Polyetheretherketone Fiber Research Articles

3D printing of high-stiffness and high-strength glass fiber reinforced PEEK composites by selective laser sintering

Glass fiber reinforced poly-ether-ether-ketone (PEEK) composites are emerging as structural materials of multifunctional devices in space applications, due to their outstanding mechanical properties, electrical insulating properties, and resistance to irradiation. Here, a new approach for preparing glass fiber/PEEK powders tailored for selective laser sintering (SLS) process is proposed. The surface of glass fiber is modified with the sulfonated PEEK following the designed procedure. The flowability of glass fiber/PEEK powders is also improved by adding the nano-scale SiO2 flow agent. The glass fiber reinforced PEEK composites are successfully 3D printed using the glass fiber/PEEK powders. Further, the enhancement of interfacial bonding between PEEK and glass fiber is analyzed through quasi-static tension tests and scanning electron microscopy (SEM) for the SLSed glass fiber reinforced PEEK composites. The average ultimate tensile strength reaches approximately 100 MPa using these optimal process parameters, while the average elastic modulus is around 7 GPa. Finally, the upper limit of fiber weight fraction is evaluated with the X-ray computed tomography (XCT) and the high-fidelity discrete element method (DEM) simulation.

Polyetheretherketone fiber-supported polyethylene glycols for phase-transfer catalysis in its surface layer

Cleaner and more efficient catalytic processes are becoming more relevant to the synthetic chemistry for reducing wastes. And herein, a commercially available ultra-high strength textile fiber polyetheretherketone (PEEK) was directionally modified by post-functionalization procedure to graft polyethylene glycols (PEG) into its surface layer to form a hydrophilic interface, and the resulted PEEK-PEG materials capable of acting as the supported phase-transfer catalysts for sorts of organic conversions in a cleaner manner were reported. The fiber samples generated during the preparation and utilization processes were observed and characterized in detail by various techniques such as morphology, mechanical properties, elemental analysis, FTIR spectroscopy and X-ray diffraction and TG analysis, and rest assured that the strategy was dependable. Moreover, the phase-transfer catalytic performance of the fiber-supported catalyst PEEK-PEG was verified in different kinds of substitution reactions, and the effects of PEG type, PEG loading and the correspondingly reaction conditions on the phase-transfer catalytic system were inspected meticulously, which were further conducive to sustain the proposed phase-transfer catalytic mechanism, and with the synergistic effect of the fiber support and PEG chain in the hydrophilic interface to afford the substitutions proceeded smoothly to obtain good to excellent product yields. Additionally, the fiber catalyst could be recycled simply and reused over 15 cycles with excellent stability under the strong caustic condition, and the catalytic system could be enlarged to the gram-scale in a spinning basket reactor, to provide a cleaner manner for phase-transfer catalysis in organic conversions with the potential of industrial application.

Influence of Polyetheretherketone radicals on interfacial interaction with carbon fiber and crystal formation of Polyetheretherketone at the interphase

This study investigates the impact of free radicals present in polyetheretherketone (PEEK) on its interfacial adhesion with reinforcing fibers and the resulting crystal formation at the interphase. Microdroplet tests revealed that the interfacial shear strength between PEEK and carbon fiber (CF) was enhanced under increased preparation temperatures or prolonged holding times in the molten state, corresponding to an upsurge in PEEK radicals, elucidated by electron spin resonance and melt rheological behavior analyses. The post-microdroplet testing fracture surface and PEEK crystal structure near the fiber were investigated through micro-Raman spectroscopy under varying reinforcing fiber types and functional group concentrations (e.g., -OH and -COOH) on the CF surface. The results revealed that PEEK crystal formation along the CF axis at the interphase is driven by noncovalent interfacial interactions, such as π interactions and hydrogen bonds. Conversely, covalent interfacial interactions suppress crystal formation.

Ultrahigh-Performance Fiber-Supported Iron-Based Ionic Liquid for Synthesizing 3,4-Dihydropyrimidin-2-(1H)-ones in a Cleaner Manner.

