Poly melt spinning

Cakmak M, Teitge A, Zachman FI G and White J L 1993 On-line small-angle and wide-angle x-ray scattering studies on melt-spinning poly(vinylidene fluoride) tape using synchrotron radiation J. Polym. Sc/. 31 371- 81... 

HoUow-fiber fabrication methods can be divided into two classes (61). The most common is solution spinning, in which a 20—30% polymer solution is extmded and precipitated into a bath of a nonsolvent, generally water. Solution spinning allows fibers with the asymmetric Loeb-Soufirajan stmcture to be made. An alternative technique is melt spinning, in which a hot polymer melt is extmded from an appropriate die and is then cooled and sohdified in air or a quench tank. Melt-spun fibers are usually relatively dense and have lower fluxes than solution-spun fibers, but because the fiber can be stretched after it leaves the die, very fine fibers can be made. Melt spinning can also be used with polymers such as poly(trimethylpentene), which are not soluble in convenient solvents and are difficult to form by wet spinning. 

Poly[5-(alkylamino)borazines] 7-10 exhibited suitable viscoelastic and thermal stabilities to be extruded in the molten state through the monohole spinneret of a lab-scale melt-spinning apparatus. Thus, an extruded filament (diameter, 200 gm) was drawn with a windup unit, that is, a graphite spool. This provided green fibers with a wide range of diameters (16 =s (f> =s 50 gm Table 2), depending on polymer architecture. 

This article is an overview of the novel technology of self-reinforced LCPs with polyesters, poly(ethylene terephthalate) (PET) and poly(ethylene naphtha-late) (PEN) [10-13, 21, 23], LCP/polyester blends in a polyester matrix form in situ fibrils which improve the mechanical properties. LCPs have an inherently low melt viscosity, and provide LCP/polyester blends that effectively lower the melt viscosity during melt spinning [24], and fast injection-molding cycles. The miscibility between the LCP and polyesters can be controlled by the degree of transesterification [25] in the reactive extrusion step, and fibril formation in LCP-reinforced polyester fibers has been studied. 

S. Kase and T. Matsuo, Studies on Melt Spinning, Part II. Steady State and Transient Solutions of Fundamental Equations Compared with Experimental Results, Fundamental Equations on the Dynamics of Melt Spinning, J. Appl. Poly. Sci., 11, 251-287 (1967). 

Bourbigot et al.85 at Lille have used poly(vinylsilsesquioxane) (POSS) in PP (110 wt%) to melt spin filaments, which were then knitted into fabrics. POSS was thermally stable and no degradation was detected in the processing conditions. They have tested the flammability of the fabrics using cone calorimetry. POSS presence had minimal effect on peak heat and total heat release values of PP fabric, but delayed the TTI. This behavior of POSS is opposite to that of layered silicates, which have minimal effect on TTI, but reduce PHRR. Authors claim that POSS does not act as a FR but only as a heat stabilizer via a decrease of the ignitability. 

Summary The heterogeneous catalytic redistribution reaction of methylchlorodisilanes provides spinnable poly(methylchlorosilanes/-carbosilanes). Especially copolymers like poly(methylchlorosilanes-co-styrenes) are suitable polymers for melt spinning. The high reactivity caused by Si-Cl bonds enables oxygen free curing methods of the melt spun polymer filaments with ammonia. The synthesis is achieved without the employment of highly reactive metals and any solvents. The thus produced SiC fibers exhibit oxygen contents lower than 1 wt. %. 

A comfortable pathway for improvement of the crystallization of poly(3-hydroxybutyrate) in a melt-spinning process is the use of nucleating agents like electron-beam irradiated PHB [28] or the reactive extrusion with peroxide [29]. 

Both conventional and liquid-crystal polymers can be processed by melt spinning. The principal requirement is that the polymer must not degrade before becoming molten. Examples are nylon-6, nylon-6,6 and poly(ethylene terephthalate) ( polyester , terylene , or dacron ) for conventional polymers and the Vectra series (see section 12.4.3) among the thermotropic liquid-crystal polymers. 

Kim, K.H., Cho, H.H., Ito, H., Kikutani, T., 2008. Fiber structure development in high-speed melt spinning of poly(trimethylene terephthalate) (PIT)—on-line measurement of birefringence. J. Polym. Sci. B Polym. Phys. 46, 847 56. 

The poly (olefin) fibers are manufactured in the largest volumes thanks to the low cost of the polymers and the simple melt-spinning production technology. Annual worldwide production of textile products based on poly(olefins) was 1.7 10 t/a in 1985, 90 % of which was isotactic poly(propylene) PP and 10 % high-density poly(ethylene) HOPE [81]. ... 

Poly(bulylene succinate) (PBS) is another biodegradable polymer which is not commonly blended with polyolefins. However, Yang et al. [94] investigated the eflect of PBS content, extrusion rate, and extensional strain rate on the melt strength and extensional viscosity of LDPE/PBS blends using a melt-spinning technique, and developed extensional master curves. Based on both the extensional master curve and a neural network method, they compared the predicted extensional viscosities with the experimental data of the LDPE/PBS blends. 

J. Yang, J.-Z. Liang, F.-J. Li, Melt strength and extensional viscosity of low-density polyethylene and poly(butylene succinate) blends using a melt-spinning technique. J. Macromol. Sci. Part B Phys. 51, 1715-1730 (2012)... 

Hyon, S.-H., Jamshidi, K. and Ikada, Y. (1984) Melt spinning of poly-L-lactide and hydrolysis of the fiber in vitro, in Polymers as Biomaterials (eds S.W. Shalaby, A.S. Hoffman, B.D. Ratner and T.A. Horbett), Prenum Press, New York, pp. 51-65. 

Fambii, L., Pegoretti, A., Fenner, R. et al. (1997) Biodegradable fibres of poly(L-lactic acid) produced by melt-spinning. Polymer, 38, 79-85. 

Lund A, Hagstrom B. Melt spinning of poly (vinyUdene fluoride) fibers and the influence of spinning parameters on P-phase crystallinity. J Appl Polym Sci 2010 116(5) 2685-93. 

Meng, Q.H. and Hu, J.L. (2008) Study on poly (e-caprolactone)-based shape memory copolymer fiber prepared by bulk polymerization and melt spinning. Polymers for Advanced Technologies, 19, 131-136. 

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