Research On Preparation And High Temperature Interface Properties Of Silicone Modified Phenolic Resin And Composite Thereof

Phenolic resin material is easy to get and cheap,showing excellent mechanical properties and ablative resistance,which can meet the requirements of high temperature field for composite material,and is an important basic raw material for aerospace,national defense and other fields.With the development of high-tech weapons and equipment,the thermal and mechanical properties of traditional phenolic resins cannot meet the needs of new fields.Therefore,it is urgent to modify the heat resistance and toughness of phenolic resin,improve the comprehensive properties of phenolic resin,and prepare carbon fiber composite materials with good fiber infiltration,excellent high temperature structural strength,thermal oxidation stability and high toughness,meeting the development requirements of national high and new technology.In this paper,organosilicon-modified phenolic resin was synthesized by in-situ polymerization with linear organosilicone chain in phenolic structure.Firstly,the effects of phenol/formaldehyde ratio on the molecular structure and heat resistance of the products were investigated.On this basis,the amount of methylphenyl dimethoxy silane was changed to prepare organosilicon modified phenolic resin containing different silanes.The influence of silane content on the heat resistance and microstructure of organosilicon modified phenolic resin was investigated.Finally,the phenolic resin modified by organosilicon was blended with HIT methyl phenyl silicone resin.Meanwhile,FTIR,XPS,DSC and TGA were used to analyze the structure and heat resistance of phenolic modified by organosilicone,and SEM was used to characterize the microstructure of phenolic/organosilicone matrix.The results showed that when phenol-formaldehyde ratio was 1:1.3 and silane phenol ratio was 1:5,1:6 and 1:8,the heat resistance of phenolic resin modified by organosilicone was excellent and its compatibility with organosilicone was good.On the basis of the above research,a series of organosilicon-modified phenolic based carbon fiber composites were prepared by using the blend resin system with good miscibility as matrix and according to the four ratios of modified phenolic resin/organosilicone: 10:0(Pure modified phenolic),8:2,6:4 and 4:6.The influences of silicone modified phenolic resin,silicone resin content and temperature with different silane content on interlaminar shear strength of composites were investigated,and the influence of silicon content on the cross section morphology of composites and the microstructure evolution of the interface of composites at high temperature were investigated by SEM.The experimental results show that the strength retention rate of composite ILSS can reach 87.9% with pure SPN-3 as matrix resin when the heat resistance temperature is below 300?.With SPN-2/SR(4:6)as matrix resin,the strength retention rate of composite ILSS was 84.0% at 500? and 42.3% at 700? when the heat resistance temperature was above 300?.