Novel synthesis of biodegradable linear and star block copolymers based on ε‐caprolactone and lactides using potassium‐based catalyst

Synthesis of star-shaped poly(lactide)s, poly(valerolactone)s and poly(caprolactone)s via ROP catalyzed by N-donor tin(ii) cations and comparison of their wetting properties with linear analogues

In this study, we report the use of N-coordinated tin(ii) cations [L1→Sn(H2O)][OTf]2·THF (1) and [L1→SnCl][SnCl3] (2) (L1 = 1,2-(C5H4N-2-CH = N)2CH2CH2) as efficient ROP catalysts, which, in combination with benzyl alcohol, afford well-defined linear poly(ε-caprolactone) (PCL) and poly(δ-valerolactones) (PVL) via an activated monomer mechanism (AMM). Thanks to the versatility of complexes 1 and 2 as catalysts, star-shaped PCL, PVL and PLA were also prepared using three-, four-, five- and six-functional alcohols. The number of arms was determined by SEC-MALS-Visco analysis. Spin-coated thin layers of linear and selected six-armed polymers were further studied in terms of their wettability to water. Attention was focused on the influence of the composition and structure of the polymers. Finally, to increase the hydrophobic properties of the studied polymers, stannaboroxines L2(Ph)Sn[(OB-(C6H4-4-CF3))2O] and L2(Ph)Sn[(OB-(C6H4-3,5-CF3)2)2O] (L2 = C6H3-2,6-(Me2NCH2)2) were applied.

Aliphatic polyester polymer stars: synthesis, properties and applications in biomedicine and nanotechnology

A critical review: the ring-opening polymerization of cyclic esters provides access to an array of biodegradable, bioassimilable and renewable polymeric materials. Building these aliphatic polyester polymers into larger macromolecular frameworks provides further control over polymer characteristics and opens up unique applications. Polymer stars, where multiple arms radiate from a single core molecule, have found particular utility in the areas of drug delivery and nanotechnology. A challenge in this field is in understanding the impact of altering synthetic variables on polymer properties. We review the synthesis and characterization of aliphatic polyester polymer stars, focusing on polymers originating from lactide, ε-caprolactone, glycolide, β-butyrolactone and trimethylene carbonate monomers and their copolymers including coverage of polyester miktoarm star copolymers. These macromolecular materials are further categorized by core molecules, catalysts employed, self-assembly and degradation properties and the resulting fields of application (262 references).