Dynamic Viscoelastic Properties of Zeolite/Polycarbonate Resin Composite Materials

Effects of zeolite on mechanical and thermal properties of composite materials in which matrix polymer is polycarbonate (PC) have been investigated using a dynamic viscoelastic method and thermogravimetry. The clinoptilolite-type zeolite powder was mixed with the PC polymer of number average molecular weight (Mn) of 24000 at various concentrations for preparing the composites desired. In the composite containing 3wt% zeolite powder, the matrix PC polymer reduced its Mn down to the value of 13000 after the mixing procedure at 280°C, accompanying with decreasing the αa absorption temperature of the composite loss modulus spectra from 158°C to 152°C and with shifting the onset of decrease in the storage moduli to lower temperaature. However, the activation energy of the glass transition in the composite was independent of the changes in Mn of PC, probably due to the polydispersity of PC molecules by the preseuce of zeolite materials. On the other hand, the activation energy of the PC decomposition decreased proportionally to the value of Mn; this comes from the catalystic effect of acidic zeolite to the decomposition reaction at the mixing temperature. It will be required for the zeolite powder with the surface treatment by suitable coupling agents when utilized as a composite filler to prevent from the decomposition of matrix polymer.