Preparation And Properties Of Poly(Ether Ether Ketone) Fibers

Poly(ether ether ketone)(PEEK) is one of the most important kinds of high-performancearomatic fibers. With composed of ether bond and ketonic bond, it has the excellentmechanical performance, good thermal stability and chemical resistance, and so on. It hasaroused wide concern when it was born. It has extensive applications in the aviation,automotive, medical, and electrical industries owing to the excellent mechanical performance,good thermal stability and chemical resistance, and so on. PEEK fibers have a uniquecombination of mechanical properties that are stable under extreme environmental conditions.Whether it is at high temperature, extreme moisture, alkaline or acidic environments, there isalmost no other fiber that will do a comparable job. Compared with similar internationalproducts, the development level of Chinese PEEK fibers has many gaps. On the hand, a fewsmall size enterprise or institution which develops PEEK fibers technology wandered up anddown at low level. On the other hand, development of Chinese fiber grade PEEK also juststarted mainly in single species. These restrict development of PEEK fibers. Developingfiber grade PEEK become very important. Therefore, from improving PEEK spinnabilitypoint of view, we designed to prepare fiber grade PEEK with controlling synthesistechnology or adding modifier. Subsequently, a series of PEEK fibers were prepared bymelt-spinning. The material which have inherent properties, good spinnability and low-costhave will has a competitive advantage in the international market. At the same time form theperspective of basic research, we study modification effects with introducing FPAEKLCP orGPPS and influence of spinnability on technology, structure and performance of fibers. Atfirst, we prepared a series of PEEK with different MFI, focuses on rheology properties,spinnability and influence of technology on structure and performance of fibers. it could beseen that PEEK with high-MFI have good flowability, spinnability, and low spinningtemperature. The fibers are cylindrical with smooth surface, uniform diameter and texturewas tight. Appear viscosity of PEEK with low-MFI was high, The shear sensitivity wasintensive, Viscous flow activation energies (ΔEη) was high, therefore its spinnability wasimproved by increasing temperature(even410oC). For spinnability, SPEEK-1>CoPEEK-1>SPEEK-2>CoPEEK-2>CoPEEK-3>SPEEK-3. For strength,SPEEK-1<SPEEK-2<CoPEEK-1<CoPEEK-2<CoPEEK-3. the improvement of mechanicalproperties of as-spun PEEK fibers with drawing was derived from the change of thecrystalline aspect, such as the increased crystalline size, the degree of perfection of thecrystals and the crystallinity. appropriate drawing temperature was control in the range of220~240oC. This should be ascribed that the movement of PEEK segments in fibersenhanced in the range of220~240oC. As a result, the orientation and crystallization tendedto be more perfect, followed by the improvements in the tensile strength and modulus offibers. The annealing also helps to improve mechanical properties due to the improvement inthe molecular orientation and crystallization arising from the annealing process.For the bad flowability and spinnability of PEEK with low-MFI, we designed tosynthesize FPAEKLCP, and add it to PEEK resin for decreasing PEEK melt viscosity, andPEEK/FPAEKLCP fibers was prepared by melt-spinning. Focuses on introducingFPAEKLCP influence on spinnability and influence of technology on structure andperformance of fibers. it could be seen that FPAEKLCP have good liquid crystalline propertyand stability of liquid crystal (the temperature range of liquid crystal state is65~70oC),FPAEKLCP possesses the matched processing temperature and the similar structure withPEEK resin。FPAEKLCP decreases the melt viscosity of PEEK, improves flow stability,decreases spinning temperature (Compared with the lower10-15oC), eases crosslinking, therebyimproves the spinnability and the quality of as-spun fibers to obtain a high-performancePEEK fiber. As previously, the improvement of mechanical properties of as-spunPEEK/FPAEKLCP fibers with drawing was derived from the improvement in the molecularorientation and crystallization. Appropriate drawing temperature was control in the range of220~240oC. As a result, the orientation and crystallization tended to be more perfect,followed by the improvements in the tensile strength and modulus of fibers. The annealingalso helps to improve mechanical properties due to the improvement in the molecularorientation and crystallization arising from the annealing process.The preparation technology and the cost of PEEK fiber is the key to itscommercialization. We improves spinnability of PEEK resin and reduce production energyconsumption by introducing GPPS to PEEK resin. The research results show that GPPS like rolling balls reduced the friction between PEEK macromolecules, decreases the meltviscosity of PEEK, improves flow stability, decreases spinning temperature (Compared withthe lower10-20oC). At the same time， a number of GPPS migration to the surface ofmelt, Effectively prevent the PEEK adhere to barrel, Inhibit heat of friction, Decrease mixingtorque and load, prevent the thermal degradation of PEEK resins. GPPS prevent or reducethe residue in the Die and mold export due to decreasing the viscosity between barrel andspinneret. GPPS eliminate the melt broken, improve uniformity of filament, appearance andgloss. A moderate amount of added GPPS wasn’t almost affected thermostability of PEEKfibers, it is very important to manufacture PEEK fibers.