Journal

 2/10/11

Max
PDMS and carbon black processing

Process: 1) Add carbon black to petri dish. 2) Add heptane until carbon black appears saturated. 3) Add PDMS to fulfill desired ratio (ignoring heptane content). I started with 6/94 %CB/%PDMS and have a few samples which should all be in the 5-10%CB by mass range. I will next use more aggressive intervals to get all the way up to percentages of 70-80%CB for further testing. The samples are sealed with tape and also stored in a refrigerator. 
Sample Carbon Black (g) Carbon Black (%) PDMS (g) Heptane (g) Comments
 1          .365          7.03  4.83 .5
Trial run, way too much PDMS
 1a  .018  7.41  2.41  2.52
 2  .061  5.35  1.079  1.04
 3  .078  7.29  .992  .58
2/15/11 

Max                

 

Same process as above.
 Nom. % Carbon Black (g) Carbon Black (%) PDMS (g) Heptane (g)Comments 
 10
 .099 9.696 .922.995  
 20 .204
 20.20 .8061.89  
 30 .296 29.66.702 2.45  Beyond 30%CB, starts to clump and crack
 40 .402 37.22.678 3.15 
 50.493  49.60.501 3.78  
 60.199  60.12.132 2.11  Cut down portions not to waste materials
 70.257  69.84.111 3.22  
2/17/11 

Max



Process edit: Add curing agent in 1:10 proportion with PDMS. I began focusing on concentrations between 10-20%CB by weight to get ideal modulus, resistance, and conductivity.   
 Nom. % Carbon Black (g) Carbon Black (%) PDMS (g) Curing Agent (g) Heptane (g) Resitance (Ohm) Comments
 10 .100 9.98.82 .0818 1.45  9180 
 12.5 .126 11.28.901 .09 2.12  12000 Beyond 12.5%CB cracked in test setup once heptane evaporated
 15 .151 14.22.828 .083 1.64  83.6 
 17.5 .18 17.26.782 .081 2.47  58 
 20 .199 19.19.760 .078 2.07  22.5 



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