Mechanical and Abrasive Wear Studies on Biobased Jatropha Oil Cake Incorporated Glass–Epoxy Composites

An investigation was made to evaluate the effect of the incorporation of jatropha oil cake (JOC) alone and in combination with silicon carbide (SiC) on the mechanical and tribological wear behaviour of glass fabric–epoxy (GE) composites. A vacuum-assisted resin transfer moulding (VARTM) technique was employed to obtain a series of GE composites containing different fillers viz., silicon carbide, jatropha oil cake and a mixture of SiC and JOC. The effect of different loads (22 and 32 N) and abrading distances from 135 to 540 m on the performance of the wear resistance of the composites were measured. The mechanical properties such as tensile behaviour and hardness of the composites were evaluated. A linear relationship was found between the wear volume loss and the abrading distances. The JOC filled GE composite exhibited a lower specific wear rate by 6 and 10% at 540 m abrading distance for a load of 22 and 32 N, respectively, as compared to that of unfilled GE composites. The worn surface features of unfilled and filled GE composites were examined using scanning electron microscopy (SEM).     

Investigation on microstructural behavior of styroflex/polyaniline blends by WAXS

Styroflex/polyaniline (STF/PAni) blends were prepared by two routes namely by in situ and thermo mechanical processing method with various PAni compositions, namely, 0, 15, 30, and 45 wt %. The influence of volume fraction of PAni in the blends and synthetic routes of the STF/PAni blends on the volume resistivity and microcrystalline parameters have been investigated. The microcrystalline parameters such as the nanocrystal size (<N>), lattice disorder (g), interplanar distance (d_hkl), width of the crystallite size distribution, surface weighted crystal size (D_s), and crystallite area were evaluated from the wide angle X‐ray scattering profiles. The different asymmetric column length distribution functions namely, exponential, reinhold, and lognormal distribution methods were employed to probe the microcrystalline behavior of the STF/PAni blends and the results are compared. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Poly(acrylamide/laponite) nanocomposite hydrogels: Swelling and cationic dye adsorption properties

Super adsorbent polyacrylamide (PAAm)/nanoclay (laponite, Lap) hydrogels were prepared by in situ free radical polymerization of AAm in an aqueous solution with clay as a crosslinker. The swelling properties and water‐soluble cationic dye adsorption behaviors of the PAAm/laponite (PAAm/Lap) nanocomposite (NC) hydrogels were investigated. The parameters of swelling and diffusion of water in dye solutions were evaluated for the PAAm/Lap NC hydrogels. The adsorption behavior of the monovalent cationic dyes such as Basic Blue 12 (BB 12), Basic Blue 9 (BB 9), and Basic Violet 1 (BV 1), were studied on the NC hydrogels. The effects of the clay content of the hydrogel on its cationic dye uptake behavior were studied. The adsorption studies indicated that the rates of dye uptake by the NC hydrogels increased in the following order: BB 9 > BB 12 > BV 1. This order is similar to the swelling results of the PAAm/Lap NC hydrogel in the dye solutions. The equilibrium uptakes of the different dyes by the PAAm/Lap NC hydrogel were nearly the same. In the dye absorption studies, S‐type adsorption in the Giles classification system was found for the BB 12 and BV 1 dyes, whereas L ‐type was observed for the BB 9 dye. After the heat treatment of PAAm/Lap, the rate of dye uptake and equilibrium dye uptake were increased. The NC hydrogels may be considered as a good candidate for environmental applications to retain more water and to remove dyes. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Studies on miscibility of polyacrylamide/polyethylene glycol blends

Miscibility studies have been conducted on solutions of blends of polyacrylamide (PAAm) and polyethylene glycol (PEG) over an extended range of concentrations in water. The ultrasonic velocity, viscosity, density, and refractive index of the blends have been measured for different compositions viz., 0/100, 10/90, 20/80, 30/70, 40/60, 50/50, 60/40, 70/30, 80/30, 90/10, and 100/0 of PAAm/PEG blends at 30°C. The interaction parameters such as μ and α have been evaluated using the viscosity data to probe the miscibility. The obtained results have been confirmed by the ultrasonic velocity, density, and refractive index. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2048–2053, 2007     

Influence of curing agent and compatibilizer on the physicomechanical properties of polypropylene/nitrile butadiene rubber blends investigated by positron annihilation lifetime technique

