Polystyrene gpps plastic granules for free sample , is a colorless, odorless, tasteless, shiny, transparent beaded or granular solid. Density is 1.04 to 1.09, transparency is 88% to 92%, refractive index is 1.59 to 1.60. In the stress function, resulting in birefringence, the so-called stress - optical effect. Product of the melting temperature is 150 to 180 ° C, thermal decomposition temperature is 300 ° C, the heat distortion temperature is 70 to 100 ° C, long-term use temperature is 60 ~ 80 °C.