Percolation network of organo-modified layered double hydroxide platelets into polystyrene showing enhanced rheological and dielectric behaviorThis paper is part of a Journal of Materials Chemistry themed issue on Advanced Hybrid Materials, inspired by the symposium on Advanced Hybrid Materials: Stakes and Concepts, E-MRS 2010 meeting in Strasbourg. Guest editors: Pierre Rabu and Andreas Taubert.Electronic supplementary information (ESI) available: TG curves, chemical analyses, XPS analyses, FTI

• Main Authors: Leroux, Fabrice, Illaik, Abdallah, Stimpfling, Thomas, Troutier-Thuilliez, Anne-Lise, Fleutot, Solenne, Martinez, Hervé, Cellier, Joël, Verney, Vincent
• Format: Article
• Language: English
• ISSN: 0959-9428; 1364-5501
• DOI: 10.1039/b926978a

A hybrid organic inorganic layered double hydroxide incorporating 2-acrylamido-2-methyl-1-propane sulfonic acid (AMPS) is characterized by means of XRD, FTIR, and XPS. The in situ polymerization is scrutinized by 13 C CPMAS as well as by a set of XRD experiments with varying temperature. It is found that the in situ polymerization is complete at 200 °C, and the hybrid framework sustains temperatures as high as 350 °C. Direct incorporation of poly(AMPS) is reported and the resulting hybrid LDH phases studied. Subsequently, all generated hybrid platelets are used as organo-modified 2D-type filler dispersed into polystyrene (PS). An immiscible PS composite structure with salient gel-like viscoelastic properties is obtained after bulk polymerization. In the low-frequency region, the typical Newtonian flow behaviour of PS is found to change progressively against filler loading into a shear-thinning behaviour evidenced by a pseudo-plateau in the elastic and loss modulus curves and associated with a shift of the glass transition temperature of PS to higher temperature. It is interpreted by hybrid LDH platelet domains presenting a large interface with the polymer, thus having the effect of restricting the plastic deformation by obstructing polymer chain motion. Such dispersed hybrid LDH tactoids forming a three-dimensional percolated network are indirectly evidenced by the enhancement of the dielectric properties illustrated by an increase in bulk dc conductivity of about one order at room temperature and in the dissipation factor. The study shows that hybrid LDH assembly is of relevance in topical applications regarding mechanical reinforcement as well as electrostatic energy dissipation. 2-Acrylamido-2-methyl-1-propane sulfonic acid organo-modifying LDH platelets give rise to a percolative network in polystyrene as shown by the formation of a gel-like polymer structure and an increase in dc conductivity.