Role of Dynamic Covalent Bond Density on the Structure and Properties of Vitrimers

Macromolecules, Journal Year: 2024, Volume and Issue: unknown

Published: Nov. 26, 2024

Vitrimers, as a novel class of dynamic polymers, require precise regulation their and mechanical properties to achieve optimal, comprehensive performance. This study utilizes coarse-grained vitrimer elastomer model, composed simple linear polymer chains by varying cross-link densities (ρ), systematically investigate the structural, dynamic, vitrimers. The results demonstrate that system number density decreases with increasing ρ due repulsion between reactive sites. characteristic glass transition temperature (Tg) increases linearly such Tg ∼ ρ, while topological Tv exhibits nonmonotonic changes versus ρ. Interestingly, bond exchange autocorrelation function indicates rate reaches maximum at intermediate attributed competition mobility Mean square displacement analysis reveals beads decreased logarithm diffusion coefficients ln D −ρ. chain segment relaxation times different can be described an exponential equation τα exp(ρ/C), whole are more sensitive density. viscoelasticity via equilibrium molecular dynamics simulations indicate higher lead greater elasticity energy dissipation capabilities, indicated storage loss moduli, derived viscosity for various barriers (ΔEsw) universal following relation η0 Uniaxial triaxial tensile tests both show high ΔEsw systems exhibit strength low strains tight stable network structure, whereas strains, voids occur stress concentration breakage covalent bonds, which reduces strength, toughness, elongation break, compared lower systems. Therefore, optimal tailoring barrier capability most excellent performance vitrimer. These findings provide crucial theoretical guidelines design optimization

Language: Английский

Dual cold- and thermal-compatible polyurethane elastomer based on flexible polybutadiene chain and metal-ligand coordination

European Polymer Journal, Journal Year: 2024, Volume and Issue: unknown, P. 113633 - 113633

Published: Dec. 1, 2024

Language: Английский