Crazing is a fine network of linear features which frequently precedes fracture in glassy thermoplastic polymers. Crazing occurs in regions of high hydrostatic tension, or in regions of very localized yielding, which leads to the formation of interpenetrating microvoids and small fibrils. If an applied tensile load is sufficient, these bridges elongate and break, causing the microvoids to grow and coalesce; as microvoids coalesce, cracks begin to form.

Polystyrene (PS) is a synthetic polymer made from monomers of the aromatic hydrocarbon styrene. Polystyrene can be solid or foamed. General-purpose polystyrene is clear, hard, and brittle. It is an inexpensive resin per unit weight. It is a poor barrier to air and water vapor and has a relatively low melting point. Polystyrene is one of the most widely used plastics, with the scale of its production being several million tonnes per year. Polystyrene is naturally transparent, but can be colored with colorants. Uses include protective packaging, containers, lids, bottles, trays, tumblers, disposable cutlery, in the making of models, and as an alternative material for phonograph records.