Preparation,Kinetic Analysis And Ceramics Of Silicon-containing Arylalkynylsilane Resin

Recently,silicon-containing arylalkynyl silane resin processes many execellent characteristics,such as high heat resistance,corrosion resistance,high residual rate and dielectric property,etc.Thus,it has gradually become a widely used high performance matrixin the field of aerospace.In this paper,phenylethynyl magnesium bromide was prepared by the Grignard reaction method,and three silicon-containing aryl alkynyl resin monomers were synthesized by substitution reaction between phenyl acetylene magnesium and chlorosilane.The curing process,curing kinetics,thermal stability,thermal decomposition kinetics and ceramic of resins were investigated.To provides reference for the preparation,processing and application of silicon-containing aryl-alkyd resins.First,Grignard reagents were prepared from magnesium,ethyl bromide and phenylacetylene,with three chlorosilanes(n-hexyl trichlorosilane,n-dodecyltrichlorosilane and n-tetradecyltrichlorosilane),respectively.Substitution reaction for the preparation of silicon-containing arylkynyl resin monomers,namely n-hexyltriphenylethynylsilane(NTPES),dodecyltriphenylethynylsilane(DTPES)and n-tetradecyltriphenylethynylsilane(TTPES).The FT-IR and NMR spectra(1H NMR,13C NMR and 29Si NMR)were used to characterize the monomer structures of NTPES,DTPES and TTPES.The Fourier transform infrared spectroscopy(FT-IR)and nuclear magnetic resonance(1H NMR,13C NMR,and 29Si NMR)were used to characterize the monomer structures of NTPES,DTPES and TTPES.Non-isothermal differential scanning calorimetry(DSC)was used to study the curing process of the resin monomer and four kinetic analysis methods(Kissinger,Ozawa,Flynn-Wall-Ozawa,and Friedman)were used to study the curing kinetics of the resin monomer and prediction of curing reaction kinetics model.The results showed that the three resin monomers all accorded with the autocatalytic reaction mechanism;the activation energies of NTPES,DTPES and TTPES resin monomers were 158.30,160.10 and 161.28 kJ/mol,respectively.The reaction series n were 0.54,0.83 and 0.76,respectively,and reaction progression mwere 0.61,0.37,and 0.33,respectively.Next,the thermal stability of poly-n-hexyltriphenylethynylsilane(PNTPES),poly-n-dodecyltriphenylethynylsilane(PDTPES)and poly-n-tetradecyltriphenylethynylsilane(PTTPES)were investigated by thermogravimetric analysis(TG).The results showed that the thermal stability of the resin decreases as the length of the carbon chain of the monomer substituent increases.Using six kinetic methods(Kissinger,Ozawa,Coast-Redfern,Achar,Friedman,and Vyazovkin-Weight methods)to calculate the average thermal decomposition activation energies of three kinds of resins were 169.62,181.12,and 187.91 kJ/mol,respectively.And three monomers conform to the autocatalytic reaction mechanism.Finally,the structure,morphology and elemental composition of the pyrolysis product of PNTPES resin at different temperatures were analyzed.The results showed that when the resin cracking temperature reached 1400 0C,with increasing cracking temperature produced more SiC crystals.There no obvious difference was observed in the morphology of the pyrolysis products at different temperatures at low magnification.And surface and inside of resin occur numerous micropores with the increase of pyrolysis temperature at high magnification.With the increase of pyrolysis temperature,the contents of C and Si increase,the content of O decreases,and SiC ceramic material formation stablely SiC ceramic materials...