Polypropylene (PP) is a semi-crystalline thermoplastic made of propylene. The plastic belongs to the commodity resins category.
PP is a lightweight material with low density that is very hard-wearing and durable. Due to its glass-transition temperature of 0°C, PP becomes brittle at low temperatures. It also has a relatively low UV resistance, and so is not well suited to outdoor applications if it has not been treated with additives that improve these properties.
PP is available in homo-, block, and random copolymer variants depending on the polymerization method used. Homopolymers often have higher rigidity, while copolymers commonly have higher impact resistance and better performance at low temperatures. The material is commonly used as a base polymer in blends with fiberglass or mineral fillers as additives to improve mechanical properties and dimensional stability.
PP is used in many application areas such as white goods, HVAC, packaging, and the automotive industry. It can be used to make water pipes, vehicle components, fans, and packaging for medications and foodstuffs.
PP can also be manufactured using renewable raw materials and is easy to recycle, which makes the material an environmentally sustainable alternative.
● Low price and density
● Excellent chemical resistance
● Good mechanical properties
● Good electrical properties
● Low moisture absorption
● Glass-transition temperature of 0°C
Some less optimal properties:
● Low UV resistance
● Poor performance at low temperatures
● Difficult to glue