We studied the crystallization of ZSM-5 zeolite by hydrothermal treatment in the absence of organic structure directing agents (OSDA) at 170, 180, and 190 °C, using Perlite as a natural source of SiO2 and Al2O3. Experimental data were fitted by nonlinear regression following the Kolmogorov–Johnson–Mehl–Avrami’s nucleation/crystallization model in order to calculate kinetic constants (k), induction periods (t 0), and Avrami’s exponents (n). A constant value of n = 3.4 implicates the same mechanism in the studied range of temperature with a contribution from three dimensions to crystal growth and a nucleation that may include both sporadic and instantaneous mechanisms. Different stages of crystallization were clearly differentiated, and specific kinetics parameters were calculated. Compared with previously reported preparations, we found that the synthesis from Expanded Perlite is a promising alternative as it not only avoids the use of OSDA but also consumes less energy. Finally, a five steps crystallization mechanism has been proposed.

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1Summary: Preparation and morphology of high density polyethylene (HDPE)/ polyamide 6 (PA 6)/modified clay nanocomposites were studied. The ability of PA 6 in dispersing clays was used to prepare modified delaminated clays, which were then mixed with HDPE. Mixing was performed using melt processing in a torque rheometer equipped with roller rotors. After etching the materials with boiling toluene and formic acid at room temperature, the morphology was examined by SEM analyses, showing that the PA 6 formed the continuous phase and HDPE the dispersed phase. X-ray diffraction patterns show that the (001) peak of the clay is dramatically decreased and shifted to lower angles, indicating that intercalated/exfoliated nanocomposites are obtained. TEM analyses confirmed the typical structure of exfoliated nanocomposites. A scheme for the mechanism of exfoliation and/or intercalation of these HDPE /PA 6/ /organoclay nanocomposites is proposed.