Rheological behaviour of oil-filled polymer nanoparticles in aqueous dispersion

Autor: Dirk Stanssens, Hesam Taheri, Pieter Samyn
Rok vydání: 2016
Předmět:
Zdroj: Colloids and Surfaces A: Physicochemical and Engineering Aspects. 499:31-45
ISSN: 0927-7757
DOI: 10.1016/j.colsurfa.2016.04.001
Popis: Hybrid organic nanoparticles of poly(styrene-co-maleimide) with 70 wt.-% incorporated palm oil (SMI/oil) were provided in aqueous dispersion for use in industrial coating processes. The rheological characteristics of dispersions with 65 wt.-% and 35 wt.-% solid content have been determined by creep, oscillatory and rotational testing under different shear stresses, shear rates, frequencies and temperatures. The effects of oil on viscoelastic properties have been demonstrated by comparative tests on a 35 wt.-% pure SMI nanoparticle dispersion. The creep and strain recovery data show viscoelastic responses only for 65 wt.-% SMI/oil dispersions at low stresses, as further detailed by the calculated Burger model parameters. The 65 wt.-% SMI/oil dispersion at higher stresses and 35 wt.-% SMI/oil dispersion over the full stress range become viscous. From strain sweep tests, the cross-over of G’ and G” demonstrates linear features at low strain and a transition into viscoelastic properties at high strain. The frequency sweep test indicates a linear solid-like behaviour with storage and loss modulus independent of frequencies at temperatures up to 70 °C. From rotational tests, the sensitivity of shear-viscosity properties to concentration and temperature has been demonstrated. The oscillatory and rotational data can be fitted by the Cox-Merz rule using dynamic viscosity and shear viscosity as a function of frequency or shear stress, while a yield point has been detected as a function of shear stress for both 65 and 35 wt.-% SMI/oil dispersions.
Databáze: OpenAIRE
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