Investigating Fast Scanning Calorimetry and Differential Scanning Calorimetry as Screening Tools for Thermoset...

Area of Science:

• Materials Science
• Polymer Chemistry
• Additive Manufacturing

Background:

• Additive manufacturing (AM) requires a diverse material library, particularly for polymer-based techniques like laser-based powder bed fusion (PBF-LB).
• Thermosetting polymers offer potential advantages but require specific characterization for PBF-LB compatibility.
• Existing characterization methods may not fully capture material behavior under PBF-LB processing conditions.

Purpose of the Study:

• To compare differential scanning calorimetry (DSC) and fast scanning calorimetry (FSC) as screening tools for thermosetting polymers in PBF-LB.
• To investigate the nonisothermal curing behavior of a model thermoset polyester powder coating across a wide range of heating rates.
• To assess the correlation between fundamental curing kinetics and PBF-LB processing requirements.

Main Methods:

• Utilized DSC and FSC to measure the curing behavior of a polyester powder coating.
• Employed nonisothermal experiments at heating rates from 5 to 7500 °C/min.
• Applied isoconversional kinetic models (Friedman and Starink) to analyze curing data.

Main Results:

• Observed curing exotherms with both DSC and FSC, confirming thermoset reactivity.
• Identified incomplete curing at higher heating rates (approaching 70% conversion), suggesting processing limitations.
• Kinetic analysis revealed reduced activation energy at higher heating rates, indicating altered curing dynamics.

Conclusions:

• DSC and FSC serve as effective tiered screening tools for evaluating thermosetting polymers for PBF-LB.
• High heating rates characteristic of PBF-LB can lead to incomplete curing of certain thermosets.
• This research informs material selection and design for advanced additive manufacturing applications.