Understanding the methods for determining degree of cure.

At Radtech, we presented work based on our experience developing methods to monitor UV cures and what differences we see between them. Work was done on a UV-curing nail polish we purchased off of Amazon. You can download the talk here.

One of the most interesting things in any curing process, whether thermally, chemically, or UV driven, is the mismatch between chemical measurements (presence of double bonds for example) and those that measure the physical properties of the system. This can lead to some interesting experiences when you are new to the field: for example, many epoxy resins reach full mechanical strength when the DSC shows 85-90% cure by tracking the heat of reaction. Similarly, other properties, say solvent resistance, permeability, etc, may have a different value.

The folks at the U.Colorado Dental School have looked at this by doing NIR and DMA on UV cured dental resins. This required building a rather complicated attachment for the DMA, but it did show the difference in the approaches.