scholarly journals Size-Controllable Melt-Electrospun Polycaprolactone (PCL) Fibers with a Sodium Chloride Additive

Polymers ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1768 ◽  
Author(s):  
Piyasin ◽  
Yensano ◽  
Pinitsoontorn
Keyword(s):  
Electrostatic Force ◽  
Electrospun Fiber ◽  
Polymer Melt ◽  
High Viscosity ◽  
Electrospinning Process ◽  
Electrospun Fibers ◽  
Glass Syringe ◽  
Melt Electrospinning ◽  
Size And Morphology ◽  
Two Parameters

Melt-electrospun polycaprolactone (PCL) fibers were fabricated by using NaCl as an additive. The size and morphology of the PCL fibers could be controlled by varying the concentration of the additive. The smallest size of the fibers (2.67 0.57) µm was found in the sample with 8 wt% NaCl, which was an order of magnitude smaller than the PCL fibers without the additive. The melt-electrospun fibers were characterized using the differential scanning calorimeter (DSC), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) techniques. Interestingly, a trace of NaCl was not found in any melt-electrospun fiber. The remaining PCL after melt-electrospinning was evaporated by annealing, and the NaCl residual was found in the glass syringe. The result confirmed that the NaCl additive was not ejected from the glass syringe in the melt-electrospinning process. Instead, the NaCl additive changed the viscosity and the polarization of the molten polymer. Two parameters are crucial in determining the size and morphology of the electrospun fibers. The higher NaCl concentration could lead to higher polarization of the polymer melt and thus a stronger electrostatic force, but it could also result in an exceedingly high viscosity for melt-electrospinning. In addition, the absence of NaCl in the melt-electrospun PCL fibers is advantageous. The fibers need not be cleaned to remove additives and can be directly exploited in applications, such as tissue engineering or wound dressing.

Study of Preparation Metallocene Based LLDPE Extra-Fibers by Melt Electrospinning Process

2012 ◽  
Vol 512-515 ◽  
pp. 2424-2427
Author(s):  
Na Zhao ◽  
Tai Qi Liu ◽  
Rui Xue Liu
Keyword(s):  
Field Strength ◽  
High Viscosity ◽  
Electrospinning Process ◽  
Electrospun Fibers ◽  
Optimal Parameters ◽  
Common Solution ◽  
Melt Electrospinning ◽  
Fine Fiber ◽  
Electrospinning Method ◽  
Solution Electrospinning

In this paper, metallocene based LLDPE (mLLDPE) extra-fine fiber , which can not be processed by a common solution electrospinning method.was successfully prepared via a melt electrospinning method. First, a self-designed melt electrospinning device was manufctured and it was used to produce mLLDPE fibers . Then LLDPE extra-fine fiber was successfully prepared by addition of viscosity-reducing additive such as wax, and the resulted fiber was charctered by SEM. Last, the optimal parameters for the preparation of mLLDPE fiber was determined. The experimental results show that commercial mLLDPE can hardly be processed to fibers because of its high viscosity. The diameter and morphology of resulted mLLDPE electrospun fibers depend on the electrospinning parameters such as electric field strength and collecting distance.

scholarly journals The Effect of Dye and Pigment Concentrations on the Diameter of Melt-Electrospun Polylactic Acid Fibers

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2321 ◽  
Author(s):  
N.K. Balakrishnan ◽  
K. Koenig ◽  
G. Seide
Keyword(s):  
Electrical Conductivity ◽  
Polylactic Acid ◽  
Electrical Resistance ◽  
Polymer Melt ◽  
High Viscosity ◽  
Electrospinning Process ◽  
Polymer Aggregates ◽  
Melt Electrospinning ◽  
Coarse Fibers ◽  
Solution Electrospinning

