The Mechanical and Crystallographic Evolution of Stipa tenacissima Leaves During In-Soil Biodegradation

• 作者: Benoit Duchemin Mohammed Amine Allal Nabil Abou-bekr Said Taibi Zakia Khelifi
• 来源期刊: 可再生材料杂志(英文)
• 学科: 工学
• 关键词: ALFA MECHANICAL testing FE-SEM XRD BIODEGRADATION
• 年，卷（期）: kzsclzzyw_2018,（3）
• 页码范围: 336-346
• 页数: 11页
• 分类号: TG1

摘要

The in-soil biodegradation of Stipa tenacissima(alfa)leaves was examined.Non-linear mechanical testing was performed at various biodegradation stages.Tensile strength,loading and unloading Young’s moduli and dissipation energy decreased with the burial time,whereas plasticity increased.Field-emission scanning electron microscopy(FE-SEM)showed that the fracture cracks propagated in the longitudinal direction in the raw material,resulting in a fracture mode consisting of a mixture of middle lamella delamination and fiber pull-out.In contrast,the cracks were perpendicular to the stem axis in the biodegraded material,demonstrating an important strength loss of the load-bearing fibers.This strength loss was correlated with rapid cellulose degradation.A novel X-ray diffraction(XRD)model was implemented in order to take into account anisotropic size broadening.For the first time,XRD demonstrated the action of biodegradation on unrefined plant tissues under quasi in-situ conditions.Biodegradation induced a progressive loss of crystalline cellulose accompanied with anisotropic crystallite thinning.