Polyetheretherketone Nanocomposites Research Articles

Increasing the toughness while reducing the viscosity of carbon nano-tube/polyether imide/polyether ether ketone nanocomposites

Polyether ether ketone (PEEK) has good mechanical properties. However, its high viscosity when molten limits its use because it is hard to process. PEEK nanocomposites containing both carbon nanotubes (CNTs) and polyether imide (PEI) were prepared by a direct wet powder blending method using a vertical injection molding machine. The addition of an optimum amount of PEI lowered the viscosity of the molten PEEK by approximately 50% while producing an increase in the toughness of the nanocomposites, whose strain to failure increased by 129%, and fracture energy increased by 97%. The uniformly dispersed CNT/PEI powder reduced the processing difficulty of PEEK nanocomposites without affecting the thermal resistance. This improvement of the strength and viscosity of PEEK facilitate its use in the preparation of thermoplastic composites.

Tribological and mechanical characterization of carbon-nanostructures based PEEK nanocomposites under extreme conditions for advanced bearings: A molecular dynamics study

Polyetheretherketone (PEEK) carbon nanomaterial-based nanocomposites, incorporating zero-dimensional (0D), one-dimensional (1D), two-dimensional (2D) and three-dimensional (3D) carbon structures have gained prominence as advanced materials with the potential to enhance tribological properties paving the way for a new era in the development of advanced bearings for high-performance machinery applications. This study delves into the forefront of friction and wear analysis, employing all atom molecular dynamics (aa-MD) simulations to engineer PEEK polymer nanocomposites with precision under elevated temperature and higher velocity. The research presents optimization of mechanical strength and tribological properties crucial to meet the demanding requirements of industrial machinery. The addition of C60 fullerenes reduced COF by 16.59% and wear rates by 6.52% due to its spherical shape and lubrication effects. Introduction of carbon-nanotubes further decreased COF by 54.54% and wear rates by 32.5%, offering resistance to abrasive and adhesive wear. S-graphene showed notable performance, reducing COF by 69.40% and wear rates by 75.03%, making it promising for sliding and wear applications. Carbon-nanocones reduced COF by 60.6% and wear rates by 72.06%, slightly higher than S-Gr due to abrasive effects and increased surface contact. These findings underscore the potential of reinforcement dimensionality in enhancing the tribological properties of PEEK based nanocomposites.

Enhanced Tribological Performance of Graphene Oxide Reinforced Polyether Ether Ketone Nanocomposites

Despite advancements in brake pad technology, issues with friction, wear rate, and stopping distance remain. Our study reported here examined the potential of a polymer-based nanocomposite, polyether ether ketone (PEEK) reinforced with graphene oxide (GO), to address these challenges. Varying concentrations of GO (1 wt.%, 3 wt.%, and 5 wt.%) were incorporated into the PEEK matrix using a Sol–Gel process. The resulting nanocomposites were analyzed using Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray spectroscopy (EDX) to study surface characteristics, while X-ray Diffraction (XRD) spectroscopy examined their crystalline structures. A pin-on-disk machine was used to test the PEEK-GO nanocomposites for their friction coefficient and wear rate under varying loads (20 kg, 30 kg, 60 kg) and track diameters (60 mm, 90 mm, 100 mm). The results demonstrated that increasing filler content (GO concentration) reduced the wear rates at lower loads and track diameters. Lower friction coefficients were observed when the track diameter and load were increased alongside a reduction in GO concentration. The enhanced tribological performance of the GO-reinforced PEEK nanocomposites was attributed to efficient load transfer between GO and the PEEK matrix, along with GO's strengthening properties. This suggests PEEK-GO nanocomposites are a promising material for brake pad applications.

Heat transfer mechanism in graphene reinforced PEEK nanocomposites.

