摘要：
As green renewable resources, wood and its composites are widely used in the construction field, which puts forward higher requirements for their flame-retardant performance. In this study, a high-temperature hydrothermal crystallization method for in situ constructing an epoxy crosslinked Si-Al zeolite-like structural wood composite (WZLC) was reported. Under the action of amine guiding agents and epoxy resin, the zeolite-like catalytic structure constructed in poplar wood comprised negative electrocatalytic sites, which can efficiently catalyze the formation of the carbon layer and endow WZLC with excellent flame retardant, smoke-suppression, and self-extinguishing properties. Compared with the untreated wood (WN), the thermal stability of the treated wood (WZLC) was greatly improved, and the amount of volatile organic compounds released during the decomposition process was significantly reduced. The heat release rate, total heat release, smoke production rate, and total smoke production of WZLC1 decreased by 50.23%, 44.14%, 45.21%, and 28.46%, respectively. Particularly, CO and CO2 yields of WZLC significantly decreased by 92.26% and 92.02%, respectively, indicating that the Si-Al zeolite-like catalytic structure displayed excellent catalytic flame retardant properties, which can effectively decrease the thermal decomposition rate and combustion risk of the WZLC. This method uses less flame retardants to achieve a good flame retardant and smoke suppression effect, thereby reducing the risk of environmental pollution caused by too many flame retardants.
摘要：
Combining bamboo processing residues with lightweight magnesium oxychlorides can produce new composite building materials that increase the utilization rate of bamboo and also improve the performance of lightweight magnesium oxychlorides. However, the incompatible interface between the two materials leads to the poor performance of the resulting composites, which limits their application in construction engineering. In this paper, a synergistic effect between surfactants and styrene-butadiene latex was used to enhance the interfacial compatibility between bamboo scraps and lightweight magnesium oxychlorides. The structure formed between the two acted as a "bridge" that enhanced the cross-linking between bamboo scraps and lightweight magnesium oxychloride, thus forming a more stable bamboo fiber-lightweight magnesium oxychloride network. The lightweight composite material obtained in this paper showed a maximum compressive stress of 6.5 MPa and a softening coefficient of 0.75.It shows great development potential in the application of light weight, high strength and water resistance building decoration materials.
摘要：
Alkali treatment of bamboo scraps was adopted to improve the interface compatibility between the organic-phase bamboo scraps of the composite material and the inorganic-phase magnesium oxychloride. Scanning electron microscopy, Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and other techniques were used to characterize bamboo scraps before and after alkali treatment. The bamboo scraps treated with alkali exhibited improved bonding properties to cementitious materials. The mechanical properties and water resistance of the composite material were evaluated. The results indicated that the mechanical strength first increased and then decreased with an increase in alkali concentration. After treatment with 3wt% NaOH solution, the composite exhibited the highest compressive strength and bending strength. The softening coefficient also reached 0.57. Alkali treatment resulted in improved bonding of bamboo scraps with magnesium oxychloride cementitious material, as confirmed by mechanical property and water resistance tests, and SEM image analysis.
摘要：
Geopolymer is a new alternative cement binder to produce concrete. In the present study, a novel geopolymer composites containing bamboo shaving (0-2 wt.%) were fabricated and exposed to the temperatures of 200 degrees C, 400 degrees C, 600 degrees C and 800 degrees C. Physical properties, micro-structure, and mechanical strengths of the geopolymer composites were evaluated before and after heating in order to understand their thermal properties, which are essential for the use as building materials. As the temperature rises, the drying shrinkage and apparent porosity of the composites increase, while the compressive and bending strengths decrease. At the temperature range of 200 degrees C-800 degrees C, the residual compressive strength rates of the geopolymer composite containning 2 wt.% bamboo shaving were respective 73.8%, 61.47%, 56.16%, and 29.56%, meanwhile, the residual flexural strength rates were respective 46.69%, 8.68%, 2.52%, and 2.33%. Correspondingly, the residual compressive strength rates of pure geopolymer were respective 72.81%, 61.99%, 54.55%, and 14.64%; the residual flexural strength rates were 48.87%, 5.69%, 3.22%, and 2.47%, respectively. Scanning electron microscope (SEM), optical microscope, and X-ray diffractometry (XRD) were applied to find the microscopic changes. The strength loss in the geopolymer composites was mainly because of the thermal degradation of bamboo shaving and shrinkage of geopolymer matrix. Bamboo shaving has great potential as reinforcer in developing low-cost geopolymer composites and may be used for applications up to 400 degrees C.
