SURFACE ENERGY CHARACTERIZATION OF THERMALLY MODIFIED SPRUCE USING INVERSE GAS CHROMATOGRAPHY UNDER CYCLIC HUMIDITY CONDITIONS

Authors

  • Susanna Källbom
  • Magnus Walinder
  • Kristoffer Segerholm KTH Royal Institute of Technology Division of Building Materials SE-100 44 Stockholm and SP Technical Research Institute of Sweden
  • Dennis Jones SP Technical Research Institute of Sweden SE-114 86 Stockholm

Abstract

The surface energy of unmodified and thermally modified spruce wood components was researched at dry and moist conditions using inverse gas chromatography. The results indicate a more pronounced heterogeneous nature of the thermally modified wood surfaces in terms of the dispersive (nonpolar) component of the surface energy, compared with that of the unmodified wood surfaces. The dispersive component of the surface energy of the thermally modified wood ranged between 44 and 38 mJ/m2 corresponding to an increase in surface coverage from a low level and up to about 10%. Suggested explanations for the more distinct heterogeneity of the thermally modified wood sample are
related to chemical changes of the wood substance which seem to result in certain micromorphological features observed by scanning electron microscopy as alternated fracture surfaces created in the grinding process; and also possible changes or redistribution of the wood extractives. An increase of the MC, representing a change from a dry condition of approximately 0% RH to ca 75% RH, of both the unmodified and thermally modified samples seemed to have a marginal influence on the dispersive component of the surface energy. Possible implications of the results in this study can be found in the tailoring of new compatible and durable material combinations, for example, when using thermally modified wood residuals as a component in new types of biocomposites.

Author Biographies

Susanna Källbom

PhD Student

Magnus Walinder

Professor

Kristoffer Segerholm, KTH Royal Institute of Technology Division of Building Materials SE-100 44 Stockholm and SP Technical Research Institute of Sweden

Research Scientist

Dennis Jones, SP Technical Research Institute of Sweden SE-114 86 Stockholm

Research Scientist

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Published

2015-10-19

Issue

Vol. 47 No. 4 (2015)

Section

Research Contributions

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