THERMAL SOFTENING OF TRANSGENIC ASPEN

Bbalazs Horvath, Perry Peralta, Charles Frazier, Ilona Maria Peszlen

Abstract


Studies on the softening behavior of in situ lignin of normal wood in a given species have never been performed before due to the relatively narrow lignin content and lignin structural variation within one species. Using transgenic trees with different levels of lignin content and/or syringyl to guaiacyl propane (S/G) ratio helped us to overcome this problem. Submersion three-point bending and parallel-plate compression-torsion dynamic mechanical analyses were conducted on one-year-old wild type and transgenic aspen (Populus tremuloides Michx.). The different genetic modifications included groups with reduced lignin content, increased S/G ratio, and both reduced lignin content and increased S/G ratio. Measurements with both methods revealed a statistically significant decrease in glass transition temperature in the reduced-lignin genetic group compared to the wild-type. Increase in the S/G ratio did not affect the thermo-mechanical properties; these results contradict claims that increasing the methoxyl groups would reduce lignin cross-linking and the glass transition temperature.

Keywords


Genetically modified trees; Transgenic aspen; Dynamic mechanical analysis; Compression-torsion, Glass transition temperature, Loss modulus, Storage modulus, Tan delta

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Welcome to BioResources! This online, peer-reviewed journal is devoted to the science and engineering of biomaterials and chemicals from lignocellulosic sources for new end uses and new capabilities. The editors of BioResources would be very happy to assist you during the process of submitting or reviewing articles. Please note that logging in is required in order to submit or review articles. Martin A. Hubbe, (919) 513-3022, hubbe@ncsu.edu; Lucian A. Lucia, (919) 515-7707, lucian.lucia@gmail.com URLs: bioresourcesjournal.com; http://ncsu.edu/bioresources ISSN: 1930-2126