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A bentonita, composta predominantemente pelo argilomineral montmorilonita que lhe confere as propriedades físicas concentra a maior parte das reservas nacionais (62%) no Estado da Paraíba. A transformação da bentonita em argila organofílica consiste em um procedimento laboratorial simples e pode ser realizada através de reação de troca dos cátions (Na+ ou Ca2+) presentes na superfície e no espaço interlamelar dos argilominerais, por cátions de sais quaternários de amônio. Neste trabalho as bentonitas organofílicas foram preparadas utilizando quatro tipos diferentes de sais quaternários de amônio, tais como: cloreto de alquil dimetil benzil amônio (Dodigen), cloreto de estearil dimetil amônio (Praepagen), cloreto de cetil trimetil amônio (Genamin) e brometo de cetil trimetil amônio (Cetremide). As argilas organofilizadas foram caracterizadas por termogravimetria, difração de raios X, análise química e por fluorescência de raios X. Os resultados confirmaram a incorporação dos sais quaternários de amônio na estrutura da argila e mostraram que dois dos quatro sais quaternários utilizados, o Praepagen e o Cetremide apresentaram uma faixa maior de estabilidade térmica.

Abstract:In this work, Polylactide/Biopolyethylene blends were developed. Although some studies have been carried out on polylactide/polyethylene blends, none of them has used polyethylene synthesized with raw material obtained from natural sources. Due to the incompatibility between polylactide and polyethylene, E-GMA and EMA-GMA compatibilizers were used. These compatibilizers present glycidyl methacrylate groups in their structure, which may react with the functional end-groups of polylactide. To evaluate the properties, the blends were characterized by mechanical tests, scanning electron microscopy (SEM) and melt flow index (MFI). The results indicated that the compatibilizers played an important role in the blends, interacting with the blends components, modifying the morphology and improving the mechanical properties.

Photodegradation of PCL was performed exposing injected specimens to ultraviolet radiation (UV-B) up to 9 weeks. Photodegradated PCL specimens were tested by Differential Scanning Calorimetry (DSC), Infrared Spectroscopy (FTIR), mechanical properties, Optical Microscopy (MO) and Scanning Electron Microscopy (SEM).Upon exposure decrease in elongation at break and increase of elastic modulus were verified, higher degree of crystallinity was observed for longer exposure what can be due to the chemi-crystallization mechanism. From IR spectra new carbonyl group (C=O) peaks were observed. Presence of micro cracks on specimens' surface was identified by MO. From morphological analyses is suggested that the photodegradation in PCL takes place by bulk erosion mechanism.