Browsing by Author "Carty, William M."
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Item Effect of CEC coverage of hexadecyltributylphosphonium modified montmorillonite on polymer compatibility(Elsevier, 2017-02-28) Çelik, Mehmet S.; Carty, William M.; Hojiyev, Rustam; Ulcay, Yusuf; Uludağ Üniversitesi/Mühendislik Fakültesi/Tekstil Mühendisliği Bölümü.; 0000-0002-2047-3169; 36026524100; 6601918936The present work was aimed to investigate polymer compatibility of hexadecyltributylphosphonium bromide (HDTBPh) modified Na-montmorillonite (Na-Mt) at different cation exchange capacity (CEC) coverages. The Na-Mt was modified at five different CEC coverages in the range of 60%-150%. The morphology, porosity, and thermal and surface properties of HDTBPh in Na-Mt interlayer were investigated. The intercalation behavior of HDTBPh investigated by X-ray diffractometry showed that the door-value reached a maximum of 23.4 angstrom at 125% CEC coverage. The specific surface area (SSA) and porosity were investigated by N-2 adsorption at -197 degrees C temperature. The SSA decreased from 57.19 m(2)/g to 24.11 m(2)/g at 150% CEC coverage, as opposed to the porosity which increased upon interaction with HDTBPh and led to a more open structure. The thermal stability, investigated by themogravimetry (TGA), slightly decreased with increasing CEC coverage. The CEC coverage of HDTBPh was found to play an important role in the clay-polymer compatibility. A simple acid-base approach involving the calculation of total energy of interaction between Na-Mt surface and polymer surface (Delta G(clay)(IF)/(poiymer/clay)) was developed to evaluate the clay-polymer compatibility. While the positive value of Delta G(clay/Polymer/Clay)(IF) indicated the clay-polymer compatibility, the negative value was ascribed to no polymer compatibility. The calculated value of Delta G(clay/Polymer/Clay)(IF) was critical for proper selection of CEC coverage for each polymer.Item Hydrophobicity and polymer compatibility of POSS-modified Wyoming Na-montmorillonite for developing polymer-clay nanocomposites(Elsevier, 2017-03-05) Hojamberdiev, Mirabbos; Çelik, Mehmet S.; Carty, William M.; Hojiyev, Rustam; Ulcay, Yusuf; Uludağ Üniversitesi/Mühendislik Fakültesi/Tekstil Mühendisliği Bölümü.; 000-0002-2047-3169; 36026524100; 6601918936The aim of the present work was to investigate the hydrophobicity and polymer compatibility of aminopropylisooctyl polyhedral oligomeric silsequioxane (POSS) - modified Na-montmorillonite (Na-MMT) towards developing polymer-clay nanocomposites. The effect of different concentrations of POSS on properties of Na-MMT was studied. The intercalation ability of the POSS molecules into the Na-MMT interlayer was analyzed by X-ray diffraction. It was found that the d(001) value was increased with increasing the POSS concentration, indicating the successful intercalation of the POSS molecules into the Na-MMT interlayer. The d(001) value was 4.12 nm at 0.4 cation exchange capacity (CEC) loading of POSS, increased at a slight rate upon further increase of CEC loading, and finally reached 4.25 nm at 1.0 CEC loading of POSS. The results of the thermogravimetric (TGA) analysis confirmed the high thermal stability of the POSS-MMT. The thermal stability was defined as a 5% mass loss (T-5) at 0.2 CEC loading of POSS was observed at 352 degrees C and slightly decreased with further increase in the POSS concentration. The porous properties, such as specific surface area (SSA), pore volume, and pore size were estimated by the adsorption of N-2 molecules on the Na-MMT surface. The SSA and pore volume were reduced with increasing the concentration of the POSS molecules due to the adsorption of the POSS molecules on the Na-MMT, while the pore size was increased upon the formation of macroporous structure. The interfacial interaction energy between water and POSS-MMT (Delta G(Clay/Water/Clay)(IF)) was used to evaluate the surface hydrophobicity, and a similar approach was also applied to assess the polymer compatibility of the developed composite. The obtained results confirm that the polymer compatibility of POSS-MMT prepared in this study is better than that of commonly used HDTMA-MMT.