TITLE:
The Influence of Organo-Clay Ratio in the HIPS-OMMT Nanocomposites Analyzed by Proton Spin-Lattice and Spin-Spin Relaxation Times
AUTHORS:
Paulo Sérgio Rangel Cruz da Silva, Lívia Rodrigues Menezes, Maria Inês Bruno Tavares
KEYWORDS:
Polymeric Nanocomposites, Nanoparticles, Relaxation Times, NMR
JOURNAL NAME:
Materials Sciences and Applications,
Vol.7 No.3,
March
21,
2016
ABSTRACT: Spin-lattice and spin-spin relaxation times are one of the most attractive tools in the solid-state nