硼改性酚醛树脂的固化及裂解

Curing and pyrolysis of boron-modified phenolic resin

采用DSC、Ozawa法、固态13C核磁共振（13C NMR）、红外光谱（IR）、裂解-气相色谱（Py-GC）和XRD研究了硼改性酚醛树脂的固化动力学、固化机制和裂解行为。结果表明：硼改性酚醛树脂的近似凝胶温度、固化温度和后处理温度分别为350.0 K、386.2 K和433.3 K,固化反应峰顶的活化能为152.4 kJ/mol;硼改性酚醛树脂的固化反应主要包括PhCH2—OH之间的反应、PhCH2—OH与B—OH之间的反应、PhCH2—OH与酚环上活泼氢之间的反应,以及醚键的歧化反应。硼改性酚醛树脂的剧烈分解温度为500~800℃,失重为14.9%;裂解生成的挥发物有CO、CO2、H2O、苯和甲苯等;在1000℃时的残碳率为67.2%;硼改性酚醛树脂在1000℃高温裂解30 min后生成了玻璃碳。

The curing kinetics,curing mechanism and pyrolysis of boron-modified phenolic resin were investigated by means of non-isothermal DSC technique,Ozawa method,solid-state 13C nuclear magnetic resonance（NMR）,infrared spectrum（IR）,pyrolysis-gas chromatography（Py-GC）and XRD.The results show that the approximate theoretical temperatures of gel,cure and post-treatment are 350.0 K,386.2 K and 433.3 K,respectively.Its apparent activation energy at exothermic peak is 152.4 kJ/mol.The curing process involves the reactions of PhCH2—OH to itself,PhCH2—OH to B—OH,PhCH2—OH to H of phenol ring as well as disproportionation of ether link.The mass loss at the range of 500 ℃ to 800 ℃ in the pyrolysis is 14.9%,and the pyrolysis products are mainly volatile compounds,such as CO,CO2,H2O,benzene and toluene.The residual carbon value at 1000 ℃ is 67.2%.The boron-modified phenolic resin is pyrolyzed into glass carbon after the heat-treatment at 1000 ℃ for 30 min.