02613nas a2200229   4500008004100000022001400041245016000055210006900215260000800284300001100292490000700303520173900310653002802049653002102077653003302098653003202131653001902163100002102182700002402203700002702227856012902254       2025                        eng d  a1042-714700aOptimization and mechanistic insights of zinc ascorbate catalyst for ring-opening polymerization of caprolactone using RSM methodology and DFT calculations0 aOptimization and mechanistic insights of zinc ascorbate catalyst  cAPR  ae701820 v363 a<p>
	Polycaprolactone (PCL) is an aliphatic polyester recognized for its exceptional versatility and biodegradability, which has garnered significant attention for a wide range of applications. This study presents an innovative methodology for the synthesis of PCL through the ring-opening polymerization (ROP) of epsilon-caprolactone (CL). The approach employs a biocompatible and environmentally benign organometallic zinc ascorbate complex as a catalyst. Derived from ascorbic acid, a well-established reducing agent, zinc ascorbate serves as a sustainable alternative to conventional tin-based catalysts, thereby mitigating environmental impact and enhancing safety measures. The catalyst operates effectively under solvent-free conditions and does not require initiators, achieving a high polymer conversion rate of approximately 79%. The optimization of the reaction parameters was conducted using response surface methodology (RSM) employing a central composite design (CCD). The structural and chemical characterization of the catalyst as well as the resulting polymers was performed using proton nuclear magnetic resonance (1H NMR), Fourier-transform infrared spectroscopy (FTIR), and x-ray diffraction (XRD) analyses. Additionally, density functional theory (DFT) calculations elucidated a four-step coordination-insertion mechanism for the polymerization of cyclic lactones, with findings supported by Gibbs free energy, electrostatic potential, and non-covalent interactions. This study underscores the potential of zinc ascorbate as a reliable, nontoxic, and cost-effective catalyst, fulfilling the increasing demand for sustainable and efficient polymerization processes in commercial and biomedical applications.</p>
10adensity function theory10aPolycaprolactone10aResponse surface methodology10aring-opening polymerization10azinc ascorbate1 aNaik, Sonali, S.1 aVedpathak, Shantanu1 aNair, Kiran, Sukumaran  uhttps://library.ncl.res.in/content/optimization-and-mechanistic-insights-zinc-ascorbate-catalyst-ring-opening-polymerization