Work

Optimization and Mechanistic Insights of Zinc Ascorbate Catalyst for Ring‐Opening Polymerization of Caprolactone Using RSM Methodology and DFT Calculations

Year: 2025

Type: article

Abstract: ABSTRACT 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 ε‐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.

Source: Polymers for Advanced Technologies

DOI: 10.1002/pat.70182

Authors: Sonali S. Naik, Shantanu Vedpathak, Kiran Sukumaran Nair

Institutions: National Chemical Laboratory, Academy of Scientific and Innovative Research, MIT World Peace University

Language: English

Topic: biodegradable polymer synthesis and properties

Subfield: Biomaterials

Field: Materials Science

Domain: Physical Sciences

SDG: Responsible consumption and production

Open Access status: bronze

Funder: National Chemical Laboratory