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This article reports on optimization of natural zeolite as filler in polypropylene composite. Effects of zeolite loading and surface treatment were performed in this work. Prior to mixing process, zeolite was ground by ring mill into a powder form. The composites were prepared using Thermo Haake Polydrive internal mixer and then compression molded according to standard test specimen. Tensile and impact tests were performed to characterize the mechanical properties of untreated and treated composites. The obtained experimental values of Young’s modulus were then related to the theoretical predictions using a Halpin—Tsai equation. The theoretical prediction resulted in greater values of tensile modulus compared to the experimental values. A morphological study was done on the tensile fractured surface using a scanning electron microscopy. A Fourier transform infrared spectra analysis was performed on the composites to study the interaction between the polypropylene and functional group of stearic acid and vinyl silane. It was found that the tensile strength, elongation at break, and impact strength decreased but the Young’s modulus increased with increasing zeolite content. The addition of coupling agents was proved to enhance the mechanical properties of zeolite/polypropylene composite. However, stearic acid has little effect in improving the composite mechanical properties in comparison with vinyl silane.

In this research, organozeolite filled ethylene vinyl acetate (EVA) composites were prepared in a melt-mixing process and followed by compression molding using hot press machine according to standard test specimen. Prior to mixing process, zeolite was modified via cationic exchange of alkylammonium ions. The effect of zeolite or organozeolite loading from 5 up to 25 volume percentages on the properties of EVA/zeolite composites was evaluated. A combination of Fourier Transform Infrared Radiation (FTIR) and scanning electron microscopy (SEM) coupled with energy dispersive X-ray (EDX) analysis were done to characterize the resultant organoclay. Tensile test was performed in order to study the mechanical properties of the composites. EVA filled with organozeolite showed better tensile properties compared to EVA filled with unmodified zeolite, which might be an indication of enhanced dispersion of organophilic clay in the composites. Meanwhile, morphological study using SEM revealed the fibrillation effect of organozeolite. Besides, thermal properties of the composites were also characterized by using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The results showed that the application of the cation exchange treatment increases both decomposition and melting temperature of EVA/zeolite composites.

Interfacial interaction in zeolite filled polymer composites was investigated in this study. Two types of polymer which are polypropylene (PP) and ethylene vinyl acetate (EVA) were used as matrix in the preparation of the composites. Moreover, different modifications of zeolite filled polymer composites such as zeolite surface treatment with vinyl silane and alkylammonium and also chemical crosslinking were done to improve the interfacial adhesion between zeolite and polymer matrix. The zeolite filled polymer composites were homogenized using Thermo Haake Polydrive internal mixer and then compression molded into sheets according to standard test specimen. Uniaxial tensile test was performed in order to evaluate the mechanical behavior of the composites. The obtained experimental data for ultimate stress was correlated with Pukanszky theoretical model. The experimental results for all systems of zeolite filled polymer composites showed a good fit to the Pukanszky model. Interfacial interaction for each system of zeolite filled polymer composites was theoretically evaluated by determining the parameter B through this model. The value of parameter B for all zeolite filled polymer composite systems differs significantly from one another thus suggesting the applicability of this Pukanszky model in characterizing the filler-matrix interfacial adhesion.

Uncrosslinked and chemically crosslinked ethylene‐vinyl acetate copolymers (EVAs) with 5–25 volume percentages of zeolite were prepared in a melt‐mixing process and then compression‐molded on a hot‐press machine according to standard test specifications. The mechanical properties measured by tensile test showed a reduction in tensile strength and elongation at break with increasing zeolite content. However, an increasing trend was observed for tensile modulus with addition of zeolite. Experimental results for ultimate stress were compared with those from Pukanszky equation. The experimental data showed a good fit to the Pukanszky model. The improvement in the interfacial interaction for crosslinked composites was also confirmed by this model. Morphological changes of EVA/zeolite composites were analyzed by scanning electron microscopy (SEM). The fractured surface of the composites indicated more complex morphology at higher zeolite loading. The influence of crosslinking induced by 2 wt% of dicumyl peroxide on the properties of EVA/zeolite composites was also investigated. The crosslinked composites showed better tensile properties than the uncrosslinked ones, a result which might be an indication of enhanced interaction between the EVA and zeolite. Density measurements, gel content determinations, and Fourier transform infrared analyses were also performed to evaluate the crosslink content of the composites. The changes in the properties of chemically crosslinked EVA/zeolite composites were observed. Meanwhile, SEM micrographs of the crosslinked EVA/zeolite composites showed better interfacial strength between zeolite and the EVA matrix as compared to that of the uncrosslinked composites. J. VINYL ADDIT. TECHNOL., 2012. © 2012 Society of Plastics Engineers