Polymers and Polymer Composites

SKY-WHITE TEMPERATURE/PH-SENSITIVE NANOCOMPOSITE MICROGELS WITH LOWER SIZE AND GOOD TEMPERATURE-SENSITIVITY

January 1, 2012 By: Qingsong Zhang; Xuewei Li; Li Chen Research article

Title: SKY-WHITE TEMPERATURE/PH-SENSITIVE NANOCOMPOSITE MICROGELS WITH LOWER SIZE AND GOOD TEMPERATURE-SENSITIVITY
Page Range: p.111-116
Author(s): Qingsong Zhang; Xuewei Li; Li Chen
File size: 317K
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Journal: Polymers and Polymer Composites
Issue Year: ppc
Volume: 20
Issue No: No.1-2

Abstract
Adopting inorganic nanoclay (lithium magnesium silicate hydrate, LMSH) as physical crosslinking agent, a kind of novel temperature/pH double-sensitive nanocomposite microgels based on N-isopropylacrylamide (NIPAM) and acrylic acid (AAc) were synthesised by using surfactant-free emulsion polymerisation method. As a comparison, the traditional poly(NIPAM-co-AAc) microgel using N,N’-methylene-bis-acrylamide(MBA) as chemical crosslinker was prepared by same method. The chemical structure, shape, particle size and phase transition behaviour of two kinds of microgels were confirmed by FTIR, XRD, SEM and DSC respectively. The results show that nanocomposite microgel was successful prepared under LMSH severing as physical crosslinker, and the prepared nanocomposite microgel dispersions present sky-blue state, different from oyster white of microgels crosslinked by MBA. The nanocomposite microgels crosslinked by LMSH present good spherical shape with hydrodynamic diameter less than 430 nm, which is much smaller than that of microgels crosslinked by MBA. In addition, the microgels crosslinked by LMSH show same good temperature-sensitivity. With increasing temperature from 20 to 50 degrees , turbidity value increases, but lower than that of poly(NIPAM-co-AAc) microgel. Although a 7 mol.% ratio of AAc/NIPAM was used, the volume phase transition temperature of microgels still keeps at about 31 degrees because of crosslinking structure of LMSH platelets. 19 Refs.


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