Research On Aerospace Composite Materials With High Strength Polymer Matrix

In recent years,under the background of vigorously promoting independent innovation,a large number of new types of machines have emerged in China,and higher requirements have been placed on new materials developed in the direction of high performance,light weight and high functionality,especially for their continuous improvement of independent supply,which have created favorable conditions for the development of new domestic aviation materials.Based on the application of high performance materials for aviation,this paper proposes to develop a modified nano-material filled high-strength composite material based on polybenzimidazole resin,which uses natural mineral sepiolite and oligomeric silsesquioxane nanoparticles respectively,by in-situ polymerization of monomer 3,4-diaminobenzoic acid（DABA）to prepare organic-inorganic nanocomposites,preliminary analysis and analysis of chemical structure,physical and mechanical properties,thermal stability of two different inorganic particle modified composites,and the application prospects of materials were analyzed.The research content and main conclusions are:Ⅰ)The in-situ polymerization of monomeric 3,4-diaminobenzoic acid（DABA）and surface-modified natural mineral sepiolite（Sep）was used to successfully prepare poly（2,5-benzimidazole）/sepiolite（ABPBI/Sep）composite.FTIR results showed that the benzimidazole ring characteristic peaks appeared at 1650¹500 cm^-1,1622,1541and 1281 cm^-1,which proved that ABPBI was successfully synthesized.Scanning electron microscopy（SEM）showed that the distribution of Sep was uniform in the ABPBI matrix.The thermal analysis showed that the end group decomposition of the ABPBI backbone occurred around 470°C,and the ABPBI backbone decomposed after580°C.The Sep was mainly the loss of bound water before 800°C,indicating that the ABPBI/Sep composite has good thermal stability.The mechanical properties test results showed that the composite strength was significantly higher than that of pure ABPBI,while the composite strength of 3%Sep content was 188.7 MPa and the elastic modulus was 3.8 GPa.Ⅱ)ABPBI/POSS composites were successfully prepared by in-situ synthesis of monomeric DABA and phenyltrisilol cage silsesquioxane（SO-POSS）.SEM results showed that the SO-POSS particles were uniformly dispersed in the ABPBI polymer matrix.The FTIR results showed that ABPBI was successfully synthesized,and a chemical reaction occurred between the ABPBI polymer and the SO-POSS inorganic nanoparticles.It is suggested that a star-shaped nuclear arm may occur.The thermal analysis results showed that the composite material was thermally stable above 495°C,and the composite material with 3%SO-POSS content has a strength of 260.3 MPa,as well as the elastic modulus is 4.9 GPa,which has the prospect of being used as a high-temperature resistant high-strength aerospace material.Ⅲ)The article also analyzed the development status and trends of new materials for aero-engines,focusing on the application characteristics and requirements of polymer-based composites.Combined with the test results of the polymer-based composites studied in this paper,the feasibility analysis of the application was carried out.This study believes that the ABPBI-based composite materials currently studied have the advantages of high strength and excellent heat resistance.It is necessary to further carry out related trial production research work on expanding production,so that the material can be comprehensively evaluated in terms of performance and cost.