Determination of the lamellar phase content in MCM-41 using X-ray diffraction, nitrogen adsorption, and thermogravimetry

Article Abstract:

An investigation in range of methods, with varying levels of complexity, accuracy and applicability, for the determination of the phase composition of different mixtures of hexagonal MCM-41 and lamellar phases.

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Expanding the pore size of MCM-41 silicas: use of amines as expanders in direct synthesis and postsynthesis procedures

Article Abstract:

The use of amines to expand the pore-size of MCM-41 silicas is discussed. It is shown that N,N-dimethylhexadecylamine is an expander that allows the synthesis of large-pore MCM-41 in mild conditions. Increasing amine in the synthesis gel increased pore size and reduced structural ordering. Treating as-synthesized MCM-41 in a aqueous emulsion of an appropriate amine can also result in up to a 3-fold increase in pore size.

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A unified interpretation of high-temperature pore size expansion processes in MCM-41 mesoporous silicas

Article Abstract:

A study was conducted to analyze the high-temperature unit-cell enlargement of MCM-41 prepared during the presence of cetyltrimethylammonium surfactants without auxiliary organics. Reasons for increases in pore volume and decreases in surface area were discussed. Results indicated that MCM-41 particles simultaneously widen in the plane perpendicular to the pore axis during pore size expansion processes.

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