含氰基和乙炔基苯并噁嗪树脂的固化行为及性能研究

以4-氨基苯氧邻苯二甲腈（BZN）、间氨基苯乙炔（APA）和多聚甲醛为原料制备了含氰基和乙炔基的苯并噁嗪树脂（BZ-BPA）。利用差示扫描量热法（DSC）、傅里叶变换红外光谱法（F T-IR）、热重分析法（TGA）分析了BZ-BPA的固化行为，得到：BZ-BPA在固化反应过程中存在两个放热峰（225℃和274℃）；在氮气氛围下，BZ-BPA固化物热失重5%的温度（T _d5）为502.6℃，800℃时质量残留率为79.8%；在空气氛围下，T _d5为506.0℃，800℃时质量残留率为29.6%。采用Kissinger法计算得到两个固化反应的表观活化能（E）：E₁=228.31 kJ/mol，E₂=87.97 kJ/mol；由Ozawa法计算得到：E₁=225.98 kJ/mol，E₂=92.26 kJ/mol；固化反应接近一级反应。考察了石英纤维增强的BZ-BPA复合材料（QF/BZ-BPA）的力学性能和耐热性能，结果显示：QF/BZ-BPA的玻璃化转变温度（T_g）为476℃；在常温下其弯曲强度为764.2 MPa，层间剪切强度为57.3 MPa；在400℃热处理2 h后，其弯曲强度为614.5 MPa，层间剪切强度为38.1 MPa；400℃热处理10 h后，其质量损失仅为2.4%。以上结果表明BZ-BPA复合材料具有优异的力学性能和耐热性能。

Curing behavior and properties of a benzoxazine resin containing cyano and acetylene groups

A cyano- and ethynyl-containing benzoxazine resin (BZ-BPA) has been prepared from 4-aminophenoxyphthalonitrile (BZN), m -aminophenylacetylene (APA) and paraformaldehyde. The curing behavior of BZ-BPA was analyzed by differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric analysis (TGA). There are two exothermic peaks (225 ℃ and 274 ℃) in the curing process of BZ-BPA. The temperature of 5% thermal weight loss (T _d5 ) of BZ-BPA cured in nitrogen is 502.6 ℃, and the residual mass rate at 800 ℃ is 79.8%. T _d5 in air is 506.0 ℃, and the residual mass rate at 800 ℃ is 29.6%. The apparent activation energies of the two curing reactions were obtained by the Kissinger method: E₁=228.31 kJ/mol, and E₂=87.97 kJ/mol. The apparent activation energies were also obtained by the Ozawa method: E₁=225.98 kJ/mol, E₂=92.26 kJ/mol. The curing process is close to a first-order reaction. The mechanical and thermal properties of quartz fiber-reinforced BZ-BPA composites (QF/BZ-BPA) were investigated. The glass transition temperature (T_g) of QF/BZ-BPA is 476 ℃. At room temperature, the flexural strength is 764.2 MPa, and the interlaminar shear strength is 57.3 MPa. After heat treatment at 400 ℃ for 2 h, the flexural strength was 614.5 MPa and the interlaminar shear strength was 38.1 MPa. After heat treatment at 400 ℃ for 10 h, the mass loss was only 2.4%. The above results indicate that the BZ-BPA composites have excellent mechanical properties and heat resistance.