Volume 17, Issue 2

A series of novel sulfonated polytriazole copolymers (PTFOSH-XX) was successfully prepared by the click reaction of 4,4′-(perfluoropropane-2,2-diyl)bis((prop-2-ynyloxy)benzene (TF), 4,4′-diazido-2,2′-stilbene disulfonic acid disodium salt (SAZ) and 4,4′-diazidodiphenyl ether (OAZ). The copolymers were characterized by Fourier transform infrared (FTIR) and proton nuclear magnetic resonance (NMR) spectroscopy. The copolymers showed high mechanical, thermal and oxidative stability and low swelling. The phase separated morphology of the membranes was confirmed from transmission electron microscopy (TEM). The membranes showed proton conductivity as high as 110 and 122 mS cm −1 at 80 and 90°C, respectively depending on the polymer repeat unit structure.

The effect of various ingredients – nanoclay (NC), azodicarbonamaide (ADCA), paraloeid K-400 and calcium stearate (Ca.St) – on thermal behavior of melt blended poly (vinyl chloride)/NC nanocomposites was investigated. Combinations of two artificial intelligence algorithms were performed for modeling of the systems. The formulation ingredients affect the thermal features of the compounds. Upon increasing the effect of various ingredients, i.e. NC, ADCA, K-400 and Ca.St, an increase in ash content was observed, hence, the thermal stability increased. The effect of ingredients on initial degradation temperature (T 5% ) and half degradation temperature (T 50% ) was not obvious. The artificial neural network (model) and the clonal selection algorithm (optimizer) were performed for proper modeling of the systems. These models were used to determine the role of T 5% , T 50% and char based on the contents of ingredients. The result successfully modeled the process parameters.

The aim of the present work was check the feasibility of thin film composite (TFC) polyamide NF500 nanofiltration (NF) membrane for simultaneous removal of hexavalent chromium [Cr(VI)] and fluoride from a synthetically prepared binary solution. The characterizations of the membrane were made with techniques like Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and atomic force microscopy (AFM). The study of simultaneous removal of Cr(VI) and fluoride ions at different parameters such as feed concentration, pressure and pH. Evaluation of mass transfer coefficient (MTC) and membrane transport parameters (MTPs) using the combined film theory-Spiegler-Kedem (CFSK) model. The estimated parameters are used to predict membrane performance for simultaneous removal of Cr(VI) and fluoride. Experimental results and model predicted results that show good correlations.

A magnesium (Mg)-rich primer can provide cathodic protection for an aluminum (Al) alloy due to the lower potential of Mg. However, the Mg-rich primer prepared by simple blends shows poor flexibility and impact resistance. In this paper, bisphenol-A type epoxy resin E-20 was graft modified by hydroxyl silicon oil (HS), amino silane coupling agent and diphenyl-methane-diisocyanate (MDI) by three different ways. Then Mg-rich primer was prepared by direct blends of modified resins. Results indicate that the introduction of siloxane groups could improve the comprehensive performance of the coating especially the flexibility and impact resistance. Furthermore, Mg-rich primer prepared from MDI modified epoxy resin even possesses excellent salt spray and aging resistance.

A cross-linked microfibrous anion exchange membrane with high ion permselectivity and robust mechanical properties was fabricated by electrospinning. Copolymer, poly N,N-dimethylaminoethyl methacrylate (DMAEMA)-co-2-hydroxyethyl methacrylate (HEMA), was selected as the electrospun material. Fourier transform infrared (FTIR) spectroscopy, 1 HNMR and scanning electron microscopy (SEM) were employed to characterize the copolymer and microfibrous mat. The electrospinning optimal parameters were determined by orthogonal experiments. Formaldehyde vapor was applied to crosslink the mat. It was observed that the water sorption decreased from 75.7% to 30.4% as the crosslinking time increased from 20 h to 32 h. The robust mat with the high tensile strength of 4.62 MPa and 50% elongation at break was obtained at 24 h. The ion permeability of NO 3 − , Cl − , SO 4 2− were 94, 91 and 87%.

A lab scale structural reaction injection molding (S-RIM) piece of equipment was designed and used to fabricate glass fiber reinforced polydicyclopentadiene (p-DCPD) composites for three different fiber contents. In order to obtain information regarding the optimal process temperature (>80°C) and the curing time (<30 s), differential scanning calorimetry (DSC) was used to investigate the curing behavior of DCPD resin under isothermal conditions. Further, a norbornene-based silane treatment was used to improve the interfacial adhesion between the glass fibers and DCPD as confirmed by the micro-droplet pull-out test and scanning electron microscopy (SEM). Fabrication of glass fiber/p-DCPD composites with improved mechanical properties was carried out based on the optimized process conditions and surface treatment of glass fiber.

