Speaker
Description
Strain-induced crystallization (SIC) is a key mechanism governing the performance of many elastomeric systems, influencing their mechanical reinforcement, thermal response, fatigue resistance, and functional properties. In this work, we present recent results obtained at the BL11-NCD-SWEET beamline of the ALBA Synchrotron using in situ wide-angle X-ray scattering (WAXS) during thermomechanical loading of two classes of sustainable elastomers.
The first study investigates thermoplastic polyurethaneurea elastomers designed for elastocaloric cooling applications. Simultaneous structural and thermal characterization revealed that amorphous chain orientation develops prior to crystallization and contributes significantly to the elastocaloric response. Above a critical orientation threshold, strain-induced crystallization occurs and provides an additional entropy-driven contribution through latent heat effects, leading to enhanced cooling performance and reversibility.
The second study focuses on natural rubber composites containing recycled ground tire rubber (GTR). In situ synchrotron WAXS demonstrates that GTR particles promote SIC by acting as nucleating sites, reducing the onset strain for crystallization and increasing mechanical reinforcement. Under combined mechanical and thermal loading, the enhanced crystallization stability delays failure and improves resistance to crack propagation despite the presence of recycled inclusions.
Together, these studies highlight the unique capability of synchrotron radiation to quantify molecular orientation, crystallization kinetics, and structural stability under realistic operating conditions. The results demonstrate how SIC can be exploited as a microstructural design principle to develop high-performance and sustainable elastomeric materials for energy-efficient cooling technologies and circular-economy rubber applications.