Study On The Spinning Process Of PPEK And The Properties,Structure Of PPEK Fiber

A series of poly(arylene ether)s containing phthalazinone moieties are the highest level of heat-resistant polymers among soluble polymers. Poly(phthalazione ether ketone)(PPEK),whose Tg is263℃, ownes good mechanical properties and excellent chemical stability,which making itself widely useful in aerospace,war industry and electron areaes etc. In order to expand the application of PPEK,it’s imperative to develop PPEK fiber.Study on the effects of hot-drawing on the mechanical properties of PPEK films indicate that hot-drawing can remarkably increase the tensile strength and modulus(2.3times of hot-drawing can increase the tensile strength by70%), which claim the feasibility of spinning PPEK fiber.Research on the properties of PPEK solution showed it does’t have the property of liquid crystal. So, wet-dry spinning method, the hot technique for making high property fibers, is unsuitable for PPEK spinning. We decide to use wet-spinning or dry-spinning to produce PPEK fiber.In this paper, we adopted both wet-spinning and dry-spinning methods to produce PPEK fiber for the first time in the world. Fiber produced by wet-spinning has low density,low mechanical properties compare with dry-spinning produced fiber. We gave emphasis study on dry-spinning conditions and morphology, mechanical properties, thermal properties, aggregative structure as well as hot-drawing of PPEK fiber obtained from dry-spinning. The results showed that PPEK fiber obtained from dry-spinning has good mechanical properties(Tensile strength was273MPa) and thermal stability(Tg:263℃,5%and10%weight loss temperature was305℃and507℃,respectively). Hot-drawing can dramatically increase the tensile strength(by about63%). XRD analysis indicated that PPEK fiber was an amorphous structure, but with high orientation compare with undrawn PPEK film.We deep analysis the aggregative structure of PPEK fiber. By means of calculating radial distribution function(RDF) of undrawn PPEK film and PPEK fiber, we obtained the distance between two molecular chains along the same direction was4.86A while distance between two molecular chains parallel fiber axis was4.77A, which explains the spinning process caused the orientation of PPEK chains along fiber axis.