Effect of rubber particle size on the impact tensile fracture behavior of MBS resin with a bimodal particle size distribution

We performed impact tensile fracture experiments on methylmethacrylate–butadiene–styrene (MBS) resin with small and large particles in a bimodal size distribution, and examined the effects of particle size on fracture behavior by fixing the total rubber content (28 wt%) and the small particle size (about 140 nm), and varying the size of large particles (about 490 nm or 670 nm). Dynamic load P¢ and displacement d¢ of singleedge- cracked specimens were measured using a Piezo sensor and a high-speed extensometer, respectively. A P¢–d¢ diagram was used to determine external work Uex applied to the specimen, elastic energy Ee stored in the specimen, and fracture energy Ef for creating a new fracture surface As. Energy release rate was then estimated using Gf = Ef/As. Values of Gf were correlated with fracture loads and mean crack velocity vm determined from load and time relationships. We then examined the effect of particle size on Gf and vm, and results indicated that particle size plays an important role in changing the values of Gf and vm.