Polyetheretherketone Research Articles

Thermal characteristics of full ceramic ball bearings under dry friction conditions

Purpose Polyether ether ketone (PEEK) and its composites exhibit favorable self-lubricating properties. They have been widely used in bearing components. This paper aims to further investigate the friction-reducing and lubricating effects of PEEK and its composite cages on full ceramic ball bearings. Design/methodology/approach In this study, 6206 full ceramic ball bearings with different cage types were tested using a bearing life tester under dry friction conditions. Thermal characteristics under various working conditions were obtained by varying the load and rotational speed, followed by a comparative analysis. A finite element simulation model was established based on the posttest film formation observed on the bearing raceways. The steady-state temperatures of different bearing components and the contact stress of the balls were determined. Findings Bearings with cages made of polyether ether ketone (PEEK) filled with carbon fibers (CF), polytetrafluoroethylene (PTFE), and graphite (PVX) exhibited lower temperature rise and steady-state temperature over the same duration. A series of posttest inspections confirmed the presence of transfer films on the balls and raceways. These transfer films were found to enhance the lubrication performance of the bearing. Simulation results further revealed that the presence of the transfer film significantly reduced the temperatures of the inner and outer raceways as well as the balls and effectively lowered the contact stress on the balls. Originality/value The operational performance of full ceramic ball bearings with different cage types under dry friction conditions was investigated. The friction-reducing and lubricating effects of PEEK and its composites used in the cages of full ceramic ball bearings were clarified.

Bioinspired Hierarchical PEEK and Amorphous Silicon Nitride Composite Coatings on Titanium Alloy Biomedical Implants.

Titanium alloys are studied for decades as bone and dental implants, showing great potential in biomedical applications. However, the relatively high stiffness and lack of resistance to bacterial corrosion in titanium-based implants are always a problem. Polyetheretherketone (PEEK) is emerging significantly as a new biomaterial for tissue engineering scaffolds, due to its excellent biocompatibility and stability, while the mechanical properties of PEEK cannot match those of natural bones and teeth. In biomineralized tissues, the incorporation of bioceramics into the organic matrix provides a strategy to enhance the mechanical properties of polymers. Inspired by this process, the current work successfully prepared a composite coating on Ti-6Al-4V (TC4) titanium alloy that contains both organic (PEEK) and inorganic silicon nitride (SiNx) phases. Combining spin coating with physical vapor deposition methods, PEEK/SiNx composite coatings that resemble the hierarchical natural mineralized organic fibers are thus realized. The Young's modulus of the "mineralized" PEEK/SiNx fibers in the composite coatings reaches 45-65GPa, comparable to the cortical bone and tooth enamel. The novel coatings exhibit superior wear and corrosion resistance. Because of the hierarchical porous structure, the affinity to simulated body fluid (SBF) is notably increased in TC4 coated with PEEK/SiNx. In vitro cell culture experiments (Alkaline phosphatase activity and qPCR tests, etc.) further verify the bioinspired composite coatings significantly improve cell adhesion, proliferation, and differentiation, potentially inspiring the development of new tissue-like orthopedic and dental implant materials.

Finite element analysis of welded titanium bar and poly ether ether ketone bar in maxillary full arch splinted interim prosthesis

Full arch fixed provisional restorations are prone to fracture during function for several reasons. Those types of fractures during the healing period eliminate the cross-arch stabilization and disrupt stress distribution patterns. FEA (Finite Element Analysis) study was carried out using edentulous maxillary models where implants and other components were represented in three dimensional (3D) geometric models. Two 3D FEA models with six implants were used. Model TB: the implants were splinted with welded titanium bar; Model PB: the implants were splinted with PEEK (Poly Ether Ether Ketone) bar. An interim full arch PMMA (Poly methyl methacrylate) prosthesis was virtually designed for both models. Both models were subjected to vertical and oblique forces with a single force magnitude of 100 N. The amount of maximum equivalent Von-Mises stresses was calculated at the cervical part of the bone cylinder (marginal bone) and both frameworks. Under bilateral vertical loading, stresses were found to be comparable at the marginal bone between titanium and PEEK splinting. The PEEK framework had better and lower stress distribution than the titanium. While under unilateral oblique forces PEEK had better mechanical response on the marginal bone. And PEEK framework itself showed higher stresses than the titanium. The behavior of PEEK and Titanium splints are comparable under the vertical bilateral load. On the contrary to the oblique load, where the stresses are higher within the PEEK splint that correspondingly transmit less stresses to the underlying structures. So, PEEK was found successful in regards to the pattern of stress distribution to both implants and marginal bone, but further studies are needed to confirm its effectiveness and broader applicability.

