Polyetheretherketone Matrix Research Articles

INDIVIDUAL 3D PRINT PEEK MATRIX IS ​​A POSSIBLE TACTICAL SOLUTION IN THE TREATMENT OF LARGE DEFECTS OF THE DIAPHYSIS OF THE HUMERUS. DESCRIPTION OF TWO CLINICAL CASES

In the case of gunshot wounds to the limbs, 7.1% of wounded servicemen are diagnosed with primary defects of bone tissue, which in 79.3% of victims exceed 3 square centimeters. In the treatment of this category of patients, the use of 3D modeling becomes especially relevant. Polyetheretherketone (PEEK) is a polyaromatic semi-crystalline thermoplastic polymer with mechanical properties favorable for biomedical applications. PEEK-based materials are becoming an important group of biomaterials used for bone and cartilage replacement, as well as in a large number of diverse fields of medicine. The possibility of using these materials in the 3D printing process increases scientific interest in them. The PEEK matrix is ​​a 3D printed custom mesh that serves as a container for the plastic material. It is important to note that the chemical inertness of the PEEK surface does not guarantee good interfacial biocompatibility and requires surface modification before its use in vivo. The use of PEEK to replace bone defects, particularly after gunshot wounds to the extremities, requires further scientific research and clinical observations. The analysis of clinical cases presented in the article aims to expand the understanding of orthopedic trauma surgeons about the possibilities of using 3D print PEEK matrix technology and help in making tactical clinical decisions in complex cases where there are significant bone defects.

Friction and wear characteristics of synthetic diamond and graphene-filled polyether ether ketone composites

Modifying tribo films using filler particles is a significant area of research in developing polymer-based tribo components to minimize material loss during the sliding process. This study focused on altering the wear characteristics of a polyetheretherketone (PEEK)/graphene high-performance polymer composite to strengthen the tribo film by adding synthetic diamond particles. The hot-pressed PEEK composite reinforced by graphene and diamond particles increased the hardness and thermal stability of the composite. Compared with pure PEEK, composites containing 1% graphene and 1% diamond particles showed an increment of 25% and 23% in hardness and thermal stability, respectively. Fourier-transform infrared spectroscopy and X-ray diffraction analysis verified the compatibility and intactness of the fillers in the PEEK matrix. The tribo properties of PEEK composites were characterized by a pin-on-disc tribometer on a counter steel surface. A PEEK composite containing 0.75 wt% graphene and 0.5 wt% diamond particles exhibited the lowest friction of 0.17 at a pressure of 1.5 MPa. The specific wear rate was low (1.78 × 10−6 mm3/Nm) for the composite containing 1 wt% graphene and 1 wt% diamond particles at a pressure of 1.5 MPa. Varying synthetic diamond and graphene filler concentrations in the PEEK matrix change the wear process by modifying the tribo film characteristics, revealing the lowest friction and wear rate. X-ray photoelectron and Raman spectroscopy show that the polymer film was transferred to the steel countersurface, and the tribo-chemical products of the tribo film contribute to a stable tribo film. The ferric oxide film and the tribo film improve the composite’s self-lubricating properties and load-bearing ability. Hence, the composite containing 0.75% of graphene and 0.5% of a synthetic diamond can be employed in the sliding bearing application of continuous conveyors used in mass production systems.

Effect of Fiber Type and Content on Surface Quality and Removal Mechanism of Fiber-Reinforced Polyetheretherketone in Ultra-Precision Grinding.

Polyetheretherketone (PEEK) is a promising thermo-plastic polymer material due to its excellent mechanical properties. To further improve the mechanical properties of PEEK, different kinds of short fibers are added into the PEEK matrix. The grinding machinability of short-fiber-reinforced PEEK varies with the effect of fiber type and content. Therefore, it is crucial to investigate the surface quality and removal mechanism of fiber-reinforced PEEK in ultra-precision grinding. In this paper, different fiber types and mass fractions of short-fiber-reinforced PEEK, including carbon-fiber-reinforced PEEK (CF/PEEK) and glass-fiber-reinforced PEEK (GF/PEEK), are employed. The grinding machinability of short-fiber-reinforced PEEK was investigated using grinding experiments with grinding wheels of different grit sizes. The effects of the fiber type and mass fraction on the surface quality and removal mechanism during grinding were discussed. The results showed that the brittle–ductile transition depth of carbon fiber was much larger than that of glass fiber, so it was easier to achieve ductile removal in grinding with the carbon fiber. Therefore, the ground surface roughness of CF/PEEK was smaller than that of GF/PEEK under the same grinding conditions. With the increase in carbon fiber mass fraction, the ground surface roughness of CF/PEEK decreased due to the higher hardness. The brittle–ductile transition depth of glass fiber was small, and it was easy to achieve brittle removal when grinding. When the glass fiber removal mode was brittle removal, the GF/PEEK surface roughness increased with the increase in glass fiber content.

