Viscoelastic Properties of Polypropylene Reinforced with Mica in 𝑇𝛼 and 𝑇𝛼𝑐 Transition Zones

Abstract

The viscoelastic properties of mica-reinforced polypropylene (PP) was studied in temperature range between −30°C and 120°C. WLF equation permits determining the free volume fraction in 𝛼 and 𝛼𝑐 transitions regions. It was shown that the value of this parameter is lower for 𝛼𝑐 transition, indicating that the free volume and thermal expansion of 𝛼 region is more than that of 𝛼𝑐 region. At a 40% loading level, it was shown that the storage and loss modulus of mica-filled PP increases dramatically (in comparison with the pure polypropylene). The relative modulus does not change significantly at glassy state but it increases for the temperature higher than 𝑇𝑔. It was also shown that mica does not affect the glass transition temperature but results in an increase in 𝛼𝑐 transition.