Guest Post by Dr. R. Bruce Prime Thermogravimetric analysis or TGA is a technique where the mass (or weight) of a material is measured as a function of temperature or time while the sample is subjected to a controlled temperature program in a controlled atmosphere [Earnest, ASTM STP 997 (1988)]. Temperature ranges for commercial TGAs are typically ambient to 1000°C or ... [Click to Continue...]

Guest Post by Dr. R. Bruce Prime In the previous post we introduced the basic operating principles of TMA and illustrated the more common measurements. In this post we describe some important applications of TMA to thermosets. As described in the previous post TMA can quantitatively measure the coefficient of thermal expansion on samples with smooth parallel sides. Many ... [Click to Continue...]

Guest Post by Dr. R. Bruce Prime Thermomechanical analysis or TMA is a simple yet very useful technique that can measure coefficient of thermal expansion, Tg and the dimensional change accompanying the relaxation of stress stored in a material. As shown in the illustration the dimensional change of a material with temperature (or time) is measured in a controlled atmosphere ... [Click to Continue...]

In our last post we described the technique called time-Temperature superposition.  Using t-T superposition, a “master curve” can be constructed that is useful in analyzing the curing of thermosets.  The requirement is to have either conversion or glass transition temperature (Tg) data as a function of time for several isothermal cure temperatures.  (Image on left courtesy of ... [Click to Continue...]

In our last post we discussed the concept of vitrification and the impact on the cure kinetics (dramatic slowing of the reaction rate in the glassy state).  When examining curing data such as the Tg versus cure time plots from the last post, it is often helpful to create a “master curve.”  Remember the Tg-time relationships had the same shape but appeared to be shifted along ... [Click to Continue...]