A series of electronically conductive nanocomposite materials that consisted of soluble polypyrrole (PPY) and layered montmorillonite (MMT) clay platelets were prepared by effectively dispersing the inorganic nanolayers of MMT clay in organic PPY matrix via an in situ oxidative polymerization with dodecylbenzene sulfonic acid (DBSA) as dopant. Organic pyrrole monomers were first intercalated into the interlayer regions of organophilic clay hosts and followed by a one-step oxidative polymerization. The as-synthesized electronically conductive polypyrroleclay nanocomposite (PCN) materials were then characterized by Fourier transformation infrared (FTIR) spectroscopy, wide-angle powder X-ray diffraction (XRD), and transmission electron microscopy (TEM). PCNs in the form of coatings with low clay loading (e.g., 1.0 wt %) on cold-rolled steel (CRS) were found to exhibit much better in corrosion protection over those of pristine PPY based on a series of electrochemical measurements including corrosion potential, polarization resistance, and corrosion current in 5 wt % aqueous NaCl electrolyte. Effects of the material composition on the thermal stability, optical properties, and electrical conductivity of pristine PPY along with PCN materials, in the form of fine powder, powder-pressed pellet, and solution, were also studied by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), UV-visible absorption spectra, and four-point probe technique, respectively. The viscosity of PPY existed in PCN materials and pristine PPY were determined by viscometric analysis with m-cresol as solvent. The heterogeneous nucleating effect of MMT clay platelets in PPY matrix was studied by wideangle powder XRD. The corresponding morphological images of the nucleating behavior of clay platelets in PPY matrix were investigated by scanning electron microscopy (SEM).

ABSTRACT:In this study, we prepared a series of polymer-clay nanocomposite (PCN) materials that consisted of an emeraldine base of poly(o-methoxyaniline) and layered montmorillonite. Organic o-methoxyaniline monomers were first intercalated into the interlayer regions of organophilic clay hosts followed by a one-step in situ oxidative polymerization. The as-synthesized PCN materials were subsequently characterized by FTIR spectroscopy, wide-angle powder X-ray diffraction, and transmission electron microscopy. The molecular weights of PMA extracted from PCN materials and bulk PMA were determined by GPC with THF as eluant. Effects of the material composition on the thermal stability, flame resistance, electrical conductivity, and corrosion inhibition performance of PMA, along with a series of PCN materials in the form of fine powder and coating, were also studied by TGA, limiting oxygen index measurements, four-point probe technique, and electrochemical corrosion measurements, respectively. Morphological images of assynthesized materials were also investigated by SEM.

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This study investigates a lambda cyhalothrin 2.5% (w/w) microemulsion formulation, with biodiesel as an alternative solvent, as a potential pesticide delivery system for oil-soluble pesticide active ingredients (AIs). This study presents a pseudoternary phase diagram of the investigated system, at room temperature by titration, and the surfactant/cosurfactant mass ratios (S/C), the oil-to-surfactant/cosurfactant mass ratios (O/SC) and the optimum formulation. This study also investigates the continuous structural inversion from water-in-oil to oil-in-water microemulsions after dilution with the water phase. The electrical conductivities of the selected system at constant S/C (5:1) and O/SC (1:1.2) ratios with biodiesel were also studied, and the percolation phenomenon was observed. The study examines the performance and stability of a formulation with biodiesel in comparison to commercial formulations. Residue and phytotoxicity tests were carried out on cabbage plants in a greenhouse. Experimental results indicate that biodiesel has good handling characteristics when it forms a microemulsion. The microemulsion formulation, with biodiesel as a solvent, had an acceptable transparent appearance, broader transparency temperature range, and better performance and stability than the commercial formulation. Using biodiesel in a pesticide formulation had no adverse effects on the AI activity and is comparatively safe for crops and plants.

In pharmacology, development of a formulated nanosuspension, a potential drug delivery system for poorly soluble drugs, has been investigated to overcome the bioavailability problems caused by weak solubility, limited chemical stability following administration (i.e., a short half-life), poor bioavailability, and potentially strong side effects requiring drug enrichment at the site of action. For first time use in a pesticide delivery system, a two-step milling process for preparing a nanosuspension in a system of active compound/surfactant/water is described in this paper. First, all the components were mixed at a certain composition to prepare a microsuspension by the general milling process. Then, the microsuspension was taken into a nanomilling process with zirconium oxide beads, having a diameter range of 0.1À0.2 mm, as the milling media to generate the nanosuspension. Therefore, a nanosuspension concentrate was formed. To demonstrate the potential applications of this novel system, it was used to make a formulation with a poorly soluble crystalline insecticide, carbofuran. In a comparative study, two kinds of carbofuran formulations, a microsuspension (commercial) and a nanosuspension, were administered to a diamondback moth (DBM) to test their efficacy and stability as a pesticide. The results indicate that carbofuran has the same efficacy at a lower dose for the nanosuspension compared to the microsuspension. The nanosuspension system was also physically and chemically stable over a period of 2 years, as indicated by the unchanged particle size and specification tests.

Slot die is a premetered coating operation in which the coating solution is extruded from a feed slot onto the surface of a substrate passing through. The defect-free region of operation is known as the “coating window”, and the wider it is, the more versatile the operation will be. The slot-coating experiments reported here were carried out with two types of coating solutions, a hard coating solution with low viscosity and a polysilica solution with high viscosity. The coating windows were measured as flow rates q versus minimum and maximum coating speeds, V min and V max, respectively. Therefore, at a given flow rate of the coating solution, there exists a minimum speed and a maximum speed that border the corresponding coating window, outside which coating defects occur. Also, in our experiments, the coating windows shifted to higher coating speed and obtained thinner coating film thicknesses through different settings of the die angle to the substrate and different geometries of die lips. The data showed that the coating windows shifted to higher speed and thinner film thicknesses when the die angle and the geometry of the die lips were varied appropriately. These results have important practical implications. The fundamental principles involved here are also applicable to other premetered coating processes.