In the last post the UV rheometer method was found to be a very sensitive measurement tool for determining the gel point during UV curing.  As seen in the figure on the left, the crossover in the dynamic loss and storage moduli can be precisely determined yielding an approximate measurement of the time to gelation.  The time to gelation is an important parameter in the ... [Click to Continue...]

In our last post, the experimental methods for measuring the rheological changes to UV exposure were presented.  This post will discuss the impact of UV exposure on the rheological properties such as the dynamic loss and storage moduli.  The thickness of the sample is important in UV curing.  If the sample is too thick, depending on the polymer/initiator combination, the UV ... [Click to Continue...]

I’d like to thank Dan for his series on UV curing of polymers.  As was pointed out, UV curing has many advantages over thermal curing in some applications.  Since I am a structure-property-process-property type of guy, the question is; how do you characterize UV curing of thermosets.  In the next couple posts we will discuss UV rheology methods and provide some key ... [Click to Continue...]

Guest Post by Dan Lamone Image Courtesy: coatingsworld.com Last week the relationship between UV curable resins and power densities was introduced; this week we will discuss UV measurement and how you can use these UV measurements to evaluate a curing process. While shopping for a UV measurement device, ask yourself the following questions: Do I need to measure ... [Click to Continue...]

Guest Blog Post by Dan Lamone Now that we’ve selected our bulb type and coverage area, we are now concerned with the amount of UV exposure to fully polymerize our resin. Our two key variables are energy density and power density. Photo Courtesy: Air Motion Systems, Inc. Most UV processes will evaluate energy density as energy / surface area, often in joules or ... [Click to Continue...]