硼改性酚醛树脂的固化及裂解

Curing and pyrolysis of boron-modified phenolic resin

  • 摘要: 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。

     

    Abstract: 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.

     

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