The thermal conductivity of graphene is in the range of 3000-5000 W m-1 K-1, showing great potential in high thermal conductivity devices. However, the thermal conductivity of graphene-reinforced polymer is typically lower than 10 W m-1 K-1, which is far from theoretical expectations. To understand the mechanisms of heat transfer in graphene-reinforced polymers, this work investigated the effect of graphene addition on the thermal conductive performance of polyetheretherketone (PEEK) matrix. The study examined the number of layers, deflection angles, and interlayer distances using molecular dynamics (MD) simulations. The results showed that the improvement of thermal conductivity of PEEK nanocomposite was not only related to the content of graphene but also to the angle between the benzene ring in the molecular chain of PEEK and the transfer direction of heat flow. Increasing the number of graphene layers is more beneficial to the enhancement of thermal conductivity. In particular, the enhancement of thermal conductivity is most significant when the number of graphene layers is the same, and the interlayer distance is less than the truncation radius.

PEEK composite resin with enhanced intumescent flame retardancy loaded with Octaphenylsilsesquioxane and nano calcium carbonate and its application in fibers

This study reported a novel strategy of introducing nano Calcium Carbonate (nCC) and Octaphenylsilsesquioxane (OPS) simultaneously into poly ether ether ketone (PEEK) as the intumescent flame retardants for the first time to address the melt flowage and drop in the fire. Good dispersion of nCC and OPS in the PEEK matrix was observed. The nanocomposites displayed lower thermal decomposition rate and higher residual chars compared with those of pristine PEEK. Cone calorimeter tests showed that the peak heat release rate, smoke production rate and the total smoke production of 5%OPS/5%nCC/PEEK decreased by 47.54%, 55.00% and 30.61%, respectively. Furthermore, the combustion mechanism of PEEK and its nanocomposite was investigated by TG-MS, which showed that nCC and OPS had a synergistic flame retardant effect. Finally, as an application verification, the PEEK nanocomposite fiber was prepared and its flame retardant properties were basically the same as the PEEK nanocomposite material, proving its huge application potential in high-performance flame retardant fabrics. This work is expected to pave the pathway about the novel eco-friendly flame retardancy and open a new avenue to develop PEEK nanocomposites.

Improved Mechanical Properties and Bioactivity of Silicate Based Bioceramics Reinforced Poly(ether-ether-ketone) Nanocomposites for Prosthetic Dental Implantology.

Polyether-ether-ketone (PEEK) biomaterial has been increasingly employed for orthopedic, trauma, spinal, and dental implants due to its biocompatibility and in vivo stability. However, a lack of bioactivity and binding ability to natural bone tissue has significantly limited PEEK for many challenging dental implant applications. In this work, nanocomposites based on PEEK reinforced with bioactive silicate-based bioceramics (forsterite or bioglass) as nanofillers were prepared using high energy ball milling followed by melt blending and compression molding. The influence of nanofillers type and content (10, 20 and 30 wt.%) on the crystalline structure, morphology, surface roughness, hydrophilicity, microhardness, elastic compression modulus, and flexural strength of the nanocomposites was investigated. The scanning electron microscopy images of the nanocomposites with low nanofillers content showed a homogenous surface with uniform dispersion within the PEEK matrix with no agglomerates. All nanocomposites showed an increased surface roughness compared to pristine PEEK. It was found that the incorporation of 20 wt.% forsterite was the most effective in the nanocomposite formulation compared with bioglass-based nanocomposites; it has significantly improved the elastic modulus, flexural strength, and microhardness. In vitro bioactivity evaluation, which used biomimetic simulated body fluid indicated the ability of PEEK nanocomposites loaded with forsterite or bioglass nanofillers to precipitate calcium and phosphate bone minerals on its surface. These nanocomposites are expected to be used in long-term load-bearing implant applications and could be recommended as a promising alternative to titanium and zirconia when used as a dental implant material.

3D Printed Strontium and Zinc Doped Hydroxyapatite Loaded PEEK for Craniomaxillofacial Implants.

