Experimental Study and Thermal Diffusivity Analysis on Whiteness Reduction of Natural Fiber Fabric Treated with Superheated Steam

ABSTRACT

The family use garment steamers with superheated steam have several advantages but lead natural fiber fabrics whiteness reduction. This study explored the four kinds of natural fiber fabric whiteness reduction both experimentally and theoretically. We first built a temperature controllable 1 atm superheated steam generator, and recorded the whiteness and decrease percentages of cotton, flax, silk and wool fabrics at 150°C, 175°C, and 200°C separately. Then we calculated the monotonically increases thermal diffusivity(α) as a function of fiber volume fraction(${\phi }_f$), and the α is divided into three regions based on the ${\phi }_f$: average region(${\phi }_f$ <0.3), transition region(0.3 < ${\phi }_f$ <0.9) and fiber region(${\phi }_f$ >0.9). The${\phi }_f$ of studied samples are all in the average region, and the whiteness reduction percentage value sequence is opposite with the α, which are a reflection of the samples average properties, which means the design of superheated fabric steamers should depend on the structures or garment types of fabrics rather than fiber types.

摘要

家用的挂烫机及相关设备使用过热水蒸气具有诸多优点, 但是可能会引起天然纤维织物的白度下降, 因此必须针对过热水蒸气对天然纤维织物的白度下降作用进行研究。本研究首先设计并实现了一种可以在1 atm下产生指定过热温度的水蒸气装置。基于此装置本研究测试了棉, 麻, 丝, 毛四种天然纤维的织物在150°C, 175°C和 200°C下的白度变化。此外还使用体积平均法给出了四种织物以纤维体积分数φ_f 为函数的热扩散系数计算方程。计算结果表明四种织物的热扩散系数根据纤维体积分数可以分为三个区域:平均区域 (φ_f ˂ 0.3) 转换区域 (0.3 ˂ φ_f 0.9) 和纤维区域 (0.9 ˂ φ_f) 。四种织物白度下降的百分比的高低排序与恰好与在平均区域内的热扩散系数的计算结果的排序相反, 二者表现出了严格的逆序排列, 而白度的下降与纤维的耐热高低排序关系不大。本文的研究表明, 对于天然纤维织物的熨烫及气蒸设备, 更多的应考虑织物的结构而非纤维本身的性质

KEYWORDS:

• Superheated steamers
• natural fiber fabric
• whiteness reduction
• three regions
• fiber thermal properties
• fiber volume fraction

关键词:

• 过热水蒸气装置
• 天然纤维织物
• 白度损失
• 三个区域
• 熨烫设备
• 纤维热性质