WOOD RESEARCH Volume 69, Number 4, 2024
JINGE XIE, HONGHAI LIU, YU XIE, and XIAOKAI ZHANG

INFLUENCE OF TEMPERATURE AND PRESSURE ON SUPERCRITICAL CO2 DEWATERING OF BAMBOO STRIPS

In this study, therepressure (15, 22.5, 30 MPa) and two temperature (45, 60°C) of ScCO2dewatering were tested on Moso bamboo (Phyllostachys edulis) strips. The aim was to research the effects of these conditions on the dewatering rate, moisture distribution, and shrinkage of bamboo. The results showed that: 1)The first cycle discharges the most water of all drying conditions. The most effective dewatering time consisted of a 15 min depressurization period and a 5 min discharge period. 2)The ScCO2 dewatering rate of bamboo strips decreased with decreasing MC, with a maximum decrease of 78%.The maximum and minimum dewatering rates were 37.04%/h and 4.41%/h, respectively. The dewatering rate was synergistically affected by temperature and pressure, which increased significantly with pressure at 45°C, but was minimized at 60°C at 22.5 MPa. 3)After dewatering, the moisture distribution in the bamboo strips shows a trend of higher moisture content(MC) in the middle and lower MC on both sides in the tangential and radial directions. 4)Most of the bamboo strips produced shrinkage after the 1st cycle of dewatering, and the overall shrinkage in the tangential direction was greater than that in the radial direction. The maximum tangential and radial shrinkage rations are 3.06% (22.5 MPa/45°C) and 0.94% (15 MPa/60°C), respectively.

WOOD RESEARCH Volume 69, Number 2, 2024
HARADHAN KOLYA, MASUMI HASEGAWA, KAZUHARU HASHITSUME, and CHUN-WON KANG

EFFECTS OF CHEMICAL AND PHYSICAL TREATMENTS ON BAMBOO CELL WALL STRUCTURE FROM ENGINEERING PERSPECTIVES

This study focuses on the effects of chemical treatment using polyethylene glycol (PEG) and physical treatment via steam explosion and microwave, with a comprehensive analysis using ATR-FTIR, X-ray diffraction, Keyence VR 6000 optical profilometer, and SEM. The aim is to elucidate alterations in bamboo cell walls following these treatments compared to untreated bamboo. The results reveal significant modifications in the chemical composition and crystalline structure of bamboo cell walls post-treatment. ATR-FTIR analysis indicates changes in functional groups, suggesting chemical interactions and modifications in the molecular arrangement of cell wall components. XRD analysis further corroborates these findings by revealing shifts in crystallinity and peak intensities, signifying structural rearrangements, as evidenced by optical images and SEM micrographs

WOOD RESEARCH Volume 69, Number 1, 2024
CHENYANG LI, YATING CAI, CHUNYAN LI, XINJIE ZHOU, YULIN LIU, LILI YU, HUI LI, and MEILING CHEN

STUDY ON THE MOST EFFECTIVE COMBINATION OF FLAME RETARDANT AND ANTI-AGING AGENT FOR BAMBOO MODIFICATION

In order to promote the universal application of bamboo materials as well as to provide reference for the study of the performance of bamboo, four kinds of flame retardants (boric acid (BA), borax (BX), ammonium polyphosphate (APP), disodium octaborate tetrahydrate (DOT)), two kinds of ultraviolet light absorbers (UV-531, nano TiO2) were added into waterborne polyurethane (WPU) to synthesize 5 kinds of modified coatings and coated on the surface of bamboo to make test materials. The flame-retardant analysis of the coated samples comprehensively explored the changes in flame retardancy of the test material after treatment. And the anti-aging test was carried out to investigate the color difference and adhesion change of the coating sample. The results show that the optimum flame retardant and anti-aging coating composition was obtained as 20% solid content of WPU, 8g coating amount of modifier, with the mass ratio of BA/BX/APP /DOT/water being 75:75:7:42:600, and the amount of UV-531 added being 1%

WOOD RESEARCH Volume 68, Number 1, 2023
Hui Guo, Caijuan Zhang, XINJIE ZHOU, Shuo Wang, LILI YU, HUI LI, and Zhi-Bin Yang