In this study, Strontium (Sr) and Zinc (Zn) doped-HA nanoparticles were synthesized and incorporated into polyetheretherketone (PEEK) up to 30 wt.% and processed by a novel approach i.e., fused deposition modelling (FDM) 3D printing for the production of patient specific cranial implants with improved bioactivity and the required mechanical performance. Filaments were produced via extrusion and subsequently 3D-printed using FDM. To further improve the bioactivity of the 3D-printed parts, the samples were dip-coated in polyethylene glycol-DOPA (PEG-DOPA) solution. The printing quality was influenced by filler loading, but was not significantly influenced by the nature of doped-HA. Hence, the printing conditions were optimized for each sample. Micro-CT and Scanning Electron Microscopy (SEM) showed a uniform distribution of bioceramic particles in PEEK. Although agglomeration of particles increased with increase in filler loadings. Differential Scanning Calorimetry (DSC) showed that the melting point and crystallinity of PEEK increased with an increase in doped-HA loading from 343 °C to 355 °C and 27.7% to 34.6%, respectively. Apatite formation was confirmed on the 3D-printed samples after immersion in simulated body fluid (SBF) for 7, 14 and 28 days via SEM, X-ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR). The tensile strength and impact strength decreased from 75 MPa to 51 MPa and 14 kJ/m2 to 4 kJ/m2, respectively, while Young’s modulus increased with increasing doped-HA content from 2.8 GPa to 4.2 GPa. However, the tensile strengths of composites remained in the range of human cortical bone i.e., ≥50 MPa. In addition, there was a slight increase in mechanical strength after 28 days immersion which was attributed to apatite formation. Water contact angle showed that the hydrophilicity of the samples improved after coating the 3D-printed samples with PEG-DOPA. Hence, based on the results, the 3D-printed PEEK nanocomposites with 20 wt.% doped-HA is selected as the best candidate for the 3D-printing of craniomaxillofacial implants.

The antibacterial and wear-resistant nano-ZnO/PEEK composites were constructed by a simple two-step method

Although the polyether ether ketone (PEEK) has excellent comprehensive properties, its non-antibacterial and low wear-resistant limit the wide application in the field of artificial joint materials. In this paper, Nano-ZnO was generated in situ on the surface of PEEK powder by one-step hydrothermal method, which improved the binding force of Nano-ZnO and PEEK matrix. Then the PEEK-based nanocomposites were prepared by melt blending with the synthesized Nano-ZnO-PEEK powders and PEEK powders. The microstructure, mechanical, biological and tribological properties of PEEK-based nanocomposites were studied. The results showed that the compressive strength of PEEK-based nanocomposites can reach up to 319.2 ± 2.4 MPa. Both PEEK and PEEK-based nanocomposites were non-toxic to cells. Meanwhile, PEEK-based nanocomposites showed good antibacterial activity against E.coli and Staphylococcus aureus, and the antibacterial activity was better with the increase of Nano-ZnO content. In addition, when the Nano-ZnO content was 5%, the wear rate of PEEK-based nanocomposites was about 68% lower than that of pure PEEK materials. Thus, PEEK-based nanocomposites has a dual function of good antibacterial property and excellent wear resistance.

Surface Morphology and Mechanical Properties of Polyether Ether Ketone (PEEK) Nanocomposites Reinforced by Nano-Sized Silica (SiO2) for Prosthodontics and Restorative Dentistry.

In the field of orthopedics and traumatology, polyether ether ketone (PEEK) serves a significant role as a suitable alternative to traditional metal-based implants like titanium. PEEK is being used more commonly to replace traditional dental products. For bonding with various adhesive agents and preserved teeth, the surface alteration of PEEK was investigated. The aim of this research was to understand how different types and contents of nano-sized silica (SiO2) fillers influenced the surface and mechanical properties of PEEK nanocomposites used in prosthodontics. In this work, PEEK based nanocomposites containing hydrophilic or hydrophobic nano-silica were prepared by a compression molding technique. The influence of nano-SiO2 type and content (10, 20 and 30% wt) on surface properties of the resultant nanocomposites was investigated by the use of scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), surface roughness analysis, and contact angle measurement. The crystalline structures of PEEK/SiO2 nanocomposites were examined by X-ray diffraction (XRD) spectroscopy. Mechanical properties were measured by microhardness, elastic compression modulus, and flexural strength. All nanocomposites showed increased surface roughness compared to pure PEEK. SEM images revealed that nanocomposites filled with low content hydrophobic nano-SiO2 showed uniform dispersion within the PEEK matrix. The introduction of 10 wt% of hydrophobic nano-SiO2 to the PEEK matrix improved elastic modulus, flexural strength, and microhardness, according to the findings. The addition of nano-SiO2 fillers in a higher weight percentage, over 10%, significantly damages the mechanical characteristics of the resultant nanocomposite. On the basis of the obtained results, PEEK/SiO2 nanocomposites loaded with low content hydrophobic nano-SiO2 are recommended as promising candidates for orthopedic and prosthodontics materials.

