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：
Wood adhesives are widely used in furniture manufacturing, the construction industry, and the fabrication of the internal components of aircraft, cars, and sports equipment. Therefore, the development of wooden adhesives with high stability, strength, and efficiency is a vital research area. Although most studies have focused on improving the bonding properties of adhesives, achieving direct interface control from wood remains a challenge. This study was designed based on the plant root-driven adhesion method to create a hyperactive-interface self-driven regulated wood capable of spreading adhesive into the wood and inducing crosslinking to improve adhesive strength. A multi-poly silicate network structure with multiple reactive sites was formed through the self-polymerization of sodium silicate and crosslinking with dimethylol dihydroxy ethylene urea (DMDHEU) to achieve densified wood and improve the reactivity of the wood surface and interior. Consequently, the environmentally friendly polyvinyl acetate (PVAc) underwent a self-driven bonding process with the wood. These findings indicate that PVAc penetrated the interior of the wood, disrupting the combination of sodium silicate and DMDHEU and grafting onto the reactive sites. This process resulted in a tightly bonded interface connection. Consequently, the shear strength increased from 4.4 to 5.5 MPa, and the wood breaking rate increased from 21.00 % to 45.80 %, representing a 25 % and 118.10 % increase, respectively. Moreover, the tensile strength of the wood in longitudinal joints, transverse joints, miter joints, and mortise-tenon joints was assessed. The results revealed that the sodium silicate/DMDHEU-regulated wood (SS/DDRW) exhibited significantly higher adhesive strength than the original wood (OW). Hence, this bionic design represents a simple and efficient strategy for developing wood adhesives.
摘要：
Traditional wood modification methods often result in the release of harmful substances and energy wastage. This study proposes an efficient and environmentally friendly modification strategy for fast-growing poplar wood. The approach involves polymerizing organic linear molecules within the cell wall to form stitches, thereby enhancing the dimensional stability and mechanical properties of wood and increasing its ability to withstand various environments. Poplar wood specimens were treated via a method that combines heat treatment with acrylic emulsion impregnation. The research findings indicated an improvement in the mechanical properties of poplar wood following the combined treatment. Moreover, poplar wood subjected to this treatment approach exhibited a 35.24 % lower water absorption rate after a 7-day water immersion test, and tangential and radial swelling rates of the wood were reduced by 29.66 % and 45.68 %, respectively. Scanning electron microscopy revealed excellent penetration of acrylic emulsion into wood cells; the emulsion infiltrated the wood and adhered to the cell walls, forming a crosslinked network structure. Analysis of the modification mechanism through X-ray diffraction, Fourier-transform infrared spectroscopy, and X-ray photoelectron spectroscopy showed that the successful infusion of acrylic emulsion compensated for the lower mechanical properties of thermally treated wood, thus improving the utilization value of poplar. The acrylic emulsion is an environmentally friendly and harmless modifier, making the modified wood suitable for various applications, including indoor furniture, logistics, and outdoor facilities. This modification strategy enables efficient resource utilization and provides valuable insights for the sustainable development of the timber industry.
摘要：
Plant fiber-reinforced polylactic acid (PLA) composites are extensively utilized in eco-friendly packaging, sports equipment, and various other applications due to their environmental benefits and cost-effectiveness. However, PLA suffers from brittleness and poor toughness, which restricts its use in scenarios demanding high toughness. To expand the application range of plant fiber-reinforced PLA-based composites and enhance their poor toughness, this study employed a two-step process involving wheat straw fiber (WF) to improve the interfacial compatibility between WF and PLA. Additionally, four elastomeric materials-poly (butylene adipate-co-terephthalate) (PBAT), poly (butylene succinate) (PBS), polycaprolactone (PCL), and polyhydroxyalkanoate (PHA)-were incorporated to achieve a mutual reactive interface enhancement and elastomeric toughening. The results demonstrated that Fe(3+)/TsWF/PLA/PBS exhibited a tensile strength, elongation at break, and impact strength of 34.01MPa, 14.23%, and 16.2kJ/m(2), respectively. These values represented a 2.4%, 86.7%, and 119% increase compared to the unmodified composites. Scanning electron microscopy analysis revealed no fiber exposure in the cross-section, indicating excellent interfacial compatibility. Furthermore, X-ray diffraction and differential scanning calorimetry tests confirmed improvements in the crystalline properties of the composites. This work introduces a novel approach for preparing fiber-reinforced PLA-based composites with exceptional toughness and strength.
