Synthesis Of PCL Research Articles

Organocatalytic Ring-Opening Polymerization of ϵ-Caprolactone with Phosphoramidimidates (PADIs) as a Bifunctional Brønsted Acid Catalyst.

In this study, an organocatalytic ring-opening polymerization (ROP) of ϵ-caprolactone (ϵ-CL) has been developed by employing PADIs as a novel and efficient acid/base bifunctional organocatalyst, which could afford metal-free poly(ϵ-caprolactone) with predictable molecular weight and narrow dispersity at a low catalyst loading under mild conditions. NMR and kinetic studies indicate that the ring-opening polymerizations of lactones catalyzed by PADIs proceed in a living and well controlled manner. Moreover, this organic Brønsted acid catalytic system could allow the synthesis of PCL with molecular weight above 60 kg/mol, as well as well-defined star polymers.

Synthesis and characterization of polycaprolactone for anterior cruciate ligament regeneration

Anterior cruciate ligament (ACL) is the most frequently torn ligament in the knee, and complete healing is unlikely due to lack of vascularization. Current approaches for the treatment of ACL injuries include surgical interventions and grafting, however recent reports show that surgeries have 94% recurrency, and that repaired tissues are biomechanically inferior to the native tissue. These necessitate the need for new strategies for scar-free repair/regeneration of ACL injuries.Polycaprolactone (PCL) is a biodegradable and biocompatible synthetic polymer, which has been widely used in the connective tissue repair/regeneration attempts. Here, we report on the synthesis of PCL via ring opening polymerization using ε-caprolactone as the monomer, and ammonium heptamolybdate as a catalyst. The synthesized PCL was characterized using Fourier Transform Infrared Spectroscopy (FTIR) and Nuclear Magnetic Resonance (NMR) spectroscopy. It was then processed using electrospinning to form nanofiber-based scaffolds. These scaffolds were characterized in terms of surface as well as mechanical properties, and compared to the properties of commercially available PCL, and of native ACL tissue harvested from sheep. In addition, scaffolds fabricated with synthesized PCL were evaluated regarding their cell attachment capacity using human bone marrow mesenchymal stem cells (hBMSCs).Our findings demonstrated that the synthesized PCL is similar to its commercially available counterpart in terms of surface morphology and mechanical properties. In addition, fibrous scaffolds generated with electrospinning showed weaker mechanical properties visa vis native ACL tissue in terms of ultimate stress, and elastic modulus. Also, the synthesized PCL can accommodate cell attachment when tested with hBMSCs. Putting together, these observations reveal that the PCL synthesized in this study could be a good candidate as a biomaterial for ligament repair or regeneration.

Synthesis of PCL– graft–PS by combination of ROP, ATRP, and click chemistry

Poly(ε-caprolactone)– graft–polystyrenes were successfully synthesized by grafting an azide end-functionalized polystyrene onto a PCL backbone with multiple pendant alkyne moieties using a “click” chemistry reaction. Both precursors, the PCL backbone and the PS side chains, were prepared separately by two different living/controlled mechanisms, ring-opening polymerisation and ATRP, respectively. Molecular weights, polydispersity indexes, and chemical compositions of the backbone and branches were controlled. The subsequent copper-catalysed Huisgen 1,3-dipolar cycloaddition of PS onto PCL was achieved at room temperature with high conversion. However, a bimodal molecular weight distribution was observed in size exclusion chromatography due to the presence of unreacted PS. Nevertheless, crude product was purified by selective fractionation in cyclohexane to achieve pure graft copolymers.