Abstract
The dynamic viscoelastic behaviour of aluminium silicate filled closed-cell microcellular ethylene-octene copolymer vulcanizates has been studied at four frequencies of 3.5,11,35 and 110 Hz and at temperature varying from −100°C to + 100°C. A plot of log of storage modulus bears a linear relationship with the log of density for both solid and closed cell microcellular vulcanizates. The relative storage modulus decreases with decrease in relative density. It is also observed that both storage modulus and tan δ are temperature and frequency dependent. The storage modulus results are superposed to form master curves of the modulus vs. log temperature-reduced frequency, using shift factors calculated by the Arrhenius equation. Strain dependent isothermal dynamic mechanical analysis was performed for double strain amplitude (DSA) varying from 0.083% to 5%. The effects of blowing agent loading on storage modulus (E’) and loss tangent (tan δ) were also studied. Cole-Cole plots of microcellular vulcanizates show a circular arc relationship with density. Plots of tan δ against E’ were found to exhibit a linear relationship, the slope of which decreases with the increase in blowing agent loading. Empirical relationship between tan δ and E’ as well as Hysteresis and strain work have been found to be linear.