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Abstract. The copolymers of ethylene and 1-hexene were prepared with half-metallocene titanium complex ([t-BuNSiMe2Flu]TiMe2) and modified methylaluminoxane (MMAO). The initial concentrations of 1-hexene were varied to investigate how the different amounts of comonomer affect on the catalytic activity of copolymerization system and microstructure of the copolymers. It has been found that this catalytic system was not active for hexene polymerization, however, it can be active when ethylene was introduced to perform ethylene-hexene copolymerization. As comonomer, 1-hexene provides positive comonomer effect on the system although very high concentration of 1-hexene was introduced. However, the microstructures of the obtained copolymers, which were examined by 13 C-NMR need to be improved because with highly alternating sequence distribution of comonomer causing them losing some essential specific thermal properties.

This work investigated the use of waste tire as a source of carbon in preparation of carbon-based catalysts for applying in ethanol dehydration. The pyrolysis of waste tire was performed to obtain the solid carbon, and then it was treated with two different acids including HCl and HNO3 prior to the activation process with different temperatures to gain suitable carbon catalysts. All carbon catalysts were characterized using nitrogen physisorption, XRD, FTIR, and acid-base titration. The catalysts were tested for catalytic ethanol dehydration in a micropacked-bed reactor under the temperature range from 200°C to 400°C. It revealed that the ethanol conversion increased with increasing the reaction temperature for all catalysts. The carbon catalyst treated with HCl and calcined at 420°C (AC_H420) exhibited the highest ethanol conversion of 36.2% at 400°C having ethylene and diethyl ether selectivity of 65.9 and 33.5%, respectively. The high activity of this catalyst can be attributed to the high acid density at the surface (18.5 μmol/m2), which was significantly higher than those of most other catalysts (less than 8.0 μmol/m2).

Two commercial nanoclays were used here as catalytic fillers for production of polyethylene (PE) and linear low-density polyethylene (LLDPE) nanocomposites viain situpolymerization with zirconocene/MAO catalyst. It was found that both types of nanoclays designated as clay A and clay B can improve thermal stability to the host polymers as observed from a thermal gravimetric analysis (TGA). The distribution of the clays inside the polymer matrices appeared good due to thein situpolymerization system into which the clays were introduced during the polymer forming reaction. Upon investigating the clays by X-ray diffractometer (XRD) and Fourier transform infrared spectroscopy (FTIR), it was observed that the crucial differences between the two clays are the crystallite sizes (A < B) and the amounts of amine group (A < B). The higher amount of amine group in clay B was supposed to be a major reason for the lower catalytic activity of the polymerization systems compared to clay A resulting from its deactivating effect on zirconocene catalyst. However, for both clays, increasing their contents in the polymerization systems reduced the catalytic activity due to the higher steric hindrance occurring.