Analysis of the influence of electrospinning
process parameters on the
morphology of poly(lactic acid) fibres

Purpose: The article focuses on the production of polymer nanofibres from poly(lactic acid) using the electro-spinning method, i.e. the technique of forming fibres in an electrostatic field. The main aim of the publication was to analyse the influence of the distance between electrodes on the morphology of one-dimensional polymeric materials obtained. Design/methodology/approach: In the practical part of the study solutions of polylactide in acetone and a mixture of chloroform/dimethylformamide (DMF) were produced. After 72 hours of mixing, no homogeneous solutions were obtained, therefore a solution consisting of a polylactide dissolved in chloroform was prepared, to which dimethylformamide was added in order to dilute the mixture. The morphology of the nanostructures obtained was analysed by means of a scanning electron microscope (SEM) equipped with an X-ray energy dispersion spectrometer (EDS), which allowed to analyse the chemical composition of the nanofibres produced. The electro-spinning method used to obtain fibres is characterized by high versatility - it gives the possibility to produce fibres from a wide range of polymers. Electro-spinning is also an economic method, and spinned fibres have a wide application potential. Findings: Nanofibres obtained by electro-spinning from the previously produced solution, regardless of the distance between the nozzle and the collector (10 or 20 cm) did not show any significant discrepancies in the values of measured diameters. Fibres obtained at increased distance between electrodes (20 cm) are characterized by a smaller average diameter value, but the difference is small, fluctuating between 48-49 nm. In the case of the sample formed during electro-spinning at the distance of the nozzle - collector equal to 10 cm and the sample produced at the distance doubled, no defects in the structure of the obtained nanofibres were observed. The analysis of topographic images of surfaces produced in the course of nanostructures' work did not show any significant influence of the distance between the nozzle and collector on the diameter of fibres. No defects in the structure of one-dimensional polymer materials obtained allowed to state that the distance between the nozzle and the collector in the range of 10-20 cm is the optimal parameter of the electro-spinning process allowing to obtain smooth, untangled fibres. Practical implications: The fibrous polymer mats obtained during the electro-spinning process of polylactide can be used as protective clothing materials, as drug delivery systems, as tissue scaffolding and as filtration membranes. Originality/value: At present, there are few articles in the literature on the electrospinning process, due to the fact that it is a constantly developing matte for the production of nanofibres. Moreover, most of the research focuses on fibres obtained from nonbiodegradable polymers, which do not have the advantages of fibres obtained from polylactide.

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An observation of the evolution of equilibrium stress on poly(lactic acid) and poly(lactic acid)/hydroxyapatite nanocomposites

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1177/0954406220939598 ◽

2020 ◽

pp. 095440622093959

Author(s):

Necmi Dusunceli

Keyword(s):

Relaxation Time ◽

Lactic Acid ◽

Polymeric Materials ◽

Relaxation Behavior ◽

Polymer Materials ◽

Material Modeling ◽

Poly Lactic Acid ◽

Equilibrium Stress ◽

Stress Levels ◽

Anomalous Relaxation

Relaxation behavior provides specific information that indicates stress development with elapsed time for the determination of material characterization and constituting of material modeling. In addition, anomalous relaxation behavior of polymeric materials enables experimental analysis of some theoretical variables in constitutive equation. Equilibrium stress is one of the most prevailing variables in material modeling and it is generally considered as unmeasurable. In this study, evolution of equilibrium stress was examined with relaxation tests of two semi crystalline polymer materials, one of which was found to reach precise equilibrium stress levels. In accordance with this purpose, extensive relaxation tests were conducted on poly(lactic acid) and poly(lactic acid)/hydroxyapatite nanocomposites specimens at a wide range of temperatures from 23 ℃ and 55 ℃, and stress levels from 1 MPa to 50 MPa for poly(lactic acid) and 51 MPa for poly(lactic acid)/hydroxyapatite nanocomposites. All the specimens were subjected tensile loading–unloading and partial retraction process. The starting points of the relaxation test were chosen on unloading segment of stress–strain curves. Evolution of stress may decay, increase or decay then increase depending on the test point on unloading curves. Relaxation behavior of poly(lactic acid) and poly(lactic acid)/hydroxyapatite nanocomposites was simulated using viscoplasticity theory based on overstress for polymeric materials. Experimental results of poly(lactic acid) and poly(lactic acid)/hydroxyapatite nanocomposites were matched with numerical results of viscoplasticity theory based on overstress for polymeric materials, and viscoplasticity theory based on overstress for polymeric material model was found to have an aptitude for predicting anomalous relaxation behavior of poly(lactic acid) and poly(lactic acid)/hydroxyapatite nanocomposites. Additionally, the effect of temperature on relaxation time was investigated with using Kohlraush–Williams–Watts time-decay function. Modeling capability of Kohlrausch–Williams–Watts model was reasonable to predict short-term simple relaxation of poly(lactic acid) and poly(lactic acid)/hydroxyapatite nanocomposites. Responses of the model showed that interaction between relaxation time and environmental temperature was related to transition from glass state to rubbery state.

