Polyaryletherketones (PAEKs) are high-performance semicrystalline polymers recognised for their remarkable thermal stability, chemical resistance, and mechanical strength. These properties make them suitable for applications across many sectors, including aerospace, automotive, and biomedical. Their crystallisation behaviour throughout the manufacturing process determines the performance of the final product. This work utilises the Self-Nucleation (SN) and Successive Self-Nucleation and Annealing (SSA) protocols to examine a range of polyetheretherketone (PEEK) - poly (ether diphenyl ether ketone) (PEDEK) copolymer variants, the impact of their molecular architecture, particularly comonomer ratios and branching, on the thermal behaviour and thermal domain regions of various polyaryletherketone (PAEKs) grades. The analysis revealed significant differences in self-nucleation region between the linear and branched variants, with a wider temperature spread in the linear PAEK grades including melt memory and self-seeding regions independent of the copolymer ratio. The SSA analysis allowed deconvolution of the fractionated melting peaks to provide semi-quantitative estimates of lamellar thickness distributions. A distinct bimodal thermal fractionation response was observed for the 65:35 composition, independently supported by broad asymmetric melting behaviour visible in standard DSC heating curves, and is discussed in terms of multiple plausible structural origins. A higher PEDEK content promotes the development of thinner lamellae in a greater proportion. These findings highlight the capability of SN and SSA to resolve crystalline heterogeneity in PEEK-PEDEK copolymers and to explain the effects of comonomer composition and molecular architecture on lamellar population distributions beyond the resolution of conventional DSC.

The crystallisation process of high-performance thermoplastic composites is complex, affecting properties such as strength and toughness. During thermoplastic composite manufacturing, such as over-moulding, the material undergoes a complex thermal history. Process optimisation requires a versatile description of material behaviour. Models to address this must predict crystallinity changes at arbitrary cooling cycles and the process's history dependence, with clear parameter identification. Differential Scanning Calorimetry (DSC) on polyether ether ketone (PEEK) showed discrepancies between dynamic and isothermal data in the crystallinity/crystallisation rate/temperature space, challenging conventional models. A fractional rate model, using the Caputo derivative, was developed to align both datasets. Two fractional kinetics model forms were proposed: one fitted data in the fractional space using Weibull distribution functions of crystallinity and temperature; the other used piecewise surface fit and interpolation. These models were tested against ramp dwell tests and predicted crystallinity with a 5 % error margin. This flexible approach is applicable to thermoplastics and their composites, in a manufacturing context for optimising processes such as over-moulding and additive manufacturing. Research data is included in "Veyrat Cruz-Guzman, Maria; Ivanov, Dmitry (2025), "Modelling of PEEK Crystallisation Kinetics Using Fractional Differential Equations", Mendeley Data, V1, doi: 10.17632/xxb 7rpm8fj.1"

We present a new polymer informatics framework that successfully predicts the glass transition temperature T g of polymers based on their chemical structure. The framework combines ideas from group additive properties (GAP) and quantitative structure-property relationship (QSPR) methods, where GAP (or group contributions) assumes that submonomer motifs contribute additively to T g, and QSPR links T g to the physicochemical properties of the structure through a set of molecular descriptors. By integrating these methodologies, our combined QSPR-GAP framework overcomes limitations inherent in using either method independently. We demonstrate its application on a data set of 146 linear homo- and copolymers of the poly(aryl ether ketone) (PAEK) family, achieving a median root mean square error of 8 K for T g, representing a significant improvement over standalone QSPR or GAP models. Moreover, using a genetic algorithm, we identify two molecular descriptors that predominantly drive T g predictions. The QSPR-GAP framework can be readily adapted to forecast other physical properties and activity (QSAR) or transferred to other polymer families, including conjugated and biopolymers.

