期刊：
材料导报,2017年31(12):96-100 and 104 ISSN：1005-023X
通讯作者：
Wu, Yiqiang(wuyq0506@126.com)
作者机构：
[肖俊华; 王健; 左迎峰; 吴义强] College of Material Science and Engineering, Central South University of Forestry and Technology, Changsha;410004, China;[詹满军] Guangxi Fenglin Wood Industry Group Co. Ltd., Nanning;530031, China;[陈秀兰] Dare Wood-based Panel Group Co. Ltd., Zhenjiang
通讯机构：
[Wu, Y.] C;College of Material Science and Engineering, Central South University of Forestry and Technology, Changsha, China
作者机构：
[左迎峰; 吴义强; 佘佳荣; 郭鑫; 江萍] College of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha;410004, China;[顾继友] Key Laboratory of Bio-Based Material Science and Technology of Ministry of Education, Northeast Forestry University, Harbin;150040, China;[左迎峰; 吴义强; 佘佳荣; 郭鑫; 江萍] 410004, China
通讯机构：
[Wu, Y.] C;College of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha, China
摘要：
Esterified starch/polylactic acid (ES/PLA) blending composite was prepared by melting extrusion with maleic anhydride esterified starch and PLA as the raw materials. The composite was accelerated aging by using UV aging box, and its properties were characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), X-ray diffraction (XRD), thermo gravimetric analysis (TGA) and mechanical testing machine. FT-IR and SEM results show that the infrared absorption peak intensities of C-O, C-H, and C=O in aged samples decrease gradually with increasing aging time. The damage degree of surface and internal of aged samples increases gradually. XRD analysis results show that after aging treatment, the crystalline diffraction peak of thermoplastic esterified starch at 2θ = 21° disappears and the diffraction peaks of PLA at 2θ = 16.5° appear, indicating that the hydrolysis rate of esterified starch is greater than that of PLA. The crystallinity of PLA in aged sample shows an increasing trend at first followed by a decreasing one along with the increasing time of aging treatment, suggesting that the hydrolysis of amorphous regions of PLA is more preferential than its crystalline regions. Because of the influence of crystal structure and the change of composition structure, the initial decomposition temperature of aging test specimen gradually increases with the extension of aging time. The maximum decomposition rate temperature and residual mass increases at first, and then decrease after the aging time extending to 1 600 h. As the aging time increases, the damage degree of combination interface between esterification starch and PLA is exacerbated, resulting in the tensile strength and bending strength of aged specimen decreasing gradually.
摘要：
The application of superhydrophobic wood is majorly limited by its durability when subjected to natural conditions. Herein, the stability of two representative superhydrophobic woods (i.e., Poplar (Populus tomentosa) and Chinese fir (Cunninghamia lanceolata)), were prepared via a one-step hydrothermal process using tetrabutyltitanate (Ti(OC4H9)(4), TBOT) and vinyltriethoxysilane (CH2CHSi(OC2H5)(3), VTES) as a co-precursor and sequentially tested under different humidity and temperature conditions. The variables including morphology, water contact angle (WCA), color parameter, chemical components of the surface, and moisture absorption property were characterized using a scanning electron microscope (SEM), WCA measurement, a colorimeter, a Fourier transform infrared (FTIR) spectroscopy, and a moisture absorption test, respectively. It was found that initial static WCAs of superhydrophobic wood were larger than 150 degrees. Micron-sized cracks were formed on the coatings after the alternating humidity and temperature aging cycles. This lowered the water repellency, but the WCA was still greater than 140 degrees. There was nearly no chemical change of wood after the aging test; the color change between the same species of untreated and superhydrophobic wood was very small, only with a difference of 0.42 and 4.05 in overall color change DE/values for Chinese fir and poplar, respectively. The superhydrophobic coatings had a trivial influence on wood moisture absorption property, which only lowered 3% in poplar and 2% in Chinese fir, respectively. (C) 2017 Published by Elsevier B. V. This is an open access article under the CC BY-NC-ND license
作者机构：
[郭鑫; 吴义强; 李贤军] College of Material Science and Engineering, Central South University of Forestry and Technology, Changsha, 410004, China;[郭鑫] College of Sciences, Central South University of Forestry and Technology, Changsha, 410004, China
通讯机构：
College of Material Science and Engineering, Central South University of Forestry and Technology, Changsha, China
关键词：
wood;water distribution;existing states
摘要：
