Innovative, Platy Nano-Additives as Efficient Flame Retardants for Polymer Nanocomposites
type: CreativeWork
description: The objective of this work was to explore inorganic layered materials (nano-additives) as innovative flame retardants for polymer nanocomposites. In particular, polystyrene (PS) nanocomposites were prepared with a variety of nano-additives including layered double hydroxides (LDHs), hectorite (hect), graphite oxide (GO), or a combination of these. The maximum flame retardant (FR) efficiency can be achieved when these nano-additives are perfectly dispersed in the polymer matrix yielding a maximum specific interface area. Good dispersion is most efficiently achieved by appropriate surface modification lowering the surface tension. Due to the unique 1:1 layered structure of kaolinite that represents two different kinds of external basal surfaces, kaolinite was used as a model to investigate selective surface modification of µ-hydroxy (gibbsite-like) surfaces. The surface modification was achieved by siderophilic ligands such as catechol derivatives. The catechol functional group (1,2-dihydroxyphenyl) forms stable chelate-complexes with the aluminum cation of the octahedral surface (OS). Modification was confirmed by bathochromic shifts of the reflection maxima of the adsorbed catechols. Furthermore, forced sedimentation measurements proved a better stability of the modified kaolinite in an organic solvent (e.g. THF). Later on, this kind of surface modification was applied to modify the structurally related materials with similar surface functionalities such as LDHs. CO3²¯-LDHs with high aspect ratio (α: 20-40) were either directly synthesized via the urea hydrolysis method at low concentration or by a two-step method including post-synthesis milling in a stirred media mill. Selective surface modification was applied using a siderophilic ligand (3,4-dihydroxybenzophenone). Consequently, suspensions of surface modified LDHs showed a better stability in THF as compared to the pristine LDH. Furthermore, surface modification restricted to the external surface diminishes the…
abstract: The objective of this work was to explore inorganic layered materials (nano-additives) as innovative flame retardants for polymer nanocomposites. In particular, polystyrene (PS) nanocomposites were prepared with a variety of nano-additives including layered double hydroxides (LDHs), hectorite (hect), graphite oxide (GO), or a combination of these. The maximum flame retardant (FR) efficiency can be achieved when these nano-additives are perfectly dispersed in the polymer matrix yielding a maximum specific interface area. Good dispersion is most efficiently achieved by appropriate surface modification lowering the surface tension. Due to the unique 1:1 layered structure of kaolinite that represents two different kinds of external basal surfaces, kaolinite was used as a model to investigate selective surface modification of µ-hydroxy (gibbsite-like) surfaces. The surface modification was achieved by siderophilic ligands such as catechol derivatives. The catechol functional group (1,2-dihydroxyphenyl) forms stable chelate-complexes with the aluminum cation of the octahedral surface (OS). Modification was confirmed by bathochromic shifts of the reflection maxima of the adsorbed catechols. Furthermore, forced sedimentation measurements proved a better stability of the modified kaolinite in an organic solvent (e.g. THF). Later on, this kind of surface modification was applied to modify the structurally related materials with similar surface functionalities such as LDHs. CO3²¯-LDHs with high aspect ratio (α: 20-40) were either directly synthesized via the urea hydrolysis method at low concentration or by a two-step method including post-synthesis milling in a stirred media mill. Selective surface modification was applied using a siderophilic ligand (3,4-dihydroxybenzophenone). Consequently, suspensions of surface modified LDHs showed a better stability in THF as compared to the pristine LDH. Furthermore, surface modification restricted to the external surface diminishes the…
author: Diar Bakerly, Bashar
date published: 2013-12-12
date modified: 2026-07-27T18:49:36Z
provider: Universität Bayreuth
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Universität Bayreuth