Quantum-Chemical Study for Understanding the Low Incorporation of 2-Methylen-1,3-Dioxepane (MDO) in Radical Ring-Opening Copolymerization with Vinyl Monomers
Year: 2026
Type: article
Abstract: Radical ring-opening polymerization (rROP) of cyclic ketene acetals (CKAs), particularly 2-methylene-1,3-dioxepane (MDO), offers a robust pathway to introduce degradable ester linkages into nondegradable vinyl backbones. However, the rational design of these materials is currently hindered by highly comonomer-dependent open-to-closed (ester vs acetal) incorporation ratios. In this study, a rigorous density functional theory (DFT) framework integrating systematic conformational sampling and implicit solvation is employed to establish a unified structure-reactivity map for MDO copolymerization across a diverse set of vinyl monomers. The computational results reveal that while MDO homopolymerization is thermodynamically driven toward quantitative ring opening due to the irreversibility of the open-chain radical, copolymerization is governed by a fine-tuned competition between the kinetic accessibility of vinyl addition and the stability of the resulting cyclic adduct. The closed-propagation barrier is primarily dictated by a SOMO-LUMO interaction, where the electronic nature and α-substitution of the comonomer modulate orbital overlap and energy. Three distinct reactivity regimes are identified: (1) high open incorporation (e.g., MDO, crotonates), where high vinyl barriers and adduct reversibility favor β-scission; (2) intermediate competition (e.g., vinyl acetate); and (3) ring-retention dominance (e.g., acrylates), where rapid vinyl addition and deep thermodynamic stabilization suppress the degradable pathway. This work provides a qualitative molecular basis for the rational selection of comonomers to maximize CKA incorporation in the open form for next-generation sustainable vinyl polymers.
Source: Macromolecules
Authors: Mikel Irigoyen, Alice Marchand, Xabier Lopez de Pariza, Timo Melchin, Aitor Barquero, Jon M. Matxain, Haritz Sardón, Jose R. Leiza, Fernando Ruipérez
Language: English
Subfield: Organic Chemistry
Field: Chemistry
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,500
Awards: G1175115578, G1204740081, G120905174, G121809054, G1272927172, G1622782223, G1855990336, G210041235, G210753366, G2262748287, G2309174360, G24120701, G252646220, G2550080368, G2601397997, G2660406951, G279363373, G2840769958, G294895050, G300979063, G34346518, G3480869486, G348919436, G3518538256, G357246561, G363809202, G3681454997, G4042783231, G410571670, G425668148, G430777504, G4442677895, G451917667, G4526231891, G464105488, G5080475149, G511979048, G5195188938, G531036588, G5421974903, G546199279, G5539308778, G5933510654, G5967599077, G6092700082, G6218905885, G7084143925, G7162266856, G7582100459, G8546142835, G8888022036, G897484643, G929308097, G99296377
OpenAlex ID: W7168773941