摘要：
The demand of thermal energy conservation and regulation using inorganic composites in green low-carbon modern society is urgent. However, the organic-inorganic heterogeneous interfacial compatibility in traditional inorganic composites mainly depends on the loose crystal layers via hydrogen bonding, which is prone to faults and the hole wall damaged under strong forces. Here, a molecular topological structure was constructed in the composites system. Our process includes generating dendritic molecular chains on bamboo fiber, activating crystals to increase active sites, and inducing the confined growth of crystals on bamboo fiber through the action of hydrogen bonding and electrostatic adsorption. A chitosan-acrylic acid graft copolymer (CS-g-PAA) was introduced, which responded to weak alkali environment, achieved multi-mode bonding effects such as dynamic hydrogen bond, ionic complex bond, enhanced covalent bond, metal coordination bond and polymer network. Therefore, achieving deep cross fusion of heterogeneous interfaces through this method endows topologically composites (TCS) with many unique properties such as lightweight ultrastrong, thermal insulation, shock absorption, and fire resistance. The TCS was 8 times stronger than traditional insulation materials, and the thermal conductivity (0.07-0.085 W.m(-1).k(-1)) was much lower than that of other inorganic insulation materials. This multifunctional TCS shows potential applications for building energy conservation, aerospace insulation, and aircraft arresting systems.
期刊：
Journal of Sustainable Cement-Based Materials,2023年12(10):1218-1227 ISSN：2165-0373
通讯作者：
Yingfeng Zuo<&wdkj&>Yiqiang Wu
作者机构：
[Li, Xingong; Wu, Yiqiang; Zuo, Yingfeng; Zheng, Long] Cent South Univ Forestry & Technol, Coll Mat Sci & Engn, Changsha, Hunan, Peoples R China.
通讯机构：
[Yingfeng Zuo; Yiqiang Wu] C;College of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha, Hunan, P.R. China<&wdkj&>College of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha, Hunan, P.R. China
摘要：
Magnesium-based aerated cement has the characteristics of noncombustibility and nontoxicity compared with traditional organic aerated materials, realizing low-carbon manufacturing and energy saving in building construction. However, the pore walls of ordinary magnesium-based aerated cement are thin and brittle and can easily collapse under force, limiting its application in energy saving. This study aimed to obtain low-cost, low-energy, lightweight, high-strength, flame-retardant, and heat-insulating thermal insulation materials. Inspired by the formation process of stacked stones, calcium stearate was adsorbed on solid particles, stabilizing the pore and forming independent lumps of gel-state crystals in this study. At the same time, the hydrogen bonds of hydroxyethyl cellulose were used to chemically stitch the dispersed crystals to form a dense laminated structure. The interfacial compatibility between bamboo scraps and magnesium oxychloride improved the load transfer efficiency. The results showed that the strength-to-weight ratio of the composites increased 2.5 times, and the softening coefficient increased about 2 times. In comparison, the mechanical properties and thermal insulation properties of the composites far exceeded those of most thermal insulation materials, providing a theoretical basis for their use in the field of multifunctional building materials.
