苯甲醇在阳离子染料染阴离子改性涤纶中的作用机理

对文题的研究表明,染料阳离子与纤维内部的阴离子经离子交换而结合。染色是放热及熵减小过程。苯甲醇的存在,提高了染色饱和值和染色速度;降低了染色亲合力、染色热及染色熵;消除了环染,其效果随染浴(或纤维)内苯甲醇浓度的升高而加强。用红外光谱法及X-射线衍射法测定了经苯甲醇水溶液处理过的聚合物的结晶性能;用差式扫描量热法、拉伸试验和动态粘弹谱等方法测定了该聚合物的熔融及力学性能。结果表明,苯甲醇渗入了聚合物(纤维)内部,并减弱其非晶区的分子间的相互作用,但不破坏结晶区,同时导致纤维溶胀,链段淌动性加强,因而促进了染色。

Mechanism of Cationic Dyeing of an Anion-Modified Polyester with Benzyl Alcohol as a Carrier

The dyeing behaviour of an anion-modified polyester with C. I. Basic Blue 5 in an aqueous solution of benzyl alcohol has been investigated. Sorption isotherms indicate that dye cations combine with anions within the fiber through ion exchange. It has been found by thermodynamic analysis that the dyeing process is an exothermic reaction with a decrease of entropy. The presence of benzyl alcohol in the dyeing bath raises the saturation value and the rate of dyeing, while the affinity, heat and entropy change of dyeing are lowered, thus leading to the elimination of ring-dyeing. All these effects are enhanced with the increase of the concentration of benzyl alcohol in the dyeing bath (or in the fiber).Crystallization properties of the polymer treated with an aqueous solution of benzyl alcohol have been determined by methods of infrared spectroscopy and X-ray diffraction. Drawing test as well as methods of DSC and DDV have been employed to determine the thermal and mechanical properties of this polymer. Experimental results indicate that benzyl alcohol penetrates into the polymer and weakens the intermolecular interaction in its amorphous region without any impairment of its crystalline region. Meanwhile, the fiber becomes swollen and its segmental mobility is further increased. The process of dyeing is therefore promoted.