In previous posts we set the stage for understanding how the viscosity profile changes during non-isothermal curing. We showed how heating rate changes the minimum viscosity, how during the initial softening of a B-staged prepreg, the viscosity is dominated by the temperature dependence and when using latent hardeners, there is no chemical reacting during the initial viscosity ... [Click to Continue...]

In our last post we showed how the chemical conversion and glass transition temperature (Tg) were correlated to the viscosity during a non-isothermal curing profile.  We will continue our analysis of the aborted rheometer data in this post. In the data presented in Part 8, the heating rate was held constant.  In reality, we did experiments at several heating rates and the ... [Click to Continue...]

In our last post we provided the background on how to correlate the viscosity, conversion, and Tg during non-isothermal curing.  We used the technique in the figure to the left to “freeze the action” along the viscosity profile and use DSC to probe how the curing was progressing. In the next figure, the percent conversion is plotted as a function of time on the left axis and ... [Click to Continue...]

Previously we described how to measure the viscosity profiles during non-isothermal curing typical for many prepreg and composite processing situations (lamination, autoclave, etc.).  The chemistry is tailored to allow for the resin to soften and flow with the chemical reaction occurring at an elevated temperature.  The elevated cure initiation is accomplished using a latent ... [Click to Continue...]

I thought I would continue the Thursday “break-ups” since the topic is an interesting one.  This post will talk about why having fun is so important. Can you think of a time, a project, a company, or any other organization where you actually had a blast working?  Too bad for those who can’t think of an occasion, but in all honesty, there has to be a situation where everyone ... [Click to Continue...]