Faculty Publications

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    Miscibility studies of starch and poly(4-styrene sulfonic acid) blend system
    (Sphinx Knowledge House info@sphinxsai.com, 2014) Sudhakar, Y.N.; Bhat, D.; Muthu, M.
    Polymeric solutions were prepared using blends of starch with poly(4-styrene sulfonic acid) (PSSA) in water and their miscibility was determined by viscosity studies at 30 °C, 40 °C and 50 °C. Using interaction parameters such as Krigbaum’s (?b), Hong’s (?kAB), Chee’s (?), Sun’s (?), polymer-polymer, blend-solvent and heat of mixing there was the existence of positive interactions in the blend polymer solutions only up to 80% PSSA content. A significant variation of miscibility was observed with increase in temperature in the sample containing 70% PSSA content. Polymer blend films obtained by solution casting showed hydrogen bonding in Fourier transform infrared (FTIR) studies. Differential thermal analysis (DTA) and thermogravimetric analysis (TGA) studies also supported the results. A uniform surface of the miscible blend films were observed in scanning electron microscopy images, whereas segregation was observed for the immiscible blends. © 2014, Sphinx Knowledge House. All Rights Reserved.
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    Revealing the Structural Organization of Gamma-irradiated Starch Granules Using Polarization-resolved Second Harmonic Generation Microscopy
    (Oxford University Press, 2023) Chen, M.-C.; Govindaraju, I.; Wang, W.-H.; Chen, W.-L.; Mumbrekar, K.D.; Mal, S.S.; Sarmah, B.; Baruah, V.J.; Srisungsitthisunti, P.; Karunakara, N.; Mazumder, N.; Zhuo, G.-Y.
    Starch is a semi-crystalline macromolecule with the presence of amorphous and crystalline components. The amorphous amylose and crystalline amylopectin regions in starch granules are susceptible to certain physical modifications, such as gamma irradiation. Polarization-resolved second harmonic generation (P-SHG) microscopy in conjunction with SHG-circular dichroism (CD) was used to assess the three-dimensional molecular order and inherent chirality of starch granules and their reaction to different dosages of gamma irradiation. For the first time, the relationship between starch achirality (χ21/χ16 and χ22/χ16) and chirality (χ14/χ16) determining susceptibility tensor ratios has been elucidated. The results showed that changes in the structure and orientation of long-chain amylopectin were supported by the decrease in the SHG anisotropy factor and the χ22/χ16 ratio. Furthermore, SHG-CD illustrated the molecular tilt angle by revealing the arrangement of amylopectin molecules pointing either upward or downward owing to molecular polarity. © 2023 Cambridge University Press. All rights reserved.