氰酸酯(CE)树脂具有高度对称的化学结构和强结晶性,固化反应温度高,固化物脆性大,容易从预浸料中结晶析出并悬浮于表面,严重影响了预浸料的表观质量、制备工艺和力学性能。文中采用F-51酚醛环氧改性CE树脂,通过预聚工艺制备了一种室温...氰酸酯(CE)树脂具有高度对称的化学结构和强结晶性,固化反应温度高,固化物脆性大,容易从预浸料中结晶析出并悬浮于表面,严重影响了预浸料的表观质量、制备工艺和力学性能。文中采用F-51酚醛环氧改性CE树脂,通过预聚工艺制备了一种室温下为半固态、成膜性好、适用期长、适用于热熔法预浸料工艺的热熔型CE树脂(代号BA221)。采用差示扫描量热法研究了BA221树脂的固化动力学和固化反应参数,获得了固化动力学方程,优化了固化制度,活化能较CE树脂降低了66.9%。采用流变法研究了BA221树脂的黏度变化规律,确定了热熔型BA221树脂的制膜温度为80℃,获得了成膜性和延展性良好的热熔胶膜。BA221树脂固化物的玻璃化转变温度为268.4℃,拉伸强度和延伸率分别为79.7 MPa和3%,弯曲强度和冲击强度分别为122 MPa和21 k J/m2,较CE树脂分别提高了96.3%,134.4%,76%和270%。扫描电镜结果表明BA221树脂固化物为韧性断裂。F-51酚醛环氧改性CE树脂效果显著,实现了CE树脂在120℃预聚、80℃成膜和180℃后固化的工程化应用目标,为制备热熔法预浸料提供了一种耐高温CE树脂。展开更多
To further enhance the ablation resistance properties of thermosetting phenolic resin matrix composites,in this work,bifunctional alkalic heptaphenyltrisilanol sodium salt polyhedral oligomeric silsesquioxane was util...To further enhance the ablation resistance properties of thermosetting phenolic resin matrix composites,in this work,bifunctional alkalic heptaphenyltrisilanol sodium salt polyhedral oligomeric silsesquioxane was utilized to catalyze the synthesis of boron phenolic resin and provide silicon source to obtain boron-silicon hybrid phenolic resin(BPOSSPR)with excellent ablative resistance.BPOSSPR possesses a low cur-ing activation energy(101.4 kJ/mol)and excellent thermal properties(initial decomposition temperature was 453.0℃and char yield at 1000℃was 72.7%).The mechanical and thermal insulation properties of carbon fiber reinforced BPOSSPR composites(CF/BPOSSPR)and high silica fiber reinforced BPOSSPR composites(HSF/BPOSSPR)are significantly enhanced.The linear ablation rate and mass ablation rate of CF/BPOSSPR are as low as 0.003 mm/s and 0.0354 g/s;those of HSF/BPOSSPR are 0.119 mm/s and 0.0264 g/s.The ablation-resistance mechanism of BPOSSPR composites is mainly due to the formation of ceramic thermal barrier layers under high temperature conditions,such as B_(2)O_(3),SiO_(2),borosilicate glass,SiC,which might play an effective role in protecting against heat flow erosion.As a result of these ex-cellent properties,the innovative heat shielding BPOSSPR composites could offer the ability to tolerate harsher environment in future aerospace applications.展开更多
文摘氰酸酯(CE)树脂具有高度对称的化学结构和强结晶性,固化反应温度高,固化物脆性大,容易从预浸料中结晶析出并悬浮于表面,严重影响了预浸料的表观质量、制备工艺和力学性能。文中采用F-51酚醛环氧改性CE树脂,通过预聚工艺制备了一种室温下为半固态、成膜性好、适用期长、适用于热熔法预浸料工艺的热熔型CE树脂(代号BA221)。采用差示扫描量热法研究了BA221树脂的固化动力学和固化反应参数,获得了固化动力学方程,优化了固化制度,活化能较CE树脂降低了66.9%。采用流变法研究了BA221树脂的黏度变化规律,确定了热熔型BA221树脂的制膜温度为80℃,获得了成膜性和延展性良好的热熔胶膜。BA221树脂固化物的玻璃化转变温度为268.4℃,拉伸强度和延伸率分别为79.7 MPa和3%,弯曲强度和冲击强度分别为122 MPa和21 k J/m2,较CE树脂分别提高了96.3%,134.4%,76%和270%。扫描电镜结果表明BA221树脂固化物为韧性断裂。F-51酚醛环氧改性CE树脂效果显著,实现了CE树脂在120℃预聚、80℃成膜和180℃后固化的工程化应用目标,为制备热熔法预浸料提供了一种耐高温CE树脂。
基金support from the Joint Fund of Advanced Aerospace Manufacturing Technology Research(No.U1837601),Key R&D Program and Key Industry Chain Project of Shaanxi Province(No.2019ZDLGY06-02-01)the Undergraduate In-novation&Business Program in Northwestern Polytechnical Uni-versity,and many thanks to Master Gang Li and Researcher Yijia Liu for their dedication to this work.
文摘To further enhance the ablation resistance properties of thermosetting phenolic resin matrix composites,in this work,bifunctional alkalic heptaphenyltrisilanol sodium salt polyhedral oligomeric silsesquioxane was utilized to catalyze the synthesis of boron phenolic resin and provide silicon source to obtain boron-silicon hybrid phenolic resin(BPOSSPR)with excellent ablative resistance.BPOSSPR possesses a low cur-ing activation energy(101.4 kJ/mol)and excellent thermal properties(initial decomposition temperature was 453.0℃and char yield at 1000℃was 72.7%).The mechanical and thermal insulation properties of carbon fiber reinforced BPOSSPR composites(CF/BPOSSPR)and high silica fiber reinforced BPOSSPR composites(HSF/BPOSSPR)are significantly enhanced.The linear ablation rate and mass ablation rate of CF/BPOSSPR are as low as 0.003 mm/s and 0.0354 g/s;those of HSF/BPOSSPR are 0.119 mm/s and 0.0264 g/s.The ablation-resistance mechanism of BPOSSPR composites is mainly due to the formation of ceramic thermal barrier layers under high temperature conditions,such as B_(2)O_(3),SiO_(2),borosilicate glass,SiC,which might play an effective role in protecting against heat flow erosion.As a result of these ex-cellent properties,the innovative heat shielding BPOSSPR composites could offer the ability to tolerate harsher environment in future aerospace applications.