Herein, a fiber-supported iron-based ionic liquid as a type of fibrous catalyst has been developed for the synthesis of bioactive 3,4-dihydropyrimidin-2-(1H)-ones (DHPMs) via three-component Biginelli reactions in a cleaner manner. The described fibrous catalyst was obtained from the commercially available polyetheretherketone (PEEK) fiber by postfunctionalization processes and was characterized and analyzed in detail by means of diversified technologies. Furthermore, the fiber-supported iron-based ionic liquids could mediate the classical three-component Biginelli reactions to proceed smoothly to gain a variety of substituted DHPMs with yields of up to 99%. The superior catalytic activities of the fibrous catalyst were ascribed to the quasi-homogeneous medium by ionic liquids generated in the surface layer of the PEEK fiber, which could afford an appropriate reaction zone and could further be available for the aggregation of substrates to facilitate the three-component reaction. Notably, the fibrous catalyst is available for recycling over 10 runs just by a pair of tweezers, and the operational procedure was capable of enlarging the catalytic system to the gram-scale without any performance degradation, which provided a cleaner manner to take advantage of the iron-based catalyst in organic synthesis with potential industrialization prospects.

Performance of 3D printed porous polyetheretherketone composite scaffolds combined with nano-hydroxyapatite/carbon fiber in bone tissue engineering: a biological evaluation

Polyetheretherketone (PEEK) has been one of the most promising materials in bone tissue engineering in recent years, with characteristics such as biosafety, corrosion resistance, and wear resistance. However, the weak bioactivity of PEEK leads to its poor integration with bone tissues, restricting its application in biomedical fields. This research effectively fabricated composite porous scaffolds using a combination of PEEK, nano-hydroxyapatite (nHA), and carbon fiber (CF) by the process of fused deposition molding (FDM). The experimental study aimed to assess the impact of varying concentrations of nHA and CF on the biological performance of scaffolds. The incorporation of 10% CF has been shown to enhance the overall mechanical characteristics of composite PEEK scaffolds, including increased tensile strength and improved mechanical strength. Additionally, the addition of 20% nHA resulted in a significant increase in the surface roughness of the scaffolds. The high hydrophilicity of the PEEK composite scaffolds facilitated the in vitro inoculation of MC3T3-E1 cells. The findings of the study demonstrated that the inclusion of 20% nHA and 10% CF in the scaffolds resulted in improved cell attachment and proliferation compared to other scaffolds. This suggests that the incorporation of 20% nHA and 10% CF positively influenced the properties of the scaffolds, potentially facilitating bone regeneration. In vitro biocompatibility experiments showed that PEEK composite scaffolds have good biosafety. The investigation on osteoblast differentiation revealed that the intensity of calcium nodule staining intensified, along with an increase in the expression of osteoblast transcription factors and alkaline phosphatase activities. These findings suggest that scaffolds containing 20% nHA and 10% CF have favorable properties for bone induction. Hence, the integration of porous PEEK composite scaffolds with nHA and CF presents a promising avenue for the restoration of bone defects using materials in the field of bone tissue engineering.

Effect of Sterilization Methods on the Morphological, Molecular, and Biocompatibility Characteristics of Nanofibrous PEEK Layers

In this work, the polyether ether ketone (PEEK) nanofibrous layers and their sterilized methods influence on molecular properties, structural properties, and biocompatibility have been discussed.Some instrument employed were gamma radiation, ultraviolet light, Ethylene oxide (EtOx) and an autoclave to sterilised the layers developed through melt-electrospinning process.umber of instruments used such as gamma radiation, ultraviolet light, ethylene oxide (EtOx), and an autoclave was used to sterilise the layers prepared via melt-electrospinning process. The SEM result unveiled that the sterilization processes changed the fibre form slightly as well as the diameter which was modified slightly as well.However, the sterilization processes did not alter the molecular weight of PEEK fibers, as far as GPC study was concerned.d biocompatibility has been explored. A number of instruments used such as gamma radiation, ultraviolet light, ethylene oxide (EtOx), and an autoclave was used to sterilise the layers prepared via melt-electrospinning process. The scanning electron microscopy (SEM) showed that the sterilization processes slightly altered the fiber’s form along with small variations in diameter. While, the sterilization processes did not achanged the molecular weight of PEEK fibers, according to gel permeation chromatography (GPC) research. In addition, the murine fibroblasts (3T3) were assessed for in vitro biocompatibility using MTT test. While cell adhesion and proliferation rate were the same across all the layers in the sterile control sample, the UV-sterilized material significantly reduced the level of cell viability. Consequently, the employed methods, namely the autoclave, EtOx, and gamma radiation were determined to be efficient to sterilise PEEK nanofibrous layers. However, solar radiation with the method may also reduce their biocompatibility.