Strategies to improve bioactive and antibacterial properties of polyetheretherketone (PEEK) for use as orthopedic implants.

Polyetheretherketone (PEEK) has gradually become the mainstream material for preparing orthopedic implants due to its similar elastic modulus to human bone, high strength, excellent wear resistance, radiolucency, and biocompatibility. Since the 1990s, PEEK has increasingly been used in orthopedics. Yet, the widespread application of PEEK is limited by its bio-inertness, hydrophobicity, and susceptibility to microbial infections. Further enhancing the osteogenic properties of PEEK-based implants remains a difficult task. This article reviews some modification methods of PEEK in the last five years, including surface modification of PEEK or incorporating materials into the PEEK matrix. For surface modification, PEEK can be modified by chemical treatment, physical treatment, or surface coating with bioactive substances. For PEEK composite material, adding bioactive filler into PEEK through the melting blending method or 3D printing technology can increase the biological activity of PEEK. In addition, some modification methods such as sulfonation treatment of PEEK or grafting antibacterial substances on PEEK can enhance the antibacterial performance of PEEK. These strategies aim to improve the bioactive and antibacterial properties of the modified PEEK. The researchers believe that these modifications could provide valuable guidance on the future design of PEEK orthopedic implants.

Novel thermally insulated ultra‐lightweight fireproof and high impact resistance advanced hybrid composite

AbstractThis work investigates the development of ultra‐lightweight, hybrid fireproof composite material. The composite panels are made of 2,5‐polybenizimidazole (ABPBI) a thermally stable high‐performance fiber and poly ether ketone (PEK) a high‐performance film. The surface of ABPBI fiber and PEK film were treated by nitrogen plasma to increase the adhesion characteristics. The composite was fabricated through the stacking method. The hybrid composite was developed by sandwiching silicone rubber foam between surface‐treated ABPBI/PEK composite. The entire sample was covered with surface‐treated ABPBI fiber using silicone adhesive. The hybrid composite was tested in exposure to dry ice, fire and compression tests. After exposure to fire for 10 min, negligible loss of material was noticed. The Scanning Electron Microscopy (SEM) analysis at the interface indicated strong interfacial adhesion between the PEK matrix and the ABPBI fiber. Limiting oxygen index (LOI) of ABPBI fiber and PEK film appear to be promising in terms of fire resistivity and hence the hybrid composite of PEK/ABPBI sandwiched by silicone foam results one of the best fireproof composite. This composite also shows significant improvement of impact and compressive strength. Analysis under Ansys Fluent software also shows similar results.

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.

Effect of Fiber Type and Content on Mechanical Property and Lapping Machinability of Fiber-Reinforced Polyetheretherketone.

Polyetheretherketone (PEEK) is a novel polymer material with excellent material properties. The hardness and strength of PEEK can be further improved by introducing fiber reinforcements to meet the high-performance index of the aerospace industry. The machinability will be influenced when the material properties change. Therefore, it is crucial to investigate the influence of material properties of the fiber-reinforced PEEK on machinability. In this paper, the main materials include pure PEEK, short carbon-fiber-reinforced PEEK (CF/PEEK), and short glass-fiber-reinforced PEEK (GF/PEEK). The effects of the fiber type and mass fraction on the tensile strength, hardness, and elastic modulus of materials were discussed using the tensile test and nanoindentation experiments. Furthermore, the fiber-reinforced PEEK lapping machinability was investigated using lapping experiments with abrasive papers of different mesh sizes. The results showed that the hardness and elastic modulus of PEEK could be improved with fiber mass fraction, and the tensile strength of CF/PEEK can be improved compared with that of GF/PEEK. In terms of lapping ability, the material removal rates of the fiber-reinforced materials were found to be lower than the pure PEEK due to the higher hardness of the fiber. During the lapping process, the material removal methods mainly included the ductile deformation or desquamation of reinforcing fiber and ductile removal of the PEEK matrix. The lapped surface roughness of PEEK material can be improved by fiber reinforcement.

