Effects of heat treatment on physicomechanical properties and biological resistance of bamboo SiO2 composites

• Main Authors: Ya-Wen Cheng, 鄭雅文
• Other Authors: 楊德新
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/15269587564027768496

碩士 === 國立中興大學 === 森林學系所 === 104 === Heat-treatment technique is an environmentally friendly method to modify wood properties in Europa. After the treatment, some mechanical properties are reduced but the dimensional stability and the biological durability of wood is increased without adding extra chemicals or biocides agents. Therefore, heat treated wood is discussed as a new material for several applications. Bamboo is used for various applications, such as light construction and building materials, scaffolding, panel and handicrafts. However, bamboos are vulnerable to decay fungi and boring insects. Similar techniques have been also successfully applied to improve the dimensional stability and biological durability of bamboos. The mechanical properties of the heat-treated bamboos, however, may decrease after thermal treatment and therefore affect the applicability of the products for structural uses. The objects of this research are to apply the sol-gel technique to implant nano-inorganic particles in the thermal treated bamboos to modify their mechanical properties, and to manufacture a green structural material – a heat-treated bamboo / nano-inorganic composite. The overall research project will be conducted and performed sequentially. Results indicated that the equilibrium moisture content was decreased with increasing heat treatment temperatures and treatment times, however there was increased in mass loss. Results also indicated that the color and surface roughness of bamboo affected by thermal treatment process. The outer layer and inner layer of L* value decreased from 77.56 to 29.69 and 79.45 to 31.32 in CIE Lab method, respectively. After impregnated with SiO2, there is a significant increase on contact angle, but as the temperature and time of heat treatment increases, the contact angle appears to have a declining trend. The mechanical strength of bamboo impregnated with SiO2 is higher than the control group, and shows an upward trend as the WPG increases; as for the bending strength, ether the impregnated bamboo or the control group shows a declining trend as the temperature and time of heat treatment increase, the higher the temperature is, the higher Brinell hardness will be, also the outer layer is normally higher than the inner layer. In addition, the thermogravimetric analysis (TGA) shows that after impregnated with SiO2, the weight residual rate and the thermal properties has an increasing trend. The FTIR results also shows that SiO2 is truly present on the surface of bamboo after impregnation, and the retention will increase with the WPG and heat treat temperature increased. As for the biological durability properties, bamboo impregnated with SiO2 can effectively reduce the mass loss ratio in an anti-termite test. Further, the WPG28 groups show the better decay resistance when compared to the WPG18 groups.