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Polyether block amide (PEBA) elastomer‐organoclay nanocomposites were prepared by a melt mixing technique. The X‐ray diffraction and transmission electron microscope analysis indicated that the nanocomposite formed a partially exfoliated nanostructure in which the organoclay was dispersed uniformly throughout the matrix at the nanometer scale. The effect of organoclay on the melting temperature (Tm), glass transition temperature (Tg), crystallization temperature (Tc), and heat of fusion (ΔHm) of the PEBA was determined by differential scanning calorimetry. Enhanced mechanical properties of the nanocomposites were observed from tensile and dynamic mechanical analysis. Thermal gravimetric analysis showed that the clay nanoparticles caused an increase in the thermal stability of the PEBA. Measurement of oxygen permeability and the degree of swelling in ASTM #3 oil indicated that the gas barrier properties and solvent resistance were greatly improved by the clay nanoparticles. Melt rheological studies revealed that the nanocomposites exhibited strong shear thinning behavior and a percolated network of the clay particles was formed. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers

Palladium nanoparticles were immobilized on PNIPAM:4-VP hydrogels. The resultant püalladium catalysts showed high activities for Suzuki-Miyaura coupling reactions in water. The recyclability of the catalysts was improved by using 4-VP as a co-monomer in the hydrogels due to reduced Pd leaching during the reactions.

Statistical approaches including Taguchi design of experiments (DOE), analysis of variance (ANOVA), and multiple linear regression analysis were employed to determine optimum processing conditions for successful preparation of a thermoplastic vulcanizate nanocomposite (TPVNC) based on thermoplastic polyurethane (TPU)/millable polyurethane (MPU) blend reinforced with an organoclay (TPU/MPU/organoclay = 50/50/3 wt/wt/wt) using an internal mixer. Total numbers of mixing layouts were designed by the application of Taguchi's orthogonal array (OA) methodology based on three parameters and three levels in the L9 selector matrix model. Mechanical properties of all runs were measured and fitted into the statistical software to determine signal to noise (S/N) ratio. Ranks of the parameters were determined based on the delta statistics of the larger is better case of the S/N ratio. The ANOVA parameters were analyzed and percentage contribution of each factor, along with the correlation coefficient of each variable, was measured. The multiple linear regression models for each property were correlated with the parameters through mathematical equations. Fourier transform infrared (FTIR) analysis was performed to examine any interfacial interactions between polyurethane matrix and organoclay. X‐ray diffraction (XRD) analysis and field emission transmission electron microscope (FETEM) were employed to analyze the dispersion of organoclays in the polymer matrix. Field emission scanning electron microscope (FESEM) was employed to observe cryo‐fractured morphology. Dynamic mechanical analysis (DMA) and dynamic shear rheometer (DSR) were used to investigate dynamic mechanical properties and rheological properties of the trials, respectively. Based on all of these characterizations, an optimum processing condition was determined. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

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