Visualizing and Characterizing the Structure of Biomaterials

Bioresources are resources derived from biological origins. Biomaterials are materials derived from bioresources. Examples include cellulose fiber, bio-based polymers and plastics, wood products, and biocomposites. Water molecules, chemical reagents, and products from biomass reactions can be transported in biomaterials through pore spaces, or through solid parts of the material (i.e. fibers, cell walls). To understand the role of pore-fiber microstructure in transport, a “random walk method” was used to determine the overall transport of moisture within biomaterials. X-ray computed tomography was used to visualize and characterize the internal 3D microstructure of porous biomaterials, utilizing Poromedia and ImageJ imaging software. Three different samples of corn stover were analyzed to determine their porosity, surface area, and tortuosity. Samples included two that were subject to pretreatment (deacetylation and mechanical refining (DMR) and DMR followed by ozonolysis (DMRO)), and a control. The average porosity, surface area, and tortuosity were all higher for the DMR and DMRO samples compared to the control samples: The average porosity was 0.4 for the DMR sample, 0.25 for the DMRO sample, and 0.15 for the control. The average surface area (in ^2/g) was 0.14 for the DMR and DMRO samples, and 0.12 for the control. The harmonic mean tortuosity in the XY direction was 1.82, 1.80, and 1.22 for the DMR, DMRO, and control samples respectively. The increase in porosity, surface area, and tortuosity all provide an additional interface for more reactions and can potentially increase diffusivity.

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