Acronym and details:   PU, PUR polyurethane rubber

Group:   thermoset as foams; thermoplastic as fibres and surface coatings

Developed:   from 1937; still widely used

Trade names:   in adapted form: Lycra; Spandex

Manufacturing process:   all

Cost:   medium

Colour:   any

Transparency:   transparent to opaque

Rigidity:   any

Feel:   varies

Smell:   none

Other:   surface scratches with fingernail

Typical uses:   furniture; paint; shoe soles; synthetic leather-like fabrics; bicycle seats; as foams, seating, large mouldings

Degradation:   discolouration followed by crumbling, the result of oxidation; foams deteriorate faster due to their greater surface area