Electrospinning of PCL-Based Blends: Processing Optimization for Their Scalable Production (original) (raw)
Related papers
Electrospun nanocomposites of poly(e-caprolactone) (PCL) incorporated with PCL-grafted cellulose nanocrystals (PCL-g-CNC) were produced. PCL chains were grafted from cellulose nanocrystals (CNC) surface by ring-opening polymerization. Grafting was confirmed by infrared spectroscopy (FTIR) and thermogravimetric analyses (TGA). The resulting PCL-g-CNC were then incorporated into a PCL matrix at various loadings. Homogeneous nanofibers with average diameter decreasing with the addition of PCL-g-CNC were observed by scanning electron microscopy (SEM). PCL-g-CNC domains incorporated into the PCL matrix were visualized by transmission electron microscopy (TEM). Thermal and mechanical properties of the mats were analyzed by differential scanning calorimetry (DSC), TGA and dynamic mechanical analysis (DMA). The addition of PCL-g-CNC into the PCL matrix caused changes in the thermal behavior and crystallinity of the electrospun fibers. Significant improvements in Young's modulus and in strain at break with increasing PCL-g-CNC loadings were found. These results highlighted the great potential of cellulose nanocrystals as a reinforcement phase in electrospun PCL mats, which can be used as biomedical materials.
Organic and Inorganic PCL-Based Electrospun Fibers
Polymers
In this work, different nanocomposite electrospun fiber mats were obtained based on poly(e-caprolactone) (PCL) and reinforced with both organic and inorganic nanoparticles. In particular, on one side, cellulose nanocrystals (CNC) were synthesized and functionalized by “grafting from” reaction, using their superficial OH– group to graft PCL chains. On the other side, commercial chitosan, graphene as organic, while silver, hydroxyapatite, and fumed silica nanoparticles were used as inorganic reinforcements. All the nanoparticles were added at 1 wt% with respect to the PCL polymeric matrix in order to compare the different behavior of the woven no-woven nanocomposite electrospun fibers with a fixed amount of both organic and inorganic nanoparticles. From the thermal point of view, no difference was found between the effect of the addition of organic or inorganic nanoparticles, with no significant variation in the Tg (glass transition temperature), Tm (melting temperature), and the degr...
ACS Sustainable Chemistry & Engineering, 2014
Solution blends of poly(L-lactic acid) (PLLA) and poly(3hyroxybutyrate-co-3-hydroxyvalerate) (PHBV) in chloroform/DMF were electrospun at room temperature on a stationary collection plate. Polymer blend ratio, PHBV hydroxyvalerate content, solvent ratio, polymer concentration, and electrospinning process parameters were varied to determine optimal electrospinning conditions. The success of each formulation at producing nonwoven mats of continuous submicron diameter fibers was evaluated by optical and scanning electron microscopy. The diameter of the blend fibers was larger than electrospun fibers of either neat electrospun polymer, with a higher PLLA ratio favoring a porous surface morphology and higher PHBV ratios favoring beaded fiber morphology. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were used to analyze the thermal properties of the fibrous mats. The glass transition temperatures of the fibers from blends decreased as the PHBV weight ratio increased. The crystallinity of the PHBV fraction decreased as the ratio of the polymer in the blend decreased, whereas the crystallinity of PLLA was unaffected by the blend ratio. Dynamic mechanical analysis (DMA) indicated that the tensile strength of electrospun PHBV was improved by blending. Porous PLLA/PHBV electrospun fibers have potential for applications that need a high surface to volume ratio such as filtration, biomedical, energy storage devices, etc.
