Poly(alkyl)acrylates are a major class of nonbiodegradable polymers which are difficult to recycle due to an all-carbon backbone. Introducing a certain number of ester bonds in the backbone via radical ring opening copolymerization of acrylates with 2-methylene-1,3 dioxepane (MDO) improves its degradability and may be promising for chemical recycling. The current work examines the influence of monomer addition profiles on the copolymerization of acrylates with MDO. We improved the homogeneity of the MDO insertion through a semibatch approach, which was demonstrated by the molecular weight distribution of fragments after alkali degradation. By detailed NMR analysis, we identified the incorporation of MDO ring retained units, formation of branches on acrylate units, and formation of branches on MDO ring open units as the key side reactions. Theoretical calculations showed that mainly kinetic factors influence the outcome of the polymerization.

Recycling and biodegradability of chain-growth polymers is an important and growing topic. Introducing ester bonds in polymers via cyclic ketene acetals (CKAs) is an interesting route to create (bio)­degradability. Incorporation of CKA monomers is controlled by reactivity ratios. Reactivity ratios of different CKA/vinyl monomer systems published in the literature were re-evaluated with the nonlinear least-squares method, taking into account the error in the 1H NMR measurements of monomer fractions in copolymers. This study confirms that the nonlinear least-squares method should be used instead of Fineman–Ross or Kellen–Tudos methods. Re-evaluated values suggest that reactivity ratios of CKA/vinyl monomer systems follow a family-like behavior.

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Poly(2‐ethylhexyl acrylate) is synthesized by conventional radical bulk polymerization both with and without 1‐dodecane thiol as chain transfer agent (CTA) at temperatures from 4 to 140 °C. Electrospray‐ionization mass spectrometry is used to analyze the polymer. This reveals the occurrence of significant β‐scission at high temperature and confirms the presence of CTA‐capped polymers at all temperatures, as well as combination products from 4 to 65 °C. Subsequent 13C melt‐state NMR analysis allows quantification of branching and β‐scission. Both are reduced when CTA is present, consistent with a “patching” effect. As expected, the amounts of β‐scission and branching increase with synthesis temperature, although β‐scission dominates at the highest temperature. The backbiting rate coefficient of 2‐ethylhexyl acrylate is determined from NMR results, taking β‐scission into account for the first time. Remarkable agreement with literature kbb values is obtained, especially for activation energy. This strongly suggests family‐type behavior for acrylate kbb.