Does biceps tenodesis screw with forked eyelet decrease the risk of Popeye deformity when compared to traditional closed eyelet screws?

Objective: While many biomechanical studies have compared various biotenodesis materials for biceps tenodesis, there is a lack of research comparing different types of interference screws. This study aimed to compare the impact of a polyether ether ketone (PEEK) forked eyelet tenodesis screw with the traditional PEEK closed eyelet whipstitching technique. The focus was on evaluating the occurrence of Popeye deformity, which is an objective predictor of a successful arthroscopic suprapectoral long head of biceps tenodesis. Methods: A retrospective analysis was conducted on patients who underwent arthroscopic rotator cuff repair and biceps tenodesis performed by a single surgeon between January 2010 and 2020 at a single center. The follow-up period was at least 1 year. Exclusion criteria included previous shoulder surgery and osteoarthritis. Patients were divided into 2 groups based on the type of tenodesis anchor used: forked eyelet tenodesis screw versus closed eyelet tenodesis screw. The occurrence of Popeye deformity was compared between the 2 groups. Results: A total of 82 patients who underwent arthroscopic rotator cuff repair and biceps tenodesis were evaluated, with a mean follow-up of 24.5 ± 4 months. The patients operated on using forked eyelet tenodesis screw were labeled as Group I (n=72) and those with traditional PEEK closed eyelet screw as Group II (n=10). There were no significant differences between the groups in terms of age (Group I: 59.4 ± 5, Group II: 58.4 ± 4, P=.896), gender (both groups predominantly male, P=.886), and body mass index (Group I: 26.7 ± 2, Group II: 27 ± 3; P=.896). The overall rate of popeye deformity in all patients was 8% (n=7). No significant difference in popeye deformity occurrence was observed between the 2 groups (Group I: 6/72 (8.3%), Group II: 1/10 (10%); P=.998). Conclusion: The incidence of Popeye deformity after arthroscopic biceps tenodesis in patients undergoing concomitant rotator cuff repair is low. The choice of fixation anchor, whether a forked eyelet or closed eyelet PEEK anchor, does not significantly influence the occurrence of Popeye deformity. Level of Evidence: Level III, Therapeutic study.

Novel reactive phenolphthalein‐based polyether ketone, its scale‐up preparation and high‐efficiency toughening in epoxy resin modification

AbstractIncorporating reactive groups that can participate in epoxy cross‐linking into traditional thermoplastic toughening agents enhances the interfacial compatibility between thermoplastic and thermosetting resins, thereby improving the impact toughness of the system. In this study, hydroxyl end groups were integrated into phenolphthalein polyether ketone (PEKC) molecular chains to engage in the cross‐linking reaction during epoxy curing, significantly enhancing the toughening effect on the epoxy system. The results indicate that hydroxyl‐terminated phenolphthalein polyether ketone (PEKC‐OH) of various molecular weights can enhance the impact strength of the epoxy system (E51/MTHPA). Among these, the PEKC‐OH‐2 resin exhibited the optimal toughening effect at an addition level of 10 phr, increasing the impact strength from 11.85 to 23.46 kJ/m2, representing a 98% improvement, without compromising the operating temperature and mechanical properties of the epoxy system. Additionally, kilogram‐scale toughening agent resins were produced through scale‐up experiments of PEKC‐OH‐2 in a 50‐L polymerization reactor, validating its applicability for industrial epoxy toughening. In summary, the PEKC‐OH synthesized in this study serves as an efficient reactive thermoplastic toughening agent, offering ease of preparation, industrial producibility, and considerable application potential.Highlights Novel hydroxyl‐terminated phenolphthalein polyether ketone (PEKC‐OH). Reactive hydroxyl end groups improved compatibility with epoxy resin. PEKC‐OH formed an interpenetrating network with epoxy, boosting impact toughness. Scaled‐up of PEKC‐OH‐2 in a 50‐L reactor for industrial production. PEKC‐OH is feasible to prepare and has great application prospect.