Sub-microfibers and nanofibers produce more breathable fabrics than coarse fibers and are therefore widely used in the textiles industry. They are prepared by electrospinning using a polymer solution or melt. Solution electrospinning produces finer fibers but requires toxic solvents. Melt electrospinning is more environmentally friendly, but is also technically challenging due to the low electrical conductivity and high viscosity of the polymer melt. Here we describe the use of colorants as additives to improve the electrical conductivity of polylactic acid (PLA). The addition of colorants increased the viscosity of the melt by >100%, but reduced the electrical resistance by >80% compared to pure PLA (5 GΩ). The lowest electrical resistance of 50 MΩ was achieved using a composite containing 3% (w/w) indigo. However, the thinnest fibers (52.5 µm, 53% thinner than pure PLA fibers) were obtained by adding 1% (w/w) alizarin. Scanning electron microscopy revealed that fibers containing indigo featured polymer aggregates that inhibited electrical conductivity, and thus increased the fiber diameter. With further improvements to avoid aggregation, the proposed melt electrospinning process could complement or even replace industrial solution electrospinning and dyeing.

scholarly journals Melt Electrospinning Writing Process Guided by a “Printability Number”

2017 ◽  
Vol 139 (8) ◽  
Author(s):  
Filippos Tourlomousis ◽  
Houzhu Ding ◽  
Dilhan M. Kalyon ◽  
Robert C. Chang
Keyword(s):  
Three Dimensional ◽  
Polymer Melt ◽  
Volumetric Flow Rate ◽  
Thermal Conditions ◽  
Electrospinning Process ◽  
Critical Parameters ◽  
Experimental Investigations ◽  
Dimensionless Numbers ◽  
Melt Electrospinning ◽  
Resistive Forces

The direct electrostatic printing of highly viscous thermoplastic polymers onto movable collectors, a process known as melt electrospinning writing (MEW), has significant potential as an additive biomanufacturing (ABM) technology. MEW has the hitherto unrealized potential of fabricating three-dimensional (3D) porous interconnected fibrous mesh-patterned scaffolds in conjunction with cellular-relevant fiber diameters and interfiber distances without the use of cytotoxic organic solvents. However, this potential cannot be readily fulfilled owing to the large number and complex interplay of the multivariate independent parameters of the melt electrospinning process. To overcome this manufacturing challenge, dimensional analysis is employed to formulate a “Printability Number” (NPR), which correlates with the dimensionless numbers arising from the nondimensionalization of the governing conservation equations of the electrospinning process and the viscoelasticity of the polymer melt. This analysis suggests that the applied voltage potential (Vp), the volumetric flow rate (Q), and the translational stage speed (UT) are the most critical parameters toward efficient printability. Experimental investigations using a poly(ε-caprolactone) (PCL) melt reveal that any perturbations arising from an imbalance between the downstream pulling forces and the upstream resistive forces can be eliminated by systematically tuning Vp and Q for prescribed thermal conditions. This, in concert with appropriate tuning of the translational stage speed, enables steady-state equilibrium conditions to be achieved for the printing of microfibrous woven meshes with precise and reproducible geometries.

A Novel Melt Electrospinning System for Studying Cell Substrate Interactions

2015 ◽  
Author(s):  
Filippos Tourlomousis ◽  
Azizbek Babakhanov ◽  
Houzhu Ding ◽  
Robert C. Chang
Keyword(s):  
Electrospun Fiber ◽  
Processing Parameters ◽  
Electrospinning Process ◽  
Melt Processing ◽  
Complex Nature ◽  
Melt Temperature ◽  
Melt Electrospinning ◽  
Culture Models ◽  
Cellular Microenvironments

Controlling cell behavior has generated immense attention in the fields of tissue engineering and regenerative medicine. Particular emphasis has been given to the creation of 3D biomimetic cellular microenvironments that replicate the complex nature of the extracellular matrix (ECM). A key factor that has not been rigorously deconstructed using scalable, layered manufacturing approaches is the structural dimension or scale aspect of in vitro culture models. Melt electrospinning represents a bio-additive manufacturing process that has been relatively under-reported. Although complex in nature, the melt electrospinning process can furnish a 3D cell delivery format with physiologically relevant 3D structural cues. In the present work, poly-ε-caprolactone (PCL) has been chosen as the biomaterial substrate. Rheological studies that guide the design phase of the reported system have been performed for the entire PCL melt processing range, implicating the governing effect of the experimental melt temperature on the scale and the topography in the final processed material. Notable challenges that arise from the nature of the process with respect to the electrospun fiber stability and resolution have been overcome through the design of a novel heating element configuration. In this paper, a reliable biofabrication process with tunable processing of the fiber diameter and alignment is reported. Fundamental parametric studies utilizing the major processing parameters demonstrate the potential for the system to precisely fabricate 3D PCL scaffolds with microstructural features.