The interfaces between thermoplastic (TP) over-moulded features and thermoplastic composite substrates are strongly affected by the process history and resulting crystallinity. However, there are no established tests to reliably examine these interfaces and the relation between process parameters and strength. To address this issue, we propose a new test, which adapts the ASTM 6415 Curved Beam Strength to explore the quality of the weld between neat TP (PEEK) and TP composites (PEEK/CF). The test optimisation was performed using Finite Element Analysis and aimed to deliver the right failure mode in the right location - the interface. This is challenging as the contrast in material properties creates the risk of premature polymer fracture or the failure plane shifting to the bulk of the composite. The study departed from the parametric exploration of material thicknesses and identified high hydrostatic stresses in the TP for the optimal thickness distribution found. Further modifications of the sample configuration, consisting of terminating the length of the TP layer, yielded a "corner with a hat" configuration. This new configuration inhibited the hydrostatic stresses while maintaining the maximum through-thickness stresses at the interface but resulted in the most probable failure mode becoming the sigma(11) fibre failure in the arms. Both the bi-material and 'hat' configurations can be a realistic and straightforward design to explore a range of processing conditions.

Lack of repeatability and undetected print defects during printing in Material Extrusion (MEX), can limit the uptake of the technology for manufacturing. Many of the conventional polymer manufacturing processes such as injection moulding and extrusion rely on sensors and in-situ process monitoring tools to control, provide feedback and adjust parameters during the process. MEX requires tight control of both the heating and cooling of the polymer in order to achieve high performance parts. For this reason, monitoring the layer temperature is of greater importance, such that (1) it allows the validation of thermal models; (2) can inform on the presence of defects in printing and potentially reduce their presence through a closed loop monitoring system; and (3) helps maintain control over important parameters such as viscosity and crystallinity. Although the literature presents often validated thermal models, the details of how these measurements are obtained are rarely presented. This study discusses in detail the challenges of measuring the layer temperature during printing of pure and Carbon fibre (Cf) based Polyaryletherketone (PAEK) polymers using an Infrared (IR) camera and proposes two data processing methods as well as a discussion of results with an optimum method recommended.

Mechanical properties in material extrusion (MEX) processes are influenced by the printing conditions and the cooling profile of extruded polymer. During cooling, the polymer transitions from a viscoelastic fluid to a "rubber" like state and ends as a glassy solid. The time taken to transition through each region is unique to individual polymers and it is linked to the melt rheology, thus indirectly affecting the layer to layer bond strength. By combining several thermal and thermomechanical methods, dynamic mechanical analysis (DMA), rotational rheometry (RR), differential scanning calorimetry (DSC) and infrared (IR) thermography, this paper defines the time a semicrystalline polymer takes to pass through each thermal transition region under a specific cooling regime. From the results, Victrex PAEK AM 200 spent 0.1 seconds in complete melt (terminal region), before beginning to solidify (rubbery region), taking a total of 0.95 seconds to reach complete solidification (glassy region). Defining these transition regions allows us to control the printing parameters for optimum interface bond strength, as the time spent in the terminal and rubbery regions governs interlayer diffusion. This is the first study to approach the combined melt rheology and solidification profile of a high-performance polymer in order to understand critical points within the printing process and identify ways of controlling them, providing quantitative values for the onset and endset of solidification of extruded polymer in MEX.

Achieving good dispersion of graphene (GNP), in polyetheretherketone (PEEK), is challenging due to the high melt viscosity, solvent resistance and processing temperature of PEEK. In addition, certain manufacturing processes tend to enhance the anisotropy due to GNP orientation within the structure. This study investigated the fabrication of nanocomposite parts through hot compression moulding (C-MOULD) and powder bed fusion (PBF) processes, using powder with GNPs fused to the surface of polymeric particles, through a process called mechanofusion. The method applies mechanical forces of compression, shear and impact to generate a mechanical bond between materials, in this case, O2 functionalised GNP and a developmental polyaryletherketones (PAEK) grade powder. The novelty of this work is in the combination of processes used for manufacturing (material preparation and actual manufacturing processes), which are scalable and efficient in comparison with existing methods (such as solvent mixing or melt-compounding). The mechanofusion GNP-PAEK composite powders were successfully printed for the first time using the EOS P800 system with notable improvements in electrical and mechanical properties. This study highlights that the mechanofusion process could be used as an efficient process for making multifunctional nanocomposite materials and this can be combined with additive manufacturing (AM) processes to produce complex components.

