Effect of composition and structure of ethylene-vinyl acetate copolymer on its alcoholysis kinetics: A combined experimental and DFT study

The alcoholysis process of ethylene-vinyl acetate copolymer (EVA) is both important and complex. In this work, we conduct experimental and computational investigations to examine the alcoholysis kinetics and mechanism of EVA with an ethylene content if less than 50 mol%. Our findings indicate that the overall structure of EVA polymer chain has little effect on the alcoholysis rate. However, the local structure of the acetate group, particularly its association with the ethylene content, significantly affects the overall alcloholysis. To predict the influence of ethylene content on the overall rate constant, we propose an empirical model based on detailed kinetic studies of triads. Additionally, we discover a self-acceleration phenomenon in EVA alcoholysis, although it is less pronounced compared to polyvinyl acetate. Furthermore, we employed quantum chemical calculation using density functional theory (DFT) to confirm the effect of structure on EVA alcoholysis. Notably, we investigate, for the first time, the influence of neighboring hydroxyl group on self-acceleration phenomenon through theoretical calculations. This work offers valuable insight into EVA alcoholysis and may serve as a guide for exploring its mechanism and designing processes for producing EVA related polymer materials.

Automated summary

This study revealed that the local structure of the acetate group in EVA, particularly its association with the ethylene content, significantly affects the overall alcoholysis rate. An empirical model based on detailed kinetic studies of triads was proposed to predict the influence of ethylene content on the overall rate constant. Additionally, a self-acceleration phenomenon in EVA alcoholysis was discovered, although it was less pronounced compared to polyvinyl acetate.