Thermoplastic List

Polypropylene Homopolymer

Specific Gravity - Low

Fatigue Resistance - Excellent

Strength/Rigidity - Excellent

Impact Strength - Moderate

Notch Sensitivity - High

Shrinkage - High

Visibility: Clear or colored

Temp - Poor at low temps

What is it used for: LE Orthotics, frames, and sockets

Polypropylene Copolymer

Specific Gravity - Low

Fatigue Resistance - Excellent

Strength/Rigidity - Moderate

Impact Strength - Excellent

Visibility - Opaque or colored

Temps - Moderate at low temps

What is it used for: LE Orthotics, frames, and sockets

Low Density Polyethylene (less crystalline)

Fatigue Resistance - Poor

Strength/Rigidity - Excellent

What is it used for: Prosthetic socket liners, TLSOs, UE orthotics, non weight-bearing

Linear Low Density Polyethylene (more crystalline)

What is it used for: Prosthetic socket liners, TLSOs, UE orthotics, non weight-bearing

High Density Polyethylene

Strength/Rigidity: same as Polypropylene Homopolymers

Shrinkage: High

What is it used for: UE orthotics, some spinal orthotics, non weight-bearing orthotics

HMWHDP (Subortholen) [High Molecular Weight High Density Polypropylene]

Mechanical properties increase

UHMWHDP (Ortholen) [Ultra High Molecular Weight High Density Polypropylene]

Mechanical properties increase even more

Ionomer (Surlyn)

Fatigue Resistance: Poor

Strength/Rigidity: Excellent

Visibility: Clear

Skrinkage: Low

Copolyester (Durrplex, Vivak)

Fatigue Resistance: Poor

Strength/Rigidity: Excellent

Visibility: Clear

Skrinkage: Low

What is it used for: check sockets

Kydex

High Impact Strength

High Stiffness

What is it used for: TLSOs