| 1. |
- Aminlashgari, Nina, et al.
(author)
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Degradation product profiles of melt spun in situ cross-linked poly(epsilon-caprolactone) fibers
- 2015
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In: Materials Chemistry and Physics. - : Elsevier BV. - 0254-0584 .- 1879-3312. ; 156, s. 82-88
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Journal article (peer-reviewed)abstract
- In situ cross-linking of poly(epsilon-caprolactone) (PCL) fiber with bis-(epsilon-caprolactone-4-yl) (BCY) was shown to be a feasible approach to compensate for reduction in molar mass of PCL during melt-spinning. The effect of in situ cross-linking on the degradation profile of melt spun PCL fibers with different amounts of BCY was evaluated using electrospray ionization-mass spectrometry. Degradation of the cross-linked fibers was carried out in aqueous medium at 37 degrees C and 60 degrees C for different periods of time. The degradation profiles were then compared with uncross-linked fiber and 3D porous cross-linked film of PCL Interesting differences in the degradation product profiles with linear, cyclic or BCY-related low molar mass compounds were observed, clearly demonstrating the effect of cross-linking and processing on the degradation process and formation of water-soluble products. In addition the degradation product profiles demonstrated that in situ cross-linking is a feasible technique for counteracting degradation reactions during melt-spinning.
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| 2. |
- Pal, Jit, et al.
(author)
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The viscoelastic interaction between dispersed and continuous phase of PCL/HA-PVA oil-in-water emulsion uncovers the theoretical and experimental basis for fiber formation during emulsion electrospinning
- 2017
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In: European Polymer Journal. - : Elsevier. - 0014-3057 .- 1873-1945. ; 96, s. 44-54
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Journal article (peer-reviewed)abstract
- Emulsion electrospinning was recently introduced to minimize the amount of organic solvent during electrospinning process. Here, we uncover the theoretical and experimental basis for the fiber formation in emulsion electrospinning by revealing the viscoelastic interaction between dispersed and continuous phase. Composite electrospun matrices of poly(epsilon-caprolactone) (PCL) with or without hydroxyapatite were devised from an oil-in-water emulsion. The fiber formation and uniformity were clearly governed by the viscoelastic interaction between the continuous and dispersed phase. Caging of droplets by optimal quantity of poly(vinyl alcohol) (PVA) in continuous phase resulted in uniform stretching and coalescence of droplets. An increased storage and loss modulus for emulsions containing optimum PVA manifested desired viscoelastic interaction between dispersed and continuous phase, which further resulted in uniform jet stretching. The visthelasticity of the emulsion could be tailored by changing the polymer concentration in dispersed or continuous phase, which enabled production of electrospun fibers with desired fineness.
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| 3. |
- Skrifvars, Mikael, 1962-, et al.
(author)
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Electrospun composite matrices from tenside-free poly(caprolactone)-grafted acrylic acid/hydroxyapatite oil-in-water emulsions
- 2017
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In: Journal of Materials Science. - : Springer Science and Business Media LLC. - 0022-2461 .- 1573-4803. ; 52:4, s. 2254-2262
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Journal article (peer-reviewed)abstract
- Composite matrices of poly(ε-caprolactone)-grafted acrylic acid (PCL-g-AA) and hydroxyapatite (HA) were prepared via electrospinning of oil-in-water emulsions. Grafting of varying amounts of AA on PCL was carried out in a twin-screw compounder using benzoyl peroxide as an initiator under inert atmosphere. A solution of PCL-g-AA in toluene, containing HA, comprised the oil phase of the emulsion, while the aqueous phase contained poly(vinyl alcohol) (PVA) as a template polymer. No emulsifier was used in making such emulsions which were found to be stable for more than a month at room temperature. Secondary interactions of AA group of PCL-g-AA with HA and PVA at the oil–water interface provided stability to the emulsion. Uniform composite fibrous matrices were produced from the resultant emulsions under controlled electrospinning conditions. The composite matrices, thus developed using minimal organic solvent, are free from emulsifiers and have high potential to be used in applications including tissue engineering
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