Errors in Thermogravimetric Experiments Resulting from Adsorption on the Counterweight
The sorption behaviour of quartz, glass, aluminum, gold and PTFE was examined with respect to their use as counterweight materials. Using nitrogen, krypton, water, alcohol and neopentane, reversible S-shaped isotherms were observed with a monolayer cover at a relative pressure of about 0.1, and up to eight layers at the saturation pressure. When organic vapours are used chemisorption may occur. Near the saturation pressure condensation effects on porous surfaces and contaminations have to be taken into account.
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