Characterisation of Porous Particle Systems

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Kevin Kendall
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United Kingdom

The objective of this paper is three fold. First,the intention is to review the porous structure of particle systems, especially those porous pastes and gels formed during powder processing operations. Second, this report critically analyses some deficiencies and unknowns in our knowledge of porous particle structuring processes. Third, the objective is to suggest future work which could resolve these problems and lead to more rational approaches to the processing of fine particles.

Since there are several levels of porosity to be found in particle systems; namely atomic and molecular pores ie nanopores less than about 1 nm in size, micropores around 1 pm in size and macropores above 1 pm; it is necessary to split part 5 of the report into three sections. The section on nanopores, which are important in catalysts, absorbents, zeolites etc has been written with the help of Dr Zholobenko. The section on micropores, where Brownian movement is a strong factor, has been compiled with the help of Dr Stainton. Large macropores are more readily measured, for example by light scattering and optical microscopy, and are dealt with in the final section.

The conclusion is that the main opportunities for novel advance are in the micro and nanopore regimes. The structuring of nano and micro-particles is dominated by molecular forces which can be measured by Atomic Force Microscopy. New computer models can begin to simulate structures resulting from these forces. Novel experimental methods, such as micro-focus X-ray, are emerging to compare with such models.