Preparation Of Organic Silicon From Rice Husk And Study On Thermal Properties Of Membrane Materials

The development of fossil fuels has promoted the development of the society.But fossil fuels is a non-renewable resources,and fossil fuels cause increasingly serious environmental pollution.Rice husk ash(RHA)is agricultural waste material which is a very abundant and non-pollution biomass resource.As a kind of renewable resource,RHA contains a lot of amorphous silica.Amorphous silica has large ratio surface.We can replace the traditional silicon source with RHA.So that we use RHA to reduce environment pollution.The high reactivity of RHA is of great research value for the synthesis of silicone.In this paper,2-methyl-2,4-pentoxysilane sol with Si-O-C structure was prepared from rice husk as silicon source.The reaction mechanism was characterized by Infrared Spectroscopy(IR).At the same time,POSS sols of different functional groups were synthesized to prepare 2-methyl-2,4-pentasiloxane/POSS composite film,so that we can improve the film-forming property of 2-methyl-2,4-pentasiloxane sol by different functional groups.At the same time,the problem of the rupture of the POSS membrane layer was improved by the silicone solution and the cross-linking of the two films during the film formation improves the heat resistance of the film.The optimum ratio of composite film was obtained by comparing the film formation,residual carbon ratio and heat resistance.In order to enhance the application of the film,the film heat resistance and thermal shock resistance needs to be further improved.Therefore,in this experiment,the composite film was modified by adding low temperature glaze.The experimental results show that the composite film has the best film performance when the ratio of 2-methyl-2,4-pentasiloxane/POSS composite film and low temperature glaze is 1:2.The structure and chemical composition of the film during the sintering process were analyzed by TG and IR.And the mechanism of high temperature resistance was obtained by XRD analysis.In order to further improve the performance of the low temperature glaze modified film.Therefore,the anti-infrared emission ability of the film layer is improved by doping the MoSi2 and Co2O3 in the film layer.This paper explored the effect of single component on the film formation of the film,and thermal shock resistance of the film after doping MoSi2 and Co2O3.The chemical changes of MoSi2 and Co2O3 in the sintering process were investigated by XRD.Finally,through the high emission test,it is proved that the MoSi2 and Co2O3 react with each other to produce new crystal phase after high temperature treatment,and the emissivity and thermal shock resistance are obviously improved.The emissivity of the film in the 20 μm-25 μm band is higher than 0.9.