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MK Plastics Technical Data

Subcategory: Composite Core Material; Polymer; Polymethacrylimide; Thermoset

 

Material Notes:

ROHACELL 71 is a low density grade and a very high strength:weight ratio.

General ROHACELL Information: ROHACELL is a closed-cell rigid expanded plastic material for lightweight sandwich construction. It has excellent mechanical properties, high dimensional stability under heat, solvent resistance and, particularly at low temperature, a low thermal conductivity. The strength and moduli values are the highest for any foamed plastic in its density range. ROHACELL is manufactured by hot forming of methacrylic acid/methacrylonitrile copolymer sheets. During foaming this copolymer is converted to polymethacrylimide.

 

Rohacell 71 IG-F

Properties Metric English Comments
Physical Properties
Density 0.0753 g/cc 0.00272 lb/in_  ASTM D 1622-63
Water Absorption 15.5% 15.5%  Equilibrium at 98% RH
Moisture Absorption at Equilibrium 1.2% 1.2% 15% RH
Moisture Absorption at Equilibrium 2.4% 2.4% 30% RH
Moisture Absorption at Equilibrium 3.6% 3.6% 50% RH
Moisture Absorption at Equilibrium 4.3% 4.3% 65% RH
Water Absorption at Saturation 16% 16% Volume %; 50 days immersion at 20fC
Moisture Expansion Max 3% Max 3% 50 days immersion at 20 fC.
Mechanical Properties
Tensile Strength, Ultimate 2.74 MPa 398 psi ASTM D 638-68
Elongation @ break 4.5% 4.5% ASTM D 638-68
Modulus of Elasticity 0.0903 GPa 13.1 ksi ASTM D 638-68
Flexural Yield Strength 2.45 MPa 356 psi ASTM D 790-66
Compressive Yield Strength 1.47 MPa 213 psi ASTM D 1621-64
Shear Modulus 0.0284 GPa 4.12 ksi ASTM C 273-61
Shear Modulus 0.0294 GPa 4.27 ksi ASTM D 2236-69
Shear Strength 1.28 MPa 185 psi ASTM C 273-61
Electrical Properties
Dielectric Constant 1.08 1.08 2.0 GHz
Dielectric Constant 1.1 1.1 26.0 GHz
Dielectric Constant 1.11 1.11  5.0 GHz
Dielectric Constant 1.13 1.13  10.0 GHz 
Dissipation Factor 0.0003 0.0003  2.0 GHz
Dissipation Factor 0.0007 0.0007 5.0 GHz
Dissipation Factor 0.0018 0.0018 10 GHz
Dissipation Factor 0.0076 0.0076 26.0 GHz
Surface Resistance 5.5E+12 ohm 5.5E+12 ohm  
Thermal Properties
CTE, linear -100fC 30µm/m-ƒC 16.7 µin/in-ƒF  
CTE, linear 20fC 3µm/m-ƒC 19.4 µin/in-ƒF ASTM D 969-70
Thermal Conductivity 0.03 W/m-K 0.208 BTU-in/hr-ft_-fF ASTM C 177-63
Maximum Service Temperature,
Air
180 ƒC 356 ƒF Dimensional stability per DIN 53424
Oxygen Index 19-20% 19-20%  
Descriptive Properties
Colour White