The Use of Solid State NMR to Characterize High Density Polyethylene/Organoclay Nanocomposites

Abstract

Recently the development of new materials, in special polymeric nanocomposites, formed by polymer and layered silicates, have gained attention. In this work nanocomposites based on high-density polyethylene matrix (HDPE) and organically modified clay were prepared by melt processing and characterized by the determination of proton spin-lattice relaxation time through solid state nuclear magnetic resonance (NMR) spectroscopy. This work has a proposal to add one quantitative technique to help the researchers to better evaluate polymeric nanocomposite, because NMR is an important tool employed to study both molecular structure and dynamic molecular behavior. The nanocomposites were mixed in a twin-screw extruder, varying the shear rate parameter: 60 and 90 rpm at 463 K. Nanocomposites obtained were characterized through X-ray diffraction; thermal analysis; impact resistance and nuclear magnetic resonance. The T1H results showed that the samples present different molecular domains according to the clay dispersion, forming an intercalated and/or exfoliated nanocomposites. The measurement of relaxation time, using low field NMR, is a useful method to evaluate changes in the molecular mobility of nanocomposite and can infer whether the sample is exfoliated and/or intercalated, since lamellar filler is used.

Applications of Spectroscopic Techniques for Polymer Nanocomposite Characterization

“…respectively as compared to PMMA. For the purpose to examine the phase structures along with phase dynamics in both exfoliated and intercalated nanocomposites, variations in molecular motion and relation between two components, solidstate NMR spectroscopic analysis of polymer/ clay nanocomposites was carried out [57], [58].…”

Change in the Properties of Linear Low-Density Polyethylene (LLDPE)/Montmorillonite Clay Nanocomposites after a Fuel-Aging Process

“…It can generate new support and responses on nanocomposite intermolecular interactions and structural organization. The use of solid-state techniques will aid in the observation of changes in the structural/microstructural and dynamical behavior, focusing on the molecular motion of the polymer chains …”