Polypropylene is a polymer whose monomer is propylene (an organic hydrocarbon with the chemical formula C3H6). The chemical formula of polypropylene is (C3H6)n. This polymer is also known as polypropene and is often denoted by the abbreviation PP. Generally, polypropylene is produced via a chain-growth polymerization reaction involving propylene. Toughness and flexibility (exhibited to a large extent especially when the polymerization process involves copolymerization with ethylene). Large thermal expansion. Resistant to organic solvents. Resistant to weak oxidizing agents. Soluble in some organic nonpolar solvents like xylene.