摘要：
Sodium silicate modification can improve the overall performance of wood. The modification process has a great
influence on the properties of modified wood. In this study, a new method was introduced to analyze the wood
modification process, and the properties of modified wood were studied. Poplar wood was modified with sodium
silicate by vacuum-pressure impregnation. After screening using single-factor experiments, an orthogonal experiment was carried out with solution concentration, impregnation time, impregnation pressure, and the cycle times
as experimental factors. The modified poplar with the best properties was selected by fuzzy mathematics and
characterized by SEM, FT-IR, XRD and TG. The results showed that some lignin and hemicellulose were removed
from the wood due to the alkaline action of sodium silicate, and the orderly crystal area of poplar became disorderly, resulting in the reduction of crystallinity of the modified poplar wood. FT-IR analysis showed that
sodium silicate was hydrolyzed to form polysilicic acid in wood, and structural analysis revealed the formation
of Si-O-Si and Si-O-C, indicating that sodium silicate reacted with fibers on the wood cell wall. TG-DTG curves
showed that the final residual mass of modified poplar wood increased from 25% to 67%, and the temperature of
the maximum loss rate decreased from 343°C to 276°C. The heat release and smoke release of modified poplar
wood decreased obviously. This kind of material with high strength and fire resistance can be used in the outdoor
building and indoor furniture.
期刊：
Journal of Building Engineering,2023年63:105506 ISSN：2352-7102
通讯作者：
Yingfeng Zuo
作者机构：
[Li, Xingong; Li, Ping; Zuo, Yingfeng; Zheng, Long; Sun, Baorong] Cent South Univ Forestry & Technol, Coll Mat Sci & Engn, Changsha 410004, Hunan, Peoples R China.
通讯机构：
[Yingfeng Zuo] C;College of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha, Hunan, 410004, PR China
摘要：
Bamboo scraps/magnesium oxychloride composites are new low carbon and environmentally friendly building materials. Its development not only reduces carbon dioxide emissions, but the use of bamboo scraps can improve bamboo utilization rates and play important roles in protecting the environment. However, in some environments, water resistance is problematic and me-chanical strength decreases, thereby seriously affecting applications in architectural settings. Natural rubber latex (NRL) can be coated after dehydration and film forming, and modified by surfactants to improve cement properties. In this study, natural rubber latex modified by sodium dodecyl sulfate (S-NRL), was used as a modifier to improve bamboo scraps/magnesium oxy-chloridee composite properties. The results showed that after S-NRL addition, latex films formed by water loss not only filled voids in bamboo scraps/magnesium oxychloride composites, but also generated surface negative charges. These were adsorbed by magnesium (Mg2+) ions, at strength phase-5, and formed surface waterproof protective films to prevent water erosion. Thus, com-posite mechanical and water resistance properties were enhanced; when S-NRL was at 0.3%, mechanical strength and water resistance properties were at a maximum after curing for 28 days.
期刊：
Wood Science and Technology,2023年57(2):329-344 ISSN：0043-7719
通讯作者：
Yingfeng Zuo
作者机构：
[Li, Xingong; Wu, Yiqiang; Li, Ping; Zuo, Yingfeng; Zhang, Yuan; Liu, Wanting] Cent South Univ Forestry & Technol, Coll Mat Sci & Engn, Changsha 410004, Hunan, Peoples R China.
通讯机构：
[Yingfeng Zuo] C;College of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha, People’s Republic of China
摘要：
This study proposed a new method for the rapid and uniform removal of lignin components from wood, which was applied to abundant fast-growing Chinese fir. Based on the lignin removal using acidic NaClO2, the impregnation process with positive pressure-negative pressure circulation was used to promote the reaction. Using this method, the time of the impregnation and discharge of lignin was shortened, and the complete cellulose skeleton of Chinese fir can be easily prepared. The lignin removal effect on crystalline structure and chemical structure was discussed. It was deduced that the macroscopic morphology of Chinese fir was complete and the end face did not crack under the positive–negative pressure cycles. The FTIR showed that the proposed method can better reduce the damage of holocellulose by delignification treatment and uniform and efficient removal of lignin. The relative crystallinity gradually increased with the increase in the cycle number, achieving a selective delignification effect. This method achieved accurate regulation of the lignin removal effect, promoted the utilization of Chinese fir in functional materials, and provided a cellulose wood-based template for the high-value utilization of Chinese fir.