Complications After Craniofacial Reconstruction With PEEK PSI Insertion: Pathological Comparison of PEEK and Titanium.

This case report explores polyetheretherketone (PEEK) patient-specific implants (PSI) in craniofacial surgery. It highlights the advantages and challenges of this innovative material. While PEEK offers biocompatibility, mechanical strength, and precision in patient-specific implant manufacturing, challenges such as limited osseointegration capabilities and potential complications, including infections and fluid collection, persist. The report discusses two cases: one characterized by a postoperative infection following maxilla reconstruction, and the other involving a peri-implant fluid collection after orbit reconstruction utilizing a PEEK PSI. Histological comparisons showed distinct tissue reactions around PEEK and titanium implants during infections. This study underscores the need for careful consideration and further research to optimize PEEK applications in craniofacial surgery, emphasizing its unique pathological characteristics and potential complications.

Investigating the effect of thermomechanical cycles on shape memory effect of four‐dimensional printed glass fiber/polyether ketone ketone composite

AbstractAssessing the shape memory effect (SME) under repetitive thermomechanical cycles is crucial for designing structures undergoing subsequent fold and deployment during functioning, such as morphing structures and soft grippers. Four dimensional (4D) printing is a revolutionizing manufacturing technology, offering dynamic feature into three dimensional (3D) printed part. This work presents the first study on 4D printing and SME assessment of glass fiber (GF)/polyether ketone ketone (PEKK) composite for morphing structures and grippers in aerospace applications. GF/PEKK composite is developed using blending, and then filament is extruded for 3D printing. Annealing is performed on the 3D printed parts and evaluated using scanning electron microscopy (SEM), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), and SME under subsequent cycles. The SEM analysis demonstrated the uniform distribution of GFs into PEKK with good interfacial bonds, indicating the appropriate selection of the process parameters. The composite depicted remarkable shape fixity (Rf) and shape recovery (Rr) of 91.07% and 96.08%, respectively, in first cycle. However, in tenth cycle, Rr is found to be decreased to 86.30%, a reduction of 9.78% is observed. Key findings of this research are the excellent storage modulus of 3150 MPa, which is 82.93% higher than PEKK. Thermal studies revealed very high glass transition temperature (Tg) of 175°C and thermal degradation temperature (Td) of 561.36°C, which is higher than PEKK (Tg = 161°C and Td = 548°C), demonstrating excellent thermal performance and showing potential for high‐temperature shape memory applications.Highlights Composite showed excellent shape fixity (91.07%) and shape recovery (96.08%). Quick shape recovery in 20 s showed potential for a swift actuator. Storage modulus of 3150 MPa is observed for the composite. Composite has a glass transition temperature of 175°C. Composite exhibited a high thermal degradation temperature of 561.36°C.

