作者机构：
[李中昊; 张晓萌; 周川玲; Lü J.; 李贤军] College of Material Science and Engineering, Central South University of Forestry and Technology, Changsha, 410004, China;Zhejiang Academy of Forestry, Hangzhou, 310023, China;[徐康] College of Material Science and Engineering, Central South University of Forestry and Technology, Changsha, 410004, China, Zhejiang Academy of Forestry, Hangzhou, 310023, China
通讯机构：
[Xu, K.] C;College of Material Science and Engineering, China
期刊：
Industrial Crops and Products,2020年145 ISSN：0926-6690
通讯作者：
Li, Xianjun
作者机构：
[Yang, Xi; Li, Xianjun; Cao, Min] Cent South Univ Forestry & Technol, Coll Mat Sci & Engn, Changsha 410004, Peoples R China.;[Liu, Xinge; Kong, Lingyu] Int Ctr Bamboo & Rattan, Dept Biomat, Key Lab Bamboo & Rattan Sci & Technol, Beijing 100102, Peoples R China.
通讯机构：
[Li, Xianjun] C;Cent South Univ Forestry & Technol, Coll Mat Sci & Engn, Changsha 410004, Peoples R China.
关键词：
Capacitive behavior;Porous carbon nanosheets;Rattan-based carbon aerogel;Supercapacitors;Wide-range of miro-mesopores
摘要：
Porous carbon materials with well distributed micro-mesopores from biomass resources for supercapacitors application have attracted considerable attention because of both the environmental issues caused by fossil and its great depletion. A novel porous nanposheets-based carbon aerogel was synthesized by a combined process of complete delignification, carbonization and chemical activation of a sustainable source of rattan. The biomass supramolecular structure changes and carbon formation were technically monitored by spectroscopy and thermochemistry. Based on the metabolic channels and preparation resulted pores, the nanposheets-based carbon aerogel shows a large number of and a wide range of miro-mesopores together with a large specific surface area (2436 m(2) g(-1)). When used as an active material for supercapacitor, such rattan derived hierarchical porous carbon aerogel reveals an inspiring specific capacitance of 221 F g(-1) at 0.5 A g(-1) and an excellent rate capability of owing 80% capacitance retention at a current density of 20 A g(-1). These promising characteristics provide a high-value solution for developing renewable rattan source into an active material for high-performance supercapacitors.
摘要：
The Box-Behnken Design (BBD) and Response Surface Methodology (RSM) was extended to study the impregnation process on optimized furfurylated bamboo. The effect of furfuryl alcohol (FA) concentration, impregnation pressure and impregnation time on weight percentage gain (WPG) and chromatic aberration (CA) of bamboo were investigated. The regression model for impregnation process was significant (p < 0.01), and the FA concentration had a significant effect on WPG, meanwhile FA concentration and impregnation time had significant effects on CA. The experimental results indicated that the optimal conditions were 18.89%, 0.41 MPa and 44.89 min for FA concentration, impregnation pressure and impregnation time, respectively. Under this condition, the WPG and CA were found to be 16.52% and 57.13 NBS respectively, which were in agreement with the predicted value (15.81% and 56.71 NBS). At optimized conditions of impregnation process, the analysis of Fourier transform infrared (FTIR) spectrometry revealed that FA could polymerized inside the bamboo or underwent a substitution reaction with the hydroxyl group within the cell wall.
作者：
He Xia;Wang Yong;Li Yunyan;Wei Yanqiang;Quan Peng;...
期刊：
Science of Advanced Materials,2020年12(8):1236-1241 ISSN：1947-2935
通讯作者：
Li Xianjun
作者机构：
[Li Yunyan; He Xia; Li Xianjun; Quan Peng; Wei Yanqiang; Wang Yong] Cent South Univ Forestry & Technol, Mat Sci & Engn Coll, Changsha 410004, Hunan, Peoples R China.;[Wang Yong] Hunan Acad Forestry, Inst Forest Prod & Ind, Changsha 410004, Hunan, Peoples R China.
通讯机构：
[Li Xianjun] C;Cent South Univ Forestry & Technol, Mat Sci & Engn Coll, Changsha 410004, Hunan, Peoples R China.
关键词：
Eucalyptus urophylla;Dielectric Properties;Moisture Content;Grain Direction;Temperature;Radio Frequency
摘要：
Dielectric properties of Eucalyptus urophylla wood were measured by using a network analyzer over an ultra-wide frequency range between 0.2 GHz and 20 GHz. The effects of moisture content (MC), temperature and frequency on the dielectric permittivity and the dielectric loss factor of Eucalyptus urophylla were investigated along different grain directions. The results showed that the dielectric permittivity along with the dielectric loss factor increased significantly with the elevation in MC. At the frequency of 2380 MHz with the MC increasing from 0% to 100%, the dielectric permittivity along different grain directions (including longitudinal, radial and tangential directions) increased by 180%, 110% and 112%, respectively, while the loss factor along these three directions increased by 1642%, 3703% and 5058%, respectively. In addition, the increase in dielectric properties of Eucalyptus urophylla wood was determined with the temperature elevating. When the temperature elevated from 20 degrees C to 140 degrees C, the dielectric permittivity at 2380 MHz along the longitudinal, radial and tangential directions, increased by 19%, 14% and 15%, respectively, while the loss factor increased by 133% at most. As the radio frequency increased, the dielectric permittivity of wood decreased. Regression equations satisfactorily described the dielectric properties of wood along different grain directions with different moisture contents.
