Multi-scale evaluation of the effect of saturated steam on the micromechanical properties of Moso bamboo

Abstract The changes in chemical composition and micro-mechanical properties of Moso Bamboo fiber cells were evaluated by applying saturated steam heat treatment at 160, 170, and 180 °C for periods of 4, 6, and 8 min, and subsequent analysis by X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopic, and nanoindentation methods. The hemicellulose and cellulose content decreased as expected, while the relative lignin content showed an upward trend. Significant changes in the bamboo micro-structure were detected by scanning electron microscope under the action of high-temperature and saturated steam. Both temperature and time were shown to affect micromechanical properties of the bamboo cell wall. In addition, higher cell wall elastic modulus and hardness were observed (a rise from 16.1 to 19.2 GPa and from 0.6 to 0.8 GPa, respectively), as compared with those of the untreated sample. Meanwhile, the creep ratio decreased after saturated steam heat treatment.

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The Influence of Saturated Steam on Moso Bamboo Quasi-static Micromechanical Properties: Nano-Scale Evaluation

10.21203/rs.3.rs-590616/v1 ◽

2021 ◽

Author(s):

Tiancheng Yuan ◽

Zhaoshun Wang ◽

Xin Han ◽

ZhuRun Yuan ◽

XinZhou Wang ◽

...

Keyword(s):

Heat Treatment ◽

Cell Wall ◽

Crystallinity Index ◽

Thermal Modification ◽

Moso Bamboo ◽

Saturated Steam ◽

Static Properties ◽

Tan Δ ◽

Increasing Temperature ◽

Steam Heat

Abstract In this paper, in order to analyze the quasi-static properties of Moso bamboo, a new, environmentally friendly and eco-friendly method was used for bamboo thermal modification under the effect of saturated steam. Under saturated steam heat treatment, the chemical composition in bamboo decreased, and the bamboo cell wall shrunk slightly. The increased crystallinity index of cellulose and decreased intensity of peaks belong to hemicellulose were confirmed by XRD and Fourier transform infrared (FTIR) spectroscopy. In addition, the highest modulus of elastic and hardness of treated bamboo were 22.5GPa and 1.1GPa at 180℃/10 min. These conclusions confirmed the micro-mechanical properties of the bamboo cell wall were enhanced by saturated steam heat treatment. The E'r of differently treated bamboo increased with increasing temperature and time, while the E''r and tan δ negatively as a function of increasing frequency. Furthermore, this thermal modification can be regarded as a useful, environmental-friendly and eco-friendly treatment to outdoor use of bamboo-based materials.

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Effect of Saturated Steam Heat Treatment on Physical and Chemical Properties of Bamboo

Molecules ◽

10.3390/molecules25081999 ◽

2020 ◽

Vol 25 (8) ◽

pp. 1999 ◽

Cited By ~ 2

Author(s):

Qiuyi Wang ◽

Xinwu Wu ◽

Chenglong Yuan ◽

Zhichao Lou ◽

Yanjun Li

Keyword(s):

Heat Treatment ◽

Moisture Content ◽

Treatment Time ◽

Flexural Modulus ◽

Initial Moisture Content ◽

Chemical Properties ◽

Saturated Steam ◽

Xrd Patterns ◽

Physical And Chemical ◽

Steam Heat

The aim of this study was to investigate the effects of the heat treatment time and initial moisture content of bamboo on the corresponding chemical composition, crystallinity, and mechanical properties after saturated steam heat treatment at 180 °C. The mechanism of saturated steam heat treatment of bamboo was revealed on the micro-level, providing a theoretical basis for the regulation of bamboo properties and the optimization of heat treatment process parameters. XRD patterns of the treated bamboo slices were basically the same. With the increase in the initial moisture content of bamboo, the crystallinity of bamboo increased first and then decreased after treatment. Due to the saturated steam heat treatment, the content of cellulose and lignin in bamboo slices increased while the content of hemicellulose decreased, but the content of cellulose in bamboo with a 40% initial moisture content increased first and then decreased. The shear strength of treated bamboo changed little within 10 min after saturated steam heat treatment, and then decreased rapidly. During the first 20 min with saturated steam heat treatment, the compressive strength, flexural strength, and flexural modulus of elasticity of the treated bamboo increased, and then decreased.

