Multiscale viscoelasticity response for bamboo after partial hemicellulose removal treatment

Abstract

Hemicellulose degradation can decrease the hygroscopicity and result in an improvement of dimensional stability for nature materials. The mechanical properties has always been used as an indicator of hemicellulose degradation, but lack of an indicator that can be reflects the additive effects of treatment condition and the effects of time. This work aimed to use multiscale viscoelasticity response to evaluate the coupled effects of physical/chemical treatment and loading time. Different conditions (hot water, acidic and saturated steam) were tested on bamboo. Macroscopic creep of bamboo slices and microscopic creep behavior of cell wall were determined. The relationship between gradient structure and viscoelasticity has been obtained. The outer slice, i.e., bamboo green, had best strength and flexural toughness. Middle slice exhibits significant viscoelasticity response. Inner slice, also called bamboo yellow, exhibits little viscoelasticity response but bad strength. The relationship between treatment conditions and macroscopic/microscopic creep also has been obtained. At macro scale, the acid group exhibits significant viscoelasticity response, while the water group and steam group exhibit more elasticity response, especially for water groups. At micro scale, the steam-treated and acid-treated group are all showed significant viscoelasticity response, while the water-treated group had lowest relative creep. This paper could be a reasonable selection support of bamboo materials for stiffness or flexible products.