Measuring the Particle Packing of L‑Glutamic Acid Crystals through X‑ray Computed Tomography for Understanding Powder Flow and Consolidation Behavior

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This work demonstrates a novel application of X-ray computed tomography (XCT). Here, it is used to study the consolidation properties of two polymorphic phases of L-glutamic acid. As part of the study, a Gamlen Powder Compaction Analyser was used to explore the consolidation behaviour of the polymorphs.

  • The morphology of free-flowed and gravity consolidated crystal powder beds of the alpha and beta polymorphic forms of L-glutamic acid was investigated using XCT.
  • XCT revealed that the alpha form consolidates under gravity more efficiently than the beta. This was attributed to the inability of the beta particles to pack efficiently along their needle axis.
  • Pure powders of the the L-glutamic acid polymorphs were compacted into tablets where the alpha form produced tablets of medium tensile strength, and the beta form could not be compacted into tablets of any tensile strength at the same compaction pressures.
  • To investigate observed compaction differences, XTC analysis was carried out on the resultant alpha tablets. This revealed the microstructure and particle density within the tablets.

CONCLUSION

This work shows how XCT could provide invaluable information as to how particulate surfaces interact within 3D powders. Such data is critical to improving computational simulations of powder processing.

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