Preparation And Characterization Of Modified Montmorillonoid/Nylon66Salt Assembly Materials

The natural phyllosilicate clays are crystalline aluminosilicates and characterized as the multilayered structure in the primary stacks. Among varieties of natural inorganic minerals, the montmorillonoid(MMT) commonly comprise two Si-O tetrahedral sheets and a sandwiched Al-O octahedral sheet as an edge-sharing2:1structure. The plate-like clays have various practical uses such as catalysts, adsorbents, metal chelating agents, and polymer/clay nanocomposites. The nanomaterials with different shapes such as nano-sphere,-cube,-wire,-tube,-fiber,-ring,-plates etc. have been widely reported. These self-assembling occurrences are mechanistically rationalized by the equilibrium of non-covalent bonding forces such as ionic charge interaction, hydrogen bonding, aromatic π-π stacking, van der Waals force, and hydrophobic effect. For the montmorillonite clay, the multilayered structure consists of8-10platelets on average in one stack, with platelet units of polydispersed dimensions of80×80×1nm. Previously, it is reported that the random platelets’ fundamental properties of ionic characteristics and high-aspect-ratio shape, and also a unique self-aligning nature during the water-evaporating process. Organically intercalated clay stacks at a proper organic/silicate ratio may undergo a self-assembling process to generate highly ordered microstructures. The self-assembly was attributed to the presence of the non-covalent bonding forces involving silicate ionic charges and organic interactions in the primary units of clay stacks. However, preparation and characterization of MMT/organics assembly materials is few reported.The industrial grade Na+MMT(ca.0.6μm～2.8μm in microscale building blocks’particle size) was directly modified by γ-Aminopropyltriethoxysilane kh-550, then uniformly dispersed in the nylon66salt solution and evaporated up to form a membrane.The membrane was polymerized to prepare amino modified MMT/nylon66salt assembly materials by high temperature and high pressure. The unique formation of lengthy rod (ca.2μm～4μm in length and1μm in diameter)and round bent-leaf shape (ca.8μm～14μm in length and1μm～2μm in width) were observed by scanning electron microscopy (SEM), and the Nitrogen content was measured by energy dispersive X-ray spectroscopy(EDS). Meanwhile, in a view of the particle size and the hierarchical structure of Na+MMT, it showed that the modified MMT and nylon66assemble ordered structures. The polycondensation time, water and inorganic phase/organic phase ratio in the system were studied in detail.The results revealed that reactive group amino was grafted onto the MMT’s lamellar, and the fuctionalized MMT was successfully prepared by modification with silane coupling agent. The modified MMT/nylon66salt assembly materials were successfully prepared by polycondensation. When the modification degree of MMT was deepened, the weight loss rate, TONSET and TMAX of modified MMT/nylon66salt assembly materials were increased, which illustrated that the assembly improved the thermal stability of assembly materials. With the extension of polycondensation time, the quantity of the round bent-leaf shape and the lengthy rod increased, their size magnified. The water in the system restrained the assemble between modified MMT and nylon66. When inorganic-organic-ratio replaced9:1with7:3, the lengthy rod in the modified MMT/66salt assembly materials disappeared, the whole material presented a cellular structure.