Evaluation of tribological and biological properties of TaB2/PEEK composite coatings prepared by electrodeposition

AbstractIt is well‐known that a lower wear rate, favorable mechanical properties, and limited inflammatory response are critical factors in determining the long‐term service of orthopedic implants. In this study, we prepare TaB2/PEEK coatings by electrophoretic deposition (EPD) of borated tantalum (TaB2) and polyether‐ether‐ketone (PEEK) particles on a pure titanium plate (TA2). Nanoindenter, reciprocating ball‐on‐disc tester, and in vitro biological experiments were used to investigate the effects of TaB2 particles on the mechanical properties, tribological properties, and biological properties of composite coatings. The results demonstrate that a small amount of TaB2 particles were equally dispersed in the PEEK matrix, and the mechanical properties are improved, resulting in better tribological properties of the coating. In particular, the wear rate of P‐TB‐3 coating in the simulated body fluid (SBF) was 72% lower than that of the PEEK coating, with a friction coefficient (COF) of 0.164 and a wear rate of 1.45 × 10−6 mm3·N−1 m−1, respectively. Furthermore, the P‐TB‐3 surface boosted Raw264.7 macrophage adherence and proliferation, with a potential to promote Raw264.7 macrophage transition to the M2 phenotype. These results suggest that the P‐TB‐3 coating prepared by EPD is considered as a promising implant replacement material.

Hydroxyapatite dispersed sulphonated PEEK composite membrane: Synthesis, structural and mechanical characterization

A synthetic composite material membrane was synthesized using Polyether ether ketone (PEEK) as a polymer matrix, reinforced with nano-Hydroxyapatite (nHAp) as the ceramic for intended use as a hip bone implant material. Notwithstanding its close resemblance with hip bone material, PEEK is chemically and biologically inert and comes with limited biocompatibility. HAp has chemical and crystallographic similarity with carbonated apatite like human bones. In the present work it was used as reinforcement with PEEK in varying weight percentages, of 2, 5, 8 and 10 to determine the optimum mix for application as a bio hip implant material. HAp reinforcement beyond 10 wt. % was not considered as it resulted in agglomeration and reduction in mechanical properties. The polymer was sulphonated to facilitate chemical interactions with the hydroxyl (-OH) group of HAp to overcome poor interfacial bonding between PEEK and nHAp. The sulphonation also reduced the chances of wear debris from implant site getting resorbed into the body. These synthetic composite samples were then characterized using techniques such as x-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscope and energy dispersive x-ray spectroscopy, to ascertain its conformity in structure and morphology. Mechanical tensile tests were also carried out to determine tensile strength, yield strength and elastic modulus of the composite membranes. The synthesized sample, with 8 wt. % of HAp reinforcement, demonstrated the most suitable properties. The work propounds a fresh approach towards synthesizing a composite membrane using Polyether ether ketone, subjected to sulphonation (SPEEK), for intended application as a hip implant. The superior surface wetting, obtained on account of sulphonation of PEEK matrix, facilitated more intimate contact with nano-hydroxyapatite (nHAp) reinforcements and assisted in establishing superior, homogeneous and improved mechanical properties throughout the membrane.

Safety assessment of the substance chopped carbon fibres, from carbonised polyacrylonitrile, for use in food contact materials.

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids (CEP) assessed the safety of chopped carbon fibres, from carbonised polyacrylonitrile, as food contact material (FCM) substance No 1086, which is intended to be used as a filler for polyether ether ketone (PEEK) polymer at up to 40% w/w. The plastic is intended for repeated use in contact with all types of foods under all conditions of use. The chopped carbon fibres have a length of ■■■■■ and a diameter of ■■■■■, with no fragments lower than ■■■■■ in any dimension. They do not include a fraction of particles at the nanoscale and are fully embedded in the PEEK matrix, and therefore the fibres and any fragments are not expected to migrate. Based on the results of a battery of three genotoxicity tests, the Panel concluded that the substance does not raise a concern for genotoxicity. Therefore, the CEP Panel concluded that the substance chopped carbon fibres, from carbonised polyacrylonitrile, with a minimum carbon content of 95% (at sizes not at the nanoscale) does not raise a safety concern for the consumer if the substance is used as a filler at up to 40% w/w for PEEK plastic in contact with all food types and under all conditions of use.

