1. Steve Peterson USDA – ARS – NCAUR October 21, 2016
Biochar as carbon black replacement: what we’ve seen and where we’re going
Steve Peterson
USDA – ARS – NCAUR
October 21, 2016

2. Carbon black: an introduction
Carbon black (CB)
First used as pigment or dye
“Bone black” used in ancient times, charring other materials yielded other names; vine black, lamp black

3. Carbon black: an introduction
Carbon black (CB)
today CB can be made in a range of sizes and structures
particle
aggregate
agglomerate

4. Carbon black: an introduction
Carbon black (CB)
today CB can be made in a range of sizes and structures
decreasing reinforcement due to surface area

5. Tires and war: the catalysts for the carbon black industry
Thompson
Goodyear
1830: Hancock and Goodyear obtain patent for mixing lampblack into rubber, but mainly for coloring
1845: Robert W. Thompson obtains 1st patent on pneumatic tire
1888: John Dunlop develops first commercial tire for bicycles
1895: Michelin brothers introduce tires to “horseless carriage”
Dunlop
Michelin brothers

6. Tires and war: the catalysts for the carbon black industry
1904: S.C. Mote (India Rubber, Gutta Percha, and Telegraph Works) discovers reinforcement qualities of carbon black; in the Diamond Rubber Company of Akron, OH, acquired the rights to use carbon black from Mote’s company
WWI initiated a high demand for rubber products, and carbon black’s advantages were shown in improved wear and lower failure rates – Germany pioneered synthetic rubber

7. Tires and war: the catalysts for the carbon black industry
WWII brought about the Synthetic Rubber Research Program since natural rubber was cut off by the Japanese
Military airplane: ½ ton Battleship: 75 tons
Tank: 1 ton Each soldier: 32 pounds
Today 70% of rubber used in manufacturing is a descendant of GR-S

8. Biochar: how is it different than carbon black?
CB from fossil fuels, biochar from biomass
biochar is typically more porous and has a higher surface area

9. Biochar: how is it different than carbon black?
Particle size vs. surface area
small particle size large surface area
highly porous materials can have large particle size and high surface area
for composite fillers, large particles = poor reinforcement

10. Biochar: how is it different than carbon black?
Purity
oils and long-chain
hydrocarbons
CxHy
wood, grass, straw, manure,
husks, shells, stovers… any
carbon-containing biomass
virtually  number of
pyrolysis techniques

11. Research targets % carbon % ash particle size feedstock dependent post
processing

12. Research targets
Overall goal: replace as much CB as possible with biochar without detrimental effects to the tensile properties of the final rubber composite
2017 estimated carbon black tire industry market: ~1.3 million tons

13. Tensile properties, our measuring stick
Rubber composites need both strength and elasticity
Focus on tensile strength, elongation, and toughness; measured with an Instron

14. Tensile properties, our measuring stick
Tensile strength – stress needed to break a sample
% Elongation – strain on sample at break point
Toughness – area under the curve

15. Tensile properties, our measuring stick
stress
strain
strong, not tough (brittle)
strong and tough
not strong, not tough

16. Past results
Began by looking at corn stover biochar/corn starch blended filler
agricultural product
45% carbon, 40% ash
at 10% total filler, a 3:1 corn starch:biochar blended filler surpassed the CB control
Takeaway: increase carbon content and decrease ash content of biochar
middle is 500x, right is 200x
200x
500x

17. Past results Lower ash, woody waste biochar 78% carbon, 2.7% ash
at 10% total filler, could replace 25-50% of the CB with biochar with equal or better tensile properties
biochar had small population of very large particles ~100 microns, suspect this weakened the composites
500x
10,000x

18. Past results Lab produced birchwood char 89% carbon, 1.8% ash
at 30% total filler, this biochar can replace up to 50% of the CB and tensile properties are within experimental error of the CB control
at 40% total filler, can replace 25% CB and tensile strength still within exp error of CB control
good biochar, use this feedstock and scale up
CB control
birchwood

19. Past results Biochar Options birch biochar 95.9% carbon, 1.68% ash
finally reached 40% total filler with no comparable loss in tensile properties at 15% replacement
now focus on particle size and surface chemistry
CB control composite, 2000x
BCO birch composite, 2000x

20. Acknowledgements NCAUR ISTC Biochar Options A.J. Thomas B.K. Sharma
Ashley Maness
Sriraam Chandrasekaran
Jason Adkins
Art Thompson
Nancy Holm
Biochar Options
Beth Meschewski
Steve Nichols
Paul Marren