Self-Made Cyclodextrin Inclusion Complexes for Enhanced Mechanical Properties of Polycaprolactone Composites

Polycaprolactone (PCL) is a widely used polymer in biomedical applications due to its excellent processability, ductility, and biodegradability. However, single-component PCL devices often fail to meet the multifunctional and high-performance demands of modern biomedical devices. In this study, we introduced biodegradable and environmentally friendly cyclodextrin (CD) to fabricate CD inclusion complexes with low-molecular-weight polycaprolactone (LPCL). These complexes were incorporated into commercial PCL to prepare the resulting composites. The effects of PCL molecular weight and CD type on the properties and inclusion ratios of the complexes were systematically investigated. Among the tested complexes, the one formed with LPCL (Mw = 8 × 10⁴) and α-CD exhibited the highest inclusion ratio (2:1), significantly enhancing the crystallization and mechanical properties of the resulting composite (PCL/8-α-CD). Compared to pure PCL, the PCL/8-α-CD composite shows a 14.8% increase in crystallinity, along with improvements of 63.6% and 30.9% in tensile strength and elongation at break, respectively. These results demonstrate that the incorporation of CD inclusion complexes can effectively enhance the mechanical performance of PCL, making it a promising candidate for high-performance biomedical applications.