Polymer blends, 3. Preparation and evaluation of the blends of shellac with polyamideimide from rosin

Polymer blends were prepared from shellac and polyamideimide. The polyamideimide was synthesized by reacting rosin maleic anhydride Diels-Alder adduct with 4,4′-diamino diphenylmethane. The compatibility of these blends was studied by solubility parameter, heat of mixing data, solution viscosity, and differential scanning calorimetry. It was found that the composition of 40 : 60, shellac : polyamideimide produces a compatible blend. The thermal behaviour of the blends was investigated.     

Preparation and characterization of heat,oil and fire resistant (HOFR) cable sheathing compounds from compatibilized polychloroprene-ethylene-propylene-diene rubber blends

Preparation of heat, oil and fire resistant (HOFR) cable sheathing compounds is attempted by blending polychloroprene (PCP) and ethylene-propylene-diene terpolymer (EPDM) using dibutyl maleate grafted EPDM (EPDMgDBM) and chlorinated polyethylene (CPE) as compatibilizer. Cure rate incompatibility has been minimised by adding the curing agents in masterbatch form. Curing characteristics of the blends have been determined by Monsanto Rheometer and Brabender Plasticorder. Morphology of the blends and compatibility have been studied by scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). Thermal properties of the blends have been characterized by ageing studies. The optimized blends, after modification with suitable fillers and other ingredients, possess better properties than the control PCP-compound and meet the specification BS 6899-84.     

Polarization‐independent liquid‐crystal‐etalon modulator

Abstract— The experimental demonstration of a polarization‐independent high‐transmission field‐sequential liquid‐crystal‐etalon modulator for portable projection‐display application is presented. Polarization independence allows for high transmission efficiency for laser illumination sources using the polarization diversity method of speckle reduction. These devices can also be considered for LED illumination sources; however, the spectral width of current LEDs does not allow for high efficiency, especially for the green channel. These devices demonstrate millisecond switching needed for field‐sequential‐color generation.     

Fabrication of anodically electrodeposited iridium oxide film pH microelectrodes for microenvironmental studies

A new method for fabrication of anodically electrodeposited iridium oxide film pH microelectrodes has been developed in this study. Novel for its tip size (3-10-microm tip diameter), the microelectrode is fabricated in a tapered glass micropipet filled with a low melting point alloy. The tapered end is recessed and platinized. Thereafter, iridium oxide is electrodeposited over the platinized end in the recessed part. The microelectrode has a very short response time (t80 < 5 s) in the pH range of 0-12 with an accuracy of 0.05 pH unit. The pH microelectrode is not affected by most ions and complexing agents of relevance in environmental and biological studies; it can be used in fluids over wide ranges of stirring speeds (0-55 rpm) and temperatures (approximately 5-40 degrees C). Redox agents such as dissolved oxygen and hydrogen peroxide have no effect on the pH response while quinhydrone, ferro- and ferricyanide, and sodium sulfide have marked effects. However, the microelectrode can still be used in any sample when calibration is done in standards having similar redox characteristics.     

Kinetics of silane grafting and moisture crosslinking of polyethylene and ethylene propylene rubber

Peroxide initiated graft copolymerization of vinyl trimethoxy silane (VTMO) and vinyl triethoxy silane (VTEO) onto polyethylene (PE) and ethylene propylene copolymer (EPR) was studied. The kinetics of grafting, studied by differential scanning calorimetry, are the same for all the systems and the activation energy for VTMO is 170 ± 4 KJ/mol. Activation energy for VTEO is 185 ± 5 KJ/mol. The VTMO and VTEO graft copolymers of PE and EPR were prepared by reactive processing in a Brabender extruder in the temperature range of 150–200°C. Moisture catalyzed crosslinking of the silane grafted copolymer was also studied. The influence of the structure of the catalyst, its concentration, moisture concentration, temperature, and time on degree and rate of crosslinking has been evaluated. Crosslinking reactions follow first order kinetics with respect to both catalyst and moisture concentration. Activation energy (E_a) of the crosslinking reaction has been determined as 65 KJ mol^?1. The mechanism of grafting and crosslinking is discussed.     

Modeling of steam–water direct contact condensation using volume of fluid approach

Direct contact condensation (DCC) of steam in subcooled water has paramount importance in many heat transfer devices in different industrial areas like nuclear, thermal, chemical plants. This work aims at the exploration of underlying physics of steam–water DCC in two dimensions using ANSYS FLUENT 14.5. The volume of fluid method is utilized for performing direct simulation of the phenomenon at the phase interface. In this work, thrust is given on the modeling of the interphase heat transfer using interfacial jump approach instead of proposed empirical correlations which have different applicability limits. User-defined functions in the FLUENT software are used for evaluating the interfacial mass transfer rate, thermal gradient across the phase interface, and interface curvature. This study also emphasizes on the prediction of transient temperature field and interface characteristics under different parametric conditions (e.g., variation of water injection velocity and water temperature). Observation reveals that the present condensation model is capable of capturing the transient temperature history as well as the flow regime transition (stratified to slug flow) induced by the interfacial instability.