Please use this identifier to cite or link to this item: https://ir.swu.ac.th/jspui/handle/123456789/15175
ชื่อเรื่อง: Structural change and moisture sorption behavior of DL-valine induced by grinding
ผู้แต่ง: Moribe K.
Piyarom S.
Tozuka Y.
Yonemochi E.
Oguchi T.
Yamamoto K.
Keywords: liquid nitrogen
valine
water
article
crystal structure
crystallization
dehydration
grinding
humidity
hydrogen bond
infrared spectroscopy
low temperature
moisture
proton nuclear magnetic resonance
vibration
water absorption
water vapor
X ray powder diffraction
วันที่เผยแพร่: 2003
บทคัดย่อ: Structural change of DL-valine crystals induced by grinding and the moisture sorption behavior were investigated. DL-valine crystals were ground using a vibrational mill under liquid nitrogen flow. Decrease in crystallinity of DL-valine, concurrently with shift of the X-ray powder diffraction peaks of lattice planes (020) and (040) to the lower diffraction angles were observed with increasing grinding time. The intact DL-valine crystals took up less than O.1% of moisture content, while ground samples showed characteristic water vapor sorption isotherms. After humidifying the 30-min ground sample with 82% RH at 40°C, the crystallinity of the sample was increased and the diffraction peaks due to planes (020) and (040) were shifted back to the angles observed in unmilled crystals. It was concluded that DL-valine crystal lattice was extended along the b-axis by grinding, via disordering of the hydrogen bond layers. Moisture-induced crystallization should occur by water absorption inside the ground sample.
URI: https://ir.swu.ac.th/jspui/handle/123456789/15175
https://www.scopus.com/inward/record.uri?eid=2-s2.0-0346271778&partnerID=40&md5=eadd3afe14a1f10b13ca04e1e604b747
ISSN: 11571489
Appears in Collections:Scopus 1983-2021

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