Furnace Black Characterization

Sid Richardson Carbon CoFort Worth, TXDr. Michel Gerspacher

005F2

DefinitionsParticle

Aggregate

= 20nm to 100nm "Diameter"= 200nm to 1,000nm "Length"= Set of Percolated Aggregates

Particle (?) Aggregate Agglomerate

Constituents Size = Tech/Scientific Challenge

005F3

Furnace ProcessHigh Temperature

RefractoryFeedstock

OilAir

NaturalGas Reaction

ZoneQuench

005F4

Specific Surface Area

005F5

Structure

3-D Morphology Key Characteristic

Summary

of

Crystallographic Studies

005F7

Methodologies

005F8

Summary

• For all furnace carbon black12Å < LC < 17Å

• CrystalliteLa ≈ 25Å

• Amorphous Carbon• No micropores• Very few surface groups (hetero atoms)

{

005F9

Effect of Heat Treatment on Amorphous CarbonRaman Study and Hydrogen Content

· Raman Spectrum of N299

1,000 1,100 1,200 1,300 1,400 1,500 1,600 1,700 1,800

Wave Number

0

50

100

150

200

250

I

Heat Treatment Temperature Amorphous Area / Total Area Hydrogen Content, (ppm)

Untreated 0.348 2407500°C 0.152 2502800°C 0.114 23931000°C 0.038 23252000°C 0.029 10

005F10

Results (Cont’d)

T < 1000°C → “Reorganization” of graphitic planes on the surfaceT > 1000°C → Formation of microcrystallites

RT 500 800 1000 2000 3000 3200Temperature

1

1.08

1.16

1.24

1.32

I Ram

an

RT 500 800 1000 2000 3000 3200Temperature

1

1.3

1.6

1.9

2.2

I 002

Surface Unorganized Carbon Identified

005F11

SRCC’s Model

005F12

Carbon Black Surface Activity• Edges of crystallites → High concentrations of π electrons

Crystallites Amorphous

A A

B

CD

• Energy ScaleEA > EB > EC

• ED ? → Role of hydrogen atoms?

Active Site

Important Surface Energy Density

005F13

Energetic Surface Structureof

Carbon Black(Summary)

A. Schroeder | R. Schuster DIK

005F14

Polymer - Filler “Bonding”

( ) ( ) ( )0

, , ,

ads ads

ads

G H T S

H Enthalpy of Adsorption

Adsorption Isotherm

T T Q f Q dQρ θ ρ∞

∆ = ∆ − ∆

∆ =

⇓

Θ = ∫

( )f Q Distribution of Energetic Sites=

005F15

Energetic Surface Structure of Carbon Black

005F16

Role of Active SitesActive sites → High density of π electrons

A Sites for Van der Waals bonding with neighbor aggregates → carbon black network

B Sites for weak (Van der Waals …)bonding with polymer chains

005F17

Carbon Black Surface Groups* As per Professor Bertrand (Belgium) ACS Rubber Division, Spring

1998

• Heterogroup → Very few

• Hydrogen atoms → Significant amount

Hydrogen Most Relevant Surface Group

005F18

Surface Hydrogen Group

• Study to be started with Professor Bertrand (Belgium)• SIMS T.O.F.• E.S.C.A. / Auger

• Surface hydrogen proportional to total hydrogenTotal Hydrogen → Leco Technique

Amorphous Carbon Hydrogen Content

005F19

• Carbon black of - same “particle” diameter (TEM)- different Nitrogen adsorption

• Special process to increase the amorphous carbon

2 2.5 3 3.5 4

ppm Hydrogen (10-3)

6

6.5

7

7.5

8

8.5

9

9.5

10

G'm

ax (M

Pa)

Hydrogen Directly Linked to Amorphous Carbon

Hydrogen Content of Amorphous Carbon