Under the action of stress, birefringence occurs, which is called stress optical effect. The melting temperature of the product is 150-180 ℃, the thermal decomposition temperature is 300 ℃, the thermal deformation temperature is 70-100 ℃, and the long-term service temperature is 60-80 ℃. After annealing treatment, the stress can be relieved and the hot deformation temperature can be increased. If a little α – methylstyrene is added in the production process, the heat resistance grade of general polystyrene can be improved.
It is soluble in aromatic hydrocarbons, chlorinated hydrocarbons, aliphatic ketones and esters, but can only swell in acetone. It can resist the action of some mineral oil, organic acid, alkali, salt, low alcohol and its aqueous solution. Its mechanical properties and dimensional stability can be maintained in humid environment due to its low water absorption. The optical properties are second only to acrylic resin. It is not affected by temperature, humidity and corona discharge. The radiation resistance is also very good. Its main disadvantages are brittle and easy to crack, low impact strength, poor heat resistance, can not withstand boiling water, can only be used at lower temperature and lower load. Poor sunlight resistance, flammable. When burning, it emits black smoke and has special odor.