Thermosensitive Silica-Pluronic-Starch model coating dispersion-Part II : The relationship between rheology and microstructure

• The colloidal interaction between the components in coating dispersions play a key role in the structural organization on a micro level, which has influence upon the macroscopic properties of the material. The viscoelastic properties of a model coating suspension, consisting of colloidal silica particles, a temperature-responsive triblock copolymer Pluronic F127 and starch were studied and related to the corresponding dried structures. Pluronic F127 was used in order to produce a temperature-sensitive starch system and to simulate the drying of a paper coating at a low shear rates. The gelation process was investigated by the change in storage modulus upon heating and the change in particle volume fraction, empty set. The results revealed a dense disordered liquid-like state at empty set less than or similar to 0.10, where the strength of attraction between particles increased with increasing particle volume fraction and increasing temperature, a solid-like microcrystalline state at empty set greater than or similar to 0.20, where the temperature did not affect the rheology of the system and a solid-like microcrystalline state were coexisting at empty set similar to 0.16. The structures detected by rheology were related to the dried structures of the corresponding suspensions. At empty set less than or similar to 0.10 and elevated temperatures, a controlled formation of self-supporting floc structure was performed, which could be used to promote the even distribution of starch within the composite material. 

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Kemiteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Chemical Engineering (hsv//eng)

Nyckelord

Thermosensitive

Pluronic triblock copolymer

Rheology

Microstructure

Gel

Composites

Chemical Engineering

Kemiteknik

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