Annealing effects on structural changes and thermal shrinkage of poly(lactic acid) draw-textured filaments

Seo, Young Ho; Han, Sung Soo; Oh, Tae Hwan; Khil, Myeong Seop

doi:10.1080/00405000.2013.827390

Cited by 8 publications

(6 citation statements)

References 22 publications

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“…19,20 To fabricate the braided stent, stent is first braided on a special mold, and then annealed at 100 C for 1 h. 21 Many studies have shown that shrinkage occurs during unconstrained annealing process for solid-state drawn PLLA monofilaments. 22,23 However, the PLLA monofilaments used for weaving cannot shrink freely since they are taut with constrained ends in the braided stents.…”

Section: Introductionmentioning

confidence: 99%

Effects of annealing constraint methods on poly(L‐lactic acid) monofilaments for application in stents annealing

Tian

Zhang

et al. 2021

Polymers for Advanced Techs

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Mechanical properties of poly(L-lactic acid) (PLLA) braided stents are closely related to the performance of the weaving monofilaments. In this study, the PLLA monofilaments were prepared via solid-state drawing (SSD) method and annealed with different constraint methods. Experimental results show that mechanical properties of fabricated monofilaments have been greatly improved by SSD method. With the constrained annealing method, mechanical properties can be further improved while negative effect is shown with unconstrained annealing method. The physicochemical properties of PLLA monofilaments were further characterized, and it is found that the draw ratio of SSD and annealing method can affect the crystallinity and crystallite size, which can directly influence the mechanical properties of the monofilaments.This work tells that it is necessary to consider collectively the effects of SSD method and annealing method of the monofilaments in order to obtain optimized mechanical properties of the braided stents.

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Section: Introductionmentioning

confidence: 99%

Effects of annealing constraint methods on poly(L‐lactic acid) monofilaments for application in stents annealing

Tian

Zhang

et al. 2021

Polymers for Advanced Techs

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“…In this study the Young's Modulus and tensile strength increased by 30% and 20% respectively following annealing due to a higher degree of crystallinity. The decrease in Young's Modulus at 90 o C and UTS could have occurred due to molecular deterioration or delamination of adjacent layers caused by thermal annealing (Seo et al, 2014). However, there was no evidence of thermal degradation within this study.…”

Section: Mechanical Propertiesmentioning

confidence: 58%

Improving the shape stability and enhancing the properties of layer dependent material extruded biodegradable polylactic acid for thin implants

Ekinci

Han

Gleadall

et al. 2021

RPJ

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Purpose This paper aims to establish an appropriate annealing method, which is necessary for shape stability and to evaluate their potential degradation performance of 1-, 3- and 5-layer material extruded polylactic-acid specimens by enhancing their thermal and mechanical properties. Design/methodology/approach The distortion of each layered printed specimen subjected to degradation was calculated in x- and y-direction. Each layered specimen was subjected to annealing at 70°C, 80°C and 90°C for 2 h and at 80°C for 1, 4, 8 and 16 h. Thermal, molecular weight and mechanical properties were calculated using, differential scanning calorimetry, gel permeation chromatography and tensile testing machine, respectively. Findings In the x-direction, distortion was 16.08 mm for one-layer non-annealed printed specimens and decreased by 73% and 83% for 3- and 5-layer, respectively, while each layered non-annealed specimen subjected to degradation at 37°C for one month. Within the outlined study, annealing treatment enhances properties such as the degree of crystallinity (%χ) up to 34%, Young’s modulus (E) by 30% and ultimate tensile strength by 20% compared to the non-annealed specimens. Practical implications The future research accomplishments will be concentrated on the design, development and optimisation of degraded biomedical implants using material extrusion thin films including drug delivery system and fixation plates. Originality/value The printed thin specimens subjected to degradation were investigated. This research developed a new understanding of the effect of the annealing temperature and time on the mechanical, thermal and molecular weight properties for each layered specimen.

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“…Furthermore, yarn shrinkage is increased when PLA yarns are textured, which further impairs downstream processes. Colour fastness also seems lower than in standard yarns, especially for bright colours [100][101][102]. Other research successfully created socks out of textured PLA yarns [103], and PLA yarn dyed with bio-based turmeric (or curcuma) could even be processed into socks [104].…”

Section: Biopolymers In False-twist Texturingmentioning

confidence: 99%

A Review on False-Twist Texturing

Ortega,

Saynisch,

Yurtseven

et al. 2024

Fibers

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The annual demand for fibres continues to rise worldwide. Consequently, more and more fibres must be produced to meet this demand, most of which are melt-spun polymeric man-made fibres. Smooth filaments made of polymers are mainly used for technical applications in industry. For use in clothing or home textiles, for example, a texturing process is used to give the filaments a crimp and thus a feel like that of natural fibres. In this state, they can be processed together with natural fibres and used in textiles. Partially oriented yarns (POY) are of great importance in texturing. The yarns are mainly crimped with the help of the so-called false-twist texturing process (FTTP). Since POY accounts for about 60% of the melt-spun filament yarn produced worldwide, the FTTP is the most important texturing process in the textile industry. In this paper, the main components of false-twist texturing (FTT) machines are explained, along with the state of the art and research for each component and its influence on the process. Relevant patents are discussed, as well as process optimisation techniques, innovative polymers, and yarn types recently used in FTT, followed by a conclusion and an outlook for the process.

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Annealing effects on structural changes and thermal shrinkage of poly(lactic acid) draw-textured filaments

Cited by 8 publications

References 22 publications

Effects of annealing constraint methods on poly(L‐lactic acid) monofilaments for application in stents annealing

Effects of annealing constraint methods on poly(L‐lactic acid) monofilaments for application in stents annealing

Improving the shape stability and enhancing the properties of layer dependent material extruded biodegradable polylactic acid for thin implants

A Review on False-Twist Texturing

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