Revisiting the Anionic Polymerization of Methyl Ethacrylate

A Computationally Informed Unified View on the Effect of Polarity and Sterics on the Glass Transition in Vinyl-based Polymer Melts

We unveil a unified view on the effect of side chains on the glass transition temperatures (Tg) in polymer melts by using molecular dynamics simulations, density functional theory calculations, and available experimental data. We use acrylates as a model system and evaluate the effect of n-alkyl side chains on Tg. We find that backbone dihedral angle fluctuations follow established patterns due to sterics, as expected. However, we also find that the dihedral angle orthogonal to the backbone, which normally is neglected when discussing the effect on Tg, introduces a secondary rotational degree of freedom which strongly impacts Tg. These results are in agreement with experiments and generalize to multiple other polymer systems, as is demonstrated using available experimental data. Conversely, n-alkyl pendant groups attached to the side group reduce Tg. Our work establishes a coherent framework that unifies previously established trends, emphasizing the polarity and size effects of n-alkyl chains on Tg.

Reversed Controlled Polymerization (RCP): Depolymerization from Well-Defined Polymers to Monomers

Controlled polymerization methods are well-established synthetic protocols for the design and preparation of polymeric materials with a high degree of precision over molar mass and architecture. Exciting recent work has shown that the high end-group fidelity and/or functionality inherent in these techniques can enable new routes to depolymerization under relatively mild conditions. Converting polymers back to pure monomers by depolymerization is a potential solution to the environmental and ecological concerns associated with the ultimate fate of polymers. This perspective focuses on the emerging field of depolymerization from polymers synthesized by controlled polymerizations including radical, ionic, and metathesis polymerizations. We provide a critical review of current literature categorized according to polymerization technique and explore numerous concepts and ideas which could be implemented to further enhance depolymerization including lower temperature systems, catalytic depolymerization, increasing polymer scope, and controlled depolymerization.

Quo Vadis Carbanionic Polymerization?

Living anionic polymerization will soon celebrate 70 years of existence. This living polymerization is considered the mother of all living and controlled/living polymerizations since it paved the way for their discovery. It provides methodologies for synthesizing polymers with absolute control of the essential parameters that affect polymer properties, including molecular weight, molecular weight distribution, composition and microstructure, chain-end/in-chain functionality, and architecture. This precise control of living anionic polymerization generated tremendous fundamental and industrial research activities, developing numerous important commodity and specialty polymers. In this Perspective, we present the high importance of living anionic polymerization of vinyl monomers by providing some examples of its significant achievements, presenting its current status, giving several insights into where it is going (Quo Vadis) and what the future holds for this powerful synthetic method. Furthermore, we attempt to explore its advantages and disadvantages compared to controlled/living radical polymerizations, the main competitors of living carbanionic polymerization.

High chemical recyclability of vinyl lactone acrylic bioplastics

Biomass-derived vinyl lactone acrylic bioplastics not only exhibit higher thermostability but also depolymerize more selectively to monomers with higher yield and purity compared to their petroleum-based vinyl ester acrylic counterpart.