期刊：
Progress in Organic Coatings,2023年174:107267 ISSN：0300-9440
通讯作者：
Yingfeng Zuo<&wdkj&>Ping Li
作者机构：
[Li, Xingong; Zuo, Yingfeng; Zhang, Mengying; Lyu, Jianxiong] Cent South Univ Forestry & Technol, Coll Mat Sci & Engn, Changsha 410004, Hunan, Peoples R China.;[Li, Ping] Cent South Univ Forestry & Technol, Coll Furniture & Art Design, Changsha 410004, Hunan, Peoples R China.;[Lyu, Jianxiong] Chinese Acad Forestry, Res Inst Wood Ind, Beijing 100091, Peoples R China.
通讯机构：
[Yingfeng Zuo; Ping Li] C;College of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha, Hunan 410004, PR China<&wdkj&>College of Furniture and Art Design, Central South University of Forestry and Technology, Changsha, Hunan 410004, PR China
摘要：
This paper describes the investigation of the effect of different concentrations of silane coupling agent KH560 (KH560) on the interface properties of silicate modified poplar wood (SMPW). These properties include the surface wettability, free energy, and film adhesion. With the exception of the film adhesion rating of SMPW treated with 0.5 % KH560 was grade 2, the film adhesion rating of SMPW treated with 1.0 %-3.0 % KH560 was grade 1. The SEM images showed that cracks between the waterborne (water-based polyurethane modified acrylic acid) varnish and SMPW gradually decreased upon increasing the KH560 concentration. The results of the FI-TR and XPS all indicated that the characteristic peak of Si-O-Si and the relative proportion of Si-O-Si groups were positively correlated with the concentration of KH560 in the treated SMPW. This indicates that KH560 was successfully grafted onto the substrate surface. After KH560 was combined with a water-based sealing primer (WBSP), the larger the concentration of KH560, the stronger the bond at 1730 cm(-1). This means that the epoxy group in KH560 reacted with WBSP and was connected with the WBSP. After drenching the SMPW with the KH560 solution that had concentrations of 0.5 %, 1.5 %, and 2.5 %, the contact angles of WBSP on the substrate's surface were 62.55 degrees, 60.10 degrees, and 49.45 degrees, respectively. The surface free energy of SMPW treated with 0.5 %, 1.5 %, and 2.5 % KH560 was 45.87, 49.55, and 50.29 (10(-3) J.m(-2)), respectively. This indicated that increasing the KH560 concentration improved the wettability, increased the SMPW free energy value, and improved the film adhesion.
期刊：
Wood Material Science & Engineering,2023年18(1):141-150 ISSN：1748-0272
通讯作者：
Zuo, Yingfeng;Li, Ping
作者机构：
[Yuan, Guangming; Zuo, Yingfeng; Zhang, Mengying; Lu, Jianxiong; Bao, Xinde] Cent South Univ Forestry & Technol, Coll Mat Sci & Engn, Changsha, Peoples R China.;[Li, Ping] Cent South Univ Forestry & Technol, Coll Furniture & Art Design, Changsha 410004, Peoples R China.;[Lu, Jianxiong] Chinese Acad Forestry, Res Inst Wood Ind, Beijing, Peoples R China.
通讯机构：
[Zuo, Yingfeng; Li, Ping] C;Cent South Univ Forestry & Technol, Coll Mat Sci & Engn, Changsha, Peoples R China.;Cent South Univ Forestry & Technol, Coll Furniture & Art Design, Changsha 410004, Peoples R China.
关键词：
Sodium silicate;impregnation modification;poplar wood;surface free energy;surface wettability;paint film adhesion
摘要：
The surface free energy of wood is an important property that influences later manufacturing process, such as wood gluing and finishing. Sodium silicate modifications of poplar wood inevitably alter wood’s surface free energy. The purpose of this study was to determine the effect of various impregnation times on the resulting surface free energy of radial and tangential sections of poplar wood specimens. The contact angles of standard probe liquids (i.e. distilled water, diiodomethane, formamide) on the surface of the wood were measured by contact angle goniometer, and a geometric average method and acid–base interaction method were applied to calculate and analyze the changes in the surface free energy. In addition, Fourier transform infrared spectroscopy was used to analyze the changes in the functional groups on the wood surface; after finishing the wood surface with water-based or oil-based paint, the paint film adhesion properties were also evaluated. The results indicate that sodium silicate modification can effectively improve the surface wettability and surface free energy of poplar wood. The modification treatment gradually creates hydrophilic groups (e.g. hydrogen bonds, free hydroxyl groups) on the wood surface, and their contents increase with increasing impregnation time. Additionally, by introducing Si-O–C moieties, the polarity, dispersion, and acid–base components of the wood surface all increase to varying degrees. Finally, the sodium silicate modification treatment worsens the adhesion of the paint films on the wood surface, although not to a significant extent.
