PS
PS
Polystyrene
Polystyrene (PS) is a synthetic hydrocarbon polymer made from the monomer styrene. It is a thermoplastic, meaning that it can be melted and reshaped multiple times without losing its properties. PS has a high molecular weight, and the polymer chains are held together by weak van der Waals forces. This gives polystyrene its characteristic lightweight and brittle nature. Polystyrene can be produced by two methods, either by suspension polymerization or by solution polymerization. The properties of polystyrene can also be modified by adding other materials to it, such as pigments, fillers, or other polymers. These properties can also be modified by adding other chemicals to the polymer. For example, polystyrene can be made more rigid by the addition of a small amount of a chemical called a crosslinking agent. This process is called crosslinking.
Polystyrene is widely used in packaging and insulation, due to its good insulation properties, low cost, and ease of manufacture. However, polystyrene is not biodegradable and can persist in the environment for hundreds of years, which is one of the main concerns about its environmental impact.
Polystyrene (PS) was first discovered in 1839 by a German apothecary named Eduard Simon. Simon isolated a white, waxy substance from natural resin, which he called “styrol.” However, it was not until the early 20th century that scientists began to understand the polymerization process that creates polystyrene. In the 1930s, a Belgian-born American chemist named Paul Schlack developed a method for polymerizing styrene to create a plastic material that he called “polystyrene.” Schlack’s process involved suspending styrene monomers in an aqueous solution and then adding a catalyst to initiate polymerization. This method is known as suspension polymerization and is still used today to produce polystyrene.
During World War II, polystyrene was used to produce a variety of products, including insulation for electrical equipment, and packaging materials for food and other goods. After the war, demand for polystyrene increased rapidly, and it became a widely used material for a variety of consumer products. One of the most well-known uses of polystyrene is for disposable foam cups and food containers. This application began in the 1950s and quickly grew in popularity due to the material’s low cost and insulating properties.
PS Material Properties and Characteristics
- Lightweight and brittle
- Good insulation properties
- Not biodegradable
- Can be modified and recycled, though recycling may prove difficult
- Flammable and releases toxic fumes when exposed to heat
- Low moisture permeability, not suitable for outdoor or high humidity applications
- Low cost and easy to process
- Low melting point and can be easily molded into different shapes and forms
- Poor UV resistance and may degrade when exposed to sunlight
- Low coefficient of thermal expansion
Applications for PS
- Packaging : Foam peanuts, egg cartons, and protective packaging for fragile items.
- Food packaging : Disposable products such as foam cups, plates, and food containers, plastic trays, cups, and containers for food service and food packaging.
- Isolation : Insulation for buildings, appliances, and electronic equipment.
- Signage and displays : Signage and displays.
- Others : Plastic models and prototypes, surface protection and cushioning for shipping fragile items, stationery items such as rulers, stencils, and foam boards, plastic molds and patterns for casting metal or other materials.
- Medical applications : Medical devices such as blood bags and test tube racks.