The present work in on the successive ionic layer adsorption and reaction (SILAR) mediated synthesis and study of variations in electrochemical behavior of PPy-Cu(OH) 2 hybrid electrodes with dip time. In the aqueous route preparation, 0.1 m pyrrole, 0.1 m CuSO 4 dissolved in acidified water (using 0.5 m H 2 SO 4 ) and H 2 O 2 (30 wt %) were used as initial ingredient sources. The peaks observed in the X-Ray diffraction (XRD) pattern of the electrode at 2θ =21.50 0 oriented along the <110> planes closely match with the peaks of Cu(OH) 2 as per JCPDS data card no. 42-0638 indicating the existence of triclinic Cu(OH) 2 in the hybrid. The characteristic peak at 1559 cm −1 in the Fourier transform infrared (FTIR) spectrum due to pyrrole ring vibrations confirms the existence of PPy in the hybrid. Energy-dispersive X-ray (EDX) analysis shows the occurrence of C, N, O and Cu in the electrode material which substantiates the formation of the hybrid. The scanning electron microscopy (SEM) images of electrodes with optimum dip time (20 s) in pyrrole show networks of interconnected nanostructures. The specific capacitance increases with the dip time in the source solutions. The electrode prepared with optimum dip time in pyrrole has produced the maximum values of specific capacitance (SC), specific energy (SE) and specific power (SP) as 127.04 F/g, 44.16 Wh/kg and 30 kW/kg, respectively, when analyzed in 0.5 m H 2 SO 4 . Impedance study of the electrode explains the mixed capacitive nature and the maximum values of solution resistance (R s ), charge transfer resistance (R ct ) and Warburg impedance (R w ) are 1.35 Ω, 143.4 Ω and 2.05 Ω, respectively.

Hybrid nanocomposites based on high-density polyethylene (HDPE)/poly (ethylene- co -vinyl alcohol) (EVOH)/clay were prepared and fully characterized. Morphological (WAXS and TEM), calorimetric (DSC), and dynamic mechanical thermal (DMTA) analyses were applied to investigate potential of nanocomposites as barrier against oxygen. Co-existence of ingredients of different nature, i.e. HDPE (general-purpose non-polar component), EVOH (engineering polar component with excellent barrier properties), nanoclay (planar one-dimensional mineral barrier nanofiller), and maleated HDPE (PE- g -MA) as coupling agent, brings about serious intricacies in view of interaction between existing phases. Conceptual/experimental analysis was performed to explore the interdependence between microstructure and oxygen barrierity of HDPE/EVOH/clay nanocomposites through the lens of interaction state in the system. Morphological measurements confirmed formation of an intercalated nanostructure, while investigations on complex viscosity, storage modulus, permeability, thermo-mechanical properties, and nanoclay interlayer galleries were all indicative of dependence of nanocomposites’ properties on molecular interactions. The performance of nanocomposite sheets as oxygen barriers was mechanistically explained.

In this work, PA-6 nanocomposites containing different amounts of nanoclay (NC) were prepared using a corotating twin-screw extruder. In practice, it is hard task to identify the relationship between the extrusion process parameters and the tensile modulus of PA-6 nanocomposites by performing several experiments. One approach to map the relationship between the process parameters and the tensile modulus of PA-6 nanocomposites is the use of a non-linear system identification tool called the adaptive-neuro fuzzy inference system (ANFIS). In this study, to achieve high modeling accuracy and generalization capability, an efficient shuffled frog leaping (SFL) algorithm is proposed to learn all the parameters of the network. A multi-input single-output (MISO) ANFIS model is constructed and learned to predict the tensile modulus of PA-6 nanocomposites. The ANFIS model is constructed, trained and tested based on a collection of experimental data sets. Acceptable agreement has been observed between the experimental results and the predicted results by the proposed model. The statistical quality of the proposed model is significant due to its good correlation coefficient R 2 values >0.98 between predicted values and experimental ones during the training and testing phase. Also, comparison results indicate the superior performance of the proposed scheme over the conventional reported methods due to its high approximation accuracy and good generalization capability.

A series of thermotropic liquid crystalline poly(amide imide)s (PAIs) with well-defined structure were prepared by the Yamazaki-Higashi phosphorylation method. To obtain the target polymers, several diimide diacid monomers (DIDAs) as mesogenic units were synthesized by the dehydration cyclization of aromatic anhydride with aliphatic 11-aminoundecanoic acid (AU). The chemical structure of these DIDAs and PAIs was confirmed via Fourier transform infrared (FTIR) and proton nuclear magnetic resonance ( 1 H-NMR) spectroscopy. Thermotropic liquid crystalline characteristics of the DIDAs and PAIs were investigated by differential scanning calorimetry (DSC), polarizing light microscopy (PLM) and X-ray diffraction (XRD) analysis. Encouragingly, all of these liquid crystalline PAIs exhibited good thermal stability, in which the decomposition temperatures are much higher than the melting temperatures of PAIs. Furthermore, the liquid crystalline PAIs can be dissolved into some common solvents such as dimethyl sulfoxide (DMSO) and m-cresol, which indicates these liquid crystalline PAIs could be processed not only by melting-processing but also by solution spin-coating.