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In Vitro and In Vivo Biosafety Analysis of Resorbable Polyglycolic Acid-Polylactic Acid Block Copolymer Composites for Spinal Fixation

Polymers ◽

10.3390/polym13010029 ◽

2020 ◽

Vol 13 (1) ◽

pp. 29

Author(s):

Seung Kyun Yoon ◽

Jin Ho Yang ◽

Hyun Tae Lim ◽

Young-Wook Chang ◽

Muhammad Ayyoob ◽

...

Keyword(s):

Lactic Acid ◽

Animal Experiments ◽

Polymeric Materials ◽

Polyglycolic Acid ◽

Poly Lactic Acid ◽

Skin Sensitization ◽

Spinal Fixation ◽

In Vivo Degradation

Herein, spinal fixation implants were constructed using degradable polymeric materials such as PGA–PLA block copolymers (poly(glycolic acid-b-lactic acid)). These materials were reinforced by blending with HA-g-PLA (hydroxyapatite-graft-poly lactic acid) and PGA fiber before being tested to confirm its biocompatibility via in vitro (MTT assay) and in vivo animal experiments (i.e., skin sensitization, intradermal intracutaneous reaction, and in vivo degradation tests). Every specimen exhibited suitable biocompatibility and biodegradability for use as resorbable spinal fixation materials.

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Stress, strain and deformation of poly-lactic acid filament deposited onto polyethylene terephthalate woven fabric through 3D printing process

Scientific Reports ◽

10.1038/s41598-019-50832-7 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 6

Author(s):

Prisca Aude Eutionnat-Diffo ◽

Yan Chen ◽

Jinping Guan ◽

Aurelie Cayla ◽

Christine Campagne ◽

...

Keyword(s):

Lactic Acid ◽

3D Printing ◽

Tensile Properties ◽

Polyethylene Terephthalate ◽

Polymeric Materials ◽

Deposition Process ◽

Woven Fabric ◽

Poly Lactic Acid ◽

Printing Process ◽

3D Printed

Abstract Although direct deposition of polymeric materials onto textiles through 3D printing is a great technique used more and more to develop smart textiles, one of the main challenges is to demonstrate equal or better mechanical resistance, durability and comfort than those of the textile substrates before deposition process. This article focuses on studying the impact of the textile properties and printing platform temperature on the tensile and deformations of non-conductive and conductive poly lactic acid (PLA) filaments deposited onto polyethylene terephthalate (PET) textiles through 3D printing process and optimizing them using theoretical and statistical models. The results demonstrate that the deposition process affects the tensile properties of the printed textile in comparison with the ones of the textiles. The stress and strain at rupture of the first 3D printed PLA layer deposited onto PET textile material reveal to be a combination of those of the printed layer and the PET fabric due to the lower flexibility and diffusion of the polymeric printed track through the textile fabric leading to a weak adhesion at the polymer/textile interface. Besides, printing platform temperature and textile properties influence the tensile and deformation properties of the 3D printed PLA on PET textile significantly. Both, the washing process and the incorporation of conductive fillers into the PLA do not affect the tensile properties of the extruded polymeric materials. The elastic, total and permanent deformations of the 3D-printed PLA on PET fabrics are lower than the ones of the fabric before polymer deposition which demonstrates a better dimensional stability, higher stiffness and lower flexibility of these materials.

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Fabrication of piezoelectric poly(l-lactic acid)/BaTiO3 fibre by the melt-spinning process

Scientific Reports ◽

10.1038/s41598-020-73261-3 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Hyun Ju Oh ◽

Do-Kun Kim ◽

Young Chan Choi ◽

Seung-Ju Lim ◽

Jae Bum Jeong ◽

...

