(High Impact Polystyrene)
High Impact Polystyrene is what its name implies. A few cents more than crystal styrene, to pay for the rubber modifier.
HIPS is opaque and very widely used. It has a lower modulus, better elongation, and is a lot less brittle than crystal styrene.
| Max Temp. | Chemical Resistance | Tensile Strength | Flexural Modulus | Impact Strength |
| 100°-150° F | Poor | 7,500-10,000 psi | 160,000 -370,000 psi | 3-7 ft-lb/in notched izod |
Pros
Optical clarity
High gloss
FDA grades available
Low cost
Good dimensional stability
Good rigidity
Cons
Flammable, but flame retardant grades available
Poor solvent resistance
Homopolymers are brittle
Subject to stress and environmental cracking
Certene
Hival
Polystyrol
Styron