engleski

Synthesis of polymer surfactants for production of MWCNT nanofluids with improved stability in polyalphaolefin and rapeseed oil

Nanofluids are engineered colloidal suspensions of nanoparticles in a base fluid often showing superior properties to base fluids, like heat transfer or tribological properties. The main problem is to obtain a long term stable nanofluid due to the agglomeration of nanoparticles. Here, we tackle the problem of stability by adding specifically tailored polymer surfactants in polyalphaolefin and or rapeseed oil to stabilize dispersion of MWCNTs. Six nanofluids of each base oil, using two commercial and four synthetized polymeric surfactants based on methacrylates, are evaluated according to the quality of dispersion and long term stability. Composition, molecular weights of synthesized polymers and their influence on kinematic viscosity are analysed by NMR, size exclusion chromatography and capillary viscosity measurements, respectively. Stability and quality of dispersion was monitored by UV-vis spectroscopy and visual observation after gravitational and centrifugal tests. Most stable nanofluids are additionally characterized by tribology tests, thermal conductivity and contact angle measurements. Stability results show high dispersion (over 80 %) for polyalphaolefin and rapeseed oil nanofluids with two different polymer surfactants even after one year.

Nanofluids ; polymeric surfactants ; stability ; carbon nanotubes

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