摘要：
In this paper, in order to continuously promote the carbon peak and neutrality targets, and accelerate the construction of the waste material recycling systems, a lightweight construction material was prepared by compounding magnesium oxychloride cement (MOC) inorganic cementitious material and waste bamboo scraps, and foaming them with hydrogen peroxide. However, the poor water resistance of MOC composites makes it difficult to meet the needs under special environmental conditions, which seriously affects their popularization and application range. To solve this problem, Polyvinyl acetate (PVAc) was used to enhance the water resistance. It was deduced that the hydrolysis products of PVAc combined with each other, under the effect of hydrogen bonding induction, can form a hydrated polymer protective film covering the exterior of MOC crystals, thus reducing the contact of water with the crystals. In addition, the protective film and the hydroxyl groups on the cellulose of bamboo scraps are interconnected by hydrogen bonding, which improves the bonding strength of MOC gelling particles to bamboo scraps. Moreover, the PVAc hydrolysis products were combined with water molecules, bamboo scraps, and phase 3 crystals in MOC by hydrogen bonding to form a gelling structure, which further improved the adhesive tightness of MOC gelling particles. These three aspects led to the increase of the softening coefficient of the modified material by approximately 14%, and a substantial increase of the water resistance. Furthermore, the addition of PVAc improved the foaming effect of the material and increased the porosity, leading to a further decrease of the density and strength of the foamed material. The study of the water resistance of this lightweight composite material effectively provides a theoretical support and technical reference for the application of water-resistant and energy-saving materials in the construction fields.
通讯机构：
[Zuo, Yingfeng] C;College of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha, Hunan 410004, PR China. Electronic address:
摘要：
Polylactic acid-based (PLA) composites are widely used in biomedicine, electrical components, food packaging and other fields, but their unsatisfactory mechanical properties such as high brittleness and poor toughness, cause problems in functional applications. This work developed a green and environmentally friendly strategy to improve PLA mechanical properties. Flexible polybutylene succinate (PBS) and alkaline hydrogen peroxide (AHP) treated straw fibers (SF) synergistically modified PLA. AHP is decomposed into a large amount of HOO-, which oxidizes the hydroxyl groups in SF to carboxyl groups to obtain oxidized straw fiber (OSF), which reacts with PLA in the molten state to form new ester bonds. The tensile strength of the OSF/PLA composite is 41.78 MPa, 38 % higher than the SF/PLA composite. The impact toughness of OSF/PBS/PLA composite is 14.47 KJ/m(2) increased by 54 % after the adding PBS, while the tensile strength was also better than the control group. The synergistic action of PLA and PBS in OSF is attributed to the formation of new chemical bonds, efficient crystallization, and compatible interface. This study provides a new strategy to produce fiber-reinforced PLA composites with good toughness. It takes positive significance for developing degradable plastics with good performance and controllable cost.
作者机构：
[毕小茜; 张源; 李萍; 吴义强; 袁光明; 左迎峰] College of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha;410004, China;[毕小茜; 张源; 李萍; 吴义强; 袁光明; 左迎峰] 410004, China
作者机构：
[Zhang Yuan; Bi Xiao-qian; Li Xian-jun; Yuan Guang-ming; Zuo Ying-feng; Li Ping] Cent South Univ Forestry & Technol, Coll Mat Sci & Engn, Changsha 410004, Peoples R China.