作者机构：
[Li, Xingong; Wu, Yiqiang; Zuo, Yingfeng; Zheng, Long] College of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha 410004, Hunan, P. R. China;[Song, Daihao; Lou, Zhichao] College of Materials Science and Engineering, Nanjing Forestry University, Nanjing 210037, Jiangsu, P. R. China
摘要：
Due to the intensification of electromagnetic pollution and energy shortages, there is an urgent need for multifunctional composites that can absorb electromagnetic waves and provide insulation. However, developing low-cost electromagnetic wave-absorbing composites that are lightweight, high strength, heat-insulating, and large-format for special environments remains challenging. Inspired by the conch shell, this article proposes a green strategy of hydration recrystallization self-assembly. Highly biologically active hydroxyapatite (HAP) was used to lock in free water to prevent porous carbon fibers from absorbing a large amount of water. Meanwhile, HAP underwent ion exchange and recombined with hydrated crystals of magnesium oxychloride to form a gelatinous HAP-5 phase crystal. The cementitious HAP-5 phase crystal was interwoven and interlocked with the support skeleton carbon fibers and metal Ni powder to form conch shell composites (Bio-CSC) with multiple interfaces via electrostatic adsorption and metal complexation. This strategy utilized inorganic substances as bridges to uniformly disperse conductive materials such as carbon fibers to construct a conductive network with an enriched interface polarization. The prepared Bio-CSC was composed of multiple heterogeneous interfaces and was lightweight and high strength, with a specific strength increase of 300%. It also provided excellent thermal insulation and electromagnetic wave absorption. Its thermal conductivity was 0.071 W·m(-1)·k(-1), and the lowest RL(min) value of -21.88 dB, with a matching thickness of only 1.2 mm. The composites in this study overcame the limitations of traditional absorption materials such as high magnetism and single function and may be used in fields such as building energy conservation and electromagnetic safety.
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：
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：
Industrial Crops and Products,2023年194:116344 ISSN：0926-6690
通讯作者：
Wu, Yiqiang(wuyq0506@126.com)
作者机构：
[Li, Kui; Wang, Huifen] Changsha Hanchuang New Material Technology Company Limited, Hunan, Changsha;410004, China;[Zuo, Yingfeng; Zheng, Long; Wu, Yiqiang] College of Materials Science and Engineering, Central South University of Forestry and Technology, Hunan, Changsha;[Li, Kui; Zuo, Yingfeng; Zheng, Long; Wang, Huifen; Wu, Yiqiang] 410004, China
通讯机构：
[Yiqiang Wu] C;College of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha, Hunan 410004, PR China
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.
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：
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.
作者机构：
[Li, Xingong; Wu, Yiqiang; Zuo, Yingfeng; Zheng, Long] Cent South Univ Forestry & Technol, Coll Mat Sci & Engn, Changsha 410004, 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 410004, P.R. China
摘要：
A common method for reducing carbon emissions and the load-bearing pressure of buildings, and while also achieving improved energy conservation is to prepare porous magnesium-based lightweight composites to reduce waste and environmental hazards. However, due to internal stress, the pores of traditional lightweight composites crack easily and collapse, resulting in composites that are brittle with poor water resistance. These materials cannot achieve both low density and high strength, which limits their application in advanced functional materials. Thus, learned from nature, inspired by swallow's nest, a solution has been proposed, which is a simple and fast chemical arrangement and assembly method. Using bamboo scraps as the supporting framework and methylcellulose (MC) molecular chains as the templates, 5-phase crystals are grown and arranged on the MC. These crystals are arranged on the bamboo scraps by chemical means with MC acting as a bridge. At the same time, using the high viscosity and flexibility of the vinyl acetate/ethylene (VAE) copolymer emulsion and the formation of magnesium acetate chelate from VAE and hydration products, crystals and bamboo scraps can be assembled. Through these organic-inorganic copolymers, an intercalated and integrated biomimetic swallow nest structure is formed. The biomimetic swallow nest structure composites (BSNSC) imitated the formation process of a natural swallow nest. It is a lightweight material with a thick wall, low connectivity rate, and regular shape. Its density is 0.42 g/cm(3), which is still in the density class of ultralight inorganic foam materials, and its compressive strength reaches 6.5 MPa, three times that of ordinary composites. The structure has a strength-to-weight ratio 3.5 times that of ordinary composites and a thermal conductivity much lower than of other thermal insulation materials. In the future, this type of lightweight composites with high strength, high heat insulation, and low density not only functions as a good energy-saving material for buildings but also a good thermal insulation material in the aerospace field.
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.
