Q800 dynamical mechanical analyzer

The mechanical properties: E”, loss modulus (mechanical energy dissipation); E’, storage modulus (mechanical energy storage); and tan δ = E”/E’, of anhydrous and humidified MPC powders (described above for the DSC experiments) were measured using a Q800 Dynamical mechanical analyzer (TA instruments^®, New Castle, DE, USA). The instrument was balanced and set at zero to determine the zero-displacement position before measurements commenced. Approximately 0.1 g of sample was placed on a metal pocket-forming sheet. This sheet was fixed inside the dual cantilever between the clamps. All results were obtained using the TA Universal Analysis software. Samples were scanned from ~50 °C below to over the α-relaxation region at a cooling rate of 5 °C/min and heating rate of 0.5 °C/min using the dual-cantilever bending mode. The α-relaxation temperatures (T_α) were determined from frequency-dependent spectra of tan δ above the glass transition [18 (link),19 ,29 (link),30 (link)].
To calculate the relaxation times (τ) of peak T_α, measured by DMA at various frequencies (f), Equation (3) was used [30 (link),31 (link)]: $$\mathsf{\tau }=\frac{1}{2\mathsf{\pi }\mathrm{f}}$$