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Foam Shells by Injection Molding April 4, 2002 Warren Steckle and Art Nobile Polymers and Coatings Group, MST-7 Los Alamos National Laboratory Los Alamos, NM 87544. Foam hemishells have been prepared by injection molding. 4 mm diameter hemishell - 400 m wall. • Teflon molds were fabricated
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Foam Shells by Injection MoldingApril 4, 2002Warren Steckle and Art NobilePolymers and Coatings Group, MST-7Los Alamos National LaboratoryLos Alamos, NM 87544
Foam hemishells have been prepared by injection molding 4 mm diameter hemishell - 400m wall • •Teflon molds were fabricated • Removal of “sprue” from injection molded part • Mold with smaller inlet made - 125µm vs. 250µm • Improve mold filling • Mold design - 12 outlets versus 6 outlets had no effect on • improving the filling of the mold • • 100 mg/cc foam shells were fabricated by a batch process • • Shells can be easily removed from mold
4.00 nm Divinylbenzene Aerogel Advantage - low viscosity Disadvantages - needs solvent exchange supercritical CO2 drying Results- Good mold filling, however: The gel is brittle & the hemisphere breaks upon removal from mold. The hemisphere shrinks and breaks in the mold during supercritical extraction. TEM of 200 mg/cc DVB foam DVB gel Dried DVB aerogel HIPE hemi for comparison
Overcome incomplete filling of the molds for the HIPE foams Fabricate DVB aerogel hemi Examine the surface finish of the HIPE foams by SEM Teflon Stainless steel As supplied Diamond turned surface Aluminum Issues and Ongoing Work
We have been able to fabricate hemishells by injection molding The surface of the foam has a different morphology than the bulk of the foam The sub-micron open cells found in the DVB aerogels might be of interest if cell size becomes an issue Conclusions