An investigation of the effects of a silicalite type zeolite on PDMS-composites

The aim of this paper was to investigate the effect of a silicalite type zeolite on PDMS-zeolite composites. The obtained results show that the introduction of a silicalite type zeolite into polysiloxane matrices results in a change of the equilibrium degree of swelling of the composites in toluene, their hardness and their thermal stability. With increasing amount of zeolite, the time required to achieve the equilibrium degree of swelling (DSe) is reduced, the DSe decreases and the hardness increases. Two ranges of the effect of the zeolite concentration on the composite characteristics were noted. At zeolite concentrations up to about 12 % there are significant changes of the DSe and the hardness with zeolite concentration, while these effects are considerably less pronounced at higher concentrations. The results obtained show that the silicalite type zeolite acts as a reinforcing filler. We believe that with increasing zeolite concentration in the composite the total number of established polymer-zeolite interactions increases, as does the spatial irregularity of the polymer network, but that the density of the interactions decreases. This could be the most probably explanation for the changes in the characteristics of the composite with changing zeolite concentration.