polycaprolactone

Polycaprolactone (PCL) is a biodegradable aliphatic polyester derived from the monomer ε-caprolactone. It is a semicrystalline thermoplastic with a relatively low melting point of about 60°C and a glass transition temperature well below room temperature (around −60°C). PCL is soluble in many organic solvents and exhibits high elongation and flexibility, but relatively low modulus compared with other polyesters.

PCL is produced primarily by ring-opening polymerization of ε-caprolactone, often using tin(II) octoate or other catalysts and simple di- or polyfunctional initiators. The molecular weight and polymer architecture are controlled by the monomer-to-initiator ratio and reaction conditions, yielding materials suitable for various processing routes. Industrial grades are available with a range of molecular weights.

Biocompatible and biodegradable, PCL degrades by hydrolysis of its ester linkages, with degradation rates influenced by molecular weight, crystallinity, and environmental conditions. In vivo, it tends to degrade slowly over months to years, making it useful for long-term applications. Its degradation products are typically non-toxic.

Applications include medical devices, drug delivery systems, tissue engineering scaffolds, sutures, and guided tissue regeneration membranes. PCL is also widely used in polymer blends and copolymers to tailor mechanical properties and degradation rates. It is a common material for additive manufacturing and electrospinning, producing micro- to nanoscale fibers, and for extrusion or injection-molding of molded parts. It is sometimes used as a packaging polymer or as a biodegradable alternative in consumer products.

PCL is generally regarded as biocompatible and has been used in numerous FDA-cleared devices and approved medical products. Ongoing research aims to optimize blends, copolymers, and composites to expand its applications.