Keyword(s):

Phase Transition ◽

Lactic Acid ◽

Crystalline Phase ◽

Melt Spinning ◽

Piezoelectric Properties ◽

Polymeric Materials ◽

Processing Conditions ◽

Post Processing ◽

Scanning Calorimetry ◽

Spinning Process

Abstract Poly(l-lactic acid) (PLLA) based piezoelectric polymers are gradually becoming the substitute for the conventional piezoelectric ceramic and polymeric materials due to their low cost and biodegradable, non-toxic, piezoelectric and non-pyroelectric nature. To improve the piezoelectric properties of melt-spun poly(l-lactic acid) (PLLA)/BaTiO3, we optimized the post-processing conditions to increase the proportion of the β crystalline phase. The α → β phase transition behaviour was determined by two-dimensional wide-angle x-ray diffraction and differential scanning calorimetry. The piezoelectric properties of PLLA/BaTiO3 fibres were characterised in their yarn and textile form through a tapping method. From these results, we confirmed that the crystalline phase transition of PLLA/BaTiO3 fibres was significantly enhanced under the optimised post-processing conditions at a draw ratio of 3 and temperature of 120 °C during the melt-spinning process. The results indicated that PLLA/BaTiO3 fibres could be a one of the material for organic-based piezoelectric sensors for application in textile-based wearable piezoelectric devices.

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Characterization of Electrospun Poly(Lactic Acid)/polyaniline Blend Nanofibers

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.332-334.317 ◽

2011 ◽

Vol 332-334 ◽

pp. 317-320 ◽

Cited By ~ 1

Author(s):

Hui Qin Zhang

Keyword(s):

Lactic Acid ◽

Composite Nanofibers ◽

Weight Ratio ◽

Electrospinning Process ◽

Poly Lactic Acid ◽

X Ray Diffraction ◽

Sem Images ◽

X Ray ◽

Ft Ir

In this study, composite nanofibers of polyaniline doped with dodecylbenzene sulfonic acid (PANI-DBSA) and Poly(lactic acid) (PLA) were prepared via an electrospinning process. The surface morphology, thermal properties and crystal structure of PLA/PANI-DBSA nanoﬁbers are characterized using Fourier transform infrared spectroscopy (FT-IR), wide-angle x-ray diffraction (WAXD) and scanning electron microscopy (SEM). SEM images showed that the morphology and diameter of the nanofibers were affected by the weight ratio of blend solution.

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An openwork like structures of polylactide – manufacturing and properties

E3S Web of Conferences ◽

10.1051/e3sconf/20184400165 ◽

2018 ◽

Vol 44 ◽

pp. 00165 ◽

Cited By ~ 1

Author(s):

Karolina Sobczyk ◽

Karol Leluk

Keyword(s):

Lactic Acid ◽

Surface Area ◽

High Surface ◽

High Surface Area ◽

Weight Ratio ◽

Electrospinning Process ◽

Poly Lactic Acid ◽

Process Conditions ◽

Fiber Morphology

Poly(lactic acid) electrospinning tests were carried out under various process conditions. Openwork structures with a high surface area to weight ratio have been obtained. Changing the parameters of the PLA electrospinning process resulted in products with different fiber morphology.

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Fabrication and Characterization of Polylactic Acid Electrospun Scaffolds Modified with Multi-Walled Carbon Nanotubes and Hydroxyapatite Nanoparticles

Biomimetics ◽

10.3390/biomimetics5030043 ◽

2020 ◽

Vol 5 (3) ◽

pp. 43

Author(s):

Athanasios Kotrotsos ◽

Prokopis Yiallouros ◽

Vassilis Kostopoulos

Keyword(s):

Mechanical Properties ◽

Carbon Nanotubes ◽

Polylactic Acid ◽

Physical And Mechanical Properties ◽

Polymeric Materials ◽

Cost Effective ◽

Electrospinning Process ◽

Wide Range ◽

Multi Walled Carbon Nanotubes ◽

Walled Carbon Nanotubes

The solution electrospinning process (SEP) is a cost-effective technique in which a wide range of polymeric materials can be electrospun. Electrospun materials can also be easily modified during the solution preparation process (prior SEP). Based on this, the aim of the current work is the fabrication and nanomodification of scaffolds using SEP, and the investigation of their porosity and physical and mechanical properties. In this study, polylactic acid (PLA) was selected for scaffold fabrication, and further modified with multi-walled carbon nanotubes (MWCNTs) and hydroxyapatite (HAP) nanoparticles. After fabrication, porosity calculation and physical and mechanical characterization for all scaffold types were conducted. More precisely, the morphology of the fibers (in terms of fiber diameter), the surface properties (in terms of contact angle) and the mechanical properties under the tensile mode of the fabricated scaffolds have been investigated and further compared against pristine PLA scaffolds (without nanofillers). Finally, the scaffold with the optimal properties was proposed as the candidate material for potential future cell culturing.

