Rheology of moso bamboo stem determined by DMA in ethylene glycol

The basic properties of moso bamboo (MB) were determined according to the International Organization for Standardization (ISO) standards and its rheological behavior was studied by dynamic mechanical analysis (DMA) in the tensile torsion stress mode after plasticization with ethylene glycol (EG). Results show that the density and the apparent lignin content of MB increases and the degree of crystallinity decreases with increasing age. Storage modulus (G′) increases from 1- to 3-year-old MB, and then decreases again with age. When the bamboo culm with the inner and outer surface planed off was divided into three layers in the radial direction, the G′ of the outer layer was always higher than that of the middle and inner layers. The glass transition temperature (Tg) of MB plasticized with EG is about 10°C lower than the water plasticized ones, and the Tg of the outer and inner layers was nearly 1–2°C higher than that of the middle layer. The overall trend of basic properties and rheological behaviors seems to exhibit a discontinuity at 3 years, which might reflect the growth of MB and mainly the thickening of cell walls.