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Rheological properties of PDMS filled with CaCo 3 : The effect of filler particle size and concentration
Author(s) -
Zhou Yabin,
Wang Shifeng,
Zhang Yong,
Zhang Yinxi,
Jiang Xuhua,
Yi Dengfeng
Publication year - 2006
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.24060
Subject(s) - thixotropy , materials science , rheology , shear thinning , polydimethylsiloxane , shear rate , composite material , particle size , shear stress , nanoparticle , particle (ecology) , nano , chemical engineering , nanotechnology , oceanography , geology , engineering
The effects of filler particle size and concentration on the rheological properties of hydroxyl terminated polydimethylsiloxane (HO‐PDMS) filled with calcium carbonate (CaCO 3 ) were investigated by an advanced rheometric expansion system (ARES). The Casson model was used to describe the relationship between shear stress and shear rate for steady‐state measurement. Micron‐CaCO 3 could not afford the CaCO 3 /HO‐PDMS suspensions obvious shear thinning behavior and a yield stress high enough, whereas nano‐CaCO 3 could provide the suspensions with remarkable shear thinning behavior and high yield stress. Incorporation of nano‐CaCO 3 into HO‐PDMS resulted in the transformation of HO‐PDMS from a mainly viscous material to a mainly elastic material. With increasing nano‐CaCO 3 content, shear thinning behavior of nano‐CaCO 3 /HO‐PDMS suspensions became more obvious. Remarkable yield stress was observed in nano‐CaCO 3 /HO‐PDMS suspensions with high filler content, and increased with increasing nano‐CaCO 3 content. The degree of thixotropy was quantitatively determined using a thixotropic loop method. It was found that nano‐CaCO 3 favored more the buildup of filler network structure in the suspensions than micron‐CaCO 3 at the same weight fraction. Furthermore, increasing nano‐CaCO 3 content accelerated the establishment of filler network structure in the nano‐CaCO 3 /HO‐PDMS suspensions. An overshoot phenomenon was observed in the nano‐CaCO 3 /HO‐PDMS suspensions at high shear rates. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3395–3401, 2006