The material. Polymer foams are made by the controlled expansion and solidification of a liquid or melt through a blowing agent; physical, chemical, or mechanical blowing agents are possible. The resulting cellular material has a lower density, stiffness, and strength than the parent material, by an amount that depends on its relative density—the volume fraction of solid in the foam. Flexible foams can be soft and compliant, the material of cushions, mattresses, and padded clothing. Most are made from polyurethane, although latex (natural rubber) and most other elastomers can be foamed.
Composition
Hydrocarbon.
General properties
Density
Price
Mechanical properties
Young’s modulus Yield strength (elastic limit) Tensile strength Compressive strength Elongation Hardness—Vickers Fatigue strength at 107 cycles Fracture toughness
Thermal properties
Melting point Glass temperature Maximum service temperature Thermal conductor or insulator? Thermal conductivity Specific heat capacity Thermal expansion coefficient
Electrical properties
Electrical conductor or insulator? Electrical resistivity Dielectric constant Dissipation factor Dielectric strength
Flexible latex foams are used for cushions, mattresses, and packaging.
Ecoproperties: material |
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Embodied energy, primary production |
*104 – |
115 |
MJ/kg |
CO2 footprint, primary production |
*4 – |
4.8 |
kg/kg |
Water usage |
*181 – |
544 |
l/kg |
Eco-indicator |
460 – |
500 |
millipoints/kg |
Ecoproperties: processing |
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Polymer molding energy |
*6.92 – |
8.38 |
MJ/kg |
Polymer molding CO2 |
*0.55 – |
0.67 |
kg/kg |
Polymer extrusion energy |
*2.71 – |
3.28 |
MJ/kg |
Polymer extrusion CO2 |
*0.21 – |
0.26 |
kg/kg |
Recycling |
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Recycle fraction in current supply |
0.1 |
О/ % |
Typical uses. Packaging, buoyancy, cushioning, sleeping mats, soft furnishings, artificial skin, sponges, carriers for inks and dyes.