Comparison of clinical outcomes of polyetheretherketone and hybrid resin crowns placed on molars for over two years

This study aimed to compare the 2-year clinical outcomes of polyetheretherketone (PEEK) and hybrid resin crowns placed on molars. Patients who received PEEK (P-Cr) and hybrid resin (H-Cr) crowns at Hiroshima University Hospital between 2016 and 2021 were evaluated in 2024 for crown conditions, including loss, fractures, and occlusal wear. No cases of crown debonding or fracture were observed in the P-Cr group. In contrast, the H-Cr group had 10 cases of loss and 4 cases of fractures. The P-Cr group demonstrated significantly fewer cases of crown debonding than the H-Cr group. Occlusal wear was observed in most crowns in the P-Cr group. Compared to the hybrid resin crowns, the PEEK crowns had a lower risk of fracture and debonding and retained long-term functionality; however, surface roughness and color changes were observed, suggesting that they may not be ideal for patients with particularly high esthetic demands. Nevertheless, physiological occlusal relationships and functionality were preserved, indicating that PEEK crowns could be a viable option for restoring molar defects.

The stress distribution of implants made of Polyaryletherketones: A 3D Finite Element Analysis

OBJECTIVE: To explore the stress distribution on the bone-implant structures caused by the Polyetheretherketone (PEEK), Polyetherketoneketone (PEKK), and titanium fixture/abutments by using the three-dimensional (3D) finite element analysis (FEA). MATERIALS AND METHODS: Six models composed of titanium, PEEK, and PEKK implant/abutments under vertical (250 N) and 45˚ oblique (100 N) loading were studied. The obtained principal and von Mises stress values from the models were evaluated. RESULTS: von Mises stresses were found to be highest in titanium implants and abutments under vertical and oblique loads. Extremely increased stress values were observed in the screws of the Polyaryletherketone (PAEK) models compared to titanium models. Lower principal stresses were observed in titanium models than PAEK models in the cancellous and cortical bone under vertical and oblique loads. CONCLUSION: PAEKs transmitted more stress to the peri-implant bone. Stress distribution in titanium models were more homogenous while stress concentrated in the bone adjacent to the coronal part of the implants and neck of the implants in PAEKs.

Carbon Fiber‐Reinforced Silicon Carbide (C/C‐SiC) Fabrication Derived From Polyetherketoneketone (PEKK) as an Alternative Thermoplastic Carbon Precursor

ABSTRACTThis study shows the first successful fabrication of a carbon fiber‐reinforced silicon carbide (C/C‐SiC) via the liquid silicon infiltration process using two thermoplastic polyetherketoneketone (PEKK) powders as carbon precursors. Samples are analyzed after each processing step and compared to polyetheretherketone (PEEK)‐derived reference samples. The carbon yield was above 65% for PEKK and 54% for PEEK, possibly due to the greater crosslinking potential of PEKK. Rheological measurements showed a higher melt viscosity of PEKK 60/40 (which consists of 60% terephtalic and 40% isophtalic moieties) than PEEK. The higher viscosity of PEKK 60/40 affected the carbon fiber‐reinforced plastic (CFRP) microstructure because it resulted in more matrix pores and some partly saturated fiber tows in the PEKK 60/40‐derived CFRP. The incomplete infiltration of fiber tows by PEKK in the CFRP state led to the undesirable reaction of the single carbon fibers during final siliconization. However, the effect was of minor influence, and the microstructure and phase composition remained unaffected. Mechanical testing of PEEK‐ and PEKK‐derived C/C‐SiC showed excellently comparable properties with a mean flexural strength above 200 MPa and a strain to failure above 0.55%. Thus, PEKK‐derived C/C‐SiC is a suitable alternative thermoplastic polymer for C/C‐SiC fabrication.

Investigation on three‐dimensional defect evolution and damage mechanisms of continuous carbon fiber reinforced PEEK composites under tensile loading