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Crystallization and Thermal Degradation of Green Nanocomposites Based on Lignin Coated Cellulose Nanocrystals and Poly(Lactic Acid)

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.737.256 ◽

2017 ◽

Vol 737 ◽

pp. 256-261 ◽

Cited By ~ 1

Author(s):

Martin Boruvka ◽

Luboš Bĕhálek

Keyword(s):

Lactic Acid ◽

Cellulose Nanocrystals ◽

Raw Material ◽

Degree Of Crystallinity ◽

Poly Lactic Acid ◽

Crystalline Cellulose ◽

Melt Crystallization ◽

Scanning Calorimetry ◽

Wide Range ◽

Twin Screw

Cellulose is almost inexhaustible source of raw material comprising at least one-third of all biomass matter. Through deconstruction of cellulose hierarchical structure can be extracted highly crystalline cellulose nanocrystals (CNC) with impressive properties. However, the main barrier in the processing of the nanocomposites based on CNC is their inhomogeneous dispersion and distribution in the non-polar polymer matrix. In this paper is this problem addressed by use of novel hydrophobic lignin coated CNC as a biobased nucleation agents in poly (lactic acid) (PLA) nanocomposites. These green nanocomposites based on natural plant derived substances have enormous potential to replace materials originated from non-renewable resources and show promise of providing degradation back into the environment when they are no longer needed. Resulted composites prepared by twin screw extrusion and injection moulding were characterized by means of scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The addition of L-CNC (1, 2 and 3 wt. %) into PLA increased melt crystallization enthalpy and decreases the cold crystallization enthalpy. The degree of crystallinity (cc) increased from 5.6 % (virgin PLA) to 8.5 % (PLA/1-L-CNC), 10.3 % (PLA/2-L-CNC) and 10.7 % (PLA/3-L-CNC). The wide range of degradation temperatures of lignin coating has been observed starting at 100 °C.

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Biocompatible Materials Based on Plasticized Poly(lactic acid), Chitosan and Rosemary Ethanolic Extract I. Effect of Chitosan on the Properties of Plasticized Poly(lactic acid) Materials

Polymers ◽

10.3390/polym11060941 ◽

2019 ◽

Vol 11 (6) ◽

pp. 941 ◽

Cited By ~ 14

Author(s):

Cornelia Vasile ◽

Elena Stoleru ◽

Raluca Nicoleta Darie-Niţa ◽

Raluca Petronela Dumitriu ◽

Daniela Pamfil ◽

...

Keyword(s):

Lactic Acid ◽

Food Packaging ◽

Polymeric Materials ◽

Poly Lactic Acid ◽

Rosemary Extract ◽

Antioxidant Compounds ◽

Innovative Drug ◽

Melt Mixing

The purpose of the present study is to develop new multifunctional environmentally friendly materials having applications both in medical and food packaging fields. New poly(lactic acid) (PLA)-based multifunctional materials containing additives derived from natural resources like chitosan (CS) and rosemary extract (R) were obtained by melt mixing. Each of the selected components has its own specific properties such as: PLA is a biodegradable thermoplastic aliphatic polyester derived from renewable biomass, heat-resistant, with mechanical properties close to those of polystyrene and polyethylene terephthalate, and CS offers good antimicrobial activity and biological functions, while R significantly improves antioxidative action necessary in all applications. A synergy of their combination, an optimum choice of their ratio, and processing parameters led to high performance antimicrobial/antioxidant/biocompatible/environmentally degradable materials. The polyethylene glycol (PEG)-plasticized PLA/chitosan/powdered rosemary extract biocomposites of various compositions were characterized in respect to their mechanical and rheological properties, structure by spectroscopy, antioxidant and antimicrobial activities, and in vitro and in vivo biocompatibility. Scanning electron microscopy images evidence the morphology features added by rosemary powder presence in polymeric materials. Incorporation of additives improved elongation at break, antibacterial and antioxidant activity and also biocompatibility. Migration of bioactive components into D1 simulant is slower for PEG-plasticized PLA containing 6 wt % chitosan and 0.5 wt % rosemary extract (PLA/PEG/6CS/0.5 R) biocomposite and it occurred by a diffusion-controlled mechanism. The biocomposites show high hydrophilicity and good in vitro and in vivo biocompatibility. No hematological, biochemical and immunological modifications are induced by subcutaneous implantation of biocomposites. All characteristics of the PEG-plasticized PLA-based biocomposites recommend them as valuable materials for biomedical implants, and as well as for the design of innovative drug delivery systems. Also, the developed biocomposites could be a potential nature-derived active packaging with controlled release of antimicrobial/antioxidant compounds.

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