Geometry effect of copper nanoparticles and nanowires on polyetheretherketone-matrix nanocomposites: Thermal conductivity, dynamic mechanical properties and wear resistance

Polyetheretherketone (PEEK)-matrix nanocomposites filled with copper nanowires (Cu NWs) and copper nanoparticles (Cu NPs) were prepared by hot compaction method. The effects of Cu NWs and Cu NPs on the thermal conductivity, dynamic mechanical performance, and tribological property of PEEK-matrix nanocomposites were investigated. Results indicate that Cu NPs and Cu NWs with different geometry exhibit different influences on the crystallization behavior, melting behavior, dynamic mechanical properties, and friction and wear behavior of PEEK matrix. Namely, Compared to Cu NPs, Cu NWs can more efficiently better dissipate heat and transfer stress at PEEK/nanofiller interface. Moreover, the friction and wear behavior of the PEEK-matrix nanocomposites is also related to the geometry of the Cu nanofillers to some extent. This is because Cu NPs can act as roll bearings to reduce friction; and Cu NWs with a high thermal conductivity can prevent softening of PEEK matrix and increase the wear resistance via well dissipating friction heat away from the sliding interface. In one word, the comprehensive properties of PEEK-matrix nanocomposites are closely related to the geometry effect of Cu NPs and Cu NWs, which could be of significance for revealing the relation between the micro morphology and the macro application of inorganic nanofillers.

Evaluation of PEEK-TiO2- SiO2 nanocomposite as biomedical implants with regard to in-vitro biocompatibility and material characterization

Polyether Ether Ketone (PEEK) exhibits superior mechanical and biological safety characteristics, and its biological inertness significantly restricts its applicability in biomedical applications. Recent researches included active ceramic particles to enhance biological activity and broaden the application range of bioactive composites in medical implants. During the current investigation, acrylic acid-functionalized ceramic TiO2 and SiO2 nanoparticles (NP) were used to reinforce the PEEK matrix. The PEEK/TiO2/SiO2 (PTS) nanocomposite was fabricated using plastic injection moulding process. Different functional groups and crystal plane orientations of the composite were found through FTIR and XRD. The morphological and elemental analysis were carried out using FESEM and the EDAX mapping technique. The thermal stability of the composite was investigated through TGA and DSC analysis. The mean diameter of the inhibition zone of PTS polymer composite is 18.125 mm and 16.375 mm against E. coli and B. subtilis, respectively, which is higher than that of the mean diameter of the inhibition zone of PEEK. In-vitro direct and indirect cytotoxicity studies were carried using the MG-63 cell line and found the cell viability as 94.30% and cytotoxicity as 5.70% on PTS nanocomposite. Cell adhesion study was carried out using MG-63 cell line on the composite surface. That demonstrated the good cell adherence and cell proliferation those were observed through SEM morphologies. Thus, the newly developed composite serves as a potential candidate in biomedical applications.

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.

Effect of Heat Treatment on the Properties of Polyetheretherketone and its Composite

Polyetheretherketone (PEEK) is a semicrystalline thermoplastic polymer with high chemical resistance, thermal stability and excellent mechanical properties. In the present work, neat PEEK and 3% bioactive glass/PEEK composites were annealed at various temperatures (100 °C, 200 °C and 300 °C) for (30 and 60) min and characterized with mechanical and density tests, differential scanning calorimetery and Fourier transform infrared spectroscopy. Results manifested bioactive glass powder enhanced the properties of the PEEK matrix. Thermal annealing at (200 and 300 °C) had a positive influence on the mechanical properties and density owing to increase in the level of crystallinity, whereas annealing at (100 °C) had not effect on the properties.

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.

Study the effect of Crystallization Factors on the Mechanical Properties of Semi - Crystalline Polymers for Transport Applications

Polyether ether ketone and which combined with carbon fiber by 20% and 30% as reinforcement which purchased from a company Tangyin Sanyou Engineering Plastic Co. Itd/China. the degree of crystallization An significant role in semi-crystalline thermoplastics is played by (e.g. toughness, stiffness and solvent resistance). Primary aim of this work is to use density, DSC and FTIR to Research into the various induced degrees of crystallinity in PEEK composites Strengthened with carbon fiber (CF). In this research, three sheets were used: virgin poly ether ether ketone (PEEK), (PEEK+20 percent carbon fiber), and (PEEK+30 percent carbon fiber). the samples’ mechanical and thermal properties produced ones were examined and compared in this study. The density test findings displayed a rise in crystallinity levels by (35.9, 54.4, 88.2) respectively, But a decrease in the degree of crystallinity when examining by DSC. The mechanical properties such as Tensile strength, Young’s module and impact strength It showed an improvement in properties with an increase in the percentage of reinforcement with CF. In addition, FTIR for pure PEEK, (PEEK+ 20 percent CF) and (PEEK+30 percent CF) is found to induce minor shafting in peaks by adding 30 percent of carbon fibers and does not cause new peaks to appear and this suggests that there is no chemical reaction between the fibers and the PEEK matrix.

