Thermorheological Complexity and Fragility in Plasticized
Lignocellulose
Sudip Chowdhury
Charles E. Frazier
10.1021/bm400080f.s001
https://acs.figshare.com/articles/journal_contribution/Thermorheological_Complexity_and_Fragility_in_Plasticized_Lignocellulose/2426170
It
is demonstrated that plasticized lignocellulose fails to satisfy
classic criteria normally required to validate time/temperature superposition
(TTS) in dynamic mechanical analysis (DMA). However, insightful relaxation
behavior is available and dismissing it would be a mistake. TTS was
applied to Liriodendron tulipifera wood
using parallel plate compressive-torsion DMA with specimens immersed
in different organic liquids, ranging from weak to strong swelling
power. While all storage moduli shifted smoothly, thermorheological
complexity was detected in loss modulus shift failures, which themselves
must reflect unknown structural features. Storage modulus shift factors
clearly distinguished solvent specific relaxation behavior and interpretations
through the WLF model or through fragility (cooperativity) analysis
are useful. However, it is demonstrated that fragility analysis is
preferred and solvents of different swelling power are compared. Coupled
with other methods, TTS and fragility analysis warrant further development
as a means to improve the understanding of structure/property relationships
in plasticized lignocellulose.
2016-02-19 12:58:57
plasticized lignocellulose
DMA
loss modulus shift failures
fragility analysis warrant
TTS
Liriodendron tulipifera wood
relaxation behavior
storage modulus shift factors
WLF