Fabrication and Characterization of Polycaprolactone (PCL)/Gelatin Electrospun Fibers
Over the past few decades, there has been considerable interest in developing electrospun fibers by using electrospinning technique for various applications. Polymer blending is one of the most effective methods in providing desired properties. In this study, synthetic polymer polycaprolactone (PCL) was blended together with natural polymer gelatin where both of them have different properties. It is done by using electrospinning technique. 10 %w/v and 14 %w/v PCL/gelatin electrospun fibers were successfully electrospun with different weight ratio. Processing parameters were set constant in this study and only solution parameters were altered. The optimized electrospun fiber formed was 14 %w/v PCL/gelatin 70:30 with average fiber diameter of 246.30 nm. No beaded fiber was formed in this scanning electron microscope (SEM) image. The result obtained also showed that by increasing the overall polymeric concentration of PCL/gelatin, average fiber diameter decreases. Fiber diameter was also found decreasing with the increase of the concentration of gelatin in the same concentratoin of PCL/gelatin blended electrospun fiber. Blending of PCL and gelatin in different weight ratio had provided different properties of electrospun fibers. It is believed that blended electrospun fibers can be used for biomedical applications.
Applied Sciences
Polycaprolactone (PCL) is one of the most used synthetic polymers for medical applications due to its biocompatibility and slow biodegradation character. Combining the inherent properties of the PCL matrix with the characteristic of nanofibrous particles, result into promising materials that can be suitable for different applications, including the biomedical applications. The advantages of nanofibrous structures include large surface area, a small diameter of pores and a high porosity, which make them of great interest in different applications. Electrospinning, as technique, has been heavily used for the preparation of nano- and micro-sized fibers. This review discusses the different methods for the electrospinning of PCL and its composites for advanced applications. Furthermore, the steady state conditions as well as the effect of the electrospinning parameters on the resultant morphology of the electrospun fiber are also reported.
Electrospinning of PCL/natural rubber blends
Journal of Materials Science, 2013
In this study, a thermoplastic/elastomeric binary blend of non-vulcanized natural rubber (NR) and polycaprolactone (PCL) was electrospun using polymer solutions consisting of varying proportions of PCL and NR. Specifically, an 8 % (w/v) NR/toluene solution was mixed with an 8 % (w/v) PCL/chloroform solution at proportions of 2, 15, 30, and 50 % (v/v). The morphological, thermal, and mechanical properties of the electrospun mats were investigated by scanning electron microscopy (SEM), differential scanning calorimetry, and uniaxial tensile tests. The SEM images demonstrated the production of micrometer-and sub-micrometer-sized fibers with no bead formation. Fibers with diameters ranging from 1.3 lm for samples with 0 % NR to 210 nm for samples containing 50 % NR were observed. Fibers with rough and smooth morphologies were observed, showing that the PCL/NR mats had phase-separated. The blend miscibility was evaluated by thermal analysis, which showed that blending did not improve the thermal stability of the systems. An investigation of the mechanical properties of the electrospun mats showed that adding NRL to the blend increased the tensile modulus, the ultimate elasticity, and the strain. Thus, non-vulcanized NR was successfully incorporated into electrospun mats, which exhibited useful mechanical properties that could be harnessed in biomaterials applications.
Materials Science and Engineering: A, 2011
Poly(-caprolactone) (PCL) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) were blended in different ratio, e.g. 30/70, 50/50 and 70/30 (w/w), by means of solvent casting or electrospinning. Microstructure, thermal and mechanical properties of cast films and non-woven mats were investigated by means of scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), differential scanning calorimetry (DSC), and uniaxial tensile test. The microstructure of PHBV/PCL solvent cast films (thickness 65-100 m) was strictly dependent on the composition of the blend, a clean phase separation was observed for the 50/50 (w/w) sample. All electrospun PHBV/PCL blends (thickness 350-800 m) were characterised by uniform and homogenous fibers, the average size was about 3 m. Both techniques led to polymeric blends comprised of separate crystalline domains associated to an amorphous interdisperse phase. It has also been demonstrated that electrospun PHBV/PCL blends showed a lower segregation degree among the crystalline domains. Solvent cast blends were characterised by superior mechanical properties in terms of tensile modulus and tensile strength compared to electrospun ones. Fractured electrospun blends showed an overall fiber rearrangement in the direction of the applied load, eventually highlighting multiple necking regions along the fibers.
Effect of Molecular Weight on Electro Spun Pcl Based Composite Fibrous Mats
BJSTR, 2017
Controlling the biodegradation of scaffolds to tune with that of the growing tissue is crucial for tissue regeneration. Although molecular weight of a polymer is known to influence its degradation, such studies have not been reported for electrospun Polycaprolactone (PCL) based composite scaffolds. In the present study, two low molecular weight PCL, 10 and 45 kDa PCL (10PCL and 45PCL) have been analyzed for their electrospun ability and biodegradation in comparison with 80 kDa PCL (80PCL) in forming pure polymeric and hydroxyapatite composite nanofibrous mats. The 45PCL and 80PCL were electro spin able but the 10PCL resulted in electro spraying of particles. However, 45PCL needed a higher concentration (20 wt.%) of polymer than the 80PCL (8 wt.%) in order to electrospin bead free uniform fibres. The fibres obtained were in the diameter range of 310±50 nm and 400±100 nm for the 45PCL and 45PCL/HA composite mats respectively. The Hydroxyapatite (HA) incorporation in the composites was confirmed through X-ray diffraction and spectroscopic methods. The 45PCL/HA composite degrades at a relatively faster rate than the 80PCL/HA composite. The electrospun mats were also found to be non cytotoxic (Live/Dead assay), commendable cellular metabolic activity (MTT assay) and good proliferation of osteoblast-like cells (HOS) as evidenced through fluorescent and scanning electron microscopy. This work demonstrated the feasibility of fabricating PCL based electrospun composite scaffolds having controlled degradation rates.
Journal of Polymer Science Part B: Polymer Physics, 2006
Electrospinning of poly(3-hydroxybutyrate) (PHB), poly(3-hydroxybutyrateco-3-hydroxyvalerate) (PHBV), and their blends was first carried out in chloroform at 50 8C on a stationary collector. The average diameter of the as-spun fiber from PHB and PHBV solutions decreased with increasing collection distance and increased with increasing solution concentration and applied electrical potential. In all of the spinning conditions investigated, the average diameter of the as-spun pure fibers ranged between 1.6 and 8.8 lm. Electrospinning of PHB, PHBV, and their blends was carried out further at a fixed solution concentration of 14% w/v on a homemade rotating cylindrical collector. Well-aligned, cross-sectionally round fibers without beads were obtained. The average diameter of the as-spun pure and blend fibers ranged between 2.3 and 4.0 lm. The as-spun fiber mats appeared to be more hydrophobic than the corresponding films and much improvement in the tensile strength and the elongation at break was observed for the blend fiber mats over those of the pure fiber ones. Lastly, indirect cytotoxicity evaluation of the as-spun pure and blend fiber mats with mouse fibroblasts (L929) indicated that these mats posed no threat to the cells.
Porous electrospun polycaprolactone fibers: Effect of process parameters
Journal of Polymer Science Part B: Polymer Physics, 2016
The effect of electrospinning process parameters (solution flow rate, applied voltage, spinning distance) on the size and surface morphology of porous electrospun poly(ε-caprolactone) was investigated in this study. Response surface methodology was implemented for the design and conduction of electrospinning experiments. The feed solution was a 12.5% w/v poly(ε-caprolactone) (PCL) solution in a binary solvent mixture of 90%v/v chloroform/ dimethyl sulfoxide. Spinning distance of 10-25 cm, applied voltage of 10-25 kV and feed flow rate of 0.5-5 ml/h were the range of limiting values of the independent variables used for the development of a central composite design. Second order polynomial equations, correlating electrospinning process parameters to relative pore coverage and fibre average diameter were developed and validated. An increase in any of the electrospinning process parameters favoured pore formation and fibre diameter increase. Under the experimental conditions investigated, the relative pore surface coverage was 15.8-31.9% and the average fibre diameter was in the range of 1.6-3.3 μm. Applied voltage was proven to be the parameter with the strongest impact on both, fibre diameter and surface morphology.