Temperature cycling effects in some glob top polymer materials

Three common glob top encapsulant materials, two epoxy‐based, and one silicone‐based, were characterized prior to temperature cycling using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), dynamic mechanical spectroscopy (DMS), gas chromatograph‐mass spectrometry (GC‐MS), and Fourier transform infrared spectroscopy (FTIR). After cycling between ‐55 to +125°C, for 1,000 cycles, the same samples were again analysed using DMS and FTIR. For the epoxy‐based samples, the DMS results indicated that temperature cycling in a humid environment can seriously affect the physical and mechanical properties of these samples. FTIR data also indicated that the molecular changes in the epoxy‐based samples appeared quite extensive after cycling, indicating a high level of degradation on the molecular scale. On the other hand, the silicon‐based glob top appeared to have survived the temperature cycling quite well.