Papers by Keyword: Polycaprolactone

Abstract: The first polycaprolactone material experimental and clinical studies were published in 1960-1970, which proved its biocompatibility and determined the absence of toxic properties. At the same time it did not receive widespread use due to insufficient rigidity and strength compared to metal implants. For a long time, relatively solid materials were used to treat injuries to the musculoskeletal system segments. The progress in materials science, development of new sterilization methods has again changed the attitude towards biomaterial implants and has attracted the attention of clinicians. In this regard, the development of predictive modeling methods to determine effective mechanical properties and optimal geometric structure of porous biomedical materials is an important task. Modeling the internal architecture of porous materials and their properties by the finite element method using computed tomography data is as close as possible to the real picture, but it is quite laborious to apply directly to large-sized scaffolds. Properties of such materials largely depend on the technology of their manufacture and processing, the geometric dimensions and cell shape. In this regard, the development and improvement of analytical methods for assessing properties of cellular structures remains relevant. The aim of this study is determining polycaprolactone effective elastic modulus based on modified Gibson-Ashby open-cell model as an implant material and osteochondral defects treatment. A practical analytical method for estimating the elastic modulus of a cellular material regardless of the scaffold volume and shape is proposed. Calculations are performed for polycaprolactone produced using selective laser sintering technology. A comparative analysis of the obtained results with experimental studies of other authors is carried out. The results can be used for evaluation analysis and calculations of medical devices strength and stiffness made of porous polycaprolactone for the bone defects treatment.

Abstract: Pineapple leaf is a significant agricultural waste in pineapple processing plants. The leaf comprises several carbohydrate polymers, including cellulose, hemicellulose and lignin. This research investigated the use of microcrystalline cellulose (MCC) extracted from pineapple leaves as a reinforcing agent in polycaprolactone (PCL) biopolymer at various MCC concentrations. MCC was extracted from pineapple leaves through several processes, including alkali treatment with sodium hydroxide (NaOH), bleaching with sodium hypochlorite (NaOCl), and acid hydrolysis with oxalic acid. Fourier transform infrared (FTIR) spectroscopy confirmed the presence of cellulose from the extracted MCC, and field emission scanning electron microscopy (FESEM) analysis revealed that the particles are of micro-size. The tensile testing results show that the elastic modulus of PCL-based biocomposite increases with higher MCC concentrations. The stiffness of the biocomposites increased by up to 9.5% with the addition of 2 wt.% of MCC as a reinforcing filler, indicating that MCC effectively enhances the mechanical properties of the biocomposite.

Abstract: This study presents a comprehensive investigation into the preparation and characterization of PCL/EA cellulose composites. The Fourier-transform infrared (FTIR) spectroscopy results confirm the successful composite fabrication, indicating the absence of chemical reactions during melt-compounding. Scanning electron microscopy (SEM) revealed distinct morphologies, with PCL forming a continuous phase and EA cellulose exhibiting a fibrous network. Despite successful embedding of EA cellulose fibers in the composite, fractured surfaces indicated poor interfacial interaction, potentially leading to fiber pull out. Thermogravimetric analysis (TGA) revealed enhanced thermal stability in the composites, while differential scanning calorimetry (DSC) indicated minimal impact on PCL melting behavior. X-ray diffraction analysis (XRD) further demonstrated enhanced crystallinity in the composites, highlighting increased order in PCL crystals. Mechanical testing revealed a modest increase in stiffness attributed to the rigid cellulose fibers. However, a decrease in yield strength, tensile strength, and elongation at break suggested reduced ductility and inferior mechanical properties, consistent with poor interfacial adhesion observed in SEM. Overall, this study contributes valuable insights into the structural, thermal, and mechanical characteristics of PCL/EA cellulose composites, offering a foundation for potential applications in various fields.

Abstract: The small size and large surface area of nano and microparticles are interesting properties for drug delivery, hypothetically capable of overcoming some limitations of conventional therapeutic medicine and diagnostic agents. Although their features are highly influenced by the polymer characteristics, these particles are known for encapsulating high amounts of drugs, improving their stability and bioavailability and enabling different administration routes. Among synthetic polymers, polycaprolactone (PCL) nanoparticles are widely studied in drug delivery due to the polymer excellent biocompatibility and degradability and for its ability to blend with other polymers. On its turn, among natural polymers, glucan has been emerging as a promising candidate for drug delivery particularly due to structure forming abilities and its immunomodulatory effects. Under the safe-by-design approach for the development of polymeric particles, this review encloses a comprehensive summary of production methods, physicochemical characteristics and immunotoxicity profiles of PCL and glucan particles developed for drug delivery.

Abstract: These days, nanofibers are used in the medical sector, such as drug delivery and wound dressing structures, because of their excellent characteristics, high permeability, and important surface area. Natural and synthetic polymers may be electrospun in the form of a blend. Besides, the antibiotics such as linezolid, enrofloxacin, and vancomycin are used in wound dressing due to their antibacterial properties. In this research, the blend nanofibrous structures made of PCL and gelatin (Gel) with a 25:75 ratio were produced for wound dressing applications. Clindamycin HCL as a drug was added to Gel and PCL polymeric solutions. Surface morphology, functional groups, and hydrophilicity of nanofibers were examined using SEM, FT-IR spectroscopy, and contact angle measurement, respectively. In addition, the antibacterial properties of nanofibers were evaluated quantitatively. The drug release mechanism of samples was investigated which the best-fitted model was recognized Korsmeyer-Peppas model. SEM images of scaffolds demonstrated uniform and bead-free morphology that, with incorporating the 6% of the drug, the diameters of mats were decreased from 398 nm to 303 nm. Moreover, the samples showed proper hydrophilicity and antibacterial properties against a gram-positive (89%) and a gram-negative (98%) bacterium. Finally, the nanofibers are capable of releasing the clindamycin gradually for 6 days.

Abstract: This study investigated the effect of polycaprolactone (PCL) loading (0.5, 1, and 3 wt%) on the morphology, tensile strength, and thermal properties of microcellular injection molded PP/PCL and PPgMA/PCL composites. We used the filler, PCL, that is micro-material in size. Results showed that 0.5 wt% loading of PCL on foamed PP has the largest tensile strength. However, tensile strength was almost similar to that of PPgMA composites. Tensile strength depends on the filler dispersion in the matrix and cell size present on the foamed composites. Good dispersion resulted in good tensile strength. The elongation decreased on PP but increased on PPgMA composites. The highest degradation temperature for PP/PCL and PPgMA/PCL was noted for 3.0 wt% PCL loading and neat PPgMA respectively. Cell size decreased and cell density increased with the addition of PCL into the PP and PPgMA matrix.

Abstract: Heavy metal adsorption (HMA) is one of the remediation techniques used to remove heavy metals from water/wastewater. Composite membranes with functionalized additives for selective adsorption are being investigated. In this study, Carbon Quantum Dots – Polyacrylonitrile/Polycaprolactone nanocomposite membranes are synthesized by electrospinning which is intended for HMA of Cu²⁺. The nanofiber mats were characterized using SEM, FTIR, and Contact Angle. Batch adsorption process were performed and to utilize the AAS for kinetic adsorption behavior analysis. SEM micrographs revealed the addition of CQD in PAN and PAN/PCL membrane matrix shifted the fiber size distribution from 50 – 100 nm to 150 – 250 nm indicates the decrease in effective surface area. FTIR analysis exhibited vibrational peaks and binding of distinct functional groups such as amine, nitrile, carboxylic, hydroxyl, and carbonyl for CQD, PAN and PCL, respectively. CQD in aqueous form further increases the hydrophilicity of PAN/PCL membrane matrix which is essential for HMA of Cu²⁺ ions. The increase of nanofiber mat’s adsorption capacity with respect to contact time obtained a maximum at 63.45 mg/g with a maximum efficiency of adsorption at 90.74%. Kinetic adsorption studies show that the pseudo – first order kinetic model best fits the data for CQD – PAN/PCL nanofiber mat in Cu²⁺ ions obtaining a correlation value of R² = 0.9418 and a rate constant k = 0.0172 min¹ indicating the adsorption behavior follows the physical adsorption process involving Van der Waals forces and hydrogen bonding between the adsorbent and adsorbate.

Abstract: Biodegradable composite from polycaprolactone (PCL) and Graphene/zinc oxide (Graphene/ZnO) is studied. The Graphene/ZnO content is at 0.5%, 1.5% in PCL. Neat PCL and composites were characterized by microstructure, mechanical properties and thermal properties. Scanning electron micrographs show that the additive has agglomerated in PCL/Graphene/ZnO. Agglomeration of the filler results in reduced tensile properties of the composite. The result from XRD indicates Graphene/ZnO can improve the crystallinity of PCL. According to the results of buried soil test and analysis, Graphene/ZnO can reduce the biodegradation rate of PCL and make the material more durable. This new biodegradable composite material can be used as a new environmentally friendly material.

Abstract: Polycaprolactone coated with chitosan microspheres have the potential to be used as delivery systems and biosensors. Polycaprolactone (PCL) is, however hydrophobic, to improve the biofunctional and potential immobilization of PCL polymer, chitosan-coated PCL microspheres (MSs) were prepared using a double emulsion solvent evaporation method. Different particle sizes were prepared by altering five parameters. When the MSs were prepared using oil to water phase ratio or oil fraction (ϕ_o) of ϕ_o = 0.95 to ϕ_o = 0.38, the MSs average diameter (D_v) reduced from 3.86 to 3.53 µm along with its coefficient of variation (CV), reduced from 18.1 to 12.3 respectively. The MSs prepared with higher polymer concentration of 6wt.% shows higher D_v (4.51 µm) and CV (25.2) compared to 1.2wt.% of PCL, which D_v = 3.86 µm with CV of 18.1. The first homogenizer speed (H1) was increased in order to prepare smaller MSs. When H1 increased from 6 000 to 10 000 rpm, MSs D_v reduced from 3.86 to 3.45 µm along with its CV reduce from 18.1 to 16.6 for ϕ_o = 0.95. It is also the same case for ϕ_o = 0.52, where the D_v reduced from 3.70 to 3.19 µm and its CV reduce from 25.8 to 25.2. The effect of NaCl concentration on MSs preparation shows, higher NaCl concentration (1.8wt.%) produced smaller D_v (D_v = 3.86 µm) compared to lower concentration of 0.9wt.%, produced D_v = 4.51 µm for ϕ_o = 0.95. The trend also follows when the MSs were prepared for ϕ_o = 0.52. The delay in adding the NaCl shows distinct effect on D_v. For both 0.9 and 1.8 wt.% of NaCl, the D_v increase from 4.51 to 6.40 µm and 4.31 to 6.17 µm respectively. Therefore, the targeted D_v for certain application could be achieved by altering the parameters above. Finally, to study the Ch-PCL potential as enzyme immobilizer, horseradish peroxidase (HRP) was used to be immobilized on to the Ch-PCL MSs. After 7 days, the HRP enzyme still show 51% activity under robust storage condition.

Abstract: Iron-modified montmorillonite-filled polycaprolactone nanofiber mats were produced via electrospinning with varying applied voltage, flow rate, needle-tip-to-collector distance, and needle diameter. Scanning electron microscopy (SEM) was used to observe fiber morphology and characteristics. The effects of varying process parameters on various fiber characteristics were evaluated using a two-level fractional factorial experimental design. The effect of voltage on fiber diameter differed with varying flow rate. At 32 ml/hr, the average fiber diameter decreased from 518.38 nm ± 289.37 nm to 466.43 nm ± 312.36 nm when the voltage is increased. At 42 ml/hr the effect of voltage on fiber diameter was reversed. The average fiber diameter was also found to decrease from 516.03 nm ± 283.48 nm to 467.96 nm ± 318.07 nm with decreasing tip-to-collector distance at 32 mL/hr flow rate. The variation of the effect of the factors on fiber diameter was mainly due to a significant loss of material observed at 12 kV and 15 cm tip-to-collector distance. Bead formation was observed for all runs with more beads being formed at 12 kV applied voltage and 15 cm tip-to-collector distance. Spherical beads were observed at 12 kV and 15 cm tip-to-collector distance while spindle-like beads were present in nanofiber membranes spun at high voltage and at the combination of low voltage and low tip-to-collector distance. The parameter setting combination of 19 kV, 32 ml/hr flow rate, 10 cm tip-to-collector distance, and 0.514 mm needle diameter yielded the lowest fiber diameter with the least amount of beading and small bead size. Small fiber diameters and less beading provide larger surface area and more exposure of the Fe-MMT particles for more efficient adsorption.