scholarly journals Revealing key parameters to minimize the diameter of polypropylene fibers produced in the melt electrospinning process

e-Polymers ◽  
2019 ◽  
Vol 19 (1) ◽  
pp. 330-340 ◽  
Author(s):  
Jonas Daenicke ◽  
Michael Lämmlein ◽  
Felix Steinhübl ◽  
Dirk W. Schubert
Keyword(s):  
Electrical Conductivity ◽  
Fiber Diameter ◽  
Sodium Stearate ◽  
Polymer Melt ◽  
Electrospinning Process ◽  
Climate Chamber ◽  
Melt Electrospinning ◽  
P 16 ◽  
Chamber Temperature ◽  
Nanoscale Fibers

AbstractThis study deals with the subject of optimizing the melt electrospinning process of polypropylene with the aim of producing nanoscale fibers. A feasibility study with two polypropylene types and different additives to adapt the material composition is performed. The polypropylene types are of different molar masses to adapt the viscosity to the process. The used additives, sodium stearate and Irgastat®P 16, have a positive effect on the electrical conductivity of the polymer melt. In addition, process parameter optimization is done by varying the climate chamber temperature, using different collector voltages and varying the nozzle-collector distance. A strong influence of the climate chamber temperature has been proven and leads to a desired temperature of 100°C. The fiber diameter is dependent on process parameters, material melt viscosity and electrical conductivity. With optimized process and material parameters, the fiber diameter could be minimized to a median value of 210 nm.

scholarly journals Bonding widths of Deposited Polymer Strands in Additive Manufacturing

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 871
Author(s):  
Cheng Luo ◽  
Manjarik Mrinal ◽  
Xiang Wang ◽  
Ye Hong
Keyword(s):  
Polymer Melt ◽  
Acrylonitrile Butadiene Styrene ◽  
High Viscosity ◽  
Numerical Results ◽  
Fused Filament Fabrication ◽  
Cross Sectional ◽  
Nozzle Height ◽  
Special Cases ◽  
Cross Sectional Profile ◽  
Sectional Profile

In this study, we explore the deformation of a polymer extrudate upon the deposition on a build platform, to determine the bonding widths between stacked strands in fused-filament fabrication. The considered polymer melt has an extremely high viscosity, which dominates in its deformation. Mainly considering the viscous effect, we derive analytical expressions of the flat width, compressed depth, bonding width and cross-sectional profile of the filament in four special cases, which have different combinations of extrusion speed, print speed and nozzle height. We further validate the derived relations, using our experimental results on acrylonitrile butadiene styrene (ABS), as well as existing experimental and numerical results on ABS and polylactic acid (PLA). Compared with existing theoretical and numerical results, our derived analytic relations are simple, which need less calculations. They can be used to quickly predict the geometries of the deposited strands, including the bonding widths.

scholarly journals Light-assisted electrospinning monitoring for soft polymeric nanofibers

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Dario Lunni ◽  
Goffredo Giordano ◽  
Francesca Pignatelli ◽  
Carlo Filippeschi ◽  
Stefano Linari ◽  
...  
Keyword(s):  
Real Time ◽  
Electrospun Fiber ◽  
Correlation Coefficients ◽  
Experimental Tests ◽  
Electrospinning Process ◽  
Analytical Models ◽  
Diameter Distribution ◽  
Soft Systems ◽  
Light Coupling ◽  
Waveguide Length

