Simulation of the Degradation of Cyclic Ketene Acetal and Vinyl‐Based Copolymers Synthesized via a Radical Process: Influence of the Reactivity Ratios on the Degradability Properties

Abstract

The radical copolymerization of vinyl and cyclic ketene acetal (CKA) monomers is a promising way to prepare degradable vinyl polymers. The reactivity of the comonomer pair is known to be dependent of the vinyl monomer structure that requires to play with experimental conditions (feed ratio, overall monomer conversion, etc.) to target a desired cumulative (average) copolymer composition. Even if the materials are completely degradable, there is no information about the homogeneity of the degraded products. This theoretical study, using kinetic Monte Carlo simulations, allows simulating degradation at the molecular level. It is shown that disparate reactivity ratios (styrene/CKA, etc.) and also a composition drift at high conversion can lead to an inhomogeneous degraded product compared to systems with similar reactivity ratios (vinyl ether/CKA, etc.). The use of reversible deactivation radical polymerization techniques does not influence the final degraded products and is only useful for the design of advanced macromolecular architectures before degradation.

Degradable polymer prodrugs with adjustable activity from drug-initiated radical ring-opening copolymerization

“…Note that some discrepancy between theoretical M n after degradation (calculated according to: 1/ F MPDL – 1) and experimental ones may appear because of unfavorable reactivity ratios, as commonly observed with CKA monomers. 59 Also, molar mass distributions stayed rather low ( Đ ∼1.5–1.8) after degradation, which is in agreement with a theoretical investigation 64 showing that stopping at low conversion for the synthesis of the copolymers is key to maintaining a certain homogeneity of the degraded products.…”

Degradable vinyl copolymers through thiocarbonyl addition–ring-opening (TARO) polymerization

“…For the DOT-acrylate system it is presumed that low feeds of DOT are incorporated fully into copolymers in the early stages of polymerization, resulting in the formation of non-degradable homo-acrylate chains for the remainder of the polymerization. 33 However, in this context it is also worth noting that SEC separates polymers by size (not mass) and that different (co-)polymers (including poly(DOT-co-PEGA), its PEGA-based fragments, and the PMMA calibration standards) do not usually show the same mass-size relationships. Nonetheless, the SEC data shown in Fig.…”

Progress in Reaction Mechanisms and Reactor Technologies for Thermochemical Recycling of Poly(methyl methacrylate)

“…Table 4. Overall steps and apparent kinetic parameters proposed by Fateh et al considering the multiphase nature of the chemical recycling; fitting based on Equations (13) and (14); R: residue [115]. MMA is formally part of the gas phase contributions.…”

“…SPW is also used as a reducing agent in blast furnaces to enable sustainable production of iron [ 12 ]. More recently, polymers are also chemically modified in their original synthesis route to enable controlled degradation or re-shaping at the end-of-life [ 13 , 14 , 15 , 16 , 17 , 18 ].…”