Driven by the need to make high temperature thermoplastic polymers more processable and expand the range of applications, this study reports on the properties of a novel PAEK material developed by Victrex (Thornton Cleveleys, UK) which is capable of undergoing crosslinking or crystallisation, two competing processes that can be adapted via specific processing temperature and time conditions. The uniqueness of this PAEK material resides in its manufacturing approach, where the crosslinkers are incorporated during the polymerisation process, and its distinct properties, including a controllable viscosity that can be tuned from low to high to allow its application in complex manufacturing processes, such as thermoplastic carbon fibre manufacturing.

In general, the mechanical properties of parts manufactured by material extrusion (MEX) process depend upon the interlayer bonding strength. In the case of high temperature polymers such as polyaryletherketones (PAEKs), the printing parameters, in particular the temperatures applied within the process, become a critical factor. The printing-structure-property relationship for these semicrystalline high temperature polymers is complex and not fully understood, often relying on statistical analysis to identify the trends between the processing parameters and the mechanical properties, while missing the microstructural interpretation in between. By controlling the temperature settings and the printing speeds, PAEK parts can be printed in an amorphous state or semicrystalline state. In both cases, molecular chain diffusion at the interface is crucial for achieving good mechanical properties. Using temperature profiles directly determined by the printing parameters, the current work investigates the formation of mobile amorphous fraction (MAF) during printing and its correlation with the correspondent Z tensile strengths. MAF is defined as the fraction of amorphous phase with a higher mobility, which is beneficial to chain d iffusion. The conditions required to generate MAF is explored by fast scanning calorimetry (FSC). The MAF-Z strength correlation is aiming to provide a deeper understanding of the complete processing-structure-property relationships of the MEX process for semicrystalline polymers. It may also provide a microstructural explanation on why slow crystallising PAEK grades are desirable in the MEX process. This study is concentrated on PAEKs which have been printed in an amorphous state to avoid the effect of crystallisation kinetics.

New Polyaryletherketones with lower melting points (LMPAEK) compared to PEEK were first introduced to the CAMX technical community in 2018. LMPAEK polymer is a specific form of polyetheretherketone (PEEK) and polyetherdiphenyletherketone (PEDEK) copolymer, optimized for composites and additive manufacturing processes, where the ratio of PEEK to PEDEK in the copolymer is proprietary within a range of 65:35 to 95:5 molarity. For the reader's convenience, the authors will refer to this copolymer as LMPAEK throughout this paper. LMPAEK products have been optimized and commercialized for composites and additive manufacturing. To be specific and not confuse these variations, we will refer to them as LMPAEK for composites, LMPAEK for additive manufacturing, or by the grade names AE250 or AM200. The benefits of LMPAEK in Automated Tape Laying (ATL) and Automated Fiber Placement (AFP) composites manufacturing include faster production times, wider processing tolerance, and enhanced interlayer adhesion for stronger parts. These benefits have since been shown to also apply to additive manufacturing and additive manufacturing composites. This paper conducts a review of over ten scientific papers and patent literature, and over 40 technical presentations and posters published in the last five years, summarizing what is known about the crystallization kinetics and rheological properties of LMPAEK, how its end -use performance compares to alternatives such as PEEK and PEKK, and identifies future work required to expand our understanding of LMPAEK in additive manufacturing and additive manufacturing composites.

This study presents a new family of backbone modified polyetheretherketone (PEEK) grades in the powder bed fusion (PBF) process, coded as PAEK1 and PAEK2, with the same chemical structure but different molecular weights. By incorporating polyetherbiphenyletherketone (PEDEK) comonomer, the optimal powder bed temperature of the new grades could be reduced to 290 degrees C, approximately 40 degrees C lower than that of PEEK. The underlying crystallisation kinetics in the PBF process was investigated by replicating the in-process temperature profiles using a flash differential scanning calorimetry (DSC) machine. This method enabled monitoring of the development of crystallisation during the process and at different deposition thicknesses. The results confirmed that the PAEK2 grade with a higher molecular weight is slower crystallising. A significant part of the crystallisation of PAEK2 was found taking place in the later stage of the printing process, i.e. the free cooling stage. This leads to a better particle coalescence and enhanced elongation, a feature previously difficult to obtain in the PBF process. The PBF PAEK2 tensile bars achieved a significant increase in mechanical performance with an outstanding 13% in elongation, reaching its yielding point. The data supports that PAEK2 is the first high temperature polymer grade in the PBF process to match its bulk mechanical properties while maintaining a high level of crystallinity in the printed parts.