AbstractContinuous carbon fiber‐reinforced polyether ether ketone (CCF/PEEK), a thermoplastic composite, holds significant promise for applications in aerospace and automotive manufacturing. However, challenges such as temperature gradients during printing and insufficient fiber impregnation result in weak interfacial properties, making internal defects and failure mechanisms key areas of research. This study employs high‐resolution synchrotron x‐ray computed tomography (SR‐CT) and digital volume correlation (DVC) to investigate the failure modes, defect evolution, and internal three‐dimensional strain distribution in CCF/PEEK samples during tensile testing. The analysis reveals that strain concentrates in regions with dense continuous fiber distribution before material failure, while post‐failure strain localizes within interlaminar cracks. Furthermore, defect evolution analysis suggests that extensive fusion and growth of defects around fibers may serve as precursors to material failure. These findings indicate that weak bonding at the fiber/resin interface is the primary cause of tensile failure in CCF/PEEK, providing valuable insights for failure prediction and optimization of molding processes.Highlights Observation of CCF/PEEK failure modes using synchrotron radiation CT. Bulk cracks are concentrated in the interlaminar and fiber/resin interfaces. Significant difference in defect evolution before and after tensile failure. Strain concentration in the CCFs aggregation region predicts tensile failure.

Cranial Reconstruction for Infiltrative Meningioma Using 68Ga-DOTATATE Positron Emission Tomography/Computed Tomography and Individual Patient Solutions CaseDesigner®: A Case Series.

Meningioma with bone involvement presents challenges for complete resection and cranial reconstruction. 68Ga-dodecanetetreaacetic acid tyrosine-3-octreotide (DOTATATE) positron emission tomography (PET)/computed tomography (CT) has emerged as an excellent modality for localizing invasive meningiomas because of molecular interaction with somatostatin receptor-2. We present a novel technique to design 3-dimensional-printed artificial cranioplasty, using combined fine-slice CT, MRI, and 68Ga-DOTATATE PET/CT with Individual Patient Solutions (IPS) CaseDesigner® software. This study's objective was to generate proof-of-concept work for a novel artificial cranioplasty protocol that combines customized cranial implant software and DOTATATE PET/CT. Three patients with invasive bone meningiomas were retrospectively identified. For each patient, the proposed protocol combines CT, MRI, and 68Ga-DOTATATE PET/CT imaging to generate a 3-dimensional cranial reconstruction within the Karl Leibinger Surgical (KLS) Martin-IPS CaseDesigner® software. Subsequently, the virtual rendering is used to manufacture a customized polyetheretherketone (PEEK) implant, along with a guiding component, which ensures precise delineation of surgical borders before craniectomy. Finally, cranioplasty with the customized implant is performed using standard techniques. The described preoperative cranioplasty design protocol was performed for each patient. Tumor invasion was visualized using 68Ga-DOTATATE PET/CT. Patient 1 presented with a recurrent right frontal meningioma with invasion into anterior skull base. In this case, IPS CaseDesigner® was used to create a mirror image PEEK implant for the left orbit and affected cranium. Patients 2 and 3 had intraosseous meningiomas invading the frontal bone; customized PEEK implants were tailored to the side of the planned craniectomy for both patients and were successfully placed without complication. Postoperatively, all patients remained neurologically intact and were discharged without complications. In all patients, the PEEK implants exhibited appropriate cranial continuity and integrity. 68Ga-DOTATATE PET/CT has high sensitivity and specificity for detecting meningiomas during preoperative planning, particularly when the tumor involves bone. IPS CaseDesigner® demonstrates excellent utility for planning and constructing customized cranioplasties tailored to each patient for skull reconstruction.

Hydroxyapatite, polyetheretherketone, and stainless steel as orthodontic mini-implant biomaterial candidates: A bioinformatic approach

