| PET fiber not only has high strength and good elastic recovery, it also has soutstanding wear resistance,high light resistance, excellent chemical resistance and other excellent properties, the fabric made of it is crisp, and what is more,compared with the natural fibers, a great advantage of PET fiber is that it can be given some special properties in processing stage, because of these features, PET fibers is more and more popular, so far, it has become the largest output, the most widely used synthetic fiber; However, PET fibers are also some disadvantages, such as poor air permeability, poor anti-static ability, which is cause that is easy for PET fiber to contaminated dust. there will be some difficult for staining, and as the improving of peoples living standards, the fibers which are more comfortable and have special properties are ever-increasing demanded. The shortcomings of PET fabric will limit its application. At present, some methods were used to modify PET fiber, including copolymerization, grafting, filling, blend, adjust the spinning process and other ways to improve its properties, obtain better processing property.Because of its unique geometry size and well mechanics properties, optics properties, electromagnetism properties and other properties, since 1991 when CNTs was first found, it has become the a focus of researchers, it can be used as an additive adding into PET in order to improve the properties of PET fiber and give more excellent properties to PET fiber. But CNTs have large surface area, high surface energy, so they are easy to aggregation, moreover, the bonding between CNTs and polymer is so weak that there is poor compatibility between them. However, whether CNTs has a good dispersion and compatibility in polymer matrix is one of the prerequisites for composite materials to gain excellent properties. Now, the problem that the interface compatibility between CNTs and polymer materials is still not well resolved, which makes it difficult for the great characteristics of CNTs to give full play, the subject of this paper is through surface modification of CNTs to improve the compatibility between CNTs and PET matrix, Therefore, this research is significant.Two different surface modification reagents TPA and SDBS were used to modify the surface of CNTs, through comparing the effect of surface modification of CNTs of the two reagents, selecting TPA modified CNTs for further using. Preparation TPA/MWNTs-OH and PET masterbatch by the twin-screw extruder through the method of melt blending, then, use the masterbatch to spin. The content of MWNTs in masterbatch, the extrusion process of masterbatch and the spinning process were studied, and the on the morphology, microstructure, thermal and mechanical properties of MWNTs-OH /PET masterbatch and MWNTs-OH/PET composite fiber were characterized, and the compatibility between CNTs and PET matrix, the effect to the properties of composite fiber by the content of MWNTs-OH in PET matrix were discussed, and get some conclusions as follows:(1)The optimum conditions of TPA modified MWNTs-OH is:the reaction temperature is 145℃, the reaction time is 4h and the content of MWNTs-OH is 11.76% wt;(2)Because of the addition of MWNTs-OH, the crystallization nucleation process has promoted,which has shorten the crystallization induction period of PET, and when it was modified by TPA, the interface interaction between MWNTs-OH and PET matrix increased, which cause effect was obvious;(3) Owing to the added of MWNTs-OH, the mechanical properties of the composite fiber were improved, with the increase of its content, the fracture strength of composite fiber was firstly increased and then decreased, when the content of TPA/MWNTs-OH was 0.2%(wt),the strength of the composite fiber was maximum, compared with pure PET fiber which was used in the test,the strength increased by about 60.5%;(4)There was obvious improvement at interface compatibility between TPA modified MWNTs-OH and PET matrix.
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