Evaluation of the Mechanical and Tribological Behavior of Polyether Ether Ketone Fiber-Reinforced Resin-Based Friction Materials Fabricated by Wet Granulation.

Resin-based friction materials (RBFMs) strengthened by polyether ether ketone (PEEK) fiber were designed and prepared in this study. Specimens incorporating PEEK fiber of 2-8 wt.% were fabricated based on wet granulation, and then the effects of the PEEK fiber content on the mechanical and tribological properties of RBFMs were systematically investigated. The results showed that PEEK fiber can sense the braking temperature and then effectively regulate the comprehensive properties of RBFMs. The specimen incorporating 6 wt.% PEEK fiber obtained the optimal comprehensive performance with a stable friction coefficient (COF), excellent fade resistance and recovery properties, and better wear resistance. The worn surface was inspected using a scanning electron microscope. After the friction-wear test, the specimen with 6 wt.% PEEK fiber presented a number of primary and secondary plateaus and a reduced number of pits with wear debris on the worn surface. The study indicated that PEEK fiber could not only enhance the mechanical and tribological properties of RBFMs at low temperatures because of their high strength and self-lubrication but also adhere to wear debris to reduce abrasive wear at high temperatures; furthermore, the adhered wear debris could form a secondary plateau under normal pressure, which could alleviate abrasion.

Effect of in situ and furnace thermal annealing on the mechanical properties and sustainability of 3D printed carbon-peek composites

The present work aims at investigating the impact of heat treatments on the mechanical, environmental and economic performances of components in carbon fibre polyetheretherketone (PEEK) composite produced using the Fused Deposition Modelling technique. The mechanical properties of PEEK can be strongly improved by performing heat treatments to maximize the degree of crystallinity in PEEK. To this purpose, the typical annealing heat treatment in a furnace, that is energy and time intensive, was compared to an innovative in situ annealing process named Direct Annealing System (DAS), which is performed during the 3D printing process. In order to evaluate the effect of heat treatment on mechanical properties of 3D printed parts, tensile tests were carried out on samples treated both using the annealing in a furnace and DAS processes. Similarly, the environmental and economic impacts of the different heat treatments were analysed by means of Life Cycle Assessment and Life Cycle Costing methodologies. The results demonstrated that the DAS system allows the improvement of the mechanical properties of carbon fibre PEEK composite, even though the highest performances can be obtained using a heat treatment in furnace. On the other hand, the DAS system is characterized by lower environmental and economic impacts than the annealing in furnace, denoting its more sustainability.

The Effect of Recycled CAD/CAM PEEK Fibers on the Transverse Strength of Repaired Acrylic Resin

One of the significant advantages of Polyether ether ketone (PEEK) is its ability to bond composite materials. This makes it a versatile material that can be used in a range of dental applications, including as a framework for fixed or removable dental prostheses. The aim of this study is to evaluate the transverse strength of heat-cured acrylic resin after reinforcing repaired material with recycled PEEK fibers obtained from a CAD/CAM machine. After milling, PEEK fibers were collected from the CAM machine. The size of the PEEK fibers was measured by utilizing a Scanning Electron Microscope (SEM); with the particle grit size being 200 µm. Thirty specimens were used and divided into three groups of heat-cured acrylic resins was evaluated. All specimens have been stored at 37°C prior to fracture, and specimens have been then repaired after fracture with an auto-polymerizing acrylic resin using Ivomet. Group A of heat-cured specimens was used as a (control group) and repaired with no additive to the self-cured acrylic repair materials. While group B has been repaired by self-cured acrylic reinforced with of 1%wt. PEEK fibers, group C has been repaired by self-cured acrylic reinforced with the addition of 2%wt. PEEK fiber. There is a difference between groups A and C; however, there is a significant difference at 0.05 when comparing with groups B and C. When compared to (1%wt. PEEK-fiber) and the control group, adding (2%wt. PEEK-fiber) improves the transverse strength of the repaired heat-cured acrylic resins.

Material Extrusion 3D Printing of PEEK-Based Composites.