Context: Orthodontic mini-implants (OMIs) are temporary devices affixed to bones that aim to improve absolute anchoring during orthodontic treatment for malocclusion. Stainless steel (SS), polyetheretherketone (PEEK), and hydroxyapatite (HA) are substitute materials that might work well together. To determine how SS, PEEK, and HA interact with bone molecular target proteins linked to resistant types of OMI, a molecular docking investigation and an in silico analysis were carried out. Aims: To analyze the binding activity of SS, PEEK, and HA to bone molecular target proteins in silico as potential OMI biomaterial candidates. Methods: Osteocalcin, osteonectin, bone morphogenic protein (BMP)4, BMP2, BMP7, alkaline phosphatase (ALP), runt-related transcription factor-2 (RUNX2), insulin growth factor-1 (IGF1), osterix, tartrate-resistant acid phosphatase (TRAPase), and collagen type 1a1 (COL1A1) biomolecular interaction patterns were used in molecular docking to identify ligand activity on target proteins using negative binding affinity. Network prediction was used to investigate the activation and inhibition of the ligand complex on target proteins. Results: Bone molecular target proteins, such as IGF1 and osteopontin, bind to SS, PEEK, and HA ligands with a strong negative binding affinity, causing ligand activation or inhibition. Out of all the variables, the combination of SS, PEEK, and HA had the largest negative value. Conclusions: As shown in silico, SS, PEEK, and HA ligands have a high binding affinity for resistance-form-related bone target proteins, such as IGF1 and osteopontin, making them potentially useful as OMI biomaterials.

3D printed porous PEEK scaffolds with stable and durable gelatin composite hydrogel coating loaded Yoda1 for in vivo osseointegration.

3D printed porous PEEK scaffolds with stable and durable gelatin composite hydrogel coating loaded Yoda1 for in vivo osseointegration.

Postoperative Sclerotic Modic Changes after TLIF:whether it is different between n-HA/PA66 and PEEK cage?

Postoperative Sclerotic Modic Changes after TLIF:whether it is different between n-HA/PA66 and PEEK cage?

Comparison of marginal and internal fit of custom-made post and core restorations milled with 4-axis and 5-axis milling machines in Polyetheretherketone and composite.

Comparison of marginal and internal fit of custom-made post and core restorations milled with 4-axis and 5-axis milling machines in Polyetheretherketone and composite.

Orbital Patient-Specific (Customized) Implants: A Report by the American Academy of Ophthalmology.

Orbital Patient-Specific (Customized) Implants: A Report by the American Academy of Ophthalmology.

Optimization of 3D-printed titanium interbody cage design. Part 1: in vitro biomechanical study of subsidence.

Optimization of 3D-printed titanium interbody cage design. Part 1: in vitro biomechanical study of subsidence.

Mussel-inspired bifunctional chimeric peptides macromolecules functionalize 3D-printed porous scaffolds for enhanced antimicrobial and osseointegration properties in bone defect repair.

Mussel-inspired bifunctional chimeric peptides macromolecules functionalize 3D-printed porous scaffolds for enhanced antimicrobial and osseointegration properties in bone defect repair.

Predicting the Fouling Behavior of Whey Protein Concentrate in Polymeric Heat Exchangers

ABSTRACTFouling in heat exchangers, particularly in the dairy industry, presents significant operational challenges, increasing energy consumption and maintenance costs. Polymeric heat exchangers, with their favorable fouling mitigation behavior, offer a potential solution to reduce these impacts. A mechanistic and an empirical fouling model were developed to predict the unique detachment mechanism of whey protein concentrate (WPC) fouling layers on polyetheretherketone (PEEK) heat exchanger surfaces caused by boiling beneath the fouling deposits. Model parameters were estimated using experimental data of the total fouling mass. Fouling experiments were carried out for different process conditions. To identify the dependency of the model parameters on the process condition, symbolic regression was applied. Previously unseen experimental data was used to validate the prediction capabilities of the models, which aim to predict fouling mass and, in case of the mechanistic model, thermal resistance. The results demonstrate that the empirical model predicts the fouling mass with an accuracy of ±20% for untrained operating conditions within the boundaries of the training set. Larger deviations (< 70%) were observed for the mechanistic model. When predicting fouling mass outside the training data set, the empirical model fails to do so when extrapolating. While the mechanistic model provides better results compared to the empirical model when extrapolating, an error of < 130% remains. The calculated thermal resistance shows discrepancies, particularly for high WPC concentrations and high heat flux. The findings suggest that PEEK heat exchangers may significantly reduce fouling‐related downtime and energy costs in dairy processing.