Crystallization Kinetics in High-Performance Polymers

Crystallisation kinetics in high-performance polymers underpins the development and application of materials such as polyetheretherketone (PEEK) and polyetherketoneketone (PEKK). These semi-crystalline thermoplastics derive their exceptional mechanical, thermal and chemical resistance from ordered microstructures formed through nucleation and growth processes. The rate and mode of crystallisation—whether under isothermal holds or non-isothermal cooling—govern lamellar thickness, spherulitic morphology and the balance between primary and secondary crystallisation. Tailoring these parameters is critical for additive manufacturing, composite fabrication and functionalisation routes. Recent advances combine calorimetric and microscopic techniques to resolve microstructural evolution at high cooling rates, while chemical modifications and processing strategies manipulate crystallisation temperature windows, nucleation density and chain mobility. The global significance spans aerospace components, hydrogen storage liners and high-temperature composites, where precise control of kinetics ensures repeatable properties and reliable performance under extreme conditions.

Research from Nature Portfolio

High-resolution studies using fast scanning calorimetry paired with in situ microscopy have mapped the evolution of PEEK microstructures under rapid thermal cycles akin to material extrusion. Detailed observations reveal that substrate temperature peaks promote the formation of thick lamellar stacks, while remelting events generate crystalline embryos that guide subsequent growth. Complementary efforts in thin-film PEEK demonstrate that quench crystallisation can yield self-assembled fibre-like crystals at the surface, enhancing ductility without compromising strength. This fibre-like morphology emerges during rapid cooling followed by controlled annealing, illustrating how unconventional crystal growth mechanisms can be harnessed to widen processing windows and improve fracture resistance.

Research from all publishers

Modelling efforts have extended to predict PEEK melting and crystallisation behaviour in additive manufacturing. A non-isothermal framework calibrated across wide cooling-rate regimes accurately forecasts melting kinetics, distinguishing simultaneous versus sequential melting of primary and secondary crystals and linking deposition parameters to crystalline degree. In compression-moulded and automated-tape-placed CF/PEKK composites, comparative studies show that processing routes influence void content and crystallinity development; rapid methods result in reduced spherulitic growth and lower mechanical performance, underscoring the need to align crystallisation time scales with fibre consolidation. Moreover, blocky bromination of PEKK preserves long sequences of unmodified segments, maintaining high crystallisability and melting temperatures while offering rapid crystallisation kinetics comparable to unfunctionalised polymers. These chemical modifications reveal a confinement-free pathway to tailor nucleation and growth temperatures without sacrificing key thermal properties.

Crystallization Kinetics in High-Performance Polymers publication trend

The graph below shows the total number of articles in crystallization kinetics in high-performance polymers across all publications each year (not limited to Nature Index journals).

Technical terms

Crystallisation kinetics: The rate and mechanism by which polymer chains arrange into ordered crystalline regions during cooling or isothermal holds.

Spherulite: A radial, spherical aggregate of lamellae that grows from a nucleation point, characteristic of semi-crystalline polymers.

Lamellae: Thin, plate-like crystalline layers formed by folded polymer chains in semi-crystalline structures.

Primary and secondary crystallisation: Primary refers to the initial nucleation and growth phase, while secondary involves further thickening and perfection of lamellae.

Fast scanning calorimetry (FSC): A technique that subjects samples to extremely high heating and cooling rates, enabling the study of rapid thermal transitions and kinetic phenomena.

References

1. Morphology analysis of PEEK 450G using scanning electron microscopy directly on fast scanning calorimetry chips. Scientific Reports (2024).
2. Enhanced Ductility of PEEK thin film with self-assembled fibre-like crystals. Scientific Reports (2018).
3. Modelling the Melting Kinetics of Polyetheretherketone Depending on Thermal History: Application to Additive Manufacturing. Polymers (2024).
4. Effect of crystallinity and morphology on the mechanical properties of CF/PEKK composites manufactured under compression moulding and automated tape placement. Materials Today Communications (2023).
5. Blocky bromination of poly(ether ketone ketone) as a means to preserve crystallizability and rapid crystallization kinetics. Polymer Chemistry (2024).