Failure Mechanisms in PMMA/ATH Acrylic Casting Dispersion

Abstract

Acrylic casting dispersion is used to fabricate particulate composites such as poly-methyl methacrylate (PMMA) filled with a fine dispersion alumina trihydrate (ATH). This composite is subjected to severe temperature variations during in-service conditions, giving rise to high thermal stresses which lead to failure by cracking. The influence of the interfacial bond strength between a particle and the matrix on the failure mechanism of acrylic casting dispersion has been investigated using in situ observations during tensile and compressive loadings. Experiments show that the failure in pure tension occurs differently than in flexure loading where the failure process is believed to be more complex. During tensile loading, it is observed that macroscopic fracture is initiated in the clusters of the reinforcing particles because of the strong interfacial bonding strength between the filler particles and matrix. For weak interfacial bond strength, the macroscopic fracture is initiated by separation of filler agglomerates from the matrix.