Fused filament fabrication of polyetheretherketone/multiwalled carbon nanotube nanocomposites: the effect of thermally conductive nanometric filler on the printability and related properties

AbstractFused filament fabrication is an additive layer manufacturing technique. It was extensively used at the beginning for the manufacturing of prototypes, and it has been adopted during the last few years for the manufacturing of fully functional components. Polyetheretherketone (PEEK) has been thoroughly investigated as a composite matrix because of its outstanding mechanical properties and thermal and chemical stability. This study is focused on PEEK nanocomposites with different amounts of carbon nanotubes (CNTs) (i.e. 3, 5, 10 wt%) produced in the form of a filament and successively 3D printed. The influence of the CNT presence on printability was studied and correlated to the nanocomposite feedstock thermal and microstructural properties, defining a substrate temperature processability window. Interestingly the addition of CNTs significantly limits the processability window due to the influence on the crystallization process and viscosity. Moreover, the thermal and mechanical properties of 3D printed bulk samples were investigated in view of the PEEK/CNT nanocomposite feedstock properties. © 2021 Society of Chemical Industry

Ionic liquid modified PEEK-MWCNTs nanocomposites with enhanced thermomechanical properties

Polyetheretherketone (PEEK) is a stable semi-crystalline thermoplastic polymer with excellent thermal and chemical properties and is used in many applications, especially as a biomaterial. However, poor mechanical properties: mismatching of elastic modulus to human bone retards the use of PEEK as a biomaterial for bone implant material. In the present study, ionic liquid (IL) modified multiwalled carbon nanotubes were used to prepare PEEK nanocomposites via internal mixer and compression molding processes. The morphologies, thermal and mechanical properties of the prepared nanocomposites were evaluated. Uniform and excellent distribution of MWCNTs into PEEK was achieved by optical microscopy. The thermogravimetric study showed that the decomposition temperature of the composites was boosted 7 % ± 0.9 as compared to those of PEEK composites prepared without IL. Moreover, the elastic modulus of the PEEK nanocomposites was improved by ionic liquid modified MWCNTs into the PEEK. Thus, the prepared PEEK nanocomposites have the potential to be used for fabricating bone implants.

Additively Manufactured Polyetheretherketone (PEEK) with Carbon Nanostructure Reinforcement for Biomedical Structural Applications

This study is focused on carbon nanostructures (CNS), including both carbon nanotubes (CNTs) and graphene nanoplatelets (GNPs), reinforcement of medical‐grade polyetheretherketone (PEEK), and in vitro bioactivity for biomedical structural applications. CNS/PEEK scaffolds and bulk specimens, realized via fused filament fabrication (FFF) additive manufacturing, are assessed primarily in the low‐strain linear‐elastic regime. 3D printed PEEK nanocomposites are found to have enhanced mechanical properties in all cases while maintaining the desired degree of crystallinity in the range of 30–33%. A synergetic effect of the CNS and sulfonation toward bioactivity is observed—apatite growth in simulated body fluid increases by 57% and 77%, for CNT and GNP reinforcement, respectively, doubling the effect of sulfonation and exhibiting a fully‐grown mushroom‐like apatite morphology. Further, CNT‐ and GNP‐reinforced sulfonated PEEK recovers much of the mechanical losses in modulus and strength due to sulfonation, in one case (GNP reinforcement) increasing the yield and ultimate strengths beyond the (non‐sulfonated) printed PEEK. Additive manufacturing of PEEK with CNS reinforcement demonstrated here opens up many design opportunities for structural and biomedical applications, including personalized bioactivated surfaces for bone scaffolds, with further potential arising from the electrically conductive nanoengineered PEEK material toward smart and multifunctional structures.

