Two compounds prepared from a commercial carbon black masterbatch were compression molded to vulcanized plates. Strip samples from the plates were degraded in hot air oven at different temperatures and after that evaluated by dynamic mechanical analysis (DMA) using two methods: (1) comparison of DMA values at 30°C, and (2) comparison of DMA curves from room temperature to 250°C. Method 1: The absolute value of complex tensile modulus  at 30°C for our samples increases with increasing temperature of previous degradation in oven. The loss factor (tan d) at 30°C reveals influence of stabilization level on degradation of our compounds. Method 2: DMA of all our samples shows unexpected continuous decrease of modulus  with increasing temperature in DMA; for sample degraded at 180°C also brittle fracture of degraded surface layers is apparent; values of ratio tan(d) to  are very sensitive to degradation and stabilization level of samples.

dynamic mechanical analysis, vulcanized rubber, thermal degradation, cross-linking, viscoelasticity.