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Biocomposites based on biodegradable polybutylene succinate (PBS) and organomodified clays (OMt) were prepared by melt blending process. The OMt nanofillers were obtained by ion exchange reaction between sodium montmorillonite (Mt) and gemini surfactants bearing 4-decyloxyphenylacetamide hydrophobic chains and ethylene or hexylene spacer. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and rheological measurement results showed that the investigated hybrids present a uniform dispersion with an exfoliation of clay into the PBS matrix, particularly for short spacer surfactant based composites. The effect of organoclay loading and composition on the thermal, mechanical, and barrier properties was also investigated. High clay loading and long gemini surfactant spacer lead to substantial improvement of Young modulus values by 21%, while low clay content induces a reduction of the hybrid's crystallinity due to strong OMt-PBS interactions. Compared to that of the neat PBS film, a significant reduction of the water vapor permeability (WVP) by 28% was obtained by adding only 3 wt % of PBS/OMt (2) which opens up prospects for this material in the field of food packaging. This study shows that gemini surfactant-modified organoclays can be used as effective nanofillers in a PBS matrix to access to value-added nanocomposites.

Polymer nanocomposites have gained much importance in the field of optoelectronics due to their unique optical properties. Refractive index engineering using nanoparticles is an effective strategy that could be applied for the fabrication of optical devices. Herein, we report three different strategies which are employed to enhance the refractive index of polymer thin films. These include incorporating cerium oxide nanoparticles onto the polystyrene matrix, secondly adding cerium oxide nanoparticles onto the cross-linkable polystyrene and thirdly by embedding functionalized cerium oxide nanoparticles onto the cross-linkable polystyrene. Refractive index of the polystyrene thin films was enhanced by dispersing neat CeO 2 nanoparticles and functionalized CeO 2 nanoparticles into the polystyrene matrix. 1.38% enhancement in the refractive index of the polymer nanocomposite thin films could be achieved using our technique. The blending of polystyrene with cerium oxide nanoparticle presents a prospective way to engineer the refractive index of polymer thin films. We firmly believe that the study will be an effective guide towards future research in the area of surface engineering of polymer thin films for refractive index enhancement.

Aromatic-containing gemini ammonium bromide surfactants with different spacer length and variable amounts were used to modify Na+-montmorillonite via ion exchange reaction. The resulting organoclays (OMt) were characterized in terms of composition and morphology using Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). The thermal stability of OMt was determined by thermogravimetric analysis (TGA). The results indicated that gemini surfactants exhibit a good efficiency to modify clay mineral. Surfactant concentration and the length of the spacer connecting the ammonium heads were found to be key parameters governing the thermal stability and the structure of the corresponding OMt. Increasing surfactant concentration and lengthening of the spacer act favorably for the achievement of higher expended interlayer clay structures with better thermal stability. Different configurations of surfactant molecules within Mt interlayers were proposed based on d(001) basal spacing.

International audience; New quaternary ammonium gemini surfactants of the general formula CnH2n+1-Ph-NHCOCH2N+(CH3)(2)-(CH2)(s)- N+(CH3)(2)CH2CONH-Ph-CnH2n+1 (with n = 8, 10,12, 14,16 and s = 2,4, 6) have been synthesized by an efficient synthetic pathway based on the quaternization of N,N,N',N'-tetramethylalkylenediamine with 2-bromo-N-(4-(alkyloxy) phenyl) acetamides. Their surface properties were investigated by surface tension, electrical conductivity and dynamic light scattering (DLS) measurements. The study shows that the incorporation of a benzene ring in the hydrophobic tail prompts micelle formation which leads to a smaller cmc values in the range of 0.21-0.009 mM compared to analogous geminis bearing alkyl hydrophobic chains. The length of the spacer and the hydrophobic chain has a pronounced effect on the aggregation behavior of surfactants molecules. This was confirmed by the average surfaces occupied by these molecules at the water-air interface calculated from the Gibbs equation. The size of the aggregates was measured by employing dynamic light scattering technique. The antimicrobial activity of investigated surfactants was evaluated against three microorganisms: Staphylococcus aureus, Escherichia coli and Candida albicans. (C) 2017 Elsevier B.V. All rights reserved.