Characterizing Microscopic Changes of Paulownia Wood under Thermal Compression


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Dogu D. , Tuncer F. D. , Bakir D. , Candan Z.

BIORESOURCES, vol.12, pp.5279-5295, 2017 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 12
  • Publication Date: 2017
  • Doi Number: 10.15376/biores.12.3.5279-5295
  • Title of Journal : BIORESOURCES
  • Page Numbers: pp.5279-5295
  • Keywords: Paulownia wood, Thermally compressed wood, Wood microstructure, Wood densification, Cell collapse, Cellular failures, HEAT-TREATMENT, DENSIFICATION, MICROSTRUCTURE, TOMENTOSA, BEHAVIOR, DEFECTS, PANELS

Abstract

This study evaluates the microscopic changes of paulownia solid wood panels subjected to thermal compression via characterizing the changes in wood microstructure. The panels, with dimensions of 500 mm x 100 mm x 20 mm, were hot-pressed in a tangential direction by using a laboratory-type hot press at a temperature of either 150 degrees C or 170 degrees C and a pressure of 2 MPa for 45 min. Microscopic investigations conducted by light microscopy showed that slightly more damage occurred in the samples compressed at 170 degrees C and 2 MPa than at 150 degrees C and 2 MPa, and that the distribution of deformation in the panels was not uniform in the growth rings of the two treatment groups. The cell collapse was not observed in the microstructure of paulownia wood after the thermal compression. Cell shapes and their arrangement in the growth ring alongside loading direction were interpreted as effective factors governing the non-uniform distribution of damage and the lack of cell collapse in the microstructure.