Temperature dependent loss tangent measurement of polymers with contact resonance atomic force microscopy

The loss tangent of individual components in a blend of polypropylene (PP) and polystyrene (PS) is measured as a function of temperature with contact resonance atomic force microscopy. The loss tangent is calculated directly from the experimentally obtained contact resonance frequency, cantilever quality factor and other operating parameters. The temperature dependent variation of the loss tangent, measured at the high frequency of AFM measurements, shows peaks at different temperatures for the different polymer materials. The loss tangent peak at approximately 53 °C for PP is identified as an alpha peak signifying crystal relaxation while the loss tangent peak at approximately 75 °C for PS is identified as a glass transition.