Effect of annealing on the crystallization and properties of electrospun polylatic acid and nylon 6 fibers

Cho, A-Ra; Shin, Dong‐Myeong; Jung, Hyun Wook; Hyun, Jae Chun; Lee, Joo Sung; Cho, Daehwan; Joo, Yong Lak

doi:10.1002/app.33262

Cited by 33 publications

(20 citation statements)

References 37 publications

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“…Its semicrystalline characteristics create additional capability to fine tune final products' performance including mechanical strength, for example, by increasing crystallinity through a thermal annealing process, or heat treatment . Obtaining optimum mechanical and biological properties for various applications require an overall understanding of the semicrystalline polymer morphology development, which largely relies on the crystallization process .…”

Section: Introductionmentioning

confidence: 99%

Influence of thermal annealing on mechanical properties andin vitrodegradation of poly(p‐dioxanone)

Zhang¹,

Jones²,

Wang³

et al. 2019

Polymer Engineering & Sci

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Poly(p‐dioxanone) (PDO), a versatile poly(ester‐ether), has been used for a variety of biomedical applications. Functional performance of this semicrystalline polymer heavily relies on its crystallinity and crystalline behavior. Upon extended exposure to heat above the glass transition temperature and below the melting temperature, PDO undergoes thermal annealing. Isothermal studies at elevated temperatures utilizing a differential scanning calorimeter were performed in order to determine the most appropriate conditions to anneal the polymer. Of the investigated mechanical properties, yield strength and elastic modulus were significantly improved with annealing. This improvement over nonannealed samples was also observed with samples subjected to phosphate‐buffered saline (PBS) solution at 37°C for 2 weeks. After 1 month continuous immersion in PBS solution, the PDO became brittle with deteriorated elongation at break but maintained yield strength and modulus. At 2 months, all specimens exhibited cracks on the surface and a complete loss of mechanical strength. The enhanced yield strength by thermal annealing creates more opportunities for PDO in medical device implants particularly in applications involving soft tissue repair and hemostasis. POLYM. ENG. SCI., 59:1701–1709 2019. © 2019 Society of Plastics Engineers

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Section: Introductionmentioning

confidence: 99%

Influence of thermal annealing on mechanical properties andin vitrodegradation of poly(p‐dioxanone)

Zhang¹,

Jones²,

Wang³

et al. 2019

Polymer Engineering & Sci

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“…This is not observed in those of the cast film counterparts, as the electrospinning process suppresses chain‐folding arrangement to form crystal lamellae of the as‐spun fibers . Improvement of crystalline content was achieved by annealing of the samples .…”

Section: Resultsmentioning

confidence: 95%

“…This is because the copolymer chains are largely elongated by the applied electric field along the solution jets during the spinning process. Upon rapid solvent evaporation, the chains are quenched, leading to restriction of chain's segmental movements and chain‐folding arrangement to form crystalline lamellae .…”

Section: Resultsmentioning

confidence: 99%

Electrospinning of poly(l-lactide-co -dl-lactide) copolymers: Effect of chemical structures and spinning conditions

et al. 2013

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Nanofibers of poly(L‐lactide‐co‐DL‐Lactide) (PDLLAx) copolymers with DL‐lactate (DLLA) contents of 0, 2.5, 7.5, and 50%, which exhibit strong structure/properties correlation, were fabricated by electrospinning. Effect of the copolymer structure and electrospinning conditions on morphology and properties of the fibers were examined by SEM, DSC, XRD, and tensile measurements. Bead‐free fibers of PDLLAx prepared from a DMF/CHCl3 mixed solvent are roughly 10‐times smaller in size (600–800 nm), with lower degree of surface porosity, compared to those of CHCl3. When CHCl3 is employed, an increase in size (2.4–5.5 μm) and surface porosity (0–45%) with relative humidity value is observed in crystallizable copolymers, whereas an amorphous copolymer shows a reverse trend. Thermal properties and chain arrangements of the electrospun fibers are critically affected by DLLA content of the copolymers and electrospinning conditions, as a result from interplay between intermolecular and intramolecular hydrogen bonding. Contents of crystalline domains and “physical crosslinks” generated from DL lactate segments are proposed as the origin of this phenomenon. Fiber mats of PDLLA with 50% DLLA content show a large improvement in all aspects of mechanical properties, which are suitable for various biomedical applications. POLYM. ENG. SCI., 54:472–480, 2014. © 2013 Society of Plastics Engineers

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“…The sample of aliphatic PK was the commercial injection‐molding grade M330A (molecular weight 60 KDa, containing 6 mol% propylene, T m ≈ 220 °C, T g ≈ 15 °C), supplied by HYOSUNG CORPORATION (Korea). The sample of PA was also the commercial HYOSUNG 1011 BRT (molecular weights around 20 KDa, T m ≈ 224.1 °C, T g ≈ 47 °C) . The equilibrium melting point of β‐form aliphatic terpolymer PK was reported as 252 °C and the heat of fusion for 100% crystalline β‐form PK was 227 J g −1 , while the equilibrium melting point of α‐form polyamide 6 was 250 °C and the heat of fusion for 100% crystalline α‐form polyamide 6 was 230 J g −1…”

Section: Methodsmentioning

confidence: 99%

Comparing Crystallization Kinetics between Polyamide 6 and Polyketone via Chip‐Calorimeter Measurement

Luo

et al. 2017

Macro Chemistry & Physics

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Polyamide 6 and aliphatic polyketone exhibit similar melting points and heats of fusion, which expose the kinetic effects of intermolecular interactions on their crystallization kinetics. The commercial chip‐calorimeter Flash DSC1 is employed to measure their crystallization rates in a broad temperature range. The results show that polyamide crystallizes faster than polyketone at high temperatures, but slower at low temperatures. The faster crystallization is attributed to a lower lateral‐surface free energy for crystal nucleation at high temperatures on account of the sheet‐like hydrogen bonding in polyamide crystals. The slower crystallization is attributed to the lower molecular mobility for crystal nucleation at low temperatures on account of the higher glass transition temperature of polyamide.

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Effect of annealing on the crystallization and properties of electrospun polylatic acid and nylon 6 fibers

Cited by 33 publications

References 37 publications

Influence of thermal annealing on mechanical properties andin vitrodegradation of poly(p‐dioxanone)

Influence of thermal annealing on mechanical properties andin vitrodegradation of poly(p‐dioxanone)

Electrospinning of poly(l-lactide-co -dl-lactide) copolymers: Effect of chemical structures and spinning conditions

Comparing Crystallization Kinetics between Polyamide 6 and Polyketone via Chip‐Calorimeter Measurement

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