| Polyphenylene sulfide (PPS), an advanced thermoplastic material, was first developed by Philip-Chevron Petroleum Co. Ltd. The molecular chain of PPS is constructed with benzene ring and sulfur atom arranged alternately, and consists three types of structure, linear, cross linked as well as hyperbranched molecular configuration. Linear PPS possess good processing ability, and can be fabricated into fiber. PPS polymer has excellent properties such as chemical resistant, thermal stability, fire retard, etc. Filtration felt fabricated by PPS fiber is mainly utilized to filtrate fluid of high temperature and corrosive chemical agents in such situation as coal power station and rubbish burning plant. The filtration felts can reduce the release of toxic gas and carry on sustainable environment development.Although PPS fiber has some great properties such as good thermal stability, excellent chemical resistance, inherent flame resistance, and precision moldability, but its cost is too high wide application, and also the bulkness is important for filtration and to prolong service life. In this thesis, PPS sheath-core composite fiber was designed by using PPS as sheath and PA66 as core. This kind fiber could get excellent properties suitable for filtration media with much low cost. In this study, three aspects were discussed including analysis of rheology behavior of PPS and PA66, the influence of processing conditions on fiber performance and acid-resistant properties of the fiber.The study on the rheological behavior showed that the storage modulus G' and loss modulus G" both increased as angle frequencyωincreasing, exhibited a linear dependence. Under the test conditions storage modulus G' of nylon 66 was higher than that of PPS, and the influence of temperature exerted on loss modulus G" of PPS was insignificant. PPS and PA66 are shear-thinning fluids, complex viscositiesη* decreased as the angle frequencyωincreasing. However, curve of complex viscosityη* vs angle frequencyωof PPS is much milder than that of nylon66.There are three main processings for fiber preparation including drying of chips, spinning and drawing. Chips should be dried, in order to reduce the moisture content, improve crystallinity degree and softening point before spinning. Drying temperature and drying time are important factors for drying efficiency. In order to reduce the possibility polymer degradation, 125℃was chosen as drying temperature and 16 hours as the drying time. During the process of spinning, screws temperature, air quench condition and spinning-box temperature are important for final fiber performance. It was found that fiber tensile strength was increased as the spinning-box temperature increasing, reached maximum at around 315℃then decreased; quenching temperature, distance, and quench speed could influence heat-shrinkage significantly. Only after drawing, the fiber could get the mechanical properties for textile processing. Drawing temperature and drawing ratio are important. In our research, first draw was carried in water bath, second draw was carried in air. Water bath drawing temperature was chosen around 65～85℃, air drawing temperature was chosen around 110～150℃. The tensile strength of fiber increased as drawing ratio increasing. When the drawing ratio was 4.1 the tensile strength could reach 3.60 cN/dtex, elongation at break was 31.12%.The eccentric sheath-core structure could impart the fiber three-dimensional permanent crimp property, which will benefit felt bulkness and consequently felt behavior and service life. Study on the WAXRD and DSC of the fiber showed that as the draw ratio increasing, the crystal lamella space became smaller, crystallinity increased, and the melting point of PPS and PA66 exhibited a small increase. The cross-section structure of fiber was observed. It was interested to find that part of the fiber core exposed out of fiber surface, and became smaller as the spinning-box temperature increased.Acid resistance of fiber was investigated, and found that the core of fiber degraded and disappeared in acid (48% sulfate solution). Only sheath part could be observed after certain period. It was found that tensile strength of fiber after acid treatment reduced at first, then showedlittle change as time extended. However, the increasing of specificsurface area would prolong service life as filtration media.
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