通讯机构：
[Zuo, Y.-F.] C;College of Materials Science and Engineering, China
摘要：
To enhance mechanical properties and improve flame retardancy and smoke suppression of fast-growing poplar wood in wood applications, the wood was impregnated and modified. An organic phenolic prepolymer and inorganic sodium silicate was used as contrasting impregnation modifiers and wood samples were impregnated by a bionic "respiration" method with alternating positive and negative pressure. The weight percentage gain, density increase ratio, mechanical properties (bending and compressive strength and hardness), and water absorption rate of inorganic and organic-impregnated modified poplar wood (IIMPW and OIMPW, respectively) were compared and these properties in IIMPW were found to be higher than those of OIMPW with the exception of the water absorption rate which was lower than the OIMPW. This was attributed to the superior absorption of sodium silicate that also improved the impregnation, reinforcement, and dimensional stability in the IIMPW. The chemical structure, crystalline structure, internal morphology, flame retardancy, smoke suppression, and thermal stability of IIMPW and OIMPW were characterized by FT-IR, XRD, SEM, CONE, and TGA. FT-IR and XRD results showed that, although IIMPW cellulose crystallinity reduced the most, more chemical bonds were come into being in IIMPW, which explained the better physical and mechanical properties of IIMPW. Compared with OIMPW, IIMPW had better flame retardant and smoke suppression performance.
期刊：
Wood Science and Technology,2022年56(5):1487-1508 ISSN：0043-7719
通讯作者：
Ping Li<&wdkj&>Yingfeng Zuo
作者机构：
[Wu, Yiqiang; Yuan, Guangming; Zuo, Yingfeng; Zhang, Yuan; Bi, Xiaoqian] Cent South Univ Forestry & Technol, Coll Mat Sci & Engn, Changsha 410004, Hunan, Peoples R China.;[Li, Ping] Cent South Univ Forestry & Technol, Coll Furniture & Art Design, Changsha 410004, Hunan, Peoples R China.
通讯机构：
[Ping Li; Yingfeng Zuo] C;College of Furniture and Art Design, Central South University of Forestry and Technology, Changsha, People’s Republic of China<&wdkj&>College of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha, People’s Republic of China
摘要：
The mechanical and flame-retardant properties of sodium silicate-impregnated fast-growing poplar have been greatly improved by a wide variety of methods, which has solved the problem of insufficient supply of natural wood to a certain extent. However, sodium silicate is easily leached and has high hygroscopicity, and sodium silicate-modified poplar (SSMP) has low anti-shrink efficiency (ASE), which make it difficult to maintain its dimensional stability. Dimethylol dihydroxyethylene urea (DMDHEU) contains polyhydroxymethyl active groups that are highly reactive with wood fibers and sodium silicate. Therefore, in this study, sodium silicate and DMDHEU were used as a composite modifier to carry out vacuum-pressure-impregnation modification on fast-growing poplar to form a bridging structure. This treatment fixed the sodium silicate and improved the dimensional stability of poplar. Mechanical properties of poplar wood were improved by modifications with sodium silicate and DMDHEU. The dimensional stability was greatly improved, and the fixation of sodium silicate was improved. Compared with the SSMP, the leaching rate and ASE of SS/DDMP were reduced by 48.82% and 41.79%, respectively. XRD, FTIR, and XPS results showed that C–O–C and Si–O–C bonds were formed between DMDHEU and the wood cell walls and sodium silicate. These bonds closely bound the cellulose crystals, which reduced the number of –OH groups being accessible for water and, thus, the moisture absorption of SS/DDMP. In addition, due to the increase in crystallinity, the heat resistance was further enhanced. The cone calorimetry results showed that SS/DDMP had the lowest heat release rate and total heat release. Compared with SSMP, the mean smoke release rate (mean SPR) and total smoke release decreased by 40.38% and 40.83%, respectively. Moreover, the release of CO and CO2 decreased. In conclusion, compared with other modification methods, the use of SS/DD impregnation to modify poplar has the potential to produce good overall performance of poplar with high-dimensional stability, flame retardancy, and smoke suppression.
