Polyaniline (PANI) in its doped state with dodecyl benzene sulphonic acid (DBSA) blended with polycarbonate and Polycarbonate/Acrylonitrile Butadiene Styrene (PC/ABS) in Chloroform were compression molded and their electrical conductivity measured. Other commodity fillers like carbon black (CB), graphite (GRA) and Carbon fibers (CF) are used to study the conductivity variation in the composite. Effects of loading levels of conductive fillers on the electrical conductivity and morphology of the blends were investigated. The DC electrical conductivity of the composites were measured employing Keithley 6221/2812A instrument and the conductivity ranges from 0.3 to 6.02 S/cm with different proportions of PANI – DBSA, MWCNTs and other filler fraction in the composites. Electrical conductivity of these composites were PANIDBSA-MWCNT > PANI-DBSA> PC-PANI-DBSA-CNT>PC-PANI-DBSA-MWCNT-CB/CF/Graphite in the conductive blend. Conductive filler of ~30 % loading showed an shielding electrical conductivity values much closer to unblended DBSA doped PANI (3 to 6 S/cm) which makes these conducting composites potential candidates as EMI shielding material for encapsulation of electronic circuits in high technological applications and transparent electrode materials in multijunction solar cells. This high electrical conductivity of the composites could be attributed to the electronic interactions between quinonoid ring of PANI and the MWCNTs and the connectivity created by the compatibilization effect of dodecyl benzene group with other fillers and the PC or PC/ABS matrix. To ensure the reproducibility of the doping procedure PANI is doped with DBSA in water and the electrical conductivity is measured. Literature value of 10.34 S/cm was reproduced.

Cadmium Sulphide nanostructures are prepared with new sol gel route by direct reduction of sulpher and its reaction with cadmium chloride in the sol. The sol was consisting of non aqueous mixture of cadmium chloride, thiourea and complexed by TEA. The solution was stirred well and heated to about 60 oC for one hour and kept for another 24 hours at sufficiently lower temperature to initiate the reaction. Green yellowish gel was obtained and characterized by optical spectrophotometer. The step like nature in transmission and band gap curves could be due to discrete energy levels in nanomaterials. To obtain the films the CdS paste was screen printed on glass substrate and annealed at 300 oC for few hours. Optical studies suggest that, the CdS particles are either of thickness of few nanometer range and/or grain size of nanometer range. This paper includes details about new sol gel technique and optical characterization of particles and films.

This paper presents a study on the properties of rice husk ash (RHA) cement composite mortars incorporating nano-SiO2. Different amounts of nano-SiO2 (0%, 1%, 3% and 5%) were incorporated into the mortars with 20% replacement of RHA. The compressive and flexural strengths of mortars were tested at 7, 28, 60 and 90 days. The water absorption test was carried out at 28 days. The drying shrinkage of mortars was measured up to the age of 42 days. Scanning electron microscopy (SEM) observation was conducted to evaluate the effect of nano-SiO2 on microstructure of cement paste containing RHA. Incorporating nano-SiO2 into RHA mortars significantly improved the mechanical strength and water absorption properties of the products. Nano-SiO2 increased the drying shrinkage of RHA mortars. SEM analysis showed that nano-SiO2 improved the microstructure of RHA pastes.