Fusion bonding theory is applied to the additive manufacturing process to predict the strength developed across the interface between the deposited layers in material extrusion based large-scale additive manufacturing. Relaxation times were determined through rheology investigations of the neat polymers and were extrapolated across the entire process temperature range to estimate the required welding times for optimal bond formation. For the calculation of bond formation during cooling from the melt, the semicrystalline polyaryletherketone is considered amorphous until the onset of crystallization which is determined by recreating the process thermal history in DSC measurements. A significant improvement in bond development during additive manufacturing is achieved through the use of specifically designed polymers with slower crystallization kinetics. Both in small-scale additive manufacturing, achieving full bonding, and in large-scale additive manufacturing, they achieve significantly higher interlaminar strength than the reference material, validated by three-point bending. A very good match between the estimated degree of bonding and the tested strength of upright printed specimens in three-point bending was found. While the fusion bonding model calculates a degree of bonding of 42.07%, mechanical testing showed 42.54% of the bulk flexural strength. The study outlines a procedure to evaluate materials for additive manufacturing by material extrusion based on small material samples to shorten and improve the process development. (c) 2020 The Authors. Polymer International published by John Wiley & Sons Ltd on behalf of Society of Industrial Chemistry

Poly aryl ether ketone (PAEK) polymers are gaining interest in 3D printing for their good mechanical properties and high service temperatures. The aim of this study was to compare the crystallisation kinetics, morphology, and mechanical properties of two different PAEK polymers used in fused filament fabrication (FFF), i.e. the fast crystallising PEEK151 (poly ether ether ketone) grade originally designed for injection moulding and the slow crystallising AM 200 grade tailored specifically for FFF. The crystallisation kinetics of both grades were examined across a wide temperature range. A method to select annealing temperatures and annealing times based on the intrinsic crystallisation behaviour of each polymer was proposed. The dual-Avrami model highlighted a different crystallite growth for AM 200 in comparison with PEEK151 with a higher rate of secondary crystallisation. Lamellar thicknesses were measured by SAXS and calculated via the Thomson-Gibbs equation. The lamellar thicknesses of primary and secondary crystallisation for AM 200 showed a stronger temperature dependence with steeper slopes when increasing the isothermal temperature. The benefit of using a slow crystallising PAEK polymer over the conventional fast crystallising grades is evidenced by the improvement in Z strength which enhances the overall isotropy of printed parts.

ADVERTISEMENT RETURN TO ISSUEPREVNoteNEXTStructural Analysis of Linear PEEK via MALDI-TOF Mass SpectrometryJonathan M. Behrendt†, Michael Benstead†‡, Adam Chaplin‡, Brian Wilson‡, and Michael L. Turner*†View Author Information† School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, U.K.‡ Victrex Technology Centre, Hillhouse International, Thorton-Cleveleys, Lancashire FY5 4QD, U.K.E-mail [email protected]; Tel 0161 275 4625.Cite this: Macromolecules 2011, 44, 22, 9054–9056Publication Date (Web):October 21, 2011Publication History Received11 July 2011Revised29 September 2011Published online21 October 2011Published inissue 22 November 2011https://pubs.acs.org/doi/10.1021/ma201580dhttps://doi.org/10.1021/ma201580dbrief-reportACS PublicationsCopyright © 2011 American Chemical SocietyRequest reuse permissionsArticle Views1177Altmetric-Citations5LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-AlertscloseSupporting Info (1)»Supporting Information Supporting Information SUBJECTS:Mass spectrometry,Oligomers,Polymer solutions,Polymers,Solvents Get e-Alerts