Thermofoam

Thermofoam is a medium density white foam that is specifically non-allergenic.  Its configuration is a closed cell, cross linked polyethylene and is a member of the olefin family of plastics.  This configuration allows the foam to provide outstanding force dispersion equally in all directions.  It is available in two densities to increase the ability of the practitioner in precise pressure application.  The compression of the foam and its hypoallergenic composition lead to high patient compliance.

Manufacturing
Thermofoam has excellent, thermoforming and thermobonding characteristics.  It can be knifed, die cut, or punched.  It can be shaped by drape, vacuum, and pressure molding techniques.  The normal forming temperature is 310 F.  Thermofoam has a short heat cycle and a very short working time (.5-2 minutes).  Once molded, it can be modified using localized heat.

Thermobonding is possible with all polypropylenes and polyethylenes, as well as other thermobonding materials.  It may be necessary to apply a vacuum interface when vacuum forming Thermofoam, due to its good mold replication accuracy and ability to mark off.  This material is self adhering at forming temperatures.

Thermofoam may not be solvent welded.  Most good plastic glues will mechanically bond the foam to plastics and provide medium strength bonds to metals.  Spot heat welding is possible, but not recommended for strength requiring bonds.  It can be cleaned using acetone.

If air holes are required to draw vacuum they should be small.  Using vacuum holes of no larger than 1/32" diameter are required to prevent marking of the foam.

Sterilization
Thermofoam is not capable to be sterilized using standard techniques.

Precautions
Thermofoam is a combustible material and therefore should be stored in a cool dry area.  The flash point of this material is 585 F.  Because it is a petroleum derivative, it gives off a heavy black toxic smoke that is dangerous to inhale and difficult to see through.  This material is not effective in most outdoor application.

Applications
Applications of this material are broad.  It can be used anytime patient compliance, extensive cushioning and dispersion of forces is needed, and when hypoallergenic is required.  It is a favorite material for liners in all shell and cuff designs in upper and lower extremity orthotics in which padding is dictated.  It can be laminated in combination with more dense foams to provide superior force dispersion while still sustaining firm support, as in the treatment of diabetic feet.  When laminated with a layer of Durofoam, it provides good characteristics of support and high comfort while supplying a hypoallergenic surface for prolonged term skin contact.

Sheet Chart
Thermofoam is a white, non-allergenic, polyethylene foam with many uses, including: liners, pads, splints, fillers.  It is closed cell, thermoformable and thermobondable.  Also known as: Aliplast, Volara.