Characterizing Mesh Size Distributions (MSDs) in Thermosetting Materials Using a High-Pressure System

Abstract

The thermoporosimetry method was adapted to determine the mesh size distribution of an acrylate thermoset clearcoat. This goal was achieved by increasing the solvent rate transfer by increasing the pressure and temperature. A comparison of the results obtained using this approach with those obtained by DMA (dynamic mechanical analysis) underlined the accuracy of thermoporosimetry in characterizing the macromolecular architecture of thermosets. The thermoporosimetry method was also used to analyze the effects of photoaging on cross-linking, which result from the photodegradation of the acrylate thermoset. It was found that the formation of a three-dimensional network followed by densification generates a modification of the average mesh size that leads to a dramatic decrease of the meshes of the polymer.

Evidence for the Phospholipid Sponge Effect as the Biocidal Mechanism in Surface-Bound Polyquaternary Ammonium Coatings with Variable Cross-Linking Density

“…The relationship between E * and the cross-linking density may be extrapolated for sufficiently thick films and small values of d . For a cross-linked polymer, the cross-linking density influences the modulus of the film, as described in eq where M c is the number-average molar mass of the chain lengths between cross-links, ρ is the bulk density of polymer, T is temperature, and R is the gas constant. , As M c decreases, E * increases, which indicates that the polymer becomes stiffer as the cross-link density increases.…”

“…where M c is the number-average molar mass of the chain lengths between cross-links, ρ is the bulk density of polymer, T is temperature, and R is the gas constant. 37,38 As M c decreases, E* increases, which indicates that the polymer becomes stiffer as the cross-link density increases.…”

Structural evolution of a constrained epoxy functional polyethylene network crosslinked by a bio-based reactant

“…The most common techniques to study network structures have been by far: swelling measurements [24][25][26], rheological analysis [8] and dynamic mechanical analysis [27] among others. From these methods, it is possible to obtain data such as number of moles of crosslinks per unit of volume and the average molar mass between junctions.…”

“…k and b are calibration constants that depend on the instrument sensitivity, sample mass and heating rate [27]. Due to the pore size independence of these constants, their knowledge is not crucial to express the size distribution of the studied systems.…”

“…A ramp from 20°C to À20°C was done to determine the crystallization temperature of confined solvent and according to previous studies [27,31,41] a very slow cooling rate (0.5°C/min) was chosen to allow a continuous thermal equilibrium inside the DSC cell. As shown in (Fig.…”