剥离型酚醛树脂/蒙脱土纳米复合材料研究

Study on exfoliated phenolic resin/montmorillonite nanocomposites

用十六烷基三甲基溴化铵(CTAB)对蒙脱土进行了有机化处理,使蒙脱土由亲水性变成亲油性。采用XRD、FTIR及TEM研究了有机蒙脱土及其在酚醛树脂中的剥离行为,制备了酚醛树脂/蒙脱土纳米复合材料并测试了其层间剪切性能和烧蚀性能。实验结果表明,经CTAB处理的蒙脱土与酚醛树脂具有良好的相容性,且CTAB的含量较多时所制得的有机蒙脱土的结构较好,根据Bragg方程计算,CTAB用量超过蒙脱土量50%时,蒙脱土的片层间距由原来的1.48 nm增加到2.33 nm;有机蒙脱土用量小于5%时生成完全剥离型酚醛树脂/蒙脱土纳米复合材料;与碳布增强酚醛树脂复合材料相比,碳布增强酚醛树脂/蒙脱土纳米复合材料的力学性能和烧蚀性能均有一定的提高和改善,层间剪切强度随蒙脱土含量的增多而增大,蒙脱土用量为15%时,层间剪切强度提高了27.1%,线烧蚀率在用量为3%时降低了48.5%,质量烧蚀率变化不明显。

The expanded- montmorillonite was organically modified from hydrophilic to hydrophobic by hexadecyl trimethylammonium bromide （CTAB）. The nanocomposites of phenolic resin/montmorillonite were prepared from it, and the exfoliation behavior of phenolic resin in the organo - montmorillonite （OMMT） had been investigated by XRD, FTIR, TEM. It was found that the affinity between the organomontmorillonite and phenolic resin was very good. Property test results showed that the mechanical and ablative properties were improved by addition of the organomontmorillonite in the nanocomposites system. According to calculation from Bragg equantion, interlayer distance of MMT was increased from 1.48 nm to 2.33 nm when mass fraction of CTAB was 50% more than that of MMT. When mass fraction of OMMT was below 5%, penolic resin/organo -montmorillonite （OMMT） nanocomposite with the whole exfoliation structure was formed. Compared with common carbon fire cloth reinforced phenolic composite, the mechanical and ablative properties of carbon fire cloth reinforced phenolic resin/OMMT nanocomposite were increased and/or modified, interlayer shear strength was increased with mass fraction of OMMT increased and it was increased 27.1% when mass fraction of OMMT was 15% but it line ablation rate decreased 48.5% and mass ablation rate was not changed obviously when mass fraction of OMMT was 3%.