A cure-kinetics-based framework linking residual stress evolution to strength degradation in carbon/cyanate ester laminates

Understanding the interplay between cure history and residual stress is critical for optimizing the processing and performance of high-temperature cyanate ester-based carbon fiber reinforced polymers (CFRPs). However, existing studies have been focused on single curing conditions, with only limited quantitative understanding of how variations in cure history govern the residual stress accumulation and the resulting changes in mechanical properties. Here, a multiscale framework is established that integrates cure kinetics, rheological characterization, and thermo-mechanical property development to elucidate how curing history governs the mechanical reliability of CFRP laminates. Experimental validation using warpage and unidirectional tensile tests reveals a direct correlation between the matrix residual stress and the transverse (90°) tensile strength. In particular, post-curing at 260 °C leads to a 32.6% increase in matrix tensile residual stress and a corresponding 36.8% reduction in transverse strength. These results confirm that variations in cure history, through their influence on residual stress development, critically govern the mechanical properties of cyanate ester-based CFRPs. The presented framework provides a quantitative pathway for rational cure-cycle design and performance prediction of high-temperature polymer composites.