Spatial Dynamics of Water Molecules Confined in Deuterated Epoxies by Quasi-Elastic Neutron Scattering

Abstract

The relationship between the water within polymer materials and their material properties is key to expanding their application scope. This study conducted quasi-elastic neutron scattering (QENS) measurements of fully carbon-deuterated epoxies to elucidate the molecular dynamics of water confined in the nanometer-scale voids (nanovoids) of epoxies, focusing on spatial information. The QENS measurements of epoxies with different stoichiometries revealed that the motion space of mobile water molecules in stoichiometric epoxy was more than twice the average size of nanovoids in the epoxy, indicating the broad distribution across multiple nanovoids. In contrast, the extents of oxirane-excess and amine-excess epoxies were close to the nanovoid size. The spatial dynamics of water and its relationship to the chemical structure will help in understanding the water diffusion mechanism and designing epoxy materials with excellent water-related properties, such as water resistance or transport.

Scalable Synthesis of Thymol-Based Bisphenol E Epoxy Monomer and Related Thermosets with Low Dielectric Constant and Density and Improved Resistance to Hygrothermal Aging

“…The impact of hygrothermal aging on the T g and E′ of the thermosets was evaluated based on DMA spectra as shown in Figure S1, and the obtained T g and E′ values are shown in Figure C,D. After immersion in boiling water for 100 h, the T g for E″ max of the treated thermosets decreased to a certain extent due mainly to the plastification of water by reducing the interaction in the network . DGEBA/44DDS shows a more dramatic decrease in T g by 40 °C from 204 to 164 °C than does DHEP/44DDS (from 167 to 147 °C by 20 °C), indicating the improved hygrothermal resistance of the latter.…”