High-performance thermoplastics like polyetheretherketone (PEEK), with their outstanding thermal stability, mechanical properties and chemical stability, have great potential for various structural applications. Combining with additive manufacturing methods extends further PEEK usage, e.g., as a mold insert material in polymer melt processing like injection molding. Mold inserts must possess a certain mechanical stability, a low surface roughness as well as a good thermal conductivity for the temperature control during the molding process. With this in mind, the commercially available high-performance thermoplastic PEEK was doped with small amounts of carbon nanotubes (CNT, 6 wt%) and copper particles (10 wt%) targeting enhanced thermomechanical properties and a higher thermal conductivity. The composites were realized by a commercial combined compounder and filament maker for the usage in a material extrusion (MEX)-based 3D-printer following the fused filament fabrication (FFF) principle. Commercial filaments made from PEEK and carbon fiber reinforced PEEK were used as reference systems. The impact of the filler and the MEX printing conditions like printing temperature, printing speed and infill orientation on the PEEK properties were characterized comprehensively by tensile testing, fracture imaging and surface roughness measurements. In addition, the thermal conductivity was determined by the laser-flash method in combination with differential scanning calorimetry and Archimedes density measurement. The addition of fillers did not alter the measured tensile strength in comparison to pure PEEK significantly. The fracture images showed a good printing quality without the MEX-typical voids between and within the deposited layers. Higher printing temperatures caused a reduction of the surface roughness and, in some cases, an enhanced ductile behavior. The thermal conductivity could be increased by the addition of the CNTs. Following the given results, the most critical process step is the compounding procedure, because for a reliable process-parameter-property relationship, a homogeneous particle distribution in the polymer matrix yielding a reliable filament quality is essential.

Fibre-reinforced multifunctional composite solid electrolytes for structural batteries

Multifunctional energy storage devices are being pursued in a quest for more reliable battery systems for use in electric vehicles. However, the full realization of these batteries rests on the fabrication of solid electrolytes with high mechanical integrity and good processibility. In the present work, high modulus polyether ether ketone (PEEK) fibres are embedded inside a Li+-ion conducting poly(ethylene) oxide matrix. The macromolecular backbone of PEO provides lithium ion transport pathways while the robust rigidity of PEEK fibres enhances mechanical strength. The Young's modulus of the composite solid polymer electrolyte (CSPE) was increased by more than two orders of magnitude (from 0.9 MPa to up to 900 MPa) in the presence of the mechanical fillers. The ionic conductivity of 3.3 x 10−4 S/cm at 60 °C enabled successful cycling of Lithium metal batteries based on these CSPEs with high capacity retention of more than 96% over 200 cycles at 0.1 C. This prototypical system provides a straightforward approach to effectively decouple the mechanical properties from the ionic conductivity which will facilitate the development of mechanically strong highly conducting electrolytes for the next generation of batteries.

Tunable Thermal, Mechanical, and Tribological Properties of Polybenzoxazine-Based Composite for Vehicle Applications

In this study, a series of composites comprising polyether ether ketone (PEEK) and carbon fiber (CF)-reinforced polybenzoxazine for high-temperature friction materials for vehicle brake applications were developed using a high-temperature compression molding technique. The objective of this research was to systematically investigate the thermal, mechanical (tensile and flexural), and tribological performance of friction materials made from polybenzoxazine-based composites by varying the PEEK/CF mass ratio. Our study reveals the substantial improvement effect of the increased content of PEEK fibers on the thermal conductivity, the coefficient of friction, and the friction strength of the polybenzoxazine-based composite materials. Meanwhile, the introduction of carbon fibers was found to have a monotonic positive effect on the mechanical (tensile and flexural) properties and wear performance of the polybenzoxazine-based composites. The polybenzoxazine-based composites exhibit high mechanical strength, with a tensile strength of 50.1–78.6 MPa, Young’s modulus of 10.2–24.3 GPa, a flexural strength of 62.1–88.3 MPa, and a flexural modulus of 13.1–27.4 GPa. In addition, the polybenzoxazine-based composite with a PEEK/CF mass ratio of 75:25 exhibits a high and stable coefficient of friction (0.33) and a specific wear rate (1.79 × 10−7 cm3/Nm at room temperature). Subsequent to the wear test at ambient temperature, the worn surfaces of five polybenzoxazine-based composite samples with various PEEK/CF mass ratios were studied using electron microscopy technology (SEM). The observation of small cracks and tiny grooves on the worn surfaces indicates a combined abrasive and adhesive wear mechanism of the material. Our experimental results clearly reveal superior mechanical properties and excellent tribological characteristics. As a result, these composites show promising potential for the application of friction materials in terms of vehicle braking system applications.

