Akademik Veri Yönetim Sistemi
JOURNAL OF POLYTECHNIC-POLITEKNIK DERGISI, sa.3, ss.1083-1090, 2022 (ESCI)
Synthesis and characterization of composites, namely clay-chitosan, organoclay-chitosan, clay-triethyl chitosan and organoclay-triethyl chitosan, were investigated by using montmorillonite (Mt) as clay mineral. Cetyltrimethylammonium bromide (CTAB, long-chained)), tetraethylammonium bromide (TEAB, short-chained)), and benzyltriethylammonium bromide (BTEAB, ringed)) surfactants were employed to modify the clay surfaces to obtain organoclay. Organoclays were labelled as CTAB-O (clay modified with cetyltrimethylammonium bromide), BTEAB-O (clay modified with benzyltriethylammonium bromide) and TEAB-O (clay modified with tetraethylammonium bromide). The structural and thermal properties were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and thermogravimetric analysis (TGA). XRD and TEM results showed that exfoliated structure was formed for clay-chitosan composites and also organoclay-chitosan composites at lower CTAB-O, TEAB-O and BTEAB-O content. However, by increasing the organoclay content, tactoid morphology was obtained for organoclay-chitosan composites. Moreover, exfoliated structure was observed for clay-triethyl chitosan (TEC) and organoclay-triethyl chitosan (TEC) composites containing 2.5%, 5%, 10% clays and organoclays respectively. Thermal degradation temperature for 10% clay-chitosan and some organoclay-chitosan composites (5% and 10% TEAB-O-chitosan; 10% BTEAB-O-chitosan) increased (about 375 degrees C) with regard to neat chitosan (350 degrees C) at 50% weight loss. Furthermore, it was observed that thermal degradation temperature of TEC composites (clay-TEC, organoclay-TEC) increased significantly in reference to composites with chitosan (clay-chitosan, organoclay-chitosan). In particular, maximum degradation temperature (965-968 degrees C) was reached for clay-TEC (2.5% and 10%), CTAB-O-TEC (5%) and BTEAB-O-TEC (5% and 10%) at 50% weight loss.