Pakistan Research Repository

ORGANOCERAMIC NANOCOMPOSITES DERIVED FROM POLYAMIDES AND CLAY

ZULFIQAR, Sonia (2008) ORGANOCERAMIC NANOCOMPOSITES DERIVED FROM POLYAMIDES AND CLAY. PhD thesis, Quaid-i-Azam University, Islamabad.

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Abstract

Various types of polyamide-clay nanocomposites were synthesized using the solution intercalation method. Compatibility between the two phases was achieved by suitably modifying both the phases for better improvement in the physical and mechanical properties of the nanocomposites. Different strategies have been adopted in order to develop various types of interactions among the two disparate phases. Therefore, the hydrophilic nature of montmorillonite was changed into organophilic by ion-exchange method using various intercalating agents with different chain lengths and functionality, such as long chain alkyl amine, amino benzoic acid, diamines and amine terminated oligomer. The intercalation was carried out in aqueous medium except for the oligomeric species because of their solubility in organic solvents like DMSO. The increase in d-spacing upon intercalation was monitored through XRD. So, these modifications in the clay structure were carried out in order to have good compatibility, uniform and homogenous dispersion in the polyamide matrices. Three different types of linear polyamide chains of either aromatic and aliphatic or purely aromatic nature were synthesized by condensing different diamines with diacid chlorides under anhydrous conditions. The structure of these polyamide matrices was elucidated through FT-IR, IH and l3C NMR spectroscopy. The molecular weight and molecular weight distributions of these polyamide matrices were determined using GPC and LLS techniques. Furthermore, these polyamide chains were selectively end-capped with either amine or carbonyl chloride end groups in order to create better interaction with the modified clays. Thin transparent films of these nanocomposites obtained were characterized with regards to XRD, TEM, mechanical, TGA, DSC and water absorption measurements. XRD and TEM results revealed the formation of exfoliated and intercalated nanocomposites. The tensile strength of nanocomposites improved considerably relative to the pure polyamides. Various polyamide based nanocomposites were found to be thermally stable. Increase in the glass transition temperature (Tg) values relative to pure polyamides determined by DSC gave a measure of interfacial interactions between polyamides and organoclays. The percent water absorption of these nanocomposite films was found to be much reduced upon the addition of modified layered

Item Type:Thesis (PhD)
Uncontrolled Keywords:organoceramic nanocomposites, polyamides, clay, polyamide-clay nanocomposites, organically modified layered silicate, polymer-layered silicate, oligomer Abstract organoceramic nanocomposites, polyamides, clay, polyamide-clay nanocomposites, organically modified layered silicate, polymer-layered silicate, oligomer Abstract
Subjects:Physical Sciences (f) > Chemistry(f2)
ID Code:2649
Deposited By:Mr. Javed Memon
Deposited On:17 Jul 2009 12:45
Last Modified:17 Jul 2009 12:45

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