Assertion: fiber optic cable's fiber | /r/MadeOf | polymethylmethacrylate
Facets:
value: usually
type: TEMPORAL
Source sentences:
text: Plastic fibers, usually made of polymethylmethacrylate, polystyrene, or polycarbonate, are cheaper to produce and more flexible than glass fibers, but their greater attenuation of light restricts their use to much shorter links within buildings or automobiles.