Graphene reinforced polyether ether ketone nanocomposites for bone repair applications

To improve the performance of polyether ether ketone matrix (PEEK) in hard tissue repair and replacement applications, we fabricated graphene nanoplatelet (G) reinforced PEEK with different filler weight concentrations (0.1%–5%) through injection moulding. The mechanical properties, surface morphology, chemical composition and thermal stability of the composites have been characterized. The biocompatibility has been assessed in vitro and the bone repair function of the composite implants have been assessed in vivo using a rabbit mandibular bone defect model. Mechanical testing results suggest that the composite samples have compressive moduli similar to that of the natural bone. Although addition of G into PEEK does not significantly influence the composite tensile, flexural or compressive moduli, it can significantly enhance the ductility and toughness of the material. On the other hand, all G-reinforced PEEK implants demonstrated enhanced adhesion and differentiation of rat bone marrow stromal cells (BMSCs), with 5% G-PEEK showing the highest bioactivity among all samples. The in vivo osseointegration data further revealed that 5% G-PEEK has the best effect in promoting osseointegration and bone regeneration, in both early stage and late stage bone re-growth. Study shows that our G-reinforced PEEK-based implants provides a promising strategy for enhancing the performance of future regenerative bone implants.

Impact of Atmosphere on Recovered Carbon Fibers From Poly Ether Ether Ketone (PEEK) Based Composites During Thermoconversion

Carbon Fibers Reinforced Polymer composites (CFRP) are high added value materials used in many manufactured products. Especially in aeronautics, thermosetting resins tend to be replaced by heat-resistant thermoplastic polymers. The aim of the work is to evaluate suitable operating conditions of thermoconversion for the recovery of carbon fibers from Poly Ether Ether Ketone (PEEK)/carbon fibers composites. Micro and pilot scale tests have been performed in nitrogen, wet nitrogen, air, and wet air. Thermogravimetric analysis of PEEK/carbon fiber composites showed a moderate decomposition onset temperature of the composite at 515 °C and 510 °C in dry nitrogen and dry air respectively. The oxidative atmosphere did not significantly impact this temperature since the first mass loss was not atmosphere dependent. However, after the first PEEK degradation reaction, the nature of the atmosphere appeared as a great issue. Total mass loss was significantly improved with temperature (full oxidation of polymer and carbon fibers up to 800 °C) and with reaction time using air. Indeed, at pilot scale, the matrix was fully degraded in air atmosphere at 550 °C for 1 h while only 42% and 46% was reached in nitrogen and steam/nitrogen respectively. Comparison of thermogravimetric data between wet and dry atmospheres revealed that steam plays a thermal retardant role leading to some differences on the matrix degradation and on the surface morphology of the carbon fiber at pilot scale. Air treatments at pilot scale induced a reduction of fiber diameters (< − 3.7%) but the tensile strengths of recovered carbon fibers were preserved with an average retention of mechanical properties of 81%-85%. It has been concluded that recycling of PEEK/carbon composite required an oxidant to split up carbon fibers from the PEEK matrix.

Poly(etheretherketone)/Poly(ethersulfone) Blends with Phenolphthalein: Miscibility, Thermomechanical Properties, Crystallization and Morphology.

Polyetheretherketone (PEEK)/polyethersulfone (PES) blends are initially not miscible, except when the blends are prepared by solvent mixing. We propose a route to elaborate PEEK/PES blends with partial miscibility by melt mixing at 375 °C with phenolphthalein. The miscibility of blends has been examined using differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMTA). When adding phenolphthalein to PEEK/PES blends, the glass transitions are shifted inward as an indication of miscibility. We suggest that phenolphthalein acts as a compatibilizer by creating cardo side groups on PEEK and PES chains by nucleophilic substitution in the melted state, although this condensation reaction was reported only in the solvent until now. In addition, phenolphthalein acts as a plasticizer for PES by decreasing its glass transition. As a consequence, the PEEK phase is softened which favors the crystallization as the increase of crystalline rate. Due to aromatic moieties in phenolphthalein, the storage modulus of blends in the glassy region is kept identical to pure PEEK. The morphological analysis by SEM pictures displays nano- to microsized PES spherical domains in the PEEK matrix with improved PEEK/PES interfacial adhesion.