Differential Scanning Calorimetry (DSC) is the most well-known and widespread thermal analysis technique for polymer characterisation. In the case of polymer-based composites, DSC is generally used to evaluate the reactivity of the resins, to identify their glass transition and to define any effects of residual crosslinking on the finished product. During DSC analysis, a prepreg sample is subjected to controlled heating, and from the recorded signal as a function of temperature (thermogram) it is possible to identify two primary thermal events: glass transition (Tg) and resin cross-linking.
Another, though less well known, use of DSC data is kinetic analysis, which ultimately makes it possible to optimise the curing cycle utilized in production. Today, it is still frequent to search for the best curing cycle through an iterative process, which requires a substantial investment of time and material. Performing a kinetic evaluation from DSC measurements requires a limited amount of material and time: a few grams of material are enough to conduct the three minimum DSC scans required for processing a kinetic model.
The model-free approach in NETZSCH’s Kinetics Neo simulation software allows for a model-free conversion fit of the measurement data with a very easy-to-use, one-click solution. Furthermore, the possibility to make laboratory analyses means avoiding the need for excessive testing on the production line.
Using NETZSCH’s DSC 214 Polyma® and Kinetics Neo simulation software, BLACKS Composites Srl, Italy and NETZSCH Analyzing & Testing improved the finished product quality of a prototype CFRP bike rim with a simultaneous reduction of the cycle time. The bike rim was processed through hand lay-up technology and subsequent autoclave curing. Based on the data from the NETZSCH DSC and the simulation software, the cycle time was reduced by 46 % compared to the cure cycle suggested on the material data sheet. Additionally, a higher degree of cure was achieved.