含硼硅酚醛树脂的制备及耐热性研究

Study on the Preparation and Heat-resistance of Phenolic Resin Containing Boron and Silicon

酚醛树脂由于成型工艺简单、成本低和具有优异耐烧蚀性能而被广范应用于航空航天和武器装备等领域。为了进一步提高酚醛树脂的耐热性,分别采用两种方法制备含硼硅酚醛树脂,研究发现,分两步将硼元素和硅元素分别以B—O—C结构和Si—O—B耐高温结构引入酚醛树脂中,制备的含硼硅酚醛树脂耐热性和力学性能均得到改善。通过研究发现,相比于未改性酚醛树脂,含硼硅酚醛的耐热性、层间剪切强度和弯曲强度均提高,当使用甲基三乙氧基硅烷制备含硼硅酚醛树脂时,其固化物在T_(5%)、T_(10%)、T_(max)和R_(800℃)分别为416.13℃、543.62℃、567.11℃和75.99%,分别提高了95.7℃、104.5℃、29.3℃和17.94%。制备的玻璃纤维增强含硼硅酚醛树脂复合材料的层间剪切强度从16.8 MPa增加至28.6 MPa,弯曲强度从132.5 MPa提高至261.9 MPa。

Phenolic resin is widely used as resin matrix of ablative resistant materials in fields of aerospace and weaponry because of its low cost,simple processibility and excellent ablative resistance.In order to further improve the heat resistance of phenolic resin to prepare phenolic resin containing boron and silicon,two methods were used in this paper.Through the analyses,it was found that the heat resistance and mechanical properties of modified phenolic resin using the method with which boron element was first introduced into the structure of phenolic resin via B—O—C structure,and silicon was introduced into phenolic resin with Si—O—B.Compared with the pure phenolic resin,the heat resistance and mechanical properties of phenolic resin containing boron and silicon using different silicon-containing compounds were improved.When methyl-triethoxysilane was used to prepare phenolic resin containing boron and silicon,the T_(5%),T_(10%),T_(max) and R_(800℃)of cured modified phenolic resin were 416.13℃,543.62℃,567.11℃and 75.99%,which were increased by 95.7℃,104.5℃,29.3℃and 17.94%,respectively.The interlaminar shear strength of glass fiber reinforced modified phenolic resin composites was increased from 16.8 MPa to 28.6 MPa,and the flexural strength was increased from 132.5 MPa to 261.9 MPa.