Polyesters by a Radical Pathway: Rationalization of the Cyclic Ketene Acetal Efficiency

Abstract

Radical ring‐opening polymerization (rROP) of cyclic ketene acetals (CKAs) combines the advantages of both ring‐opening polymerization and radical polymerization thereby allowing the robust production of polyesters coupled with the mild polymerization conditions of a radical process. rROP was recently rejuvenated by the possibility to copolymerize CKAs with classic vinyl monomers leading to the insertion of cleavable functionality into a vinyl‐based copolymer backbone and thus imparting (bio)degradability. Such materials are suitable for a large scope of applications, particularly within the biomedical field. The competition between the ring‐opening and ring‐retaining propagation routes is a major complication in the development of efficient CKA monomers, ultimately leading to the use of only four monomers that are known to completely ring‐open under all experimental conditions. In this article we investigate the radical ring‐opening polymerization of model CKA monomers and demonstrate by the combination of DFT calculations and kinetic modeling using PREDICI software that we are now able to predict in silico the ring‐opening ability of CKA monomers.

Degradable Vinyl Random Copolymers via Photocontrolled Radical Ring‐Opening Cascade Copolymerization**

“…As a representative class of rROP monomer, cyclic ketene acetals (CKAs) (Figure 1A) have been extensively investigated since the 1980s [9] . Despite recent progress made by Dove, [10–14] Nicolas, [15–20] and Sumerlin, [21, 22] unfavorable reactivity ratios in the copolymerization of CKAs with other vinyl monomers often led to gradient or tapered compositions of the resultant copolymer [23] . The gradient composition in turn resulted in highly dispersed degradation products and large non‐degradable fragments, as part of the copolymer lacked main‐chain degradable units.…”

Towards nanoparticles with site-specific degradability by ring-opening copolymerization induced self-assembly in organic medium

“…35,36 It has recently received increasing attention thanks to the ability of CKA to copolymerize with some traditional vinyl monomers by both free-radical polymerization and RDRP. 37 In the past few years, rROP of CKAs has made significant progress from both fundamental 38,39 and applicative [40][41][42][43] perspectives. 44 The rROPISA process was illustrated by the copolymerization in heptane between benzyl methacrylate (BzMA) and two different CKAs, either 2-methylene-4-phenyl-1,3-dioxolane (MPDL) or 5,6-benzo-2-methylene-1,3-dioxepane (BMDO), from a poly(lauryl methacrylate) (PLMA) macro-chain transfer agents (CTAs).…”

100th Anniversary of Macromolecular Science Viewpoint: Degradable Polymers from Radical Ring-Opening Polymerization: Latest Advances, New Directions, and Ongoing Challenges

“…However, it is only very recently that a rationalization of the ring-opening ability of CKA monomers was developed . The behavior of model CKAs was successfully predicted using a combination of density functional theory (DFT) calculations and kinetic modeling via PREDICI, which was further supported by an experimental study.…”