Mesoporous materials are promising structures for application in catalysis and adsorption due to high surface area and large pore size. Mesoporous materials were synthesized by the hydrothermal method with novel surfactants, distinct from those observed in the literature, in order to carry out a study of its structure and to obtain materials with better textural properties. The structures synthesized with the surfactants Igepal CO630 and Brij O20 presented the best results of specific surface area, 1074 and 1075 m2.g-1, respectively. The obtained materials were characterized by XRD, TG/DTG, N2 adsorption-desorption, and FTIR techniques. XRD patterns indicated that the highly ordered mesoporous silica structures, such as MCM-41 and MCM-48, using CTMABr as the structure-directing agent and the SBA-15, SBA-16 and other SBA structures using different block copolymers were obtained. Through N2 adsorption-desorption isotherms, it was observed type IV isotherms, attributed to mesoporous materials. The FTIR spectra presented similar behaviors with characteristic vibrational bands of MCM and SBA type materials.

INTRODUÇÃOAs zeólitas são aluminossilicatos cristalinos contendo canais microporosos e/ou cavidades em sua estrutura. Sua rede cristalina é constituída de tetraedros de SiO 4 e AlO 4 ligados por átomos de oxigênio, formando assim uma rede tridimensional de tetraedros TO 4 [1]. O estudo destes materiais desperta cada vez maior importância devido algumas de suas propriedades intrínsecas (estabilidade térmica, acidez, entre outras), e também devido a algumas de suas aplicações como trocadores iônicos, adsorventes e catalisadores na indústria petroquímica [2].A técnica de difração de raios X (DRX) é a mais indicada

The thermo-catalytic degradation of polyethylene (PE) and ultra-high molecular weight polyethylene (UHMWPE) was studied in the presence of zeolites (ZSM-5, ZSM-22, and ferrierite) with different pore systems and textural properties. The zeolites were physically mixed with polymers in the proportion of 30 wt% and submitted to thermogravimetric analysis at heating rates of 5, 10, 20, and 30 °C.min-1. The activation energy of the degradation process was determined using the Flynn-Wall-Ozawa method. The addition of zeolites to polymers has considerably reduced the temperature of degradation. ZSM-22 demonstrated greater efficiency in the degradation of PE because it has a smaller crystallite size, promoting a shorter diffusional path for the polymer fragments coming from the surface. Ferrierite showed a lower energy level in the degradation of UHMWPE, showing the need for synergy between the accessibility of the structure and acidity of the catalyst to promote the cracking of this polymer.