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Properties of Chinese fir modified by impregnating silicate biomimetic respiration(PDF)

Journal of Forestry Engineering[ISSN:2096-1359/CN:32-1862/S]

Issue:
2020 No.06
Page:
57-63
Research Field:
木材科学与技术 执行主编:吴义强 梅长彤
Publishing date:
2020-11-01

Info

Title:
Properties of Chinese fir modified by impregnating silicate biomimetic respiration
Author(s):
LI Ping1 ZHANG Yuan1 ZUO Yingfeng1 LYU Jianxiong2 WANG Xiangjun3 WU Yiqiang1*
1. College of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha 410004, China; 2. Research Institute of Wood Industry, Chinese Academy of Forestry, Beijing 100091, China; 3. Tianying (Guangdong) Wood Industry Technology Limited Company, Jiangmen 529700, Guangdong, China
Keywords:
Chinese fir wood modificationsilicate bionic respiration method physical and mechanical properties heat resistance
PACS:
S781.7
DOI:
10.13360/j.issn.2096-1359.202002014
Abstract:
Chinese fir has some major drawbacks, such as loose structure, light and soft, low strength, etc. Impregnation modification is an important method to improve its properties. However, the traditional organic resin impregnation modification had the serious problems of releasing toxic gas, inflammable, etc. In view of this, the mechanical properties, dimensional stability, fire resistance and smoke suppression of Chinese fir can be significantly improved by impregnation of inorganic materials, which can convert low grade Chinese fir into the high value wood products. The silicate modified Chinese fir was prepared by the bionic respiration method, in which, sodium silicates were used as the impregnating modifier, and the compound of sulfate, calcium salt and phosphate were as the curing agents. The effects of sodium silicate modulus, sodium silicate concentration, impregnation pressure, impregnation time, breathing times and respiration rate (negative pressure time/positive pressure time) on the weight percentage gain and mechanical properties of modified Chinese fir were studied. The micro morphology and heat resistance of the modified wood were characterized by the scanning electron microscopy (SEM) and thermogravimetry (TGA). The results showed that, when the sodium silicate modulus was 3.4, the sodium silicate concentration was 30%, the impregnation pressure was 0.5 MPa, the impregnation time was 3 h, the breaths time was 6 times, and the respiration rate was 2∶4, the weight percentage gain, bending strength, compressive strength and three section hardness of the modified Chinese fir were the best. After the silicate biomimetic modification, the transverse section and longitudinal section of the modified Chinese fir were filled with silicates, which was also the reason for the improvement of the mechanical properties of Chinese fir. The TGA analysis showed that the heat resistance of the modified Chinese fir was significantly improved compared with that of unmodified Chinese fir.

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Last Update: 2020-11-11