The effect of calcium sulfate whiskers on the interlaminar and interfacial properties of CF/PMMA composites

This study improves weak interlaminar properties of carbon fiber-reinforced PMMA (CF/PMMA) laminates by incorporating calcium sulfate whisker (CSW)/PMMA interleaf films. Compared to direct whisker sprinkling, the film method enables uniform CSW dispersion and stabilization in the matrix. ILSS and IFSS tests revealed that 6 wt% CSW content optimized performance: ILSS reached 51.8 MPa (46.9% increase vs 35.3 MPa control) and IFSS achieved 40.2 MPa (83.1% increase vs 21.9 MPa control). Excessive CSW (>6 wt%) caused agglomeration, reducing ILSS and IFSS—particularly IFSS due to interfacial defects. Microscopic analysis demonstrated that CSW enhances interlaminar strength through crack deflection, pinning, matrix pull-out, and fracture mechanisms, while improving interfacial adhesion via mechanical anchoring with carbon fibers. The film-introduction strategy effectively enhances the interlaminar shear strength and overall quality stability of CFRP laminates, while establishing a research foundation for interfacial optimization in CSW-reinforced composites.