摘要：
To improve the hydrophobicity and thermoplastic processability of starch, lactic acid esterified starch (LA-e-starch) was prepared by in-situ solid phase esterification with corn starch as the raw material and LA as the esterifying agent. Fourier transform infrared spectroscopy confirmed that the esterification reaction was successful. The optimal esterification efficiency of LA-e-starch was obtained when the LA proportion was 20% by mass, catalyst ratio at 3%, reaction temperature 80 degrees C and reaction time 2.5 h. LA-e-starch was characterized by scanning electron microscopy (SEM), contact angle (CA) analysis, X-ray diffractometry (XRD), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA) as well as its water absorption rate evaluated. Results showed that in-situ solid phase esterification mainly occurred on starch granule surfaces and did not destroy the starch granularity. LA-e-starch surfaces were covered with a layer of polylactic acid resin, which caused starch granules to stick together. The initial contact angle of LA-e-starch was clearly larger than that of native starch and the water absorption rate lower than native starch in a 168 h test time, which showed that esterification effectively improved the hydrophobicity of starch. This esterification destroyed the crystalline structure of starch to some extent, resulting in a crystallinity reduction to 25.16%. In addition, the gelatinization temperature and enthalpy were lower than those of native starch. XRD and DSC analyses indicated that esterification modification increased starch thermoplasticity. Also, LA-e-starch exhibited better thermal stability than native starch, from which it was inferred that this application of esterification could improve the thermoplastic processability of starch modify the interfacial compatibility between starch and polymer resins.
摘要：
Wood carbon slices derived from wood scraps for constructing energy storage electrodes are very important, because they have excellent characteristics, such as structural stability, long cycle life, abundant resources and low prices. However, they have low capacitance as electrode materials for supercapacitors. In this paper, we design a new concept to obtain a porous wood carbon electrode with a large specific surface area. Firstly, CO2 is used to activate carbonized wood to open some closed pores and create some new pores. The activated wood is then soaked into KOH solution to further create new pores. Finally, the carbonized wood is modified with HNO3. After the above treatments, the number of nanopores with a diameter of approximately 2 nm is greatly increased within the wood carbon slices, and their specific surface area is increased to 703.5 m(2) g(-1). The single electrode material shows excellent performance with a high specific capacitance of 285.6 F g(-1) and a high energy density of 38.0 mWh cm(-3), which has more than twice the capacitance of the supercapacitor based on biomass carbon materials modified by diluted HNO3. Therefore, the application of wood scraps can meet the basic energy storage needs and realize the waste into treasure.
摘要：
The synthesis and electrical double-layer capacitor (EDLC) application of hierarchical porous bio-carbons with micropores to macropores have attracted considerable attention due to the limited fuels and environmental issues. The dependence of EDLC performance on the microstructure, pore texture, electrical conductivity and surface functionality of porous carbon aerogels (PCAs) originating from bamboo cellulose, were investigated. The result demonstrates that the highest stability EDLC has excellent cycle life with 100% capacitance retention at 30,000th cycle, which is mainly attributed to a hierarchically porous structure of owning a large micropore volume and a small mean pore size instead of the highest specific surface area. The superior capacitance and rate capability are highly dependent on the surface area and pore volume of PCAs, which are improved by increasing both activation temperature and KOH mass. These results provide another view for developing renewable and high-stable supercapacitors based on porous carbon aerogels with a large micropore volume.
摘要：
The objective of this paper was to develop a novel cross-linking agent to improve the water resistance of soy-based adhesive. The cross-linking agent was synthesized by polypropylenglycol diglycidyl ether (PPDGDE) and triethylene tetramine (TETA), and characterized by Fourier transform infrared spectroscopy (FTIR) to investigate the reaction between PPDGDE and TETA. The adhesive samples were analyzed by FTIR and X-ray photoelectron spectrometer (XPS). Also, three-plywood panels were prepared to examine the shear strength. The water-insoluble content and thermal behavior of all adhesive samples were also investigated in detail. The results showed that the wet shear strength of the plywood bonded by the resulting adhesive increased by 161.3% to 0.81 MPa with 65% water-insoluble content compared to the unmodified soy-based adhesive, which met the requirements of type-II applications (Chinese Standard GB/T 9846.3). Through FTIR and XPS analyses, it was found that the cross-linking degree and hydrophobic groups of the resulting adhesive were both increasing. Because PPDGDE and TETA established a network structure with epoxy groups after the synthesis reaction, which afterward formed an interpenetrating network structure with soy protein molecules, and thus enhanced water resistance of the resulting adhesive. Moreover, TG analysis demonstrated that thermal stability of the modified adhesive was much better than the pristine adhesive, also verifying the formation of network structure.
