1 Department of Chemical and Biological Engineering, University of Ottawa, Ottawa, ON K1N 6N5, Canada.
2 Department of Chemical and Materials Engineering, Concordia University, Montreal, QC H3G 1M8, Canada.
3 Department of Process Engineering and Applied Science, Dalhousie University, Halifax, NS B3H 4R2, Canada.
4 Institute for Polymer Research (IPR), Department of Chemical Engineering, University of Waterloo, Waterloo, ON N2L 3G1, Canada.

This investigation introduces the first estimation of ternary reactivity ratios for a butyl acrylate (BA), 2-methylene-1,3-dioxepane (MDO), and vinyl acetate (VAc) system at 50 °C, with an aim to develop biodegradable pressure-sensitive adhesives (PSAs). In this study, we applied the error-in-variables model (EVM) to estimate reactivity ratios. The ternary reactivity ratios were found to be r₁₂ = 0.417, r₂₁ = 0.071, r₁₃ = 4.459, r₃₁ = 0.198, r₂₃ = 0.260, and r₃₂ = 55.339 (BA/MDO/VAc 1/2/3), contrasting with their binary counterparts, which are significantly different, indicating the critical need for ternary system analysis to accurately model multicomponent polymerization systems. Through the application of a recast Alfrey-Goldfinger model, this investigation predicts the terpolymer's instantaneous and cumulative compositions at various conversion levels, based on the ternary reactivity ratios. These predictions not only provide crucial insights into the incorporation of MDO across different initial feed compositions but also offer estimates of the final terpolymer compositions and distributions, underscoring their potential in designing compostable or degradable polymers.