酚醛树脂/蒙脱土纳米复合材料的制备及固化反应动力学研究

STUDIES ON THE PREPARATION AND CURING REACTION KINETICS OF PHENOLIC RESIN/MONTMORILLONITE NANOCOMPOSITE

利用自制的有机蒙脱土 ,采用浇模固化成型法制备酚醛树脂 /六次甲基四胺 /蒙脱土纳米复合材料 ,并用XRD观察有机蒙脱土分别在热塑性和热固性酚醛树脂中复合行为 .研究发现 ,由于两种树脂的固化反应机理不同 ,热固性酚醛树脂与蒙脱土复合 ,可得插层型纳米复合材料 ;而采用热塑性酚醛树脂进行固化 ,则得到部分剥离的纳米复合材料 .通过DSC进一步研究热塑性酚醛树脂 /蒙脱土复合体系的固化反应动力学 .运用Kissinger ,Flynn Wall Ozawa ,Crane方法求出活化能和反应级数等动力学参数 .结果发现 ,加入蒙脱土使固化反应活化能下降 ,反应级数减小 ,从而有利于固化工艺的实现 ,便于纳米复合材料实际应用 .

The nanocomposite of phenolic resin/hexamethylenetetramine/montmorillonite,which was obtained by the treatment of inorganic montmorillonite,are prepared by casting and curing,and phenol resin exhibit crosslinked chains by chemical bonds forming a three dimensional network while the mechanisms of phenol resin are different.As a result,it has been investigated by X ray diffraction(XRD) that the peak of 16 MMT(2 θ =4 02°) disappeared,and the first peak( n =1) of montmorillonite at the resol phenol resin/16 MMT appeared at 2 θ =2 50～2 56°,while the diffraction peak of montmorillonite at the novolac resin/16 MMT has not easily been found.Thus,resol types of resin can form the intercalated nanocomposite with the lattice spacing of 3 53～3 45 nm,while novolac phenolic resin can partly form the exfoliated nanocomposite.The curing reaction of novolac phenolic resin has been studied by differential scanning calorimetry (DSC) at various heating rates.Some kinetics parameters including the reaction order and activation energy were calculated with Kissinger,Flynn Wall Ozawa and Crane methods.The curing kinetic of novolac phenol resin gives information that activation energy and reaction order decrease with the addition of organic montmorillonite.The value of obtained for the neat novolac resin was 162 3 kJ/mol,and those of the systems with 5,7 and 10 percents of organic montmorillonite were 139 2,142 8 and 122 6 kJ/mol, respectively.It was observed that the reaction order of the pure system was 1 13,and the systems with 5,7 and 10 percents of organic montmorillonite were 0 95, 0 92, 0 95.With the reduction of the activation energy and the raction order,it is possible to take advantage to the application of nanocomposite.