In the present study, untreated and silver exchanged natural zeolite–polypropylene (PP) composites were prepared and characterized
by means of different techniques (TGA, DSC, mechanical tests, density measurements, optical microscopy and colorometer).
The effects of zeolite loading and silver concentration on the composite properties were investigated. The thermal
characterization studies showed that the addition of the zeolite increased the crystallinity of the composites acting as a nucleating
agent in PP crystallization and retarded the degradation of PP. At low silver concentrations, the zeolite behaved as a decelerating
agent in PP degradation, however at higher silver concentrations, the composites degraded at a faster rate than pure PP. The
experimental densities of the composites were found to be lower than the theoretical densities. When the tensile tested samples
are considered, the densities were even lower indicating porous structure of the films. From the optical micrographs of the tensile
tested films, it was clearly seen that the stretching along the machine direction caused hole formation around the particles. The
optimum conditions obtained in this study for the PP–silver zeolite composite film production are in the range of 2–4 wt% zeolite
treated with 4.36 mg Ag+/g zeolite. At higher zeolite loadings, the film becomes brittle and at higher Ag+ concentrations, the film
produced was discolored.
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