Using Peek as a Framework Material for Maxillofacial Silicone Prosthesis: An In Vitro Study.

There are often bonding problems between acrylic resins and silicone. PEEK (polyetheretherketone), which is a high-performance polymer, has great potential for the implant, and fixed or removable prosthodontics. The aim of this study was to evaluate the effect of different surface treatments on PEEK to be bonded to maxillofacial silicone elastomers. A total of 48 specimens were fabricated from either PEEK or PMMA (Polymethylmethacrylate) (n = 8). PMMA specimens acted as a positive control group. PEEK specimens were divided into five study groups as surface treatments as control PEEK, silica-coating, plasma etching, grinding, or nano-second fiber laser. Surface topographies were evaluated by scanning electron microscopy (SEM). A platinum-primer was used on top of all specimens including control groups prior to silicone polymerization. The peel bond strength of the specimens to a platinum-type silicone elastomer was tested at a cross-head speed of 5 mm/min. The data were statistically analyzed (α = 0.05). The control PEEK group showed the highest bond strength (p < 0.05) among the groups. No statistical difference was found between control PEEK, grinding, or plasma etching groups (p > 0.05). The lowest bond strength was seen in the laser group, which was not statistically different from silica-coating (p > 0.05), and statistically different from control PEEK, grinding, or plasma groups (p < 0.05). Positive control PMMA specimens had statistically lower bond strength than either control PEEK or plasma etching groups (p < 0.05). All specimens exhibited adhesive failure after a peel test. The study results indicate that PEEK could serve as a potential alternative substructure for implant-retained silicone prostheses.

Bond strength of various post-core restorations with different lengths and diameters following cycle loading

PurposeThis in vitro study aims to evaluate the bonding strengths of Polyether ether ketone (PEEK), Polyether ketone (PEKK), Fiber, and Zirconia (ZrO2) post-core restorations with posts in different diameter and length following chewing simulator. Materials and methodsEndodontic treatment was performed on 256 intact maxillary central teeth. The test specimens were prepared in four groups according to the types of materials: Glass fiber post-composite core (FB-n:64), Zirconia post-core (Zr-n:64), PEEK post-core (PE-n:64), and PEKK post-core (PK-n:64). The groups were divided into four subgroups according to diameter and length (n:16): Group 1: 10 mm length 1.75 mm diameter, Group 2: 10 mm length 1.5 mm diameter, Group 3: 7 mm length 1.75 mm diameter, Group 4: 7 mm length 1.5 mm diameter. Custom PEKK, PEEK, Zirconia post-cores, and Zirconia crowns were milled on the CAD/CAM. The post-cores and crowns were cemented to the teeth with dual-cure resin cement. After that, all subgroups were divided into control and cyclic loading groups. During the cycling, the control test group was kept in distilled water at 37±1oC before the push-out test. Half of the specimens were loaded with 250,000 cycles and 50 N with a chewing simulator. All test specimens had 1.5 mm sections taken from their roots. Then, the push-out test was applied to these sections for bond strength. Data were analyzed by Mann-Whitney U test, Shapiro-Wilk, Kruskal-Wallis's test, and Chi-Square. The statistical significance level was determined as 0.05. ResultsThe bond strength of all test groups decreased after the cycling loading. The bond strength values of zirconia posts showed a statistically significant difference (p < 0.05). The 10 mm length 1.75 mm diameter posts made of Zirconium had the highest bond strength observed in all control and cyclic loading groups of test specimens (9.74 MPa-6.25 MPa). The PEEK test specimens with a 7 mm length and 1.75 mm diameter showed the weakest bond strength in all control and cyclic loading groups (5.44 MPa-3.37 MPa). The average of the cervical region's bond strength values was statistically significantly higher than the apical region (p < 0.05). ConclusionWithin the limitations of this study, one-piece custom-milled Zirconia post-cores appear promising, as they perform well under functional forces, especially in the anterior region. In addition, custom-milled PEKK post-cores might be considered a suitable alternative to prefabricated fiber-reinforced posts.

