CAP vs. RPU

CAP belongs to the thermoplastics classification, while RPU belongs to the thermoset plastics. There are 14 material properties with values for both materials. Properties with values for just one material (14, in this case) are not shown.

For each property being compared, the top bar is CAP and the bottom bar is RPU.

Cellulose Acetate Propionate (CAP)Rigid Thermoset Polyurethane (RPU)

Metric UnitsUS Customary Units

Mechanical Properties

Elongation at Break, %		35 to 50
Elongation at Break, %		90

Flexural Modulus, GPa		1.2 to 1.9
Flexural Modulus, GPa		2.0

Flexural Strength, MPa		29 to 56
Flexural Strength, MPa		83

Tensile Strength: Ultimate (UTS), MPa		28 to 45
Tensile Strength: Ultimate (UTS), MPa		60

Thermal Properties

Specific Heat Capacity, J/kg-K		1480
Specific Heat Capacity, J/kg-K		1750

Thermal Conductivity, W/m-K		0.25
Thermal Conductivity, W/m-K		0.19

Thermal Expansion, µm/m-K		14
Thermal Expansion, µm/m-K		63

Vicat Softening Temperature, °C		85 to 110
Vicat Softening Temperature, °C		120

Electrical Properties

Dielectric Strength (Breakdown Potential), kV/mm		15
Dielectric Strength (Breakdown Potential), kV/mm		19

Electrical Resistivity Order of Magnitude, 10^x Ω-m		16
Electrical Resistivity Order of Magnitude, 10^x Ω-m		13

Otherwise Unclassified Properties

Density, g/cm³		1.2
Density, g/cm³		1.2

Common Calculations

Strength to Weight: Axial, points		6.5 to 10
Strength to Weight: Axial, points		14

Strength to Weight: Bending, points		17 to 23
Strength to Weight: Bending, points		28

Thermal Diffusivity, mm²/s		0.14
Thermal Diffusivity, mm²/s		0.090