High‐speed melt spinning of various grades of polylactides

Schmack, G.; Tändler, B.; Optiz, G.; Vogel, Roland; Komber, Hartmut; Häußler, Liane; Voigt, Dieter; Weinmann, Sandra; Heinemann, Moritz; Fritz, H.‐G.

doi:10.1002/app.13170

Cited by 55 publications

(38 citation statements)

References 14 publications

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“…Purification methods have been established to reduce the contamination of PHAs,52 however, they are not applicable to pellets. Molecular weight and polydispersity are decisive factors regarding spinnability 53. GPC measurements of the extruded pellets yielded a molecular weight of $\overline {M} _{{\rm w}} $ = 260 kDa, implying a reduction of 47% compared to the PHBV powder.…”

Section: Resultsmentioning

confidence: 99%

Biodegradable Bicomponent Fibers from Renewable Sources: Melt‐Spinning of Poly(lactic acid) and Poly[(3‐hydroxybutyrate)‐co‐(3‐hydroxyvalerate)]

Hufenus

Reifler

Maniura‐Weber

et al. 2011

Macro Materials & Eng

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PHBV is produced by bacteria as intracellular carbon storage. It is advantageous concerning biocompatibility and biodegradability, but its low crystallization rate hinders the melt‐processing of fibers. This problem can be overcome by combining PHBV with PLA in a core/sheath configuration and introducing a new spin pack concept. The resulting PHBV/PLA bicomponent fibers show an ultimate tensile stress of up to 0.34 GPa and an E‐modulus of up to 7.1 GPa. XRD reveals that PLA alone is responsible for tensile strength. In vitro biocompatibility studies with human fibroblasts reveal good cytocompatibility, making these fibers promising candidates for medical therapeutic approaches.magnified image

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Section: Resultsmentioning

confidence: 99%

Biodegradable Bicomponent Fibers from Renewable Sources: Melt‐Spinning of Poly(lactic acid) and Poly[(3‐hydroxybutyrate)‐co‐(3‐hydroxyvalerate)]

Hufenus

Reifler

Maniura‐Weber

et al. 2011

Macro Materials & Eng

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“…The filament diameter was as low as 12 lm at spinning velocity of 5000 m/min. Schmack et al 19 have studied the high-speed melt-…”

Section: Introductionmentioning

confidence: 99%

Effect of process parameters on properties of wet‐spun poly(L,D‐lactide) copolymer multifilament fibers

Rissanen

Puolakka

Hukka

et al. 2009

J of Applied Polymer Sci

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, multifilament fibers were prepared by wet-spinning and the effects of the spin draw ratio and the coagulant on the morphological, thermal, and mechanical properties of the filaments were studied. The hydrolytic degradation of filaments was studied in vitro. The filament diameter and the mechanical properties of filaments were highly dependent on the spin draw ratio, whereas the coagulant had no or minor effect. The filament diameters were in the range of 11-36 lm and the maximum tenacity of 150 MPa was obtained at the spin draw ratio of 7.0 for both copolymers. The copolymer had the main importance on the crystallinity of filaments, but it was also affected by the duration of the coagulation process. The crystallinities of P(L,D)LA 96/4 filaments were in the range of 5-16%, whereas P(L,DL)LA 70/30 filaments were totally amorphous. The degree of crystallinity had effect on the hydrolytic degradation of filaments. The tenacity loss of P(L,D)LA 96/4 filaments was about 10% and that of P(L,DL)LA 70/30 filaments was as high as 50% after 24 weeks in vitro.

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“…With increasing spinning velocity, the beginning of cold crystallization shifts toward lower temperatures, the cold crystallization range decreases, and the crystallinity increases. The thermal properties indicate that a higher speed of spinning induces increased orientation in the fibers and also a higher degree of orientation-initiated crystallization [31]. Hot drawing and annealing of the melt-spun filaments is performed to improve their mechanical properties.…”

Section: Melt-spun Pllamentioning

confidence: 99%

“…In one study, the effect of increasing molecular weight on properties of melt-spun PLA fibers was reported [31]. The mechanical properties of PLA fibers were found to improve with increasing molecular weight of polymers with similar M w /M n .…”

Section: Melt-spun Pllamentioning

confidence: 99%

Spinning of Poly(Lactic Acid) Fibers

Agrawal¹

2010

Poly(Lactic Acid)

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A fiber or a filament (a continuous form of fiber) is the fundamental unit of textile materials. It has a unique combination of high strength (tensile, bending, torsional, or compression), high flexibility (i.e., low modulus), extensibility, and shows recoverability on deformation. Most of these properties are observed in one principal direction, which is known as the axis of the fiber. Since all textile structures from one to three dimensional (yarn, fabric, or braids, etc.) are built using this basic structural unit, these structures also possess the above unique properties.These unique properties of a fiber or a filament are the result of a microstructure (morphology) in which the majority of the polymer chains are oriented in the direction of the axis of the fiber. The more oriented the polymer molecules are in this direction, the better properties the resulting fiber/ filament is likely to have. For producing man-made fibers, the polymers (either natural or synthetic) must be unfolded and extended unidirectionally to an extremely large extent resulting in a very high aspect (length to diameter) ratio and high orientation. This is known as spinning.In spinning, a small amount of polymer ($1 g) may be elongated to over 9000 m in length while the other dimension (diameter) is only in microns. This requires precise control over the spinning process to enable such unidirectional extension in the melt form. In fiber formation, all efforts are directed at controlling the microstructure of the polymer so that the properties mentioned above are obtained with respect to the principal axis of the fiber. This is unlike other polymer processing methods such as injection molding, compression molding, extrusion, and blowing, and so on, where mostly isotropic properties are desired and only a little attention is directed toward making a controlled microstructure in terms of molecular orientation and spatial arrangement. The engineering complexity of the spinning operation is evident from the fact that, in modern spinning plants, a large amount of polymer is expected to be continuously converted (spun) into filaments with nearly no breaks.In spinning, polymer melt or solution is extruded from a fine hole and is elongated by applying a external tensile force on the extruded portion. As the polymer melt or solution is pulled, it is cooled or precipitated, respectively, to form a solid filament. This filament is then usually subjected to post-spinning operations such as drawing, which applies unidirectional stretching to the material in a semisolid form, and heat setting, which is crystallization to equilibrium. Other post-spinning processes such as texturing are simply variations of the drawing and heat setting processes to impart curvilinear shape to an otherwise straight filament. This gives physical bulk to the filaments. The process of fiber formation is complete only when both spinning and post-spinning operations are carried out. MELT SPINNING LINEMelt spinning is a process of producing filaments from a polymer melt. Ho...

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High‐speed melt spinning of various grades of polylactides

Cited by 55 publications

References 14 publications

Biodegradable Bicomponent Fibers from Renewable Sources: Melt‐Spinning of Poly(lactic acid) and Poly[(3‐hydroxybutyrate)‐co‐(3‐hydroxyvalerate)]

Biodegradable Bicomponent Fibers from Renewable Sources: Melt‐Spinning of Poly(lactic acid) and Poly[(3‐hydroxybutyrate)‐co‐(3‐hydroxyvalerate)]

Effect of process parameters on properties of wet‐spun poly(L,D‐lactide) copolymer multifilament fibers

Spinning of Poly(Lactic Acid) Fibers

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