纤维管增强聚偏氟乙烯中空纤维膜界面处理及性能研究

发布时间：2018-03-24 21:42

本文选题：纤维管　切入点：偶联剂　出处：《天津工业大学》2017年硕士论文

【摘要】：随着社会的经济发展和人口增长,水资源短缺和水环境污染已成为制约我国经济和社会发展的重要因素。因此,为了而对恶化的水资源质量与经济发展之间的矛盾,我们迫切的需要一种适合时代发展的水资源处理技术,膜生物反应器技术应运而生。传统应用于膜生物反应器中的单质聚偏氟乙烯中空纤维膜强度低,在面对恶劣的水环境下,难以满足使用要求,纤维管增强聚偏氟乙烯中空纤维膜能够很大程度上提升膜强度,但是由于纤维管与铸膜液之间的结合强度不佳,在使用过程中经水流冲击及振荡,增强膜界面层会产生剥离现象,大大影响了纤维管增强中空纤维膜的使用寿命,因此寻求在不影响增强膜自身性能条件下,增强膜界面结合情况的方法,具有十分重要的意义。首先,本文选取两种纤维管:编织管、针织管,作为聚偏氟乙烯中空纤维膜增强体,采用两种方法对纤维管进行改性,1.分别使用偶联剂KH570及丙烯酸酯粘合剂对两种纤维管外表面进行涂覆改性;2.采用不同低温等离子体处理时间对两种纤维管外表面进行刻蚀,并通入氧气,将少量亲水基团接枝在纤维管外表面,增加纤维管外表面亲水性。实验讨论了不同纤维管输送速度、不同改性剂用量、不同低温等离子体处理时间对未改性、改性纤维管增强膜水通量、孔隙率、平均孔径、拉伸强度、爆破强度的影响。不同纤维管输送速度对纤维管增强膜水通量、平均孔径及孔隙率影响较大,对于纤维管增强膜拉伸强度影响较小。改性剂的用量对纤维管增强膜各项性能影响不一,过多或过少的改性剂用量都不能达到膜使用要求。低温等离子体处理纤维管时间的长短主要影响的是膜的界面结合情况。其次,对不同纤维管输送速度、不同低温等离子体处理纤维管时间、不同改性剂用量下的纤维管增强膜进行相同条件的超声波破坏作用,测得超声波前后纤维管增强聚偏氟乙烯中空纤维膜水通量,讨论了不同条件下纺制的膜丝的界面结合情况,结合增强膜综合性能及超声波前后水通量变化得出最优工艺条件:KH570偶联剂和丙烯酸酯粘合剂最佳用量皆为3 g/5m,低温等离子体刻蚀编织管外表面最佳时间为10 min,低温等离子体刻蚀针织管外表面最佳时间为15 min,使用改性剂的纤维管增强膜和未使用改性剂的编织管增强膜最佳输送速度为15 m/min,未使用改性剂的针织管增强膜最佳针织管输送速度为20 m/min。丙烯酸酯粘合剂对编织管增强膜界面结合改性效果最好,KH570偶联剂对针织管增强膜界面结合改性效果最好。
[Abstract]:With the economic development and population growth of our society, water shortage and water environment pollution have become an important factor restricting the economic and social development of our country. We urgently need a kind of water resources treatment technology suitable for the development of the times. Membrane bioreactor (MBR) technology emerges as the times require. The membrane strength of PVDF hollow fiber used in membrane bioreactor is low, and in the face of harsh water environment, It is difficult to meet the requirements of application. The membrane strength can be greatly enhanced by the fiber vascular reinforced polyvinylidene fluoride hollow fiber membrane. However, due to the poor bonding strength between the fiber tube and the casting solution, the flow of water impinges and oscillates in the process of operation. The interfacial layer of the enhanced membrane will be stripped, which greatly affects the service life of the fiber tube reinforced hollow fiber membrane. Therefore, the method of enhancing the interfacial bonding of the membrane without affecting the performance of the enhanced membrane is sought. First of all, this paper selects two kinds of fiber tubes: braided tubes and knitted tubes as membrane reinforcements of polyvinylidene fluoride (PVDF) hollow fiber. Two methods were used to modify the fiber tube. 1. The external surface of the two kinds of fiber vascular tubes was coated with coupling agent KH570 and acrylate adhesive. The external surface of the two kinds of fiber vascular tubes was etched by different low temperature plasma treatment time. By adding oxygen, a small amount of hydrophilic groups were grafted onto the outer surface of the fiber tube to increase the hydrophilicity of the outer surface of the fiber tube. The effects of water flux, porosity, average pore size, tensile strength and blasting strength on the water flux, average pore size and porosity of the membrane reinforced by the modified fiber vascular tube were studied. The effect of the amount of modifier on the tensile strength of the fiber tube reinforced membrane is different, and the influence of the content of the modifier on the properties of the fiber tube reinforced film is different. Too much or too little modifier dosage can not meet the requirements of membrane use. The length of treatment time of low temperature plasma mainly affects the interfacial bonding of the membrane. Secondly, for different transfer speed of fiber tube, The water flux of polyvinylidene fluoride (PVDF) hollow fiber membrane was measured before and after the treatment with different low temperature plasma treatment time and different modifier dosage under the same conditions. The interfacial bonding of filaments spun under different conditions was discussed. Combined with the comprehensive properties of the enhanced membrane and the change of water flux before and after ultrasonic wave, the optimum technological conditions were obtained: the optimum dosage of the coupling agent and acrylic adhesive was 3 g / 5 m, the optimum time of etching the outer surface of the braided tube by low temperature plasma was 10 min, and the optimum time was low. The optimum temperature plasma etching time is 15 min, the optimum conveying speed of fiber tube reinforcement film using modifier and braided tube reinforcement film without modifier is 15 m / min, and that of knitting tube reinforcement film without modifier is 15 m / min. The transfer rate of knitted pipe is 20 m / min. The effect of acrylates adhesive on the interfacial modification of braided tube reinforced film is the best, and that of KH 570 coupling agent is the best.
【学位授予单位】：天津工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB383.2

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