Understanding the fracture toughness of gadolinium- and lead-containing plexiglass

Toughened gadolinium- and lead-containing plexiglasses (GLCPs) were prepared via copolymerization using ethoxylated bisphenol A dimethacrylate (BPAxEODMA, x = 2, 4, 10) as comonomer and network regulator. As-obtained modified GLCPs possessed highly improved toughness, with satisfactory shielding and optical performances. The fracture mechanism was studied then in terms of fracture surface analyses. The results disclosed that both the impact strength and the fracture toughness (K-IC) increased with the increase of fatty chain lengths or concentrations of BPAxEODMA, and the surface morphology strongly depended on the fracture processes. A morphological evolution, from mirror region to haze one, and finally to hackle region, was visible on all GLCP samples. However, the morphological characteristics of each region, such as size and roughness as well as the appearance of ring-banded structure and firework-like pattern, were completely different. The crack propagation mechanism was utilized to correlate the fracture surface morphology with fracture process of the samples. The relationship between K-IC of the samples and their crosslinking networks was well-built in this way. This work proposes valuable information around fabricating the anti-radiation GLCPs with high and tailorable mechanical performance.