Cellulose Acetate Butyrate (CAB)
CAB is a thermoplastic, further classified as a cellulosic plastic.
The properties of CAB include two common variations. This page shows summary ranges across both of them. For more specific values, follow the links immediately below. The graph bars on the material properties cards further below compare CAB to: cellulosic plastics (top), all thermoplastics (middle), and the entire database (bottom). A full bar means this is the highest value in the relevant set. A half-full bar means it's 50% of the highest, and so on.
Mechanical Properties
Elongation at Break
50 to 55 %
Flexural Modulus
0.8 to 1.7 GPa 0.12 to 0.25 x 106 psi
Flexural Strength
21 to 57 MPa 3.0 to 8.3 x 103 psi
Tensile Strength: Ultimate (UTS)
20 to 50 MPa 2.9 to 7.3 x 103 psi
Tensile Strength: Yield (Proof)
17 to 40 MPa 2.5 to 5.8 x 103 psi
Thermal Properties
Glass Transition Temperature
140 °C 280 °F
Heat Deflection Temperature At 1.82 MPa (264 psi)
53 to 82 °C 130 to 180 °F
Heat Deflection Temperature At 455 kPa (66 psi)
68 to 92 °C 150 to 200 °F
Specific Heat Capacity
1460 J/kg-K 0.35 BTU/lb-°F
Thermal Conductivity
0.25 W/m-K 0.14 BTU/h-ft-°F
Thermal Expansion
14 µm/m-K
Vicat Softening Temperature
90 to 120 °C 190 to 240 °F
Electrical Properties
Dielectric Constant (Relative Permittivity) At 1 MHz
3.6
Dielectric Strength (Breakdown Potential)
15 kV/mm 0.59 V/mil
Electrical Resistivity Order of Magnitude
16 10x Ω-m
Otherwise Unclassified Properties
Density
1.2 g/cm3 72 to 75 lb/ft3
Limiting Oxygen Index (LOI)
18 %
Refractive Index
1.5
Water Absorption After 24 Hours
1.2 to 1.6 %
Common Calculations
Resilience: Ultimate (Unit Rupture Work)
9.5 to 26 MJ/m3
Strength to Weight: Axial
4.8 to 12 points
Strength to Weight: Bending
14 to 25 points
Thermal Diffusivity
0.14 to 0.15 mm2/s
Followup Questions
Further Reading
SPI Plastics Engineering Handbook of the Society of the Plastics Industry, Inc., 5th ed., Michael L. Berins (editor), 2000
Modern Plastics Handbook, Charles A. Harper (editor), 1999
Plastics Materials, 7th ed., J. A. Brydson, 1999
CRC Materials Science and Engineering Handbook, 4th ed., James F. Shackelford et al. (editors), 2015