Twenty Kinds of Plastics and Their Properties—(14) PMMA
14.PMMA polymethyl methacrylate
Typical application range:
Automotive industry (signal lamp equipment, dashboard, etc.), pharmaceutical industry (blood storage container, etc.), industrial applications (video disc, light diffuser), daily consumer goods (beverage cups, stationery, etc.).
Injection molding process conditions:
Drying process: PMMA has a hygroscopic property, so it is necessary to dry before processing. It is suggested that the drying condition is 90 °C and 2~4 hours.
Melting temperature: 240~270 °C.
Mold temperature: 35~70 °C.
Injection speed: medium
Chemical and physical properties:
- PMMA has the optical properties and weatherability of fine, white light transmittance is as high as 92%.
- PMMA products have very low birefringence, especially suitable for making DVDs and so on.
- PMMA has the properties of room temperature creep. With the increase of load and time, the phenomenon of stress cracking can be caused.
- PMMA has good impact resistance.