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Tiruvalla, India

Thomas R.,Mar Thoma College | Boudenne A.,University Paris Est Creteil | Ibos L.,University Paris Est Creteil | Candau Y.,University Paris Est Creteil | Thomas S.,Mahatma Gandhi University
Journal of Applied Polymer Science | Year: 2010

Thermal conductivity and diffusivity of carboxyl-terminated copolymer of polybutadiene and acrylonitrile (CTBN) and hydroxyl-terminated polybutadiene (HTPB) liquid rubber- modified epoxy blends were investigated. A good agreement was observed between the calculated values of the specific heat estimated from thermal conductivity, diffusivity, and density measurements and the DSC results. Measurements of the thermal conductivity values of HTPB/Epoxy blends were in good agreement with three simple theoretical models, which have been used thereafter for the estimation of the unknown value of the thermal conductivity of CTBN (kCTBN = 0.24 Wm-1K-1). The morphology of the rubber-modified epoxy blends has been quantified and indicate a tendency towards co-continuous phase upon the inclusion of higher weight percentage of rubber (-30 wt %). Moreover, we notice a significant enhancement of the thermal conductivity during this morphological shift. © 2010 Wiley Periodicals, Inc. Source

Parameswaranpillai J.,Cochin University of Science and Technology | Joseph G.,Cochin University of Science and Technology | Chellappan R.V.,Cochin University of Science and Technology | Zahakariah A.K.,Mar Thoma College | Hameed N.,Deakin University
Journal of Polymer Research | Year: 2015

Polypropylene (PP) and polystyrene (PS) blends were prepared by melt processing in a haake at 180 °C. PP/PS blends are immiscible and the blend morphologies were characterized by scanning electron microscopy. The viscoelastic properties were characterized using dynamic mechanical analysis (DMA) with reference to blend ratio. The blend morphologies such as matrix droplet and phase inverted morphologies were observed. The storage modulus of the blends increased with increase in PS content and the value was maximum for neat PS. DMA showed changes in the polystyrene glass transition temperatures (Tg) over the entire composition range. There was a sharp increase in the Tg of PS with increasing PP content in the blend and a 12 °C elevation in Tg was observed. The increase in Tg was explained by proposing a new model based on the physical interaction between the blend components. It is assumed that the different effects by the PP phase resulted in the formation of constrained PS chains leading to high Tg values. The addition of PP-g-MAH has a positive effect on the morphology, increases the storage modulus, and decreases the Tg till 80/20 blends. However, for PP/PS blends with higher concentrations of PS, the PP-g-MAH has little effect or adverse effect on the morphology, and storage modulus, but decreases the Tg. © 2015, Springer Science+Business Media Dordrecht. Source

Idicula M.,Mar Thoma College | Joseph K.,SB College | Thomas S.,Mahatma Gandhi University
Journal of Reinforced Plastics and Composites | Year: 2010

Short randomly oriented banana and sisal hybrid fiber reinforced polyester composites, banana/polyester composites and sisal/polyester composites were fabricated at different fiber loading say, 0.20 to 0.50 Vf. Composites were prepared by varying the relative volume fraction of the two fibers at each fiber loading. When the fiber loading was increased; tensile, flexural, and impact properties increased. Better performance was shown by composites having volume fraction, 0.40 Vf. Tensile strength, tensile modulus, flexural strength, and flexural modulus showed a positive hybrid effect when the volume ratio of the fiber was varied in the hybrid composites at each fiber loading. Maximum tensile strength was observed in composites having volume ratio of banana and sisal 3:1. When the volume ratio of sisal was increased, the impact strength of the composite increased. Different layering patterns were tried at 0.40 Vf, keeping the volume ratio of fibers 1:1. Tensile properties were slightly greater in the trilayer composite with banana as the skin material. Bilayer composites showed higher flexural and impact property. SEM studies were carried out to evaluate fiber/matrix interactions. Experimental results were compared with theoretical predictions. © 2010 SAGE Publications. Source

Moinuddin M.K.,Osmania University | Bagyanarayana G.,Osmania University | Thomas J.,Mar Thoma College
Research Journal of Pharmaceutical, Biological and Chemical Sciences | Year: 2016

Warangal district is located at 18.0°N 79.58°E, occupies an area of 12,846 square kilometres with one-fourth of the geographical area under forests, this region is very useful for forest management and biodiversity conservation, types of forests are dry deciduous and moist deciduous mixed forests with a few evergreen species, there are two Wild Life Sanctuaries they are Pakhal Wild Life Sanctuary and Eturnagaram Wildlife Sanctuary. Eturnagaram wild life sanctuary is located near the Maharashtra, Madhya Pradesh and Andhra Pradesh border. It is one of the oldest sanctuary in Telangana state. Such kind of forest least explored for microfungi excepting the sporadic works on mycorrhizal fungi, rusts, powdery mildews and hyphomycetes. Hence, we have taken an interest in the identification and documentation of black mildews of foliicolous fungi occurring on the forests plants of Pakhal and Eturnagaram wild life sanctuaries regions of warangal district of Telangana state. The black colonies of these fungi increase the temperature of the infected parts and cause physiological imbalance in the entire leaves. They decrease the photosynthetic efficiency of the plants, affect the hormonal and phenolic compound levels. This paper includes an account of an interesting black mildew micro fungus collected from Eturnagaram wild life sanctuary Telangana state. Microscopic study of the fungus revealed it to be hitherto undescribed species. Hence, it is taxonomically described as new to science belonging to the genus Asterina, namely Asterina maeruaicola sp. nov. Source

Varghese H.T.,Fatima Mata National College | Mariamma K.C.,M E S College | John K.,Mar Thoma College | Mathew S.,Mar Thoma College | And 3 more authors.
Journal of Raman Spectroscopy | Year: 2010

The Fourier transform Raman(FT-Raman)and Fourier transform infrared (FT-IR) spectraof2-[acetyl(4-bromophenyl)carbamoyl]-4-chlorophenyl acetate were studied. The vibrational wavenumbers were examined theoretically using the Gaussian03 set of quantum chemistry codes, and the normal modes were assigned by potential energy distribution (PED) calculations. The simultaneous Raman and infrared (IR) activations of the C=O stretching mode in the carbamoylmoiety show a charge transfer interaction through a π-conjugated path. From the optimized structure, it is clear that the hydrogen bonding decreases the double bond character of the C=O bond and increases the double bond character of the C-N bonds. The first hyperpolarizability and predicted IR intensities are reported. The calculated first hyperpolarizability is comparable with the reported values of similar structures, which makes this compound an attractive object for future studies of nonlinear optics.Optimized geometrical parameters of the compound are in agreement with similar reported structures. © 2009 John Wiley & Sons, Ltd. Source

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