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不同污渍在棉织物上的吸附及脱附研究
Study Onadsorption and Desorption of Different Stains on Cotton Fabrics
【作者】 杨立强;
【导师】 刘学民;
【作者基本信息】 江南大学 , 化学工艺, 2012, 硕士
【摘要】 近年来,由于各种化学纤维用量不断增长,新型去污剂也不断改进,纺织品上污垢的去除还需要更进一步研究。小天鹅公司作为国内知名洗衣机生产商,研究洗衣机最基本的洗涤机理可以直接为产品开发人员提供程序优化方面的支持,提高洗衣机的洗涤效果,不断满足用户的需求。此项研究是和小天鹅公司合作的项目,为公司新产品的研发提供了一定的理论支持。本论文主要通过探索棉织物和几种典型油污的结构成分,研究其吸附/脱附热力学,动力学行为。分子模拟结果表明,油类分子在棉纤维上的吸附性能与温度,压力,分子极性,链数目,官能团的种类,吸附构型等许多因素有关。随着压力增大,吸附量也随之增大,油类分子在100KPa时达到平衡,水溶性分子在400KPa才趋于平衡。升高温度,吸附量先增加,然后到达一点再下降,然后趋于平衡。磷脂酰胆碱和蓖麻油酸甘油脂在308K达最大值,其他分子在328K达到最大值。根据吸附热分布曲线,L-阿拉伯糖和棉纤维的吸附作用较单一,其他分子吸附作用较复杂。油类分子和棉纤维的吸附构型均为平铺方式,并且磷脂酰胆碱和棉纤维的吸附能绝对值最大,吸附最稳定。链结构和官能团的不同对吸附量的影响也很大。范德华力和静电力对结合能的贡献较多,吸附量越大,结合能越大。通过棉织物对液体石蜡,磷脂,蓖麻油,羊毛脂,阿拉伯树胶等污渍的吸附实验研究,表明各类污渍的吸附量随着污渍浓度的增大而增大,在200mg/ml之后逐渐平缓。各种污渍的吸附均可用Freundlich等温式拟合,属于非单层,异质性吸附。吸附量由大到小的顺序为:阿拉伯树胶,磷脂,蓖麻油,羊毛脂,液体石蜡。各种污渍的吸附均符合准二级动力学方程,液体石蜡的吸附速率最快,阿拉伯树胶最慢。棉织物对污渍的脱附等温线表明污渍浓度越高,脱附量越大,羊毛脂最难脱附。随着时间的增大,脱附量增大,到20min时不再变化。各种污渍的脱附均符合准二级脱附动力学方程。阿拉伯树胶的脱附速率最快。通过SEM和IR光谱分析,可以观察到纤维表面污渍的附着形态,纤维上官能团的变化。洗涤后纤维的红外光谱图分析得出有些污渍和纤维之间还有化学吸附产生。通过测定纤维表面上水和乙醇接触角大小,计算未沾染污渍的纤维,沾染污渍后的纤维和清除污渍后纤维表面的自由能大小,结果表明棉纤维沾染上污渍后,水和乙醇的接触角均增大,表面自由能均减小。沾染了污渍的棉纤维在洗涤后接触角均减小,表面自由能增大。最后,关于此项研究的进一步工作做了讨论。
【Abstract】 In recent years, with growing of a variety of chemical fiber consumption,a new detergent has been improved, we also need further study for removal of dirt on textiles. The little swan company as a well-known domestic washing machine manufacturer,they will do some research on basic washing mechanism to provide developers with program optimization supports, enhance the effect of washing machines, and continuously meet the needs of users. We had a cooperation with little Swan company for this research project,we provided a certain amount of theoretical support for new product. This paper mainly through explored the structure of several typical oil and cotton fabrics, studied the Thermodynamics and dynamic behavior of adsorption/desorption.Molecular simulation results showed that the adsorption properties of oil onto the cotton fiber is related with temperature, pressure, molecular polarity, the number of chain, type of functional group, adsorption geometry and many other factors. As the pressure increases, adsorption capacity also increased, the oil molecules was balanced in 100KPa, the water soluble molecules was balanced in 400KPa. When increased the temperature,the adsorption first increased at one point , and then with the at the temperature reduced, became balanced. Phosphatidylcholine and Castor oil acid glycerides was up to the maximum value in 308K, other molecules reaches its maximum value in 328K. The adsorption heat distribution curve told us the adsorption of l-arabinose and cotton fibers is single interaction, the adsorption of other moleculars were more complex. The adsorption configuration of Oil molecules on cotton fiber was tiled. The absolute valueof adsorption energy for phosphatidylcholine was the most, it was the most stable adsorption. Chains and functional groups had a great effect on the amount of adsorption. The Van der Waals forces and static power had a strong contribution to the binding energy,the bigger the adsorption capacity was,the larger the binding energy was.The experimental study of Liquid paraffin, phospholipids, castor oil, lanolin, Gum Arabic adsorption on the cotton fabric showed that with all kinds of concentration of stains increased, the amount of absorption increased, gradually subdued after the 200mg/ml. belonging to a monolayer, heterogeneity of adsorption,various stains were fitted to Freundlich isotherm adsorption. The Adsorption order from largest to smallest was: Gum Arabic, phospholipids, castor oil, lanolin, liquid paraffin. Various stains were agreed with quasi-second dynamic equation of adsorption, the adsorption rate of liquid paraffin was the fastest, Gum Arabic was the slowest.Desorption isotherms of the stains showed that with higher stain concentration the desorption rate was higher,the lanolin was the hardest to desorpt. As time increased, desorption rate increased, it would no longer be changed in 20min. Various stains were agreed with quasi-second dynamic equation of desorption. The desorption rate of gum Arabic was the fastest. From the SEM and IR spectroscopy, attachment patterns and functional groups of fiber surface can be observed. From IR spectrum analysis of fiber after washing we knew that there was chemical adsorption between the stains and fibers.By measuring the contact angle of water and ethanol on fiber surface,we evaluated surface free energy of a contaminated dirt fibers, fibers and fiber after cleaned. Results showed that after contaminated, the contact angle of water and ethanol were all increased, the surface free energy were all decreased.When the contaminated fibers were after cleaned, the the contact angle of water and ethanol were all reduced, the surface free energy were all increased.Finally, further works on this study were discussed.
【Key words】 Cotton fabric; oil stains; adsorption; desorption; molecular simulation;