Microstructural control of fatigue-crack growth in a brittle,two-phase polymer

Fatigue-crack propagation in a brittle, two-phase polymer important in bioengineering applications has been studied. It was found that the polymeric microstructure, although based on PMMA, enhances the fatigue-crack growth resistance of the composite polymer, in comparison with pure PMMA. This enhanced behaviour derives from several micromechanisms, i.e. (1) crack front pinning by constituent particles, (2) a reduction of the intrinsic PMMA crack growth rate within the partially polymerized MMA matrix, and (3) crack-tip wandering and energy absorption through microcrack nucleation at matrix voids lying within the path of the crack.