反相气相色谱法探究镁铁水滑石及其改性材料的表面性质

采用反相气相色谱法(IGC)探究司班20(Span-20)、吐温-80(Tween-80)、曲拉通X-100(Triton X-100)分别与十二烷基苯磺酸钠(SDBS)复合改性镁铁水滑石材料(即SDBS/Span-LDHs、SDBS/Tween-LDHs、SDBS/Triton-LDHs)的表面性质, 通过表面吸附自由能(-ΔG⁰)、表面能色散组分(γ_s^d)及酸碱作用自由能(-ΔG^sp)这三个参数探讨材料改性前后的变化。结果表明, 水滑石经改性后的-ΔG⁰值均比未改性材料的值小, 其中SDBS/Triton-LDHs的-ΔG⁰值最小, 说明SDBS/Triton-LDHs材料的稳定性最好, 且水滑石材料改性后碱性减弱, 其中SDBS/Triton-LDHs材料的碱性最弱。此外, 各类水滑石的γ_s^d值均随着温度的升高而减小, 因此, 在制备聚合物/水滑石类材料时, 可提高温度来改善其与聚合物的相容性。

Surface Properties of Magnesium-iron Hydrotalcite and Its Modified Products by Inverse Gas Chromatography

The magnesium-iron hydrotalcite was modified by three nonionic surfactants (Span-20, Tween-80, Triton X-100) combined with sodium dodecyl benzene sulfonate (SDBS), respectively, and surface characterizations of modified hydrotalcites were investigated using inverse gas chromatography (IGC). The free energy of adsorption (-ΔG⁰), dispersive component of the surface energy (γ_s^d) and acid-basic action free energy (-ΔG^sp) were determined to explore the changes between MgFe-LDHs and modified hydrotalcites. The results show that the -ΔG⁰ of the modified hydrotalcites are lower than that of MgFe-LDHs, among which the -ΔG⁰ of the SDBS/Triton-LDHs is the lowest, indicating the best stability. The alkalinity of modifed hydrotalcites is weakened and the alkalinity of SDBS/Triton-LDHs is the weakest. In addition, the γ_s^d decreases with temperature increase. Therefore, the compatibility with polymer can be improved by increasing the temperature in preparation of polymer/hydrotalcite materials.