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Keywords:

  • silicone rubber;
  • modified nano CaCO3;
  • photo oxidation;
  • mechanical property

Abstract

Photo-oxidative degradation of treated and untreated nano CaCO3: silicone rubber composite was studied under accelerated UV irradiation (≥290 nm) at different time intervals. Prolonged exposure to UV leads to a progressive decrease in mechanical and physical properties along with the change in behavior of filler-matrix interaction. This was due to decrease in cross-linking density with increase in mobility of rubber chains. Meanwhile, synthesized nano CaCO3 was modified with stearic acid for uniform dispersion in rubber matrix. The increase in carbonyl (>CO), hydroxyl ([BOND]OH), CO2, and alkene functional groups on the UV exposed surface of treated and untreated nano CaCO3: silicone rubber composites at different time intervals was studied using Fourier transform infrared (FTIR) spectroscopy. The change in morphological behavior of filler-matrix interaction after UV exposure was studied using SEM. Overall, the study showed that the treated nano CaCO3: silicone composites were affected more by UV exposure than untreated nano CaCO3: silicone composites and pristine composite after UV exposure. This effect was due to peeling of stearic acid from the surface of CaCO3, which makes the rubber chains slippery and thus separation of filler and rubber chains takes place with initiation of fast-degradation. Copyright © 2011 John Wiley & Sons, Ltd.