蒙脱土(MMT)作为一种天然矿物质, 在树脂胶粘剂的增强改性方面应用前景广阔。 为了探明蒙脱土增强作用机理, 本文采用有机蒙脱土改性脲醛树脂, 利用傅里叶红外光谱仪(FTIR)和X射线衍射仪(XRD)分析蒙脱土和改性树脂的化学和晶体结构; 并制造木质复合材料, 采用纳米压痕技术(NI)比较研究复合材料界面区域树脂的纳米力学性能, 测定复合材料的宏观胶合强度。 FTIR和XRD分析表明, 经十六烷基三甲基溴化铵分析纯(CTAB)改性后的蒙脱土在2　929和2　855 cm-1附近出现新的吸收峰, 蒙脱土原土中的金属阳离子和有机阳离子实现有效交换, 其(001)面强衍射峰向小角度移动, 蒙脱土原土纳米片层的间距从1.51 nm增加至2.71 nm, 有助于蒙脱土均匀分散于树脂体系中, 并与体系中聚合物分子基团发生化学反应。 蒙脱土片层的物理填充、 化学反应形成的弹性体结构使得胶粘剂在加载过程中可以有效地分散应力, 从而有利于提高脲醛树脂的力学性能, 有机蒙脱土改性脲醛树脂的微观弹性模量和硬度分别增加了66.9%和24.2%。 改性后树脂的耐水性能得到明显改善, 木质复合材料的湿胶合强度增加了约97%。

Montmorillonite (MMT) is a natural mineral that has great potential as reinforcing filler in wood adhesives. In order to study the reinforcing mechanism more clearly, organic MMT-reinforced urea-formaldehyde adhesive (UF-OMMT) was prepared to analyze its chemical properties and crystal structure with Fourier Transform Infrared Spectroscopy (FTIR) and X-Ray Diffraction (XRD). The nanomechanical properties of UF, UF-MMT and PF-OMMT adhesives in the interphase of wood-based composite were analyzed by nanoindentation (NI) and the macro-bonding strength of composite were also tested. The results of FTIR and XRD indicated that in the spectra of MMT modified by cetyltrimethyl ammonium bromide (CTAB), the new peaks appeared at 2 929 and 2 853 cm-1corresponding to C—H stretching vibrations of the organic intercalation agent (CTAB). The (001) diffraction peak of MMT was shifted to a lower angle and the lamellar repeat distance increases from 1.51 nm to 2.71 nm after organic modification. The ion exchange of the cations in montmorillonite with organic ammonium ions and the separating and disorder crystalline improved the compatibility of the modified clay with the polymers and the dispersion of the layers into the matrix. The good physical filling of MMT particles and the elastomer formed during the reaction could transfer and distribute loads between components more homogenously, therebycontributing to the improved mechanical properties of adhesives. As compared to the untreated UF, the reduced elastic modulus and hardness of UF-OMMT in the interphase increased by about 66.9% and 24.2%, respectively. At the macroscale, the bonding strength of plywood bonded with UF-OMMT increased by about 97% as compared to that of unmodified UF resin. The positive effects of montmorillonite on water and heat resistance can be attributed to the better barrier properties of the interphase.