Thermal and Rheological Properties of Nanosilica Dispersions in a Siloxane Polymer

Dinkar, S and Dhanabalan, A and Laxmi, S and Patel, M and Ramakrishnan, I and Pallavi, M B and Thimmappa, B H S (2012) Thermal and Rheological Properties of Nanosilica Dispersions in a Siloxane Polymer. Nano Trends: A Journal of Nanotechnology and Its Applications, 12 (3). pp. 12-25. ISSN 0973-418X

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Abstract

Filled silicone elastomers are useful in a number of applications such as cable insulations, seals and tubing for food and processing equipment, keypads, baby nipples, and pacifiers, shaft seals, anode caps, sparkplug boots, membranes, implants, drug release carriers, electronic encapsulations, photocopier rolls, molds for replication of art or denture, window or sanitary seals, adhesives, adhesive-controlled release coatings for paper, and thermal shielding due to their unique properties. In such composites, particle size, shape, surface characteristics, structure of particle and preparation methods play a critical role on the final bulk properties. The structured fillers are known to raise the viscosities of resultant composites, leading to processing problems. To tackle this problem a discrete particle with spherical silica is considered for such applications. However, these particles are typically present in the form of dispersion. Hence, there is a need to understand the effect of dispersion medium of commercial colloidal silica particle on the bulk properties of silicone composites. In this study, we investigated the effect of commercially available colloidal nanosilica dispersions on rheological properties of composites, using aqueous and organic dispersions. Polydimethyl siloxane (PDMS) is chosen as a polymer matrix and four different colloidal silica (CS) dispersions are used as fillers. The rheological analyses showed that the composites prepared from CS dispersed in isopropanol (IPA) and CS dispersed in methylethylketone (MEK) showed significant enhancement in viscosity at higher loadings as compared to ones prepared with CS dispersed in polar solvents such as water and methanol (MeOH), possibly indicating different degrees of interfacial interaction mediated by the dispersions.

Item Type: Article
Uncontrolled Keywords: isopropanol, polydimethylsiloxane, colloidal silica, rheological properties
Subjects: Engineering > MIT Manipal > Chemistry
Depositing User: MIT Library
Date Deposited: 03 Sep 2013 10:52
Last Modified: 13 Sep 2013 09:23
URI: http://eprints.manipal.edu/id/eprint/137021

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