copolymerizes

Copolymerizes is the act of forming a copolymer, a polymer that contains two or more different monomer units within its backbone or side chains. Copolymerization combines distinct monomers into a single macromolecule, enabling a broader range of properties than homopolymers.

Copolymer structures are commonly classified by the arrangement of monomer units: random copolymers have irregular sequences; alternating copolymers alternate monomer units in a regular pattern; block copolymers consist of long blocks of one monomer followed by blocks of another; graft copolymers have chains of one monomer grafted onto a backbone of another.

Polymerization methods include radical polymerization (in bulk, solution, emulsion, or suspension) and ionic polymerization (anionic or cationic). Controlled or living polymerization techniques, such as ATRP, RAFT, or other living methods, offer greater control over chain length and sequence. Coordination polymerization enables well-defined architectures for certain monomers. The relative reactivity of monomers, described by reactivity ratios, influences whether the resulting copolymer is random, alternating, or blocky.

Properties of copolymers can differ significantly from those of the constituent homopolymers. Adjusting composition and sequence can modify glass transition temperature, toughness, chemical resistance, clarity, and processability. Common industrial examples include styrene–butadiene copolymers used in tires (SBR) and ethylene–vinyl acetate copolymers used in films and packaging. More complex terpolymers such as ABS combine three monomers to achieve improved mechanical properties.

Characterization relies on spectroscopic and chromatographic methods to determine composition and microstructure; NMR is used to assess sequence distribution, while gel permeation chromatography provides molecular weight information. Process considerations include monomer compatibility, reaction temperature, solvent choice, and safety due to exotherms and potential toxicity of monomers. Copolymerization remains a central strategy for tailoring polymer properties.