Abstract A real-time tool to monitor the electrospinning process is fundamental to improve the reproducibility and quality of the resulting nanofibers. Hereby, a novel optical system integrated through coaxial needle is proposed as monitoring tool for electrospinning process. An optical fiber (OF) is inserted in the inner needle, while the external needle is used to feed the polymeric solution (PEO/water) drawn by the process. The light exiting the OF passes through the solution drop at the needle tip and gets coupled to the electrospun fiber (EF) while travelling towards the nanofibers collector. Numerical and analytical models were developed to assess the feasibility and robustness of the light coupling. Experimental tests demonstrated the influence of the process parameters on the EF waveguide properties, in terms of waveguide length (L), and on the nanofibers diameter distribution, in terms of mean $$\widehat{D}$$ D ^ and normalized standard deviation $$\chi$$ χ . Data analysis reveals good correlation between L and $$\widehat{D}, \chi$$ D ^ , χ (respectively maximum correlation coefficients of $${\rho }_{L,\widehat{D}}$$ ρ L , D ^ = 0.88 and $${\rho }_{L,\chi }$$ ρ L , χ = 0.84), demonstrating the potential for effectively using the proposed light-assisted technology as real-time visual feedback on the process. The developed system can provide an interesting option for monitoring industrial electrospinning systems using multi- or moving needles with impact in the scaling-up of innovative nanofibers for soft systems.

Numerical simulation of gas‐assisted polymer‐melt electrospinning: Parametric study of a multinozzle system for mass production

2020 ◽  
Vol 60 (9) ◽  
pp. 2111-2121
Author(s):  
Youbin Kwon ◽  
Jihyun Yoon ◽  
Seung‐Yeol Jeon ◽  
Daehwan Cho ◽  
Kwangjin Lee ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Mass Production ◽  
Parametric Study ◽  
Polymer Melt ◽  
Melt Electrospinning

scholarly journals Roughness and Fiber Fraction Dominated Wetting of Electrospun Fiber-Based Porous Meshes

Polymers ◽  
2018 ◽  
Vol 11 (1) ◽  
pp. 34 ◽  
Author(s):  
Piotr Szewczyk ◽  
Daniel Ura ◽  
Sara Metwally ◽  
Joanna Knapczyk-Korczak ◽  
Marcin Gajek ◽  
...  
Keyword(s):  
Contact Angle ◽  
Electrospun Fiber ◽  
Three Dimensional ◽  
Contact Angles ◽  
Electrospun Fibers ◽  
Surface Geometry ◽  
Wetting Contact Angle ◽  
Fiber Fraction ◽  
Significant Difference ◽  
Entrapped Air

Wettability of electrospun fibers is one of the key parameters in the biomedical and filtration industry. Within this comprehensive study of contact angles on three-dimensional (3D) meshes made of electrospun fibers and films, from seven types of polymers, we clearly indicated the importance of roughness analysis. Surface chemistry was analyzed with X-ray photoelectron microscopy (XPS) and it showed no significant difference between fibers and films, confirming that the hydrophobic properties of the surfaces can be enhanced by just roughness without any chemical treatment. The surface geometry was determining factor in wetting contact angle analysis on electrospun meshes. We noted that it was very important how the geometry of electrospun surfaces was validated. The commonly used fiber diameter was not necessarily a convincing parameter unless it was correlated with the surface roughness or fraction of fibers or pores. Importantly, this study provides the guidelines to verify the surface free energy decrease with the fiber fraction for the meshes, to validate the changes in wetting contact angles. Eventually, the analysis suggested that meshes could maintain the entrapped air between fibers, decreasing surface free energies for polymers, which increased the contact angle for liquids with surface tension above the critical Wenzel level to maintain the Cassie-Baxter regime for hydrophobic surfaces.

In-syringe dispersive solid phase extraction: a novel format for electrospun fiber based microextraction

The Analyst ◽  
2014 ◽  
Vol 139 (23) ◽  
pp. 6266-6271 ◽  
Author(s):  
Gang-Tian Zhu ◽  
Xiao-Mei He ◽  
Bao-Dong Cai ◽  
Han Wang ◽  
Jun Ding ◽  
...  
Keyword(s):  
Solid Phase Extraction ◽  
High Throughput ◽  
Solid Phase ◽  
Electrospun Fiber ◽  
Electrospun Fibers ◽  
Phase Extraction ◽  
Dispersive Solid Phase Extraction

A rapid and high-throughput in-syringe dispersive solid phase extraction (dSPE) system using electrospun fibers as adsorbents is presented.

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