Slow Crack Growth in Post-Consumer Recycled High-Density Polyethylene

An experimental study of slow crack growth behavior ofpost-consumer recycled high-density polyethylene blended with virginhigh-density polyethylene copolymer has been done. The study has beenperformed under constant load and in baths of distilled water at 40, 60,80°C. The specimen used is notched with sidegrooves. The test results of crack growth have been analyzed usinglinear fracture mechanics and the rate process theory. The results showthat the resistance to crack growth increases monotonically with theamount of virgin material. The activation energy of the slow crackpropagation is independent of the blend composition and agrees with theenergy required by a known mechanism of pull out of tie molecules fromcrystalline lamellae.