Guest Post by Huan Lee, Lambient Technologies The ion viscosity of a thermoset is the frequency independent resistivity (rDC). In many cases ion viscosity is proportional to mechanical viscosity before gelation and proportional to modulus after gelation, making ion viscosity a useful probe of material state through the entire cure. Figure 1 shows the behavior of a ... [Click to Continue...]

Guest post by Huan Lee, Lambient Technologies In Part 10 of this series, I defined ion viscosity (IV) as the frequency independent resistivity (ρDC) of a polymer, which correlates with viscosity before gelation and modulus after gelation. For dielectric cure monitoring it is important to understand how to identify ion viscosity and isolate it from other factors. Many in ... [Click to Continue...]

Guest Post by Huan Lee, Lambient Technologies In the first post of his series about dielectric cure monitoring (DEA), Jeff Gotro mentioned the “AHA” moment at a Gordon Conference when he heard Prof. Stephen Senturia speak about dielectric sensors. At that time Steve, with myself and several others in his research group at MIT, had recently founded Micromet Instruments to ... [Click to Continue...]

In the previous posts in this series we have presented the fundamentals of dielectric cure monitoring and have shown how the dielectric loss factor can be a way to monitor the viscosity changes that occur during thermoset curing.  The previous posts also showed how the frequency response can be observed to determine either the glass transition temperature on heating or ... [Click to Continue...]

In this post we will use all of the information presented in the series and show a very interesting case study on how dielectric measurements in conjunction with complex viscosity measurements can shed light on the physical changes occurring during thermoset curing. We have seen that dipoles can be used to determine both the glass transition region and if vitrification is ... [Click to Continue...]