Wood-water relationship has been studied since the beginning of wood research. With the development of new technology,vast modern analytical method are emerging,and the study of wood-water relationship is changing from macro to micro scale and from cell to molecular level. The main objective of this paper was to review the modern analytical techniques which have been applied to study the wood-water relationship. This paper was divided into four parts. Firstly, the extremely heterogeneity of the wood cell wall structure and chemical composition and the highly complex states of water were discussed,and then the distribution and existing states of water in wood was summarized as an active field of the research about wood-water relationship. Secondly,the application of four kinds of analytical techniques,such as magnetic resonance imaging(MRI),computed tomography(CT),neutron imaging(NI) and vibrational spectroscopic imaging,in the study of water distribution were summarized. Meanwhile,the advantages and limitations of these four techniques were provided. Some of the latest research progress was: Vibrational spectroscopic imaging techniques such as micro-FTIR and confocal Raman could offer visual examination and spectral information of chemical functional groups in situ,and owned high spatial resolution on the micrometer length scale. The spatial resolution of micro-FTIR imaging technique was 6.25 μm by the instrumental parameters,and the spectral changes indicated that the adsorbed water concentration was nonuniform at the cell structure level. Meanwhile,the spatial resolution of confocal Raman imaging technique was higher than 1 μm,and the spectral changes indicated that the amount of water in the cell corner(CC) was less than that in the middle layer of secondary wall(S2) throughout the entire range of relative humidity(RH) levels. Thirdly,the recent advances in the application of four kinds of analytical techniques,such as near infrared(NIR) spectroscopy,nuclear magnetic resonance(NMR),fourier transform infrared spectroscopy(FTIR) and Raman spectroscopy,were discussed in the study of existing states of water in wood. The advantages and limitations of these four techniques were also provided. Some of the latest research progress was: The micro-FTIR spectroscopy and a specially designed sample cell were used to examine the molecular association of adsorbed water with wood during adsorption process. It was confirmed that carboxyl CO,C—O groups as well as OH groups were active sites for water adsorption. Meanwhile,strongly,moderately and weakly hydrogen-bonded water molecules were identified and assigned. What's more,according to the variation trend of these hydrogen-bonded water molecules,three sections were divided for adsorption process. Furthermore,the existing states of water in each section was demonstrated as CO…(HOH) …OH or OH…(OH_2) …OH、WATER…HOH… WATER,and tetrahedral structure. Finally,some future research subjects in the research about wood-water relationship were proposed,such as applying new approaches with greater accuracy and higher resolution,developing the convincing component band analysis.
作者机构：
[Luo, Yan; Liu, Xiaomei; Wan, Hui; Shmulsky, Rubin] Mississippi State Univ, Dept Sustainable Bioprod, Mississippi State, MS 39762 USA.;[Wu, Yiqiang] Cent South Univ Forestry & Technol, Sch Mat Sci & Engn, Changsha 410004, Hunan, Peoples R China.;[Wang, Xiaodong (Alice)] Lulea Univ Technol, Wood Prod Engn, Forskargatan 1, SE-93187 Skelleftea, Sweden.;[Chu, I. Wei] Mississippi State Univ, Inst Imaging & Analyt Technol, Mississippi State, MS 39762 USA.
通讯机构：
[Wan, Hui] M;Mississippi State Univ, Dept Sustainable Bioprod, Mississippi State, MS 39762 USA.
关键词：
Isocyanate resin;Molecular weights;Morphology and structure;Phenolic resins
摘要：
Co-polymer systems of methylene diphenyl diisocyanate (MDI) and phenol-formaldehyde (PF) resins with different molecular weights were characterized by infrared spectroscopy (FTIR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The FTIR and TGA coupled with differential thermogravimetric (DTG) results showed that higher molecular weight of PF resins not only promoted the reaction of isocyanate and PF co-polymer system, but also resulted in a better thermal property of prepared co-polymers. The XRD results revealed that higher molecular weight led to a higher proportion of ordered or crosslinking structures in the hybrid resin system. The relationship between the thermal resistance, mechanical properties and the molecular weights of phenolic resins needs further study.
作者：
Jiang, Ping;Jia, Shan Shan;Wang, Shuang;Xiao, Jun Hua;Liu, Wenjie;...
期刊：
JOURNAL OF BIOBASED MATERIALS AND BIOENERGY,2016年10(4):284-289 ISSN：1556-6560
通讯作者：
Wu, Yiqiang
作者机构：
[Wu, Yiqiang; Xiao, Jun Hua; Jia, Shan Shan; Wang, Shuang; Jiang, Ping; Liu, Wenjie] Cent South Univ Forestry & Technol, Coll Mat Sci & Engn, Changsha 410004, Hunan, Peoples R China.
