Kopolymers

Kopolymers, often referred to as copolymers, are polymers formed from two or more different monomer species. The arrangement of monomer units defines the architecture: random copolymers have monomers interspersed; alternating copolymers carry regularly alternating monomers; block copolymers consist of contiguous blocks of each monomer; graft copolymers have side chains of one monomer attached to a backbone of another.

Synthesis methods: Copolymers are typically prepared by copolymerization of the monomers using radical polymerization, ionic polymerization, or controlled/living polymerization techniques. Block copolymers are commonly made by sequential monomer feeding or by living polymerization, while graft copolymers can be formed by grafting polymers onto a preformed backbone.

Structure-property relationships: The monomer selection, composition and microstructure influence glass transition temperature (Tg), crystallinity, toughness, solubility, barrier properties, and processing behavior. Random copolymers can improve processability and modify properties; block copolymers can create phase-separated morphologies that yield thermoplastic elastomers; graft copolymers can impart surface or compatibility characteristics.

Applications and examples: Copolymers are used broadly, including styrene–butadiene copolymers in tires (SBR), ethylene–vinyl acetate copolymers in packaging, and acrylonitrile–butadiene–styrene (ABS) terpolymers in consumer products. They are also used as compatibilizers in polymer blends, adhesives, coatings, and specialty materials. Tailored kopolymers are central to advances in biomedicine and electronics.