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The effects of thermal treatment on the nanomechanical behavior of bamboo (Phyllostachys pubescens Mazel ex H. de Lehaie) cell walls observed by nanoindentation, XRD, and wet chemistry

Holzforschung ◽

10.1515/hf-2016-0124 ◽

2017 ◽

Vol 71 (2) ◽

pp. 129-135 ◽

Cited By ~ 15

Author(s):

Yanjun Li ◽

Chengjian Huang ◽

Li Wang ◽

Siqun Wang ◽

Xinzhou Wang

Keyword(s):

Cell Wall ◽

Thermal Treatment ◽

Cell Walls ◽

Treatment Time ◽

Lignin Content ◽

Phyllostachys Pubescens ◽

X Ray Diffraction ◽

Wet Chemistry ◽

X Ray ◽

Wet Chemical

Abstract The effects of thermal treatment of bamboo at 130, 150, 170, and 190°C for 2, 4, and 6 h were investigated in terms of changes in chemical composition, cellulose crystallinity, and mechanical behavior of the cell-wall level by means of wet chemical analysis, X-ray diffraction (XRD), and nanoindentation (NI). Particularly, the reduced elastic modulus (Er), hardness (H), and creep behavior were in focus. Both the temperature and treatment time showed significant effects. Expectedly, the hemicelluloses were degraded and the relative lignin content was elevated, while the crystallinity of the cellulose moiety was increased upon thermal treatment. The Er and H data of the cell wall were increased after 6 h treatment at 190°C, from 18.4 to 22.0 GPa and from 0.45 to 0.65 GPa, respectively. The thermal treatment led to a decrease of the creep ratio (CIT) under the same conditions by ca. 28%. The indentation strain state (εi) also decreased significantly after thermal treatment during the load-holding stage.

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Three-Dimensional Zinc Mapping inside Aluminum Foams Using Synchrotron X-Ray Microtomography

Materials Science Forum ◽

10.4028/www.scientific.net/msf.561-565.1677 ◽

2007 ◽

Vol 561-565 ◽

pp. 1677-1680 ◽

Cited By ~ 2

Author(s):

Tomomi Ohgaki ◽

Y. Takami ◽

Hiroyuki Toda ◽

Toshiro Kobayashi ◽

Y. Suzuki ◽

...

Keyword(s):

Heat Treatment ◽

Cell Wall ◽

Concentration Distribution ◽

Three Dimensional ◽

Aluminum Foams ◽

X Ray ◽

Precipitated Phase ◽

Zn Concentration ◽

In Situ Experiments

Three-dimensional zinc mapping based on X-ray K-edge scanning has been performed. By microtomographies with energies above and below the K-absorption edges of the elements, the concentration distribution of the elements is evaluated during in-situ experiments, respectively. It is found that the Zn concentration distribution during the heat treatment was changed inside the cell wall of the aluminum foams and it has been homogenized. Also several precipitated phase transformation can be three-dimensionally visualized by the CT-method tuning X-ray energies.

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Comparison of colors, microstructure, chemical composition and thermal properties of bamboo fibers and parenchyma cells with heat treatment

Journal of Wood Science ◽

10.1186/s10086-021-01988-2 ◽

2021 ◽

Vol 67 (1) ◽

Author(s):

Jieyu Wu ◽

Tuhua Zhong ◽

Wenfu Zhang ◽

Jiangjing Shi ◽

Benhua Fei ◽

...

Keyword(s):

Heat Treatment ◽

Thermal Properties ◽

Chemical Composition ◽

Lignin Content ◽

Treatment Temperature ◽

Composition Analysis ◽

Chemical Compositions ◽

Cellulose Content ◽

Parenchyma Cells ◽

Bamboo Fibers

AbstractThe effects of heat treatment at various temperatures on mechanically separated bamboo fibers and parenchyma cells were examined in terms of color, microstructure, chemical composition, crystallinity, and thermal properties. The heat-treated parenchyma cells and fibers were characterized by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), chemical composition analysis, and thermogravimetric analysis (TGA). The results revealed that the colors of bamboo fibers and parenchyma cells were darkened as treatment temperature increased. The microstructure of the treated fibers and parenchyma cells slightly changed, yet the shape of starch granules in parenchyma cells markedly altered at a temperature of above 160 °C. The chemical compositions varied depending on the heat treatment temperature. When treated at 220 °C, the cellulose content was almost unchanged in fibers but increased by 15% in parenchyma cells; the hemicellulose content decreased and the lignin content increased regardless of fibers and parenchyma cells. The cellulose crystal structure was nearly unaffected by heat treatment, but the cellulose crystallinity of fibers changed more pronouncedly than that of parenchyma cells. The thermal stability of parenchyma cells after heat treatment was affected more substantially compared to fibers.

