A commercially available polyimide fiber was investigated as a possible precursor for the formation of carbon fibers. The
thermal response of the fiber was thoroughly investigated using DSC, TMA and TG. These responses were dependent on the atmosphere
and tension during scanning. The fiber was stabilized at high temperatures both in inert and oxidative environments and the
effect of these stabilization treatments on the structure and properties of the fiber was carefully followed. During heating,
the fiber showed shrinkage tendency at small tensions, but at higher tensions the fibers could be stretched. Among the two
environments investigated, air was more effective than nitrogen in getting a more stable fiber.
Authors:D. Zhang, G. Bhat, S. Malkan, and L. Wadsworth
Polypropylene homopolymer (PP) and a copolymer (P/E) were processed using the Reicofil® spunbonding line at the Textiles and
Nonwovens Development Center of the University of Tennessee, Knoxville. The properties of the filament samples taken before
thermal-bonding were determined through a variety of techniques such as differential scanning calorimetry, thermomechanical
analysis, thermal deformation analysis and mechanical properties. The two process variables investigated, primary air temperature
and throughput had a strong influence on the structure and properties of both the filaments and the bonded nonwovens. As the
primary air temperature and throughput decreased, there was a tendency for decrease in filament diameter with a simultaneous
increase in their crystallinity, birefringence and thermal stability. The copolymer filaments showed lower crystallinity and
orientation for all the corresponding processing conditions.
Authors:C. Ravindra Reddy, S. Ramesh, Y. Bhat, G. Nagendrappa, and B. Jai Prakash
Different metal ion-exchanged montmorillonite based clay catalysts (Mn+-mont; Mn+ = Al3+, Fe3+, Cr3+, Zn2+, Ni2+, Mn2+, Cu2+ and H+) were prepared and characterized by various physico-chemical techniques. The clay catalysts were evaluated for the esterification
of propionic acid with p-cresol. Our DRIFTS (Diffuse Reflectance Infrared Fourier Transform Spectroscopy) study of the catalysts treated with propionic
acid supported the very well established mechanism of esterification. Furthermore, the esterification was conducted in the
presence of different solvents such as benzene, toluene, o-xylene and 1,4-dioxane. Interestingly, the reaction carried out in the presence of 1,4-dioxane did not yield any product.
The role played by this specific solvent in preventing the formation of ester product has been investigated by DRIFTS study
involving catalyst and solvent interaction.
Authors:N. Sinha, V. Priyanka, K.T. Ramya, T. Leena, J.A. Bhat, Harikrishna, N. Jain, P.K. Singh, G.P. Singh, and K.V. Prabhu
Abiotic stresses are major constraints to wheat productivity in many parts of the world. Tolerance to abiotic stresses can be achieved indirectly by selection for morpho-physiological traits. Physiological trait based breeding has been associated with improved performance under stress; and hence can combat and adapt wheat to drought and heat stress. Therefore, in the present study, phenotyping was carried out for agro-physiological traits in 52 diverse wheat germplasm lines under timely sown, rainfed and late sown environments for two years. Mean yield of the genotypes over the six environments were positively correlated with NDVI, days to maturity and negatively correlated with canopy temperature. The phenotypic data validated marker-trait associations of a number of meta-QTLs identified earlier for different physiological and agronomic traits. Six and seven meta-QTL genomic regions were found to be consistent in their expression for two years under rainfed/restricted irrigation and late sown environments, respectively. Expression analysis of the underlying candidate gene AK248593.1 in meta-QTL26 region revealed two folds higher expression in the NILs carrying the co-localized SSR markers. The linked markers of the thirteen meta-QTL regions associated with different traits can be used for effective transfer of the QTLs through marker assisted selection in wheat breeding programmes.