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%

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

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.

Influence of vacuum impregnation pressures on the nanomechanical characteristics and photocatalytic performance of nano TIO2-furfuryl alcohol/balsa wood-based composites

In this work, a nano TiO2-FA/balsa wood-based composites were successfully fabricated by mechanical stirring assisted vacuum impregnation method, and the influence of different impregnation pressures on the microstructure, nanomechanical characteristics and photocatalytic performance of obtained composites were investigated. Results show that the nano TiO2-FA compound modifier was impregnated in the tracheid and attached to the wood cell walls. SEM revealed that the size of TiO2 nanoparticles grow larger as the impregnation pressure increases, and the presence of TiO2 globules with some areas agglomerated on the wood cell wall surface. Compared with the unmodified wood, the elastic modulus of cell walls for nano TiO2-FA/balsa wood composites prepared under 0.45 MPa significantly increased by 160.5%, and the hardness improved from 0.36 ± 0.04 GPa to 0.84 ± 0.08 GPa. Furthermore, the UV-Vis showed that the composite exhibited a high removal rate of methylene blue (10 mg.L-1), up to 88.74% within 240 min.

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.

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.