Dynamic mechanical analysis of polyurethanes and carbon nanotube based composites obtained from PET waste

In this work, an attempt is made to present an in-depth investigation on the temperature and frequency dependences of viscoelastic properties of polyurethanes and PU nanocomposites containing multi-walled carbon nanotubes (CNTs) obtained from polyethylene terephthalate (PET) waste through dynamic mechanical analysis. The experimental results indicate that NCO/OH molar ratios and nanoparticles can have a marked effect on the ultimate properties and performance of the polyurethanes and their corresponding nanocomposites produced from PET waste. The opposite effects of the reinforcing and steric hindrance of CNT in the studied nanocomposites can be the reason for the observation of some unexpected results. Relaxation spectra were also subsequently calculated by means of two consecutive approximation methods. Good conformity was observed between the data from storage modulus (E) and loss (modulus) E by the second approximation in relaxation spectra which confirmed the internal consistency of the experimental data. In the end, TEM images confirmed the effect of the reinforcing of CNT in the PUCNT-2 as demonstrated by DMA results. POLYM. COMPOS., 39:E754-E764, 2018. (c) 2016 Society of Plastics Engineers