A series of thermoplastic vulcanizates of polypropylene (PP)/nitrile butadiene rubber (NBR) (50/50) have been prepared by melt‐mixing method, using phenolic resin/SnCl₂ as the curing system and maleic anhydride‐functionalized PP (PP‐g‐MA) and carboxylated NBR (NBRE‐RCOOH) as the compatibilizing system. Triethylenetetramine was also employed to promote the reaction between the functionalized polymers. The effects of curing agent and compatibilizer on the mechanical and morphological properties have been studied. A novel technique based on positron annihilation lifetime spectroscopy has been used to measure the free volume parameters of these systems. The positron results showed minimum free volume size and free volume fraction at 5.0% of the curing agent suggesting some crosslinking in the rubber phase. The reduction in free volume holes at 2.5% of the compatibilizer is interpreted as improvement in the interfacial adhesion between the components of the blend. The observed variation of free volume fraction is opposite to the tensile strength and exhibits the correlation that, lesser the free volume more is the tensile strength at 2.5% of the compatibilizer in the blend. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4672–4681, 2006     

Synthesis and characterization of ethylene vinyl‐acetate/polyaniline blends prepared by emulsion polymerization technique

A series of ethylene vinyl acetate‐polyaniline (98/02, 95/05, 93/07, … … 50/50) (EVA‐PAni) blends were prepared by the emulsion polymerization technique and made into sheets by the compression molding at 150°C. These sheets were characterized by electrical, physico‐mechanical, thermal, X‐ray and morphological studies. All electrical properties of EVA‐(PAni)_TSA blends increased with an increase in PAni content. The conductivity, dielectric constant and tan δ values increased from 1.34 × 10^?14 to 2.89 × 10^?2 S/cm, from 2.113 to 19.845, from 0.094 to 4.789. Tensile strength increased with an increase in PAni content up to 7% and drastically decreased above 15%, while the percentage elongation at break decreased with an increase in PAni content. TGA studies revealed that the thermal stability of PAni improved after blending with EVA. EVA‐PAni blends were found stable up to 110°C. X‐ray diffractograms of EVA‐PAni blend showed an intense peak at 26° (2θ), reflecting the influence of EVA crystallinity. Scanning electron micrographs confirmed the two‐phase morphology of the system.     

Electrical,physicomechanical, and X‐ray studies on ethylene‐vinyl acetate copolymer/polyaniline blends

The conductive blend consisting of ethylene‐vinyl acetate (EVA) and a polyaniline/p‐toluene sulfonic acid (PAn/TSA) complex were prepared by a thermal doping process using a Brabender plasticorder at 150°C. The conductivity, dielectric constant, dissipation factor, mechanical behavior, and structural aspects of these blends were investigated. A higher percentage of the PAn/TSA complex in the EVA matrix resulted in an increase in the electrical properties and a decrease in the mechanical properties like the tensile strength and percentage of elongation. These results were compared with the microcrystalline parameters of the blend obtained from X‐ray profile analysis. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1730–1735, 2002     

Investigation on Sliding Wear Behaviour and Mechanical Properties of Jatropha Oil Cake-Filled Glass-Epoxy Composites

The effect of Jatropha oil cake (JOC) filler incorporation into glass fabric-epoxy (G-E) composites and its sliding wear and mechanical properties were evaluated. The sliding distance and applied load are the process parameters at constant sliding velocity. The results show that JOC-filled composites exhibit better sliding wear performance at all test conditions. The wear loss increases with an increase in sliding distance and applied load, whereas under the same conditions, the specific wear rate decreases. The operating wear mechanisms have been studied at higher and lower sliding distances at applied loads of 10 and 20 N by using scanning electron microscope (SEM). The SEM results indicate more severe damage to matrix and glass fibre in unfilled composite systems compared to JOC-filled composite.     

Free volume and the physico‐mechanical behaviour of polyurethane/polyacrylonitrile interpenetrating polymer networks: positron annihilation results

A series of semi‐interpenetrating polymer networks (SIPNs) of polyurethane (PU) and polyacrylonitrile (PAN) in the weight ratios 90/10, 70/30, 60/40 and 50/50 PU/PAN were prepared using polyethylene glycol, 4,4′‐diphenylmethane diisocyanate and acrylonitrile by sequential polymerization. Differential scanning calorimetry and scanning electron microscopy techniques were used to find the glass transition temperature and surface morphology of SIPNs. The tough and transparent SIPN films were characterized for physico‐mechanical properties such as density, surface hardness and tensile properties. Positron annihilation lifetime spectroscopy (PALS) was used to measure the free volume behaviour of the IPNs. The sorption behaviour of IPNs with benzene penetrant was also measured. An attempt was made to correlate the PALS results with the mechanical and sorption properties of the SIPNs. Copyright © 2005 Society of Chemical Industry