反相气相色谱法表征表面活性剂与硅烷偶联剂复合改性水滑石的表面性质

Inverse gas chromatography characterize hydrotalcite modified by surfactant and silane jointly

采用共沉淀法制备了镁铝摩尔比为2∶1的镁铝水滑石(Mg/Al-HT),用SDS(十二烷基硫酸钠)、MTMS(γ-甲基丙烯酰氧丙基三甲氧基硅烷)及二者复合改性镁铝水滑石,得到SDS-HT、MTMS-HT及SDS-MTMS-HT 3种杂化材料。通过反相气相色谱法,采用非极性和极性探针来研究Mg/Al-HT、SDS-HT、MTMS-HT及SDS-MTMS-HT的表面性质。由探针分子的保留时间,计算了表面吸附自由能(ΔG0)、表面能色散组分(γsd)、酸碱作用自由能(ΔGsp)及相互作用参数(χ12)。结果表明,杂化材料γsd明显低于水滑石γsd,经过改性的水滑石表面碱性减弱,且改性后的水滑石与有机物的亲和性均得到明显改善,SDS-MTMS-HT与有机物间相容性最好。利用XRD、FT-IR、TG及DTA分析方法对样品进行表征,表明SDS插入水滑石层间,而MTMS在水滑石表面缩合,SDS-MT-MS-HT热稳定性、疏水性最好,即与有机物亲和性最佳。

Magnesium-aluminum hydrotalcite compound with Mg/Al ratio of 2∶1 was synthesized by coprecipitation.Then the Mg/Al-HT was modified by SDS,MTMS and both of them to yield three hybrid materials which are SDS-HT,MTMS-HT and SDS-MTMS-HT.The surface properties of Mg/Al-HT,SDS-HT,MTMS-HT and SDS-MTMS-HT were characterized by inverse gas chromatography,using polar and non-polar probes.The free energy of adsorption(ΔG0),the dispersive component of the surface energy(γds),the specific interaction energy(ΔGsp) and the interaction parameters(χ12) were estimated by using the retention time of different probes.The results indicated that γds of hybrid samples is lower than that of Mg/Al-HT,the surface of hydrotalcite compound became less basic after treating.The affinity between modified-hydrotalcite compound and organic compounds was improved obviously,interaction between SDS-MTMS-HT and organic compounds was the strongest.The samples were investigated by XRD,FT-IR,TG and DTA,showing that SDS has been adopted in the interlayer,MTMS has condensed with the hydroxyl groups on the hydrotalcite surface,the sample modified by SDS and MTMS is the most stable and hydrophobe of all,namely,has the best affinity.