WOOD RESEARCH Volume 69, Number 3, 2024
CHENYANG LI, YATING CAI, XINJIE ZHOU, RUOGU XU, HAN YU, LILI YU, HUI LI, XIAO WANG, and SHU-GUANG LI

PREPARATION PROCESS AND INTERFACE MODIFICATION ON THE MECHANICAL PROPERTIES OF BAMBOO FIBER/POLYPROPYLENE CARBONATE COMPOSITES

In this study, bamboo fiber (BF) and polypropylene carbonate (PPC) were used to prepare BF/PPC composite materials. The single factor test combined with orthogonal experiment was used to investigate the effects of different hot pressing process conditions (hot pressing temperature, hot pressing pressure and hot pressing time) on the mechanical properties of BF/PPC composites. Based on the hot pressing process results, the filler nano-calcium carbonate (Nano-CaCO3), γ-aminopropyl triethoxysilane (KH550) and maleic anhydride (MAH) were added respectively to the composites to improve the interface between BF and PPC in order to increase the mechanical properties of the composites. The results showed that the reasonable preparation conditions of BF/PPC composites with the best mechanical properties were set at 170°C, under 1.9 MPa for 10 min. Compared with PPC samples, the tensile modulus, bending modulus and impact strength of BF/PPC composites could be increased to 102%, 38.69% and 65.13%, respectively. The optimal interface modification treatments have been proved that nano-CaCO3 with 10% content could increase the tensile modulus and impact strength to 70.53% and 65.84%, while the best result for the bending modulus of BF/PPC composites was modified with MAH with 2.5% content, which could increase to 28.46%

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 69, Number 1, 2024
YATING CAI, CHENYANG LI, CAIJUAN ZAHNG, YULIN LIU, LILI YU, HUI LI, and XIAO WANG

PREPARATION AND PERFORMANCE OF ANTI MILDEW GLUED LAMINATED BAMBOO

In order to strengthen the anti-mildew and anti-aging properties of bamboo when exposed outdoors, the glued laminated bamboo was impregnated with four different kinds of anti-mildew agents: tebuconazole, 3-Iodo-2-propargyl butyl carbamate (IPBC), NaBF4/didecyl dimethyl ammonium chloride (DDAC), boric acid/borax, and waterborne polyurethane coatings modified with boric acid/borax and triazole (UV1130), nano-TiO2 and nano-SiO2 were coated respectively. The modified coated glued laminated bamboo was characterized and analyzed through the experiments of wear resistance, three-point bending resistance and mildew resistance. The results showed that the glued laminated bamboo impregnated with 0.5% NaBF4/DDAC, and then coated with the waterborne polyurethane modified with boric acid/borax and nano TiO2 (the mass ratio:7.5/7.5/1.0) possessed the best mildew resistance, mechanical properties and weather resistance

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 2, 2022
Caijuan Zhang, Hui Guo, XINJIE ZHOU, LILI YU, HUI LI, and Zhi-Bin Yang

Effects of differrent boron-based flame retardants on the combustibility of bamboo filaments

In this study, eight types of boron-based flame retardants were performed to evaluate the effects of different boron components on the combustibility of the bamboo filaments. Disodium octaborate tetrahydrate, boric acid/borax, and nano-ZnBO4 were used as the active flame retardant components. Besides, other inorganic flame retardants including nano-SiO2 and ammonium polyphosphate (APP) were also introduced in order to increase the flame retardant of these boron-based components. The combustibility of the bamboo filaments treated with different flame retardants were evaluated by cone calorimeter analysis. The results showed that the flame retardants including the heat release and smoke release resistance of the bamboo filaments with different boron-based components and nano-SiO2 or APP, could be significantly improved, especially, in the samples treated with the compound flame retardant composed of boric acid, borax and nano-SiO2, which was attributed to the synergistic effect of these flame retardant components.

WOOD RESEARCH Volume 63, Number 5, 2018
Zhenzhong Tang, LILI YU, Yi Zhang, Lizhi Zhu, and Xiaojun Ma

Effects of nano-SiO2/polyethylene glycol on the dimensional stability modified ACQ treated southern pine

Southern yellow pine (Pinus sp.) wood cubes were vacuum-pressure treated with nano-SiO2 solution and different concentrations of ACQ/polyethylene glycol (0.5%, 2.5% and 5.0%) modified solutions. The effects of polyethylene glycol concentrations and nano-SiO2 addition on the water absorption, air drying shrinkage and moisture swelling stability of treated wood were investigated. The results showed that during the whole process of water absorption and air drying shrinkage, the better stability of nano-SiO2 modified ACQ treated wood could only be obtained with the ratio of 2.5% polyethylene glycol addition. However, nano-SiO2 and polyethylene glycol modification could take little effect on the moisture and water swelling resistance of treated wood with different treatments.

WOOD RESEARCH Volume 64, Number 6, 2019
Jing Zahng, Jingjing Gao, LILI YU, Lizhi Zhu, and Xiaojun Ma

Dimensional stability of nano-SiO2/emulsified wax modified CuAz-treated wood after one year outdoor exposure test

Samples were vacuum-pressure treated with nano-SiO2 water solutions with BET specific surface area of 60,150, 200, 380 respectively, and then impregnated with copper azole (CuAz) preservatives or emulsified wax modified CuAz preservatives. The effects of emulsified wax and nano-SiO2 on the dimensional stability were investigated according to standard GB/T 1934 (2009) after one year outdoor exposure test. The results showed that the addition of nano-SiO2 or/and emulsified wax could reduce the water absorption rate of treated wood, and the best water repellent was observed in the samples treated with BET specific surface area of 60 m2.g-1. The addition of wax into nano-SiO2 modified wood was essential to improve the radial and tangential swelling and shrinkage stability of nano-SiO2 treated wood. The bigger BET specific surface area of nano-SiO2 would be adversely affected the dimensional stability of the treated wood.

WOOD RESEARCH Volume 66, Number 3, 2021
Chunyan Lv, Caijuan Zhang, XINJIE ZHOU, Mingyu He, LILI YU, and Zhenzhong Tang

Effect of different pre-treatments on the permeability of glue-laminated bamboo

In this study, hydrothermal treatments (duration: 2 h, 5 h, 8 h; temperature: 60°C, 80°C, 100°C), ultrasonic treatments (duration: 60 min, 90 min, 120 min; temperature: 40°C, 50°C, 60°C; ultrasonic power: 400 W, 600 W, 800 W) and freeze-drying treatments (vacuum degree: 0.05 mbar, 0.1 mbar, 0.5 mbar, 1.0 mbar, 1.7 mbar) were performed respectively to improve the permeability of glue-laminated bamboo. The effects of different pre-treatments on the permeability were compared according to the water absorption test and the mercury intrusion porosimetry test. The microstructure change of the samples was observed by scanning electron microscope (SEM). The results showed that freeze-drying treatment was an effective way to increase the permeability of the samples, in which the water absorption rate can be increased by 47%, and the porosity can be increased by 10% at 0.5 mbar vacuum. From SEM analysis, some small holes appeared in the cell wall of the freeze-dried samples, because he free water inside the samples was changed into ice, and the volume became larger, and the pore diameter of the bamboo was enlarged.

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.