27.12.2012 Views

DESIGN, ASSEMBLY AND CHARACTERIZATION OF COMPOSITE ...

DESIGN, ASSEMBLY AND CHARACTERIZATION OF COMPOSITE ...

DESIGN, ASSEMBLY AND CHARACTERIZATION OF COMPOSITE ...

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

(PEO) tail with 40 units of ethylene oxide (EO), is used to stabilize carbon black in<br />

aqueous medium. Two similarly structured PEO surfactants (Makon 10 and Makon 12,<br />

Stepan, Northfield, Illinois) with 10 and 12 units of EO respectively on their hydrophilic<br />

tails, are used for comparison. Defoamer (Surfynol DF-210, Air Products and Chemicals,<br />

Inc., Allentown, PA) is used as received. ABA block copolymer (Pluronic F-127, P2443-<br />

250G, SigmaAldrich, St. Louis, MO) is dissolved in de-ionized (DI) water as 40% by<br />

weight stock solution. Hydroxypropyl methylcellulose (HPMC) (Methocel F4M, Dow<br />

Chemical Company, Midland, MI) is dissolved in DI water as 5% by weight stock<br />

solution. DI water wherever mentioned has a nominal conductivity 5×10 -4 (ohm·cm) -1 .<br />

Paraffin oil (Ultra-Pure, Lamplight Farms, Menomonee Falls, WI) is used for the oil bath.<br />

3.2.2 Surfactant Concentration Determination<br />

To determine optimal surfactant concentration, varying amounts of carbon black<br />

and surfactant NP 4070 are separately added to pre-determined DI water to yield aqueous<br />

suspensions with varying carbon black and surfactant concentration. The detailed<br />

suspension composition is shown in Table 3.1. A sonic dismembrator (model 500, Fisher<br />

Scientific, Pittsburgh, PA) is used, at 50% of maximum power for 10 minutes, to assist<br />

breaking apart carbon black agglomerates. Subsequently, rheometry (C-VOR 200, Bohlin<br />

Instruments, Cirencester, Gloucestershire, UK) is used to characterize the apparent<br />

viscosity profile for each carbon black suspension in a sweep of shear rate from 0.2-3 s -1 .<br />

82

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!