Comparation of different environment-friendly anti-mildew agents on bamboo

Four kinds of environmental anti-mildew agents (boric acid/borax, 3-iodo-2-propynyl-butyl-carbamate (IPBC), sodium tetrafluoroborate/didecyl dimethyl ammonium chloride (NaBF4/DDAC), tebuconazole) were used to treat bamboo with different concentrations respectively. The optimal concentration of each anti-mildew agent and the comparison of the anti-mildew capacity were evaluated with Aspergillus niger, Trichoderma viride and Penicillium citrinum, respectively. The results showed that the optimal anti-mildew agent concentrations of boric acid/borax (F1), IPBC (F2), NaBF4/DDAC (F3) and tebuconazole (F4) were 3.0%, 1.5%, 0.5% and 0.4%, respectively, and the average control efficacy of the three test molds was 73.15%, 92.03%, 88.43% and 98.67%, respectively. The order of anti-mildew capability of these four anti-mildew agents with their optimal concentrations was F4 > F2 > F3 > F1.

WOOD RESEARCH Volume 67, Number 5, 2022
Ziwei Wang, Xianghua Yue, Jing Li, Hankun Wang, and Genlin Tian

Research on the structure and connections of pits in different cells of moso bamboo (Phyllostachys pubescens)

The plant grows within the transportation of water and nutrients, including radial and longitudinal, but bamboo only exists pits in the radial, so it plays an irreplaceable role at this moment. This study aims at giving rise to further understanding of the biological functions of pits in bamboo. Light microscopy (LM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were applied to investigate the structure and connections of bamboo pits. The results show that the arrangement of pits is significantly different, including alternate, scalariform and opposite arrangements. The presence or absence of the bordered on different cells is also displayed distinctively, these characteristics extremely affect the transportation of water and nutrients in bamboo.

WOOD RESEARCH Volume 61, Number 5, 2016
Chu Jie, Ma Li, and Zhong Yang

Comparison of bamboo fibers in sulfuric acid, sodium hydroxide and glycerin pretreatments

The chemical compositions and structural characterizations of bamboo samples with three pretreatments using sand bath to heat were comparatively studied with Fourier infrared spectrum (FTIR). The results showed that the holocellulose and cellulose yields increased significantly and the dilute alkali (NaOH) pretreatment performed better lignin removal rate than that of dilute acid (H2SO4) and glycerin pretreatments.Furthermore, when the same solutions were used, the compositional changes were more remarkable at 135 than at 117°C, and the similar degradation of hemicelluloses was observed for the different pretreatments. With sodium hydroxide at 135°C, compared to un-treated bamboo, cellulose increased by 14.21 % and hemicellulose decreased to 13.98 %, counting the removal of lignin to 20.29 %. In which, the bamboo expressed the betterdelignification with sand bath and higher temperature and combinations with other methods of glycerin pretreatment should be evaluated in the future work.

WOOD RESEARCH Volume 61, Number 2, 2016
Hong Yun, Kaifu Li, Dengyun Tu, and Chuanshuang Hu

Effect of heat treatment on bamboo fiber morphology crystallinity and mechanical properties

This study aimed to investigate the fiber morphology, crystalline structure and mechanical properties of heat-treated bamboo. Moso bamboo was treated by superheated steam at 120, 140, 160, and 180ºC. Fiber morphology and crystalline structure of heat-treated Moso bamboo were researched by transmission electron microscope and X-ray diffraction. The mechanical properties of heat-treated bamboo were tested in the paper. The result showed that the relative crystallinity and length-width ratio of heat-treated bamboo were increased with increased temperature. The elastic modulus of bamboo was increased as the temperature rose from 120 to 140ºC. and then decreased with higher temperature, which was associated with the increase of the crystallinity.

WOOD RESEARCH Volume 62, Number 4, 2017
Yuzhi Xu, Baojin Wang, and Yi Shen

Study on laser cutting technology of bamboo

The research advances of laser cutting technology were first stated. Then to study the performance of bamboo laser cutting and obtain the optimum technological parameters, we used a laser cutting machine with 60 W power laser tube and observed the magnified kerf shape. We found laser cutting perpendicular to the fiber direction was more difficult than other cutting directions under the same conditions. The notch depth was the deepest by parallel cutting and the notch width was the widest by oblique cutting. When the thickness of laser-cut bamboos was 3 mm, we obtained moderate kerf width, thinner carburization zone and better kerf quality under laser nozzle height 20 mm, cutting speed 30 m.min-1 and laser output power 48 W, which were the optimum technological parameters of bamboo laser cutting.