Super tough graphene oxide reinforced polyetheretherketone for potential hard tissue repair applications

Biocompatible polyetheretherketone (PEEK) is a favorable material for hard tissue repair due to its similar elastic modulus to that of the human bone. In this work, graphene oxide (GO) reinforced PEEK nanocomposites with different GO loading have been prepared by injection molding. Mechanical testing reveals that the toughness of the reinforced composite varies with the GO loading, with 0.5% GO giving the greatest elongation at break (86.32% greater than pristine PEEK). The underlying toughening mechanism has been attributed to the well-dispersed GO forming π-π* conjugations at the GO/PEEK interface. These conjugations also acted as the nucleation sites for oriented crystallized region in PEEK. As the GO content increases further (e.g > 0.5%), the fillers tend to agglomerate and would disturb the crystallites of PEEK and serve as stress concentration sites, resulting in decreased toughness. The biocompatibility of the composites has been evaluated in vitro, and the results showed that the addition of GO into PEEK favors the adhesion and spreading of bone marrow stromal stem cells, demonstrating the strong potential of our GO reinforced PEEK composites in applications such as hard tissue repair and replacement.

Engineering the mechanical properties of CNT/PEEK nanocomposites.

Poly-ether-ether-ketone (PEEK) was deeply investigated as a composite matrix because of its outstanding mechanical properties and thermostability. However, the performance improvement of fiber-reinforced PEEK composites was moderate according to a great number of experimental investigations. An insightful understanding of the deformation and interfacial failure in the PEEK composite is needed to guide the future fabrication of high-performance PEEK plastics. In this paper, Molecular Dynamics (MD) simulation was employed to evaluate the mechanical properties of carbon nanotube (CNT) reinforced PEEK nanocomposites. It was found that the weak interface between CNTs and the PEEK matrix leads to the flaws in the CNT/PEEK nanocomposite. A CNT-functionalization strategy was used to introduce H-bonds between CNTs and the PEEK matrix, improving the overall mechanical performance of the CNT/PEEK nanocomposite. Numerical examples validate that the addition of amino groups on CNTs can significantly improve the interfacial failure shear stress and elastic modulus of the CNT/PEEK nanocomposites. This mechanism study provides evidence and a theoretical basis to improve the mechanical performance of fiber-reinforced PEEK for lightweight structures in advanced equipment.

Effect of hexagonal boron nitride on high-performance polyether ether ketone composites

In this paper, we prepared and characterized nanocomposites of polyether ether ketone (PEEK) containing hexagonal boron nitride (h-BN) nanofiller from 1 to 5 wt%. Using various techniques, we studied the friction and wear properties, thermal conductivity, morphology, and mechanical and thermomechanical properties of the nanocomposites. Adding h-BN nanoparticles to the PEEK improved the properties of the resulting nanocomposites. At 5 wt% h-BN content, it exhibited optimum improvement of friction and wear properties, thermal conductivity, hardness, and storage modulus. Thus, we demonstrated that PEEK nanocomposites reinforced with h-BN have a great potential as multifunctional materials for future industrial applications.

Synthesis and Characterization of alumina nanofiber reinforced Poly ether ether ketone (PEEK)

The effects of reinforcing Poly ether etherketone (PEEK) with alumina nanofiber have been studied. The nano-composites were prepared by first dispersing the fibre in solvent and then undertaking the synthesis of PEEK. Nanocomposite materials with 1wt.%, 2.5wt.% and 5wt.% of alumina nanofiber have been prepared successfully by dispersing the alumina nanofiber in Sulfolane as solvent and upon sonication for 30 minutes. Transmission electron microscopy and scanning electron micrographs indicated excellent dispersion and interactions between PEEK matrixes with the added alumina nanofibers. Differential scanning calorimeter shows changes in melting and crystallization point and degree of crystallinity for 1wt.% nanocomposites. The result also indicated that alumina nanofiber serves as nucleating agents in PEEK nanocomposites. The X-ray diffractogram data indicated that the crystallinity of the PEEK nanocomposites was highest for 1wt.% alumina nanofiber. The thermogravimetry analysis, shows that thermal stability for alumina nanofiber/PEEK nano-composites was enhanced compared to that of the pure PEEK.