Polyetheretherketone fiber-supported TBD as an efficient fibrous superbase catalyst for organic conversions in continuous-flow processing

The development of clean catalytic technologies in continuous-flow processing for efficient organic conversions has a positive influence on the fine chemicals and pharmaceutical manufacturing. Herein, the commonly used organic superbase 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) was immobilized on the commercially available ultra-high strength textile fiber polyetheretherketone (PEEK) to report a polymer-supported basic catalyst (PEEK-TBD) for three types of organic conversions in cleaner continuous-flow processing. The fiber catalyst was prepared through an improvement strategy and verified as a heterogeneous fibrous superbase catalyst in the microtubule reactor to mediate the Knoevenagel condensation-cyclization between salicylaldehydes and activated nitriles for the synthesis of iminocoumarins in ethanol (10 samples, yields 91–97%) after turning the flow rate, substrate concentration, and catalyst padding quantity, additionally, PEEK-TBD was also effective for the cyanosilylation of carbonyl compounds for the synthesis of cyanogen compounds in acetonitrile, as well as the substitution reaction of aniline and carbonate for the synthesis of N,N’-substituted urea in toluene in continuous-flow processing. Moreover, the resulting fiber samples were characterized in detail by sorts of analytical methods and techniques to further confirm the dependability of this methodology, and the clean and valid gram-scalable procedure of PEEK-TBD in continuous-flow processing has extensive application prospects on the chemical productions.

Black tantalic oxide submicro-particles coating on PEEK fibers woven into fabrics as artificial ligaments with photothermal antibacterial effect and osteogenic activity for promoting ligament-bone healing

• Black tantalic oxide (BTO) submicro-particles were prepared. • PEEK fibers with BTO coating were woven into fabrics (PBT) as artificial ligaments • PBT exhibited optimized surface properties and photothermal antibacterial effects. • PBT with excellent osteogenic activity promoted ligament-bone healing Design of artificial ligaments possessing both osteogenic activity and antibacterial effect that promotes ligament-bone healing and prevents bacterial infection in bone tunnels for anterior cruciate ligament (ACL) reconstruction remains a significant challenge. In this study, black tantalic oxide (BTO) submicro-particles with oxygen vacancies and structure defects were fabricated by using traditional white tantalic oxide (WTO) through magnesium thermal reduction (MTR) method, and BTO was coated on polyetheretherketone (PEEK) fibers (PKF), which were woven into fabrics (PBT) as artificial ligaments. PBT with BTO coating exhibited excellent photothermal performance, which possessed not only antibacterial effects in vitro but also anti-infective ability in vivo. PBT with optimized surface properties (e.g., submicro-topography and hydrophilicity) not only significantly facilitated rat bone mesenchymal stem cells (BMSC) responses (e.g., proliferation and osteogenic differentiation) in vitro but also stimulated new bone formation for ligament-bone healing in vivo. The presence of oxygen vacancies and structure defects in BTO did not change the surface properties and osteogenic activity of BPT while displaying an outstanding photothermal antibacterial effect. In summary, BPT with osteogenic activity and photothermal antibacterial effect promoted bone regeneration and prevented bacterial infection, thereby promoting ligament-bone healing. Therefore, PBT would have tremendous potential as a novel artificial ligament for ACL reconstruction.

Application of polyetheretherketone (PEEK) posts: evaluation of fracture resistance and stress distribution in the root: in vitro and finite element analyses.

To evaluate the feasibility of using a milled polyetheretherketone (PEEK) post and core in endodontically treated teeth with or without a ferrule. Sixty bovine tooth roots were endodontically treated followed by cementation of intraradicular retainers (IR), according to each experimental group: a) non-ferrule glass fiber post (f0FP); b) 2-mm-ferrule glass fiber post (f2FP); c) non-ferrule resized glass fiber post (f0PR); d) 2-mm-ferrule resized glass fiber post (f2PR); e) non-ferrule PEEK post and core (f0PPC); and f) 2-mm-ferrule PEEK post and core (f2PPC). Metal crowns were made and cemented. A periodontal ligament was simulated using polyether. A force was applied to the palatine portion of each sample at 45°, until fracture. Fracture resistance data were submitted to two-way ANOVA and Tukey's test (α = 0.05). Three-dimensional digital models were developed to calculate the tensions formed in the root using finite element analysis. Models of glass fiber posts and PEEK posts and cores were evaluated with or without a ferrule. The results were analyzed by the Mohr-Coulomb criterion. The type of IR was not influenced by fracture strength (p = 0.243). There were significant statistical differences among the remaining factors. Ferrule groups had greater fracture resistance, and the failure mode of teeth with a ferrule was more catastrophic than the non-ferrule group. A ferrule increases fracture resistance and influences failure mode; the PEEK post and core did not modify the biomechanics of endodontically treated teeth, and resembled the glass fiber post results. The crack initiation point differed between the ferrule and non-ferrule groups.