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Multi-scale characterization of the effect of saturated steam on the macroscale properties and surface changes of moso bamboo

Materials Express ◽

10.1166/mex.2021.1954 ◽

2021 ◽

Vol 11 (5) ◽

pp. 740-748

Author(s):

Tiancheng Yuan ◽

Jie Liu ◽

Shouheng Hu ◽

Xinzhou Wang ◽

Xianmiao Liu ◽

...

Keyword(s):

Mechanical Properties ◽

Heat Treatment ◽

Great Influence ◽

Modulus Of Rupture ◽

Saturated Steam ◽

Vascular Bundles ◽

Multi Scale ◽

Light Yellow ◽

Scale Characterization

Bamboo is a woody material that has become a key substitute for wood resources in many fields. This study is aimed to analyze the effects of saturated steam (140, 160, 180 °C) on physical, crystallinity, chemical composition, mechanical properties as well as microstructures at different periods (4, 6, 8, 10 min). Expectedly, a reduction of hemicellulose and cellulose and increment of relative content of lignin in bamboo when temperature above 160 °C was positive to reduce the equilibrium moisture content (EMC). Thus, the hygroscopicity improved and the parenchyma cells and vascular bundles were shrunk slightly. Both temperature and time positively affected the crystallinity of bamboo samples in comparison with the control. Heat treatment parameters affect the mechanical properties of bamboo. When the treatment was carried out at 140 °C, the modulus of rupture (MOR) and modulus of elastic (MOE) increased in comparison to no treatment; Furthermore, The MOR and MOE decreased by 40% and 19% compared with that of the untreated bamboo at 180 °C for 10 min. The temperature and time had a great influence on a*, b*, and L* of the bamboo. The results showed that during the heat treatment, the bamboo color changed from light yellow to dark red-brown, and the overall color changed evenly. Among them, a* increased firstly and then decreased, indicating that the treated bamboo was reddish, while b* and L* mainly showed a downward trend. The ΔE value positively corresponded to heat treatment severity.

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Multi-Scale Analysis of Changes in Crack-Free Flattened Moso Bamboo After Saturated Steam Treatment and Flattening Process

Science of Advanced Materials ◽

10.1166/sam.2021.4009 ◽

2021 ◽

Vol 13 (7) ◽

pp. 1259-1267

Author(s):

Tiancheng Yuan ◽

Xiao Xiao ◽

Xin-Han ◽

Yifei Wu ◽

Xinzhou Wang ◽

...

Keyword(s):

High Temperature ◽

Moisture Content ◽

Mechanical Analysis ◽

Moso Bamboo ◽

Steam Treatment ◽

Saturated Steam ◽

Main Peak ◽

Multi Scale ◽

Main Chemical Composition ◽

The Relationship

ABSTRACTIn this study, Moso bamboo was firstly softened by saturated steam and then pressed flat by a machine. The modification effect (high-temperature saturated steam) was characterized by FTIR, XRD, SEM, and wet chemistry. The dynamic mechanical analysis (DMA) was used to investigate the effects of three variables (temperature, time, and moisture content) on the thermal-mechanical properties of Moso bamboo. The results indicated that high-temperature saturated steam can effectively soften bamboo cells under high pressure at high temperature. As expected, in comparison with reference samples, the content of hemicellulose and cellulose decreased, while that of relative lignin increased. The results of the changes in main chemical composition were further confirmed by FTIR, which showed that the intensity of the main peak belongs to hemicellulose decreased, so the polysaccharide such as hemicellulose went through the process of hydrolysis and pyrolysis. An increase in the moisture content of bamboo led to a decrement in storage modulus value, which can be attributed to the plasticizing effect. Both temperature and time had a positive effect on the reduction in glass transition temperature. This conclusion not only helps to understand the relationship between bamboo and water, but also provides guide for the utilization and production process of crack-free flattened bamboo board and its products in the construction and building fields.

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Temperature effects on lignin, hemicellulose and cellulose in tropical and temperate grasses

Australian Journal of Agricultural Research ◽

10.1071/ar9790621 ◽

1979 ◽

Vol 30 (4) ◽

pp. 621 ◽

Cited By ~ 65

Author(s):

CW Ford ◽

IM Morrison ◽

JR Wilson

Keyword(s):

Cell Wall ◽

Growth Temperature ◽

Lignin Content ◽

Significant Negative Correlation ◽

In Vitro Digestibility ◽

Panicum Maximum ◽

Cellulose Content ◽

Stage Of Development ◽

Increasing Temperature

Thirteen tropical and 11 temperate grasses were grown in controlled environment under day/night temperatures of 21/13, 27/19 and 32/24°C. Neutral detergent fibre (NDF) was prepared from the fifth leaf on the main stem of each plant, 2 days after it had reached maximum length. Panicum maximum var. trichoglume (tropical) and Lolium perenne cv. S24 (temperate) were also harvested at 4,8, and 12 days after this stage of development. For the tropical grasses NDF values, corrected for starch and protein, decreased with increasing growth temperature, whereas in the temperate species they increased. In the tropical group the decrease in NDF was due to a lower cellulose content, whereas hemicellulose and lignin levels generally tended to increase slightly with increasing temperature. In the temperate grasses, lignin, hemicellulose and cellulose levels all showed a consistent increase with growth temperature. At each growth temperature the lignin content of the species in the tropical group had a significant negative correlation with in vitro digestibility, and lignin appeared to be more closely associated with hemicellulose than with cellulose. In contrast, at each temperature, variation in digestibility between species of the temperate group was not correlated with lignin. Levels of cell wall components in the later-harvested material from Lolium varied in a similar manner to that of the younger growth stage, whereas older Panicum cell wall constituents showed more variability.

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Determination of the Effects of Superheated Steam on Microstructure and Micromechanical Properties of Bamboo Cell Walls Using Quasi-Static Nanoindentation

Forests ◽

10.3390/f12121742 ◽

2021 ◽

Vol 12 (12) ◽

pp. 1742

Author(s):

Tiancheng Yuan ◽

Xiaorong Liu ◽

Youming Dong ◽

Xinzhou Wang ◽

Yanjun Li

Keyword(s):

Elastic Modulus ◽

Cell Walls ◽

Superheated Steam ◽

Lignin Content ◽

Crystallinity Index ◽

X Ray Diffraction ◽

Untreated Sample ◽

X Ray ◽

Micromechanical Properties

In this paper, quasi-static nanoindentation was applied for investigating the influence of superheated steam on microstructure and micromechanical properties of Moso bamboo cell walls. The changes of mico-morphology, chemical composition, cellulose crystallinity index, micro-mechanical properties of bamboo were analyzed via scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR), and nanoindentation. As expected, the content of hemicellulose and cellulose showed a downward trend, whereas the relative lignin content increased. Elastic modulus and hardness of the cell wall increased compared with that of the untreated sample. The elastic modulus and hardness of bamboo increased from 11.5 GPa to 19.5 GPa and from 0.35 GPa to 0.59 GPa. Furthermore, results showed that the creep resistance positively correlated to treatment severity.

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Evaluation of the effects of compression combined with heat treatment by nanoindentation (NI) of poplar cell walls

Holzforschung ◽

10.1515/hf-2013-0084 ◽

2014 ◽

Vol 68 (2) ◽

pp. 167-173 ◽

Cited By ~ 20

Author(s):

Xinzhou Wang ◽

Yuhe Deng ◽

Siqun Wang ◽

Chen Min ◽

Yujie Meng ◽

...

Keyword(s):

Mechanical Properties ◽

Heat Treatment ◽

Cell Wall ◽

Cell Walls ◽

Lignin Content ◽

Cellulose Crystallinity ◽

Hot Press ◽

Longitudinal Elastic Modulus ◽

Modification Method ◽

Compressed Wood

Abstract A combination of compression and heat treatment is a modification method that has great potential for improving the mechanical properties and dimensional stability of wood materials in industrial application. The objective of this project was to track changes in the microstructure, chemical composition, cellulose crystallinity, and mechanical properties of the treated poplar cell wall to investigate the mechanism of modification. Poplar boards were compressed at 100°C and subsequently treated in the hot press at 200°C. The results indicated that the treatment contributed to a reduction in porosity without obvious mechanical compression and damage to the cell wall. Hemicellulose degraded, however, and the relative lignin content and cellulose crystallinity increased during the process. The observed increase in relative lignin content and crystallinity may contribute to the improvement of mechanical properties. The longitudinal elastic modulus and hardness of poplar cell walls increased significantly from 12.5 and 0.39 GPa for the control to a maximum of 15.7 and 0.51 GPa for compressed wood with HT, respectively.

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