摘要：
In this paper, thermogravimetric (TG) analysis was carried out to make clear the curing properties of soy flour-based adhesives (SFAs) enhanced by waterborne polyurethane (WPU) with different addition levels. The kinetic parameters were evaluated by a thermal dynamics method, including activation energy and preexponential factor. In addition, the structure characteristics of both soy flour and modified soy flour-based adhesives were tested by Fourier transform infrared spectroscopy (FTIR). The results revealed that the FTIR spectra of pristine soy flour-based adhesives were different from those of soy flour after alkali treatment and waterborne polyurethane modification. Furthermore, there were four main degradation phases in the derivative thermogravimetric (DTG) curves of modified soy-based adhesives while there were two phases of a defatted soy flour sample. The kinetics analysis demonstrated that the curing process could be described as a consecutive first-order curing process. Moreover, with the addition level of WPU growing, the apparent activation energy of each phase of the curing process was increasing compared with that in pristine soy-based adhesives.
摘要：
The objective of this paper aimed to develop a novel method to prepare enhanced bamboo-based materials. Furfuryl alcohol (FA) was used as the modification agent with maleic anhydride (MA) as the catalyst. Different bamboo samples were prepared with different FA addition level (10 wt%, 20 wt% and 30 wt%). The furfurylated bamboo samples were characterized by confocal laser scanning microscopy (CLSM), Fourier transform infrared spectrometry (FTIR), X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA). Moreover, the physical and mechanical properties including weight percent gain (WPG), water uptake (WU), thickness swelling (TS), modulus of rupture (MOR), and modulus of elastic (MOE) were investigated in detail. Additionally, the decay resistance of pristine and furfurylated bamboo samples was also investigated. The results showed that FA resins were incorporated into bamboo and polymerized within cell walls. The WPG, WU, and TS were dependent on FA addition level. When the FA addition level reached 30 wt%, the physical properties were all improved significantly. However, due to acidic MA as the catalyst, MOR of furfurylated bamboo samples was enhanced only 2.5% while MOE was weakened. The thermal stability and decay resistance of furfurylated bamboo were all enhanced significantly compared to pristine bamboo. Especially, furfurylated bamboo treated with 30 wt% FA achieved Class I Strong Decay Resistance (<10%) with 5.3% of mass loss.
作者机构：
[Hu, Jinbo; Liu, Yuan; Lu, Zhou; Hu, JB; Chang, SS; Chang, Shanshan; Li, Xianjun; Liu, Gonggang; Zhu, Xiu] Cent South Univ Forestry & Technol, Hunan Prov Key Lab Mat Surface & Interface Sci &, Coll Mat Sci & Engn, Shaoshan South Rd 498, Changsha 410004, Hunan, Peoples R China.;[Du, Xiaoqing] Foshan Univ, Sch Mat Sci & Energy Engn, Foshan 528300, Peoples R China.
通讯机构：
[Hu, JB; Chang, SS] C;Cent South Univ Forestry & Technol, Hunan Prov Key Lab Mat Surface & Interface Sci &, Coll Mat Sci & Engn, Shaoshan South Rd 498, Changsha 410004, Hunan, Peoples R China.
摘要：
Bamboo with the outstanding properties, such as good mechanical strength, fast growth rate and low growth cost, is considered as one of utilitarian structural nature materials. But bamboo is easy to get mildewed resulting in disfiguration and fungi corrosion. In this work, a facile method was developed to improve the mildew-proofing capability of bamboo. Mussel-inspired polydopamine (PDA) with biomimetic adhesion function and highly active functional groups was employed to immobilize highly-dispersed Ag and TiO2 nanoparticles on the surface of bamboo via an in-situ growth method. Integrating the uniform PDA coating, photocatalytic function of TiO2 nanoparticles and bactericidal role of Ag nanoparticles, the mildew-proofing capability of bamboo is enhanced significantly. The results show a non-covalent interaction is more likely to account for the binding mechanism of PDA to bamboo. And the prepared bamboo samples show good photocatalytic performance and have excellent resistance leachability. Meanwhile, the mildew-proofing property of prepared bamboo sample was greatly improved.
作者机构：
[左迎峰; 肖俊华; 李萍; 王健; 李贤军; 吴义强] College of Material Science & Engineering, Central South University of Forestry & Technology, Changsha;410004, China;College of Art & Design, Xiangnan University, Chenzhou;423000, China;[左迎峰; 肖俊华; 王健; 李贤军; 吴义强] 410004, China
通讯机构：
[Wu, Y.] C;College of Material Science & Engineering, Central South University of Forestry & Technology, Changsha, China
