Thermo-Mechanical Behavior of Genetically Modified Populus trichocarpa

Charles W. Edmunds, Ilona Peszlen, Vincent L. Chiang, Stephen S. Kelley, Zachary D. Miller, Mark F. Davis, Erica Gjersing, Perry Peralta

Research output: Contribution to journalArticlepeer-review

Abstract

Wood processing is often performed at elevated temperatures under moisture-saturated conditions; therefore, it is important to understand the impact of the lignin content and lignin chemical structure on the thermo-mechanical properties of wood. In this study, genetically modified Populus trichocarpa wood specimens with down-regulated cinnamyl alcohol dehydrogenase, cinnamate 3-hydroxylase, and cinnamate 4-hydroxylase with altered lignin contents and/or lignin structures were utilized to probe the relationship between the lignin content, lignin monomer composition, and thermo-mechanical properties of solid wood. The thermo-mechanical properties of these unique samples were measured using dynamic mechanical analysis and the nuclear magnetic resonance (NMR) spin-spin relaxation time. The results showed that the transgenic P. trichocarpa samples had decreased storage and loss moduli compared with the wildtype. The solid-state NMR revealed increased lignin molecular mobility in the reduced-lignin transgenic lines. Also, noticeably reduced glass transition temperatures (Tg) were observed in the transgenic lines with reduced lignin contents and altered lignin monomer compositions compared with the wildtype. The increased lignin molecular mobility and reduced Tg in these samples can probably contribute to wood utilization and processing, such as lignin removal for pulp and paper and biofuels production, as well as particle consolidation during wood composite manufacturing.

Original languageAmerican English
Pages (from-to)4760-4773
Number of pages14
JournalBioResources
Volume14
Issue number2
DOIs
StatePublished - 2019

Bibliographical note

Publisher Copyright:
© 2019, North Carolina State University.

NREL Publication Number

  • NREL/JA-2700-74158

Keywords

  • Cinnamate 3-hydroxylase (C3H)
  • Cinnamate 4-hydroxylase (C4H)
  • Cinnamyl alcohol dehydrogenase (CAD)
  • Dynamic mechanical analysis
  • Genetically modified poplar
  • Glass transition temperature
  • Lignin
  • Viscoelastic properties

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