Lipase-Catalyzed Copolymerization of ω-Pentadecalactone with p-Dioxanone and Characterization of Copolymer Thermal and Crystalline Properties

Abstract

Candida antarctica Lipase B (CALB), a metal-free enzyme, was successfully employed as catalyst for ring-opening copolymerization of omega-pentadecalactone (PDL) with p-dioxanone (DO) under mild reaction conditions (<80 degrees C, atmospheric pressure). Poly(PDL-co-DO) with high molecular weight (Mw > 30 000) and a wide range of comonomer contents was synthesized using various PDL/DO feed ratios. During the copolymerization reaction, large ring PDL was found to be more reactive than its smaller counterpart DO, resulting in higher PDL/DO unit ratios in polymer chains than the corresponding PDL/DO monomer ratios in the feed. The copolymers were typically isolated in 50-90 wt % yields as the monomer conversion was limited by the equilibrium between monomers and copolymer. 1H and 13C NMR analysis on poly(PDL-co-DO) formed by CALB showed that the copolymers contain nearly random sequences of PDL and DO units with a slight tendency toward alternating arrangements. Copolymerization with PDL was found to remarkably enhance PDO thermal stability. Differential scanning calorimetry (DSC) and wide-angle X-ray scattering (WAXS) results demonstrate high crystallinity in all copolymers over the whole range of compositions. Depending on copolymer composition, the crystal lattice of either PDO or PPDL hosts units of the other comonomer, a behavior typical of an isodimorphic system. In poly(PDL-co-DO), both melting temperature and melting enthalpy display a minimum at 70 mol % DO, that is, at the pseudoeutectic composition. WAXS diffractograms show one crystal phase (that of either PPDL or PDO) on either side of the pseudoeutectic and coexistence of PPDL and PDO crystals at the pseudoeutectic.

Porous Polymeric Bioresorbable Scaffolds for Tissue Engineering

“…Trimethylene carbonate is also widely used as co-monomer with lactic acid, glicolic acid or ε-caprolactone in order to obtain scaffolds with elastomeric properties [62][63][64][65][66].…”

“…This might reduce inflammatory reactions caused by fast release of acidic by-products and they might be particularly interesting for long-term applications. Moreover, PDL has been successfully copolymerized with comonomers such as trimethylene carbonate [63], ε-caprolactone [64], and p-dioxanone [65], thus enabling material scientists to tailor corresponding hydrolysis rate and biomaterial physical properties for targeted applications.…”

“…Similarly to P(DL-CL), in P(DL-DO) the two monomeric units cocrystallize in the same lattice, with a behaviour, in this case, typical of a isodimorphic system [66]. The adjustment of ES parameters allows obtaining many different fibre morphologies in terms of presence of beads and bead shape, fibre porosity and dimension.…”

Hydrolases Part I: Enzyme Mechanism, Selectivity and Control in the Synthesis of Well-Defined Polymers

“…Indeed, as observed by several groups, copolymerization of CL and PDL [120], CL and VL [121], PDL and 2-oxo-12-crown-4 (OC) [122,123], CL and OC [124], PDL and p-dioxanone (DO) [125], and CL and 1,5-dioxepan-2-one (DXO) [126] afforded random copolymers, as evidenced by differential scanning calorimetry, 1 H-NMR, 13 C-NMR, and solid state NMR. For example, in the copolymerization of PDL and OC, the rate of PDL polymerization was five times lower than the rate of OC polymerization [123].…”

Candida antarctica Lipase B as Catalyst for Cyclic Esters Synthesis, Their Polymerization and Degradation of Aliphatic Polyesters

“…In addition, de Geus et al also synthesized PPDL with high M n about 80 kg mol −1 which was used to prepare high strength fibers with tensile strength up to 0.74 GPa [96]. Due to the good thermal and mechanical properties of PPDL, PDL was copolymerized several times [97] with p-dioxanone (DO) (ester-ether) in order to improve thermal stability of polydioxanone (PDO) and its tensile strength. PDO can be used in drug delivery, reconstructive surgery, cardiovascular and bone repair applications.…”