TY - JOUR
T1 - Direct verification of incipient mechanochemical interaction between two metallic species mediated by OH groups
AU - Senna, M.
AU - Watanabe, T.
AU - Isobe, T.
PY - 1996
Y1 - 1996
N2 - Incipient chemical interaction between Ca(OH)2 and SiO2 at the contact point of dissimilar solid particles under mechanical stress was examined by X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance (EPR), solid state nuclear magnetic resonance (NMR), as well as conventional analytical tools. Rapid electronical interaction in the presence of active OH groups was detected by XPS as a chemical shift of the binding energy of Si2p and Ca2p electrons. Detailed analysis of FT-IR with H-D exchange and preadsorption treatments by pyridine and NH3 proved to be a versatile tool to show that acid-base reaction is the main mechanism of Si-O-Ca complex formation. Appearance and survival of strong Brønsted acid site confirmed by IR also demonstrates the formation of Si-O-Ca bonds. 1H-solid state NMR evidenced the increase in the acidity by polarization of the OH groups during milling. A radical mechanism, examined by EPR, also plays a significant role in the incipient interaction, together with above-mentioned electron pair mechanism.
AB - Incipient chemical interaction between Ca(OH)2 and SiO2 at the contact point of dissimilar solid particles under mechanical stress was examined by X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance (EPR), solid state nuclear magnetic resonance (NMR), as well as conventional analytical tools. Rapid electronical interaction in the presence of active OH groups was detected by XPS as a chemical shift of the binding energy of Si2p and Ca2p electrons. Detailed analysis of FT-IR with H-D exchange and preadsorption treatments by pyridine and NH3 proved to be a versatile tool to show that acid-base reaction is the main mechanism of Si-O-Ca complex formation. Appearance and survival of strong Brønsted acid site confirmed by IR also demonstrates the formation of Si-O-Ca bonds. 1H-solid state NMR evidenced the increase in the acidity by polarization of the OH groups during milling. A radical mechanism, examined by EPR, also plays a significant role in the incipient interaction, together with above-mentioned electron pair mechanism.
KW - Acid-Base Reaction
KW - Mechanochemical Interaction
KW - OH Groups
KW - Radical Mechanism
KW - Solid State NMR
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U2 - 10.4028/www.scientific.net/msf.225-227.521
DO - 10.4028/www.scientific.net/msf.225-227.521
M3 - Article
AN - SCOPUS:0030422453
VL - 225-227
SP - 521
EP - 526
JO - Materials Science Forum
JF - Materials Science Forum
SN - 0255-5476
IS - PART 1
ER -