Preparation And Properties Of High Silia Glass Fiber Reinforced Carbon Matrix Composites

The problem of energy shortage has been becoming an prominent concern in modern society with the social progress and industrial development.The energy can be converted into heat through various devices,which is one of the major ways for the energy utilization.Therefore,it is becoming active research area that developing the energy-saving materials with excellent thermal insulation performance by adopting new technologies and improving production processes.Fiber-reinforced porous carbon-based insulation material is one of the energy-saving and material-reducing composite materials.It is widely used in aerospace,machinery,construction,storage,etc.,which shows good performance in sound absorption,heat insulation,heat preservation,etc.Thus,the study on porous carbon-matrix composites is very practical.Firstly,an environmentally-friendly water-soluble phenolic resin was synthesized by alkali-catalyzed method.Carbon spheres were prepared by hydrothermal synthesis reaction.Then the porous carbon precursors were prepared by mixing them.Finally,he porous carbon was obtained after high temperature heat treatment.The chemical structures of water-soluble phenolic resins and carbon spheres were characterized by using infrared spectroscopy?FT-IR?.The mechanical properties,micro-morphology,and thermal properties of porous carbon were analyzed by microcomputer-controlled electronic universal testing machine,scanning electron microscope?SEM?,laser thermal conductivity meter,and differential scanning calorimeter?DSC?,respectively.The results show that the prepared porous carbon have the best performance with the addition amount of the carbon spheres particles is 10%.Its apparent density,compressive strength and flexural strength are 1.035 g·cm^-3,7.04 MPa,and 7.69 MPa,respectively.It shows brittle fracture in the compression fracture mode,and exhibits good thermal shock resistance.The thermal conductivity of the porous carbon was 0.097 W·m^-1·?^-1at room temperature,and s0.241 W·m^-1·?^-11 at 300?.In order to prepare porous carbon-based composites with good properties,the high-silica glass fibers with excellent properties were selected as reinforcing materials.Thus,a mixed system of carbon spheres,high-silica glass fibers,and water-soluble phenolic resins was used to form precursors.After the carbonization,carbon-based composites with porous structures were obtained.The mechanical properties,micro-morphologyandthermalpropertieswerealsocharacterizedby computer-controlled electronic universal testing machine,scanning electron microscope?SEM?and laser thermal conductivity instrument,respectively.The results show that the performance of porous carbon matrix composites is best when the amount of added fiber is 6%.Its compressive strength and flexural strength are 7.55 MPa and 8.20 Mpa,respectively.It also shows good thermal shock resistance.Compared with other samples,the thermal conductivity of porous carbon matrix composites increases slightly.The thermal conductivity is 0.254 W·m^-1·?^-1at room temperature,0.442 W·m^-1·?^-1at300?.Based on the heat transfer process of porous carbon,simulating by the ANSYS finite element analysis software,the temperature distribution cloud diagrams were established;then the heat transfer model was constructed.The results show that each cell area covers a number of different temperature zones because the thermal conductivity of the gas is much smaller than that of the solid phase.