Study On POSS Hybrid Zirconium-containing Phenyl Silicone Resin

POSS is widely used in hybridizing and modifying polymers due to its excellent performances,which improves all aspects of the properties of the polymer,so as to obtain a new kind of composite material.Three uncondensed hydroxyl groups in polyhedron oligomeric sesquiloxane?T₇-POSS?can react with the groups in the polymer and then be introduced into the polymer.Comparing with the original polymer,the thermal stability of the composite material obtained by modifying with T₇-POSS is greatly improved.In this paper T₇-POSS was used to hybridize Zirconium-containing phenyl silicone resin.Firstly T₇-POSS was prepared by Phenyltriethoxysilane?PTES?with the method of hydrolytic condensation,and then using Phenyltriethoxysilane?PTES?,Diphenyldimethoxysilane?DPDMS?,Tetraphenyldimethylsiloxane?TPDS?,Zirconiumoxychloride as raw materials with the method of the hydrolytic condensation to prepare Zirconium-containing phenyl silicone resin.Finally the T₇-POSS modified the Zirconium-containing phenyl silicone resin,after which the high temperature resistant hybrid silicon resin was acquired.At last,a heat resistant coating was prepared by hybrid Zirconium-containing phenyl silicone resin.The specific research contents are as follows:?1?T₇-POSS was prepared by the method of hydrolytic condensation with Phenyltriethoxysilane?PTES?as raw material?hydrochloric acid as catalyst and acetone as solvent.Discussed the effects of reaction time,temperature,pH and amount of monomer on the T₇-POSS yield.Appropriate reaction condition was obtained by optimization of process:With the 5%of Phenyltriethoxysilane by the solvent volume in reaction vessel,stirred 13¹4 hours with reflux at temperature 55?and the pH of solution was 5.After the separation and purification of crude product the final product was obtained with the yield of10.2%.The structure and composition of the T₇-POSS were tested and identified by Fourier transform infrared spectrometer?FT-IR?,X-ray diffraction?XRD?,¹H-nuclear magnetic resonance spectra?¹H-NMR?,²⁹Si-nuclear magnetic resonance spectra(²⁹Si-NMR),Transmission electron microscope?TEM?,Nano-particle surface potential analyzer.Finally it proved that using Phenyltriethoxysilane acid hydrolytic condensation method successfully prepared target product?incomplete condensation cage-like T₇-POSS in high purity whose average particle size was 1.5nm.Thermogravimetric analysis?TGA?showed that thermal weight loss of T₇-POSS was 5%at temperature 490?,incomplete condensation cage-like T₇-POSS has better thermal stability.?2?A Zirconium-containing phenyl silicone resin with Si?O?Zr covalent bond was synthesized using dichloroxyzirconium,phenyltriethoxysilane?PTES?,diphenyldimethoxysilane?DPDMS?and tetraphenyldimethylsilane?TPDS?as raw materials,and ethanol as the solvent,by sol-gel method and hydrolytic condensation at temperature 60°C.It was then cured under 170°C for 3⁵ h.The coating obtained was characterized by Fourier transform infrared spectra?FT IR?,X-ray diffraction?XRD?,Thermogravimetric analysis?TGA?and Scanning emission microscope?SEM?,and its mechanical properties were tested.The effect of the composition of raw materials on the properties of coatings was investigated.The results showed that the heat resistance of the phenyl silicone is improved by adding Zirconium.When at the temperature 60?,reaction time was 6 h,1.3 times mole as much water as the alkoxy,n?Zr??n?Si?=0.15⁰.20,n?Ph??n?Si+Zr?=1.20¹.35?Ph is the total amount of substance of phenyl in DPDMS and PTES?,the zirconium-containing phenyl silicone coating with a smooth appearance and excellent heat resistance performance can be obtained,which loss only 5%of weight under the temperature of about 500°C.?3?Different amounts of T₇-POSS were used for hybrid modification of Zirconium-containing phenyl silicone resin,and the effects of different amounts of T₇-POSS on various properties of Zirconium-containing phenyl silicone resin were discussed.The proper dosage of T₇-POSS was determined by analyzing the appearance,light transmittance,hardness,flexibility and other properties of T₇-POSS hybrid Zirconium-containing phenyl silicone resin.Fourier transform infrared spectra?FT-IR?,X-ray diffraction?XRD?,Differential scanning calorimetry?DSC?,thermogravimetric analysis?TGA?,Scanning electron microscope?SEM?were made use of testing the performances and the cross section morphology with the different contents of T₇-POSS hybrid Zirconium-containing phenyl silicone resin,verified the the best dosage of T₇-POSS.Hybrid Zirconium-containing phenyl silicone resin performed exceedingly good heat-resistant when dosage of 6%T₇-POSS,which loss only5%of weight under the temperature of about 530°C.Compared to the Zirconium-containing phenyl silicone had improved significantly.?4?A heat resistant coating was prepared by T₇-POSS hybrid Zirconium-containing phenyl silicone resin,pigments,filters,additives and methylbenzene as solvent.The effect of pigments,grinding time,coupling agent,curing temperature,content of resin on the coating was investigated.The weight loss of coatings was tested by Thermogravimetric?TG?,Fourier transform infrared spectrum?FT-IR?had been used to analyze the variations of ignited and non-ignited coatings,the morphology of ignited coatings was appraised by Scanning electron microscope?SEM?.The consequences manifested that coatings prepared by Zirconium hybrid phenylsilicone resin performed excellent high temperature resistance.As the temperature increased,the adhesion and the hardness of cured film were significantly promoted,whose adhesion and hardness were?and 6 at temperature 800?,Secondary film formation of glass powder enhanced the heat resistance of the coatings,coupling agent shortened curing time and reinforced adhesion of coatings.