Non Destructive Characterization of Photochemically Generated Crosslinking Gradients in Polymers
Photopolymers are extensively used in the field of coating technology, stereolithography, but also to fabricate optical elements. A good knowledge of the crosslinking process at the local scale is essential to characterize these materials and to control their quality, especially in regard to the optical or the mechanical properties, because the viscoelastic constants of the polymer as also its refractive index depend on the crosslinking density. Microechography provides a means to resolve structure heterogeneities in small volumes down to the wavelength of longitudinal sound waves in the material. In a first approach, microechography was applied to the study of small polymer disks that were photocured either through a two-level amplitude mask or a progressive neutral density filter.
KeywordsCrosslinking Density Radial Gradient Acoustic Microscopy Tetraethylene Glycol Scanning Acoustic Microscopy
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