通讯机构：
[Wu, Yiqiang] C;Cent South Univ Forestry & Technol, Coll Mat Sci & Engn, Changsha 410004, Hunan, Peoples R China.
关键词：
CHITOSAN;CHITOSAN-GRAFT-POLY(2-(DIMETHYLAMINO) ETHYL METHACRYLATE);FRESH-KEEPING;GRAPE;PH- AND TEMPERATURE RESPONSIVE
摘要：
The pH- and temperature-responsive chitosan-graft-poly(2-(dimethylamino) ethyl methacrylate) (CS-g-PDMAEMA) were synthesized via atom transfer radical polymerization (ATRP) and evidenced by FTIR spectroscopy. Chitosan macroinitiator (CS-Br) was prepared by phthaloylation of amino groups of chitosan and acylation of hydroxyl groups of chitosan with 2-bromoisobutyryl bromide. The pH and temperature responses of the copolymer micelles were characterized by particle diameter and particle size analyzers. The film prepared from CS-g-PDMAEMA was used as a coating film on the surface of the grape. And the film prepared from 1 wt% CS-g-PDMAEMA solution was able to slow the loss of water in grape. The results revealed that the CS-g-PDMAEMA had potential application as active coating materials in the storage of fresh grape.
摘要：
For lignocellulosic materials, water adsorption is extremely important for its product performance. For gaining a deeper understanding of moisture adsorption mechanisms, the molecular interactions between adsorbed water and a typical lignocellulosic material (i.e., wood) were studied using in-situ microscopic Fourier transform infrared (micro-FTIR) spectroscopy and a specially designed sample cell. The spectral shifts of 1733 cm(-1), 1604cm(-1) and 1236 cm(-1) and different spectra between the moist and dry spectra indicated that carbonyl C=O and C-O groups preferred to combine with water molecules to form hydrogen bonds. From component band analysis of the spectral range of 2900-3700 cm(-1), three peaks at 3178 cm(-1), 3514cm(-1) and 3602 cm(-1) were identified and assigned to strongly, moderately and weakly hydrogen-bonded water molecules, respectively. According to the variation trend of these hydrogen-bonded water molecules, three sections were divided for the adsorption process. Furthermore, the molecular structure of water absorbed by hydrophilic groups of wood in each section was demonstrated. (C) 2015 Elsevier B.V. All rights reserved.
作者机构：
[Qin Y.; 彭辉艳; 邓凌峰; 吴义强] School of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha, 410004, China
通讯机构：
[Deng, L.] S;School of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha, China
作者机构：
[Li, Xingong; Li, Yun; Wu, Yiqiang; He, Xia; Cheng, Xiyi; Li, Xianjun] Cent South Univ Forestry & Technol, Mat Sci & Engn Coll, Changsha 410004, Hunan, Peoples R China.;[Liu, Dandan] Nanjing Forestry Univ, Coll Furniture & Ind Design, Nanjing 210037, Jiangsu, Peoples R China.;[Huang, Qiongtao] Yihua Enterprise Grp Co Ltd, Yihua Timber Ind, Shantou 515834, Guangdong, 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：
Dimensional stability;Energy storage and saving;Polyethylene glycol (PEG);Thermal properties;Wood
摘要：
Green fir wood (Pseudotsuga menziesii) was modified with polyethylene glycol (PEG) to produce wood composites for energy storage and conversion. The PEG-modified wood composites were evaluated based on their dimensional stability, durability, and thermal properties by various analytical methods. The differential scanning calorimetry (DSC) results showed the melting temperature and the latent heat of the phase change material (PCM) composite were 26.74 °C and 73.59 J/g, respectively. Thermal cycling tests and thermogravimetric analysis confirmed the composite exhibited good thermal stability, reliability, and chemical stability. All treated specimens were free from noticeable defects, and the addition of a surface varnish coating prevented PEG from leaching. The PEG-modified composites exhibited improved dimensional and thermal performance, which makes this material a potential candidate for economical and green, lightweight building materials.
作者机构：
[左迎峰; 赵星; 吴义强] College of Material Science & Engineering, Central South University of Forestry & Technology, Changsha;410004, China;[张彦华; 顾继友] College of Material Science & Engineering, Northeast Forestry University, Harbin;150040, China;[左迎峰; 赵星; 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
