Mechanical properties of flax fibres treated by alkaline,enzyme and steam-heat

In recent years there has been interest in using flax fibres to produce composites because of a number of attributes, including low density, biodegradability and high mechanical properties. It was found that treatment of flax fibres may be required to improve the bond quality with a resin. These treatments also have an impact on the properties of the fibres themselves. The objective of this project was to evaluate the impact of three treatment methods on the mechanical properties of flax fibres. The three treatment methods were alkaline, enzyme and steam-heat. After treatment, flax fibres were tested in tension using a universal test machine. Results showed that tensile strength and Young's modulus of flax fibre can be enhanced significantly by the three treatment methods, compared with untreated flax fibres. Enzyme treatment was shown to be the best approach to improve mechanical properties of flax fibre than alkaline and steam-heat treatment.

蒸汽介质热处理对毛白杨木材颜色的影响

以毛白杨木材为研究对象,采用蒸汽介质热处理方法在氧气含量低于2%的密闭容器中以温度170～230℃、时间1～5h的处理条件对其进行热处理。结果表明:随着处理温度的升高和处理时间的延长,色饱和度差ΔC*逐渐减小、色差ΔE*和色相差ΔH*逐渐增大,说明热处理后木材的颜色由原色逐步过渡到深褐色。方差分析和多重比较结果表明:热处理温度比热处理时间对毛白杨木材颜色变化的影响更为重要。此外,进一步得出了色差值与热处理温度、时间三者之间的回归模型。利用此特性,对一些浅色木材进行热处理,可赋予其凝重的颜色,同时还可增强其尺寸稳定性,从而提高其产品附加值,扩大应用领域。