WOOD RESEARCH Volume 64, Number 5, 2019
Ying Guan, Hui Gao, Wenqi Li, Jun Rao, and Yuqi Zhang

Preparation and characterization of antibacterial films from bamboo

The aim of this research was to prepare lignocellulose films reinforced with chitosan (CS), nano-ZnO (NZO), or nano-TiO2 (NTD) by casting method. The chemical structures of the films were characterized with FT-IR, which showed no chemical bonds formed but certain interactions among the hydrogen bonds. X-ray diffraction confirmed that the main structure of blend films was unchanged comparing to lignocellulose film. Derivative thermogravimetry (DTG) presented that the residual masses of lignocellulose/chitosan (LCCS) film, lignocellulose/TiO2 (LCTD) film, and lignocellulose/ZnO (LCZO) film were 23.43%, 19.27%, 27.68% at 700°C, respectively. Ultimate tensile strength and strain to break of all blend films were decreased with addition of CS, NZO, and NTD, respectively. LCCS film was more effective against Escherichia coli and Staphylococcus aureus than LCTD film and LCZO film. Potential antimicrobial applications in the orthopedic field and perspectives regarding future studies in this field were also considered.

WOOD RESEARCH Volume 65, Number 5, 2020
Zhongxi Zhou, Chungui Du, Huilong Yu, Xiaoling Yao, and Qiuli Huang

Promotion effect of nano-SiO2 on hygroscopicity, leaching resistance and thermal stability of bamboo strips treated by nitrogen-phosphorus-boron fire retardants

Whereas hygroscopicity an leaching resistance often have a bad influence on performance of fire-retardants, in this work, nano-SiO2 sol was added to different nitrogen-phosphorus-boron fire retardants to make four new compounds to impregnate bamboo strips, named: (1) ammonium dihydrogen phosphate + disodium octaborate tetrahydrate (AD), (2) ammonium dihydrogen phosphate + disodium octaborate tetrahydrate + nano-SiO2 sol (ADS), (3) ammonium dihydrogen phosphate + boric acid (AB), and (4) ammonium dihydrogen phosphate + boric acid + nano-SiO2 sol (ABS). After that, the hygroscopicity, leaching resistance and thermal stability were studied by scanning electron microscopy (SEM), energy dispersive X-Ray spectroscopy (EDX), thermogravimetric (TG) and fourier-transform infrared spectrometer (FTIR), and the optimal compound fire retardant is ABS. The results show that the addition of nano-SiO2 sol can not only reduce the hygroscopicity of fire-retardant bamboo strips effectively, but also improve its leaching resistance. The results also indicate that compared with non-fire-retardant bamboo strips, the thermal stability of bamboo strips treated with AB and ABS was improved significantly, and there was no significant difference between AB and ABS.

WOOD RESEARCH Volume 66, Number 2, 2021
CHUNYAN LI, XINJIE ZHOU, Changhao Yang, LILI YU, HUI LI, and Benhua Fei

Effects of different flame retardant treatments on the combustibility of bamboo filament

Bamboo filaments were treated with boric acid and borax (the mass ratio of 1:1, the concentration of 20%) with four different treatment methods including atmospheric immersion, cold and hot bath immersion, vacuum impregnation and vacuum-pressure impregnation. The different treatment methods on the boron loading were analyzed and the corresponding flame resistance of bamboo filaments were evaluated by the cone analysis. The results showed that suitable treatment method with optimized processing indexes, such as hot and cold bath immersion in the condition of 100°C/2 h and 20°C/2 h with 3 cycles, was more credible to accelerate the percentages of boron loading in the bamboo filaments, and the lowest result was found in the samples with vacuum impregnation. Compared to the untreated samples, the heat and smoke release would be decreased significantly, especially for the samples with the promising hot and cold treatment, and promising pressure treatment, attributed to the more stable boron fixed in the bamboo filaments.