Quaternary ammonium salt functionalized polyetheretherketone fiber: A novel fibrous material for phase-transfer catalysis

Herein, the commercially available ultra-high-strength textile fiber polyetheretherketone (PEEK) was directionally functionalized by afterward immobilization procedures to graft quaternary ammonium salts into its surface layer, and the resulted fibrous materials were capable of acting as the heterogeneous-supported phase-transfer catalysts were presented in the etherification of halogenated nitrobenzenes for the synthesis of nitroanisoles. The acquiring fiber samples from different processes were observed and characterized detailedly by diversified technologies of morphologies, mechanical properties, elemental analysis, FTIR spectroscopy, X-ray diffraction, and thermogravimetric analysis to confirm the reliability of this methodology. Moreover, the effect of functionalized degree on the PEEK fiber was inspected, and the phase-transfer catalytic system mediated by the fibrous material showed superior performance in terms of simple procedures, high yields of nitroanisoles (up to 99%), and excellent recyclability (over 30 cycles). Additionally, the newly developed fibrous catalyst exhibited superior stability (at least for 4 months) and effectively gram-scale operation in a concise spinning basket reactor, which is very attractive for various phase-transfer catalysis reactions in chemical productions.

Fabrication and mechanical properties of different types of carbon fiber reinforced polyetheretherketone: A comparative study

ObjectivesTo find alternative non-metallic materials as dental implants for clinical application, different types of carbon fiber reinforced polyetheretherketone were fabricated and investigated. MethodsContinuous carbon fiber reinforced polyetheretherketone fabrics were fabricated with polyetheretherketone fibers and carbon fibers. Different kinds of carbon fiber reinforced polyetheretherketone were synthesized by setting specific experiment parameters of injection or hot press molding. Various mechanical tests were performed to determine the mechanical properties of different carbon fiber reinforced polyetheretherketone, pure polyetheretherketone and pure titanium. ResultsPolyetheretherketone composites presented outstanding mechanical and thermal properties after incorporating carbon fiber. The bending and tensile strength of short carbon fiber reinforced polyetheretherketone were close to human bone, and the bending strength of continuous carbon fiber reinforced polyetheretherketone reached 644 MPa, even higher than that of pure titanium. ConclusionsThe mechanical properties of polyetheretherketone composites are more similar to bone tissue than titanium, and the stress shielding phenomenon may be inhibited. They may become promising materials as substitutions for titanium and prospective materials in bone tissue engineering.

Phytic acid/magnesium ion complex coating on PEEK fiber woven fabric as an artificial ligament with anti-fibrogenesis and osteogenesis for ligament-bone healing.

Development of an artificial ligament possessing osteogenic activity to enhance ligament-bone healing for reconstruction of anterior cruciate ligament (ACL) is a great challenge. Herein, polyetheretherketone fibers (PKF) were coated with phytic acid (PA)/magnesium (Mg) ions complex (PKPM), which were woven into fabrics as an artificial ligament. The results demonstrated that PKPM with PA/Mg complex coating exhibited optimized surface properties with improved hydrophilicity and surface energy, and slow release of Mg ions. PKPM significantly enhanced responses of rat bone marrow stem cells in vitro. Moreover, PKPM remarkably promoted M2 macrophage polarization that upregulated production of anti-inflammatory cytokine while inhibited M1 macrophage polarization that downregulated production of pro-inflammatory cytokine in vitro. Further, PKPM inhibited fibrous encapsulation by preventing M1 macrophage polarization while promoted osteogenesis for ligament-bone healing by triggering M2 macrophage polarization in vivo. The results suggested that the downregulation of M1 macrophage polarization for inhibiting fibrogenesis and upregulation of M2 macrophage polarization for improving osteogenesis of PKPM were attributed to synergistic effects of PA and sustained release of Mg ions. In summary, PKPM with PA/Mg complex coating upregulated pro-osteogenic macrophage polarization that supplied a profitable anti-inflammatory environments for osteogenesis and ligament-bone healing, thereby possessing tremendous potential for reconstruction of ACL.