These days, polypropylene is made from polymerization of propene monomer (an unsaturated organic compound – chemical formula C₃H₆) by:

·         Ziegler-Natta polymerization or

·         Metallocene catalysis polymerization

Structure of PP Monomer C3H6

Ziegler-Natta Polymerization Or Metallocene Catalysis

Structure of Polypropylene (C3H6)n

Upon polymerization, PP can form three basic chain structures depending on the position of the methyl groups:

·         Atactic (aPP) – Irregular methyl group (CH₃) arrangement

·         Isotactic (iPP) – Methyl groups (CH₃) arranged on one side of the carbon chain

·         Syndiotactic (sPP) – Alternating methyl group (CH₃) arrangement