Meaning
Semicrystalline thermoplastic polyester produced by the ring-opening polymerization of epsilon-caprolactone provides high flexibility and a very low melting temperature of sixty degrees Celsius. This specialized polymer, known widely as polycaprolactone, possesses excellent biocompatibility and a slow biodegradation rate that makes it highly suitable for biomedical applications. It blends easily with other resins to modify their impact strength and processing characteristics.
Its low transition temperature restricts its use in hot environments but makes it highly useful for low-temperature shaping.
Thermal Behavior
Extremely low melting points allow this material to be processed using standard equipment without risking thermal degradation of active ingredients or blended compounds. This thermal profile means that polycaprolactone requires very little energy to melt and flows easily through complex runner systems. However, its low glass transition temperature of minus sixty degrees Celsius means the polymer remains highly flexible and ductile at room temperature.
This ductility prevents it from being used in applications that require high structural rigidity.
Compounding Integration
Compounders often utilize this polymer as a polymeric plasticizer to improve the toughness of brittle bioplastics like polylactic acid. It acts to absorb mechanical energy and prevent catastrophic crack propagation under load. When combined with other materials, it must be distributed evenly to avoid phase separation and inconsistent mechanical performance.
Part Production
Processing parameters must be adjusted to account for the slow solidification rate caused by the low crystallization temperature. Long cycle times are often necessary to allow the moulded parts to develop sufficient green strength before ejection. Applying active cooling to the mould helps reduce these cycles and prevents part deformation during ejection.
