Finger millet is one of the important minor cereals, and carbohydrates form its major chemical constituent. Recently, the millet is processed to prepare hydrothermally treated (HM), decorticated (DM), expanded (EM) and popped (PM) products. The present research aims to study the changes in the microstructure of carbohydrates using X-ray diffraction and scanning electron microscopy. Processing the millet brought in significant changes in the carbohydrates. The native millet exhibited A-type pattern of X-ray diffraction with major peaks at 2θ values of 15.3, 17.86 and 23.15°, whereas, all other products showed V-type pattern with single major peak at 2θ values ranging from 19.39 to 19.81°. The corresponding lattice spacing and the number of unit cells in a particular direction of reflection also reduced revealing that crystallinity of starch has been decreased depending upon the processing conditions. Scanning electron microscopic studies also revealed that the orderly pattern of starch granules changed into a coherent mass due to hydrothermal treatment, while high temperature short time treatment rendered a honey-comb like structure to the product. However, the total carbohydrates and non-starch polysaccharide contents almost remained the same in all the products except for DM and EM, but the individual carbohydrate components changed significantly depending on the type of processing.

A series of polyethylene oxide (PEO)/starch blends were prepared by extrusion and their films were prepared by compression molding. It was observed that the presence of characteristic peaks of PEO and starch at 845 and 1643.7 cm À1 , respectively, in FTIR spectra of PEO/starch blends favors the blending of PEO/starch. The physicomechanical and optical properties of PEO/starch-blended films were measured. The tensile strength of the blended films decreased, whereas the haze values increased with an enhanced starch concentration in PEO/starch blends. The results obtained were correlated with microstructural parameters such as, crystallite size and lattice strain determined using wide angle X-ray scattering (WAXS) data. The X-ray line profile analysis shows that the crystallite shape area is maximum in PEO and decreases with the addition of starch.

Polyaniline doped with dodecylbenzene sulfonic acid and conductive carbon black (PAn.DBSA/ CB) hybrid materials have been prepared by in situ polymerization. The electrical resistivity of the PAn/CB was measured as a function of CB. The minimum resistivity was noticed for the composites with 25 wt % of CB as compared to other systems. Small angle x-ray diffraction data was used to characterize the molecular arrangements of these composites. The refinement parameters such as periodicity (L), phase lengths ( and ), phase ratio (/), and probability distribution of phases [c Z (crystalline), c Y (amorphous)] for PAn, CB, and PAn/CB composites have been measured by SAXS data. It was observed that there is decrease in the crystallinity with increase in CB content in the composites.

Polymer blending is an effective method for providing desirable polymeric materials with properties useful for the packaging industry. In the study reported, blends of chitosan/poly(ethylene oxide) (PEO) were prepared in various weight ratios with and without glycerol. Line profile analysis of the X‐ray diffraction patterns of these blended films was carried out. Microstructural parameters such as crystallite size and lattice strain were determined using paracrystalline modelling of X‐ray data. These values were correlated with physico‐mechanical and optical properties of the chitosan/PEO blends with and without glycerol to understand the holistic behaviour of the blends. Two prominent Bragg reflections at 2θ ≈ 19° and 23° were observed in the wide‐angle X‐ray diffraction patterns of the glycerol‐based chitosan/PEO blended films of various ratios. Interruption of PEO crystallization with chitosan results in an amorphous polymer network and hence a reduction in crystallite size by almost 97.7%. For glycerol‐based blends, the crystallite size/area decreases to 94.4% of the virgin crystallite size. The X‐ray profile analysis supports the results for the physico‐mechanical properties of the blends. The results show that the addition of 20 wt% of glycerol results in an increase of the elongation at break by more than 150%, meaning that these chitosan/PEO films could be applied in flexible packaging. Copyright © 2010 Society of Chemical Industry

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