Polymer / Clay / Alkali Metal Ion Intercalation Compound Structure And Properties Of Study

In this paper, Polymer/Clay nanocomposites were synthesized through solution intercalation methods, XRD and FT-IR were applied to confirm the intercalation of polymers in the clay layers. X-ray photoelectron spectroscopy (XPS) was applied to study the influences of Poly(ethylene oxide)(PEO), Poly(propylene oxide)(PPO), Crown either(18-C-6) and diethylene glycol(DEG) on the Chemical circumstance changes of K~+, Na~+ and Ca~2+ inter Montmorillonite(MMT) and Laponite(Lap) layers. The influences of polymers and organic molecules on the electron binging energy of interlayer cations were measured, and the interactions between polymers and interlayer cations were discussed. Alike 18-C-6, the binding energy of the K2p and Nals electrons decrease when PEO was introduced into the MMT and Lap interlayer spaces, this result manifests the interactions between PEO and K~+, Na~+. Inside the MMT and Lap interlayer spaces, PPO and diethylene glycol did not influence the electron binding energy of K~+, Na~+, so there were no interactions between PPO, diethylene glycol and K~+, Na~+. Inside the MMT interlayer spaces, PEO and PPO did not influence the electron binding energy of K~+, Na~+, there were no interactions between PEO, PPO and K~+, Na~+.The water content of polymer/clay nanocomposites under the conditions of different relative humidity was measured, and the relationship between water contents and interlayer space was studied. Combined with the X-ray photoelectron spectroscopy results, the interactions of polymers, organic molecules, clay and alkali metal ions in the composites were discussed. In the MMT/PEO/K~+ composites, K~+ coordinated with MMT and PEO to form stable complex, and under the conditions of different relative humidity, the water contents of the MMT/PEO/K~+ composites were low and the interlayer space kept nearly constant. In the MMT/PEO/Na~+ composites, Na~+ coordinated with MMT and PEO to form unstable complex, water molecules could destroy this complex, and under the conditions of different relative humidity, the water contents of the MMT/PEO/Na~+ composites were high and the interlayer space was increased with water contents.In the MMT/PEO/Ca2+ composites, there was no interaction between Ca2+ and PEO, the water content and interlayer space of MMT/PEO/Ca2+ composites increase with the increase of relative humidity.In the MMT/PPO/K+ nanocomposites, there was no interaction between PPO and K+, at lower relative humidity, the water content was low and the interlayer space kept nearly constant;at higher relative humidity, the water content and interlayer space of the composites increase with the increase of relative humidity. In the MMT/DEG/K+ nanocomposites, there was no interaction between diethylene glycol and K+, and H-binding may be established between diethylene glycol and the clay surface, with the increase of relative humidity, water molecules can destroy the H-binding, and water content increases with the increase of relative humidity. The diethylene glycol is small molecular, and do not affect the interlayer space, so the interlayer space of MMT/DEG/K+ nanocomposites kept nearly constant with the increase of relative humidity.In the MMT/PPO/Na+ nanocomposites, there was no interaction between PPO and Na+, the composites' interlayer space increase with the increase of relative humidity. The hydrophilicity of PPO is weaker then PEO, PPO covers part of the surface of MMT, so the water content of MMT/PPO/Na+ nanocomposites was lower then Na-MMT under the conditions of different relative humidity. In the MMT/DEG/Na+ nanocomposites, there was no interaction between diethylene glycol and Na+, and H-binding may be established between diethylene glycol and the clay surface, with the increase of relative humidity, water molecules can destroy the H-binding, and water content increases with the increase of relative humidity. The diethylene glycol is small molecular, and do not affect the interlayer space, so the interlayer space of MMT/DEG/Na+ nanocomposites increase with the increase of relative humidity.The interlayer spaces of polymer/MMT nanocomposites can be affected by water content of composites, when XRD was applied to study the interlayer spaces of polymer/MMT nanocomposites, the water content of the samples must be considered. In this paper, the conformation of PEO inside the MMT layers was studied with FT-IR, Raman and XRD methods. Because of the presence of MMT, IR can provide fewinformation about the conformation of PEO, but can not provide the information of the affect of different interlayer cations on the conformation of PEO;the presence of fluorescence comes from MMT disturbs the Raman spectrum, Raman can provide no useful information about the conformation of PEO.The species of interlayer cations and synthesis methods of polymer/MMT nanocomposites can affect the conformation of PEO. The conformation of PEO in MMT/PEO/K+, MMT/PEO/Na+ and MMT/PEO/Ca2+ were studied through interlayer space measurement with XRD, and the composite samples sufficiently washed or unwashed were also studied in this paper. In MMT/PEO/K+, MMT/PEO/Na+ and MMT/PEO/Ca2^ nanocomposites, PEO adapt stretched or twisted helical conformation.In the unwashed MMT/PEO/Na" nanocomposites, Na+ and PEO can't form stable complexes in water suspensions. With the increase of PEO/clay in the suspensions, the interlayer space increases, indicates that PEO adapt stretched conformation. With the increase of PEO/clay, more PEO molecules intercalated into MMT layers, the stretched helical conformation tends to shrink, lead to the increase of the interlayer space. In the washed MMT/PEO2k/Na+ nanocomposites, with the increase of PEO/clay in the suspensions, the interlayer space kept nearly constant. WTien the PEO molecule adapt a stretched helical conformation, the molecule lies on the clay surface, and there are more contact (adsorption) points between PEO molecule and clay surface, the PEO molecule is difficult to be desorbed by washing process. At high PEO/clay, the stretched helical conformation slirinks and the contact points decreases, the PEO molecule is easy to be desorbed by washing process. For the composites prepared at high PEO/clay, the washing process dissolved part of the PEO adsorbed on the clay surfaces, only those molecules with stretched helical conformation left, therefore the interlayer space kept nearly constant with the increase of PEO/clay. For the MMT/PEOiook/Na+ composites, there were no obvious differences between washed and unwashed samples, this may be owing to the huge molecular weight of PEOiook, which lead to more contact points of PEOiook than PEOak, the PEOiook molecule adsorbed is difficult to be desorbed by washing.In MMT/PEO/K+ nanocomposites, K+ and PEO can form stable complexes even in water suspensions, and the stretched helical conformation is fixed in the MMT layers, the interlayer space kept nearly constant with the increase of PEO/clay. The adsorbed PEO molecules can't be desorbed during the washing process, so the washing process do not affect the interlayer space of MMT/PEO/K+ nanocomposites.