Browsing by Author "Church, JS"

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    Dispersing single-walled carbon nanotubes in ionic liquids: a quantitative analysis
    (Royal Society of Chemistry, 2013-08-15) Hameed, N; Church, JS; Salim, NV; Hanley, TL; Amini, A; Fox, BL
    The efficiency of various ionic liquids, specifically the 1-butyl-3-methylimidazolium tetrafluoroborate, hexafluorophosphate, chloride and dicyanamide salts, in dispersing single walled carbon nanotubes has been examined. The SWCNTs were dispersed in the ILs at varying concentrations by grinding. All of the ILs were found to be effective dispersants for nanotubes and quantitative evidences including X-ray scattering, Raman spectroscopy and UV-visible spectroscopy unambiguously showed that BMIM[BF4] is the most efficient IL while BMIM[DCA] is the least effective IL. A quantitative analysis of the interactions between SWCNTs and ionic liquids by analyzing their scattering and spectral features is put forth.© 2013, The Royal Society of Chemistry.
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    Effects of thermal denaturation on the solid-state structure and molecular mobility of glycinin
    (American Chemical Society, 2011-06-01) Huson, MG; Strounina, EV; Kealley, CS; Rout, MK; Church, JS; Appelqvist, IAM; Gidley, MJ; Gilbert, EP
    The effects of moisture and thermal denaturation on the solid-state structure and molecular mobility of soy glycinin powder were investigated using multiple techniques that probe over a range of length and time scales. In native glycinin, increased moisture resulted in a decrease in both the glass transition temperature and the denaturation temperature. The sensitivity of the glass transition temperature to moisture is shown to follow the Gordon-Taylor equation, while the sensitivity of the denaturation temperature to moisture is modeled using Flory's melting point depression theory. While denaturation resulted in a loss of long-range order, the principal conformational structures as detected by infrared are maintained. The temperature range over which the glass to rubber transition occurred was extended on the high temperature side, leading to an increase in the midpoint glass transition temperature and suggesting that the amorphous regions of the newly disordered protein are less mobile. C-13 NMR results supported this hypothesis. © 2011, American Chemical Society
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    Enhanced mechanical performance of CNT/polymer composite yarns by γ-irradiation
    (Springer Nature, 2014-02-22) Cai, JY; Min, J; Miao, MH; Church, JS; McDonnell, J; Knott, RB; Hawkins, S; Huynh, C
    Multiwall carbon nanotube (CNT) spun yarns were subjected to γ-irradiation in an oxygen rich environment, followed by the application of epoxy to form CNT/epoxy composite yarns with a high CNT fraction. The method for fabrication of the CNT/polymer composite yarns was presented, and the effect of γ-irradiation on the mechanical performance of the pure CNT spun yarns and their epoxy composite yarns were studied. The γ-irradiated CNT yarns were also characterized by X-ray Photoelectron Spectroscopy and Raman spectroscopy. The results of this study have demonstrated that the γ-irradiation is an effective micro-engineering tool to improve mechanical properties of the CNT spun yarn and its epoxy composite yarn. © 2020 Springer Nature Switzerland AG
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    Reconstitution properties of micellar casein powder: effects of composition and storage
    (Elsevier, 2011-11-01) Schokker, EP; Church, JS; Mata, JP; Gilbert, EP; Puvanenthiran, A; Udabage, P
    A problem associated with micellar casein (MC) powders is their poor reconstitution properties. In this study, we prepared MCs with different salt and protein compositions and having different reconstitutabilities directly after production. Reconstitutability further decreased during storage at 30 degrees C. Differential scanning calorimetry, infrared spectroscopy, and small angle X-ray scattering showed that the powders were very similar on a molecular or sub-micellar level, indicating that the loss of reconstitutability is probably controlled by higher order structural changes, such as cross-linking between casein micelles, possibly involving intermolecular beta-sheet formation. The reconstitutability of MC could be improved by adding sodium caseinate to the concentrated milk before spray drying. This novel approach to improve reconstitutability can easily be incorporated into the existing processing protocol. We propose two possible mechanisms for the protecting effect of the non-micellar caseins.(C) 2011 Elsevier Ltd. All rights reserved.