Effect of Clay Modifier on the Structure and Transport Properties in Polyurethane/Clay Nanocomposites as Barrier Materials

In this study, nanocomposites of Thermoplastic Polyurethane (TPU) clay are synthesized and used as a gas barrier property. The NCO-terminated TPU prepolymer was prepared by solution polymerization method using a ۱:۲ ratio of Polyethylene glycol (PEG۲۰۰۰) and Tolylene ۲,۴-diisocyanate (TPI). Organo-modified montmorillonite clay, Cloisite ۲۵A(C۲۵A) was used as ample compatibilization with PEG/TPI matrix. The prepared nanocomposite was characterized by Fourier Transform InfraRed (FT-IR) spectroscopy, X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), and ThermoGravimetric Analysis (TGA). The main functional group peaks of the nanocomposite materials are observed in FT-IR spectroscopy. The nanocomposites exhibited better thermal stabilities than pristine Polyurethane which is investigated by TGA. Thermal stability in the sample with ۵ wt.% of TPU/C۲۵A-۵ material has improved up to ۷۰ºC. The XRD results have confirmed the penetration of clay into TPU matrix, with the disappearance of the characteristic peak (۲θ = ۴.۸۱º) corresponding to the d-spacing of the organoclay. SEM analysis confirmed the dispersion of nanoclay in TPU matrix. The mechanical properties of nanocomposites such as the tensile strength and Young's modulus of TPU/Cl۲۵A nanocomposites were increased with increasing clay percentage. The gas permeability test was studied using a Membrane separation testing unit. Significant improvements in barrier properties were observed. A remarkable decrease was seen in polyurethane incorporated with ۵ Wt.% organoclay when tested with oxygen and nitrogen gas.

کلیدواژه ها:

Polyurethane ، Organoclay ، Nanocomposites ، Gas barrier properties