Material forms pellets, granules, films

For TG work it is generally recommended to use as little sample as possible within the limits of resolution of the microbalance. The homogeneity of a sample can sometimes limit how little sample can be used, e.g., in case of polymeric materials. Powdered samples, of small particulate size, have the ideal form for TG studies. However, in polymer science, samples are often also in the form of films, fibres, sheets, pellets, granules or blocks. The packing density should be as uniform as possible. 

Zeolite materials are used commercially as shape/ size selective catalysts in the petrochemical and petroleum refining industry, and as molecular sieving separation media for gases and hydrocarbons. For both applications, zeolites are used in powder composite form such as pellets and granules. In this entry, we focus on zeolite membranes. We define zeolite membranes as a continuous phase of zeolite-based materials (pure zeolite or composite) that separate two spaces. Zeolite membranes are generally uniform thin films attached to a porous or a nonporous substrate. They can also be self-standing without a substrate. Note that we have included zeolite films and layers on nonporous substrate in this entry because we believe many of the synthesis strategies and applications reported for those nonporous substrates are easily transferred to a porous substrate to prepare a zeolite membrane. 

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