Vulcanised rubber

Acronym and details:    also known as ebonite and in USA as hard rubber. It is made from chemically altered natural rubber. The process involves heat and sulphur

Group:   thermoset

Developed:   reaction when heated with a large percentage of sulphur to make it rigid discovered in 1839; still in use in 1930s

Trade names:   Vulcanite; Ebonite

Manufacturing process:   compression moulding; fabrication, including turning

Cost:   medium

Colour:   typically black (fades to brown) but can also be red

Transparency:   always opaque

Rigidity:   rigid

Feel:   hard

Smell:   sulphurous rubbery


Typical uses:   match boxes; combs; fountain pens; imitation jet jewellery; denture palates (with pigmentation to resemble gums); pipe stems

Degradation:   often faded to a greyish greenish brown shade