Change in Micro-Morphology and Micro-Mechanical Properties of Thermally Modified Moso Bamboo.

Tiancheng Yuan,Yaqian Huang,Xinzhou Wang,Tao Zhang,Yanjun Li

doi:10.3390/polym14030646

Tiancheng Yuan, Yaqian Huang + Show 3 more

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https://doi.org/10.3390/polym14030646

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Abstract

In recent years, saturated steam heat treatment has been considered as an environmentally friendly and cost-effective modification method compared with traditional heat treatment media. In this study, bamboo was treated by saturated steam, and the change in chemical composition, cellulose crystallinity index, micro-morphology, and micromechanical properties were analyzed by a wet chemistry method, Fourier transform infrared (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), nanoindentation, and so on. Results illustrated that the parenchyma cell walls were distorted due to the decomposition of hemicellulose and cellulose in bamboo samples. As expected, the hemicellulose and cellulose content decreased, whereas the lignin content increased significantly. In addition, the cellulose crystallinity index and thus the micromechanical properties of bamboo cell walls increased. For example, the hardness increased from 0.69 GPa to 0.84 GPa owing to the enhanced crystallinity index and lignin content.

Highlights

Due to global climate change, there is an urgent need to find a woody material that can replace wood and reduce the deforestation of native trees and the loss of forest resources [1,2]
In this study, saturated steam heat treatment enhanced the dimensional stability of bamboo samples due to the decomposition of hemicellulose
Results showed that parenchyma cells deformed due to the degradation of chemical composition in bamboo cell walls

Summary

Introduction

Due to global climate change, there is an urgent need to find a woody material that can replace wood and reduce the deforestation of native trees and the loss of forest resources [1,2]. It is necessary to find alternative woody materials which are low cost, have excellent mechanical properties, and are easy to harvest, versatile, and renewable, to solve the above problem [3,4,5,6,7]. Bamboo has gained more attention due to its abundance, sustainability, excellent physical properties, and ease of harvest. When grown in an outdoor setting, bamboo is prone to being attacked by fungi and insects due to its abundance of nutrients. Several modification methods have been applied to decrease the hygroscopicity and increase the durability of bamboo and bamboo-based products, such as chemical modification, acetylation, and thermal modification [8,9,10,11]. Thermal modification is a useful approach for increasing mechanical properties and dimensional stability [12,13]

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