechanical property especial impact toughness can be acquired underproperly adding nanometer silica before cyanate ester resin polymerization.In order to avoid the disadvantage of cyanate ester resin high viscosity whichmakes homogeneous disperse difficulty in the procedure of adding solid nanometerparticles, on the basis of using nanometer silica to improve CE, Sol-gel technology isadopted in the experiment of improving cyanate ester resin, meanwhile, probe themanufacturability of improving CE. The results indicate that CE improved and make silica spread enough by small particle through semi-colloidal or pre-colloidal underright moulding condition of status nascendi nanometer colloid and adding time oftetraethoxysilane (TEOS) processed by anhydrous solvent. This SiO2/CE compositeovermatch former several CE improved by solid nanometer particle in fatigue strengthand impact toughness. The transmission electron microscope (TEM) analyses indicatethat silica is involved in less particles and no obvious birdnesting exist.Disquisition on phase structure characteristic of improved group ofnano-SiO₂/PMMA/CE, nano-SiO₂/PAN/PMMA/CE, increase in PMMA, discretephase, bicontinuous phase and opposite phase structure appear in composite insequence, and bicontinuous phase form about critical point. Phase size and interval arevaried according to curing temperature. The relaxation time of improved group ofPMMA in various temperature can be well fitted with WLF equation, it indicates thatviscoelasticity effect operate on the separating procedure of composite phase.Sol-gel method checks the polymerization rate and tansformation of activationenergy of PMMA/CE and PAN/PMMA/CE, meanwhile probes the relations betweenreaction condition of multi-component and structure and performance of composite.The results indicate that initiator has more effect on composite structure andperformance. The lower intensity of initiator, the enough disperse of nanometerparticle and the higher temperature of heat decompose and vitrification of composite.Testing results of XRD and TEM show that more interface reaction exists betweenmultipolymer and nanometer particles, and sologel-SiO₂/PAN/PMMA/CE hasexfoliation structure. The disperse of nanometer particles is markedly improved andstrengthen interface acting force when polar monomer AN introduced into PMMA/CEpolymer. After compounding PAN/PMMA/CE and nanometer particles, compositevitrification and heat decompose temperature and mechanical property are improved invarious extent.