Plastics

Acrylonitrile butadiene styrene (ABS)

General information

Description

ABS is a thermoplastic co-polymer of acrylonitrile and styrene with butadiene extensions. These extensions give ABS a high impact strength which makes it more expensive than polystyrene. Being a co-polymer of styrene it can produce a tinny sound when tapped upon. ABS often has a high gloss. The presence of butadiene extensions makes ABS opaque. Mixing acrylate with the resin pellets makes the final product more transparant.

History

ABS was patented in 1948 and has been commercially available since 1954.

Production, Application, Appearance

ABS granules are processed by injection moulding and extrusion. Due to its high impact strength it used much for the manufacturing of for example high quality toys (Lego, Fischerprice), computer casing, keycaps, suitcases and car bumpers. ABS extruded into a filament is used in 3D printing.

Properties

Material properties

Thermoplast
Density: 1.03-1.09 g/cm3
Melting point: 220-260 °C
Glass transition temperature: 90-115°C

Identification properties

Cell structure (foam): not applicable
Smell: no characteristic smell
Touch: no characteristic touch
Sound: Rigid = clear. Can sound tinny; film = (?) no characteristic sound
UV-radiation (when clear): not applicable
Polarizing filters (when clear): not applicable

Degradation

Process

Photo-oxidation

Details

None

Symptoms

Yellowing; surface becomes matte; surface becomes rougher; loss of mechanical properties resulting in tears, fractures, embrittlement, stress cracking, soiling.

Susceptibility

UV-radiation: High - ABS discolours rapidly
Light: High
Oxygen/Ozone: Low
Temp: Low
RH: Medium

Preventive conservation

Recommendations

UV-RADIATION: keep below 10 µW/lm Exclude UV with filters or no-UV light source
LIGHT: 1 just noticeable change in approx. 1 Mlx.h Limit light dose by reducing intensity and exposure time
OXYGEN / OZONE: ambient conditions
TEMP: common indoor conditions 10-30°C
RH: common museum conditions 40-60% RH fluctuations: setpoint ±10% or ±5% when allowing seasonal fluctations between 35-65%"