5178
Tayseer Abd El-Hameed Abd El-Dayem Zidan
Synthesis and characterization of some polymer clay nanocomposites for industrial applications
polymer clay nanocomposites, layered silicate, in-situ bulk polymerization, exhibit structure
As the polymer/clay nanocomposites are of great interest due to their importance in advanced technology, different polymer/clay nanocomposites, in this thesis, are prepared and characterized. The thesis is divided into three parts. In the first part, four quaternary ammonium salt monomers are synthesized from N,N-dimethylaminoethyl methacrylate (DMAEMA) and subsequently polymerized to afford cationic polymers. The synthesized monomers and polymers are characterized by Fourier transform infrared (FTIR) and proton nuclear magnetic resonance (1H NMR) spectroscopy. Molecular weights of the synthesized polymers are determined using gel permeation chromatography (GPC). Polymer/clay nanocomposites are prepared using solutionintercalation method and characterized by FTIR, X-raydiffraction (XRD), high-resolution transmission electron microscopy (HRTEM), energy dispersive X-ray (EDX) and thermogravimetric analysis (TGA). The dielectric properties of the polymer/clay nanocomposites are studied as a function of both temperature and frequency. In the second part, poly(diallyldimethylammoniumchloride), PDADMAC, with low and high molecular weight and with concentrations 0.5, 1 and 2 times the cation exchangecapacity (CEC) of the clay is used to modify sodium bentonite clay to prepare hybrid PDADMAC/clay nanocomposites using solution-intercalation method. The prepared hybrids are characterized by FTIR spectroscopy, XRD, HRTEM, and TGA. The room temperature dielectric properties were studied as a function of frequency in which the values of real (ε1) and imaginary (ε2) parts of relative permittivity are calculated and discussed. In the third part, poly(N,N-dimethylaminoethylmethacrylate)/clay nanocomposites are prepared using in-situ bulk polymerization method. N,N-dimethylaminoethyl methacrylate (DMAEMA) was alkylated using hexyl bromide to afford quaternary ammonium salt which was then used in organic modification of clay. The organoclay is dispersed in DMAEMA monomer using concentrations 1, 3, and 5 wt. % and bulk polymerization reaction is conducted. The prepared nanocomposites were characterized using FTIR, XRD, HRTEM and TGA. Optical, dielectric and mechanical properties were also investigated. The behaviour of the real and imaginary parts of the dielectric constant of polymer and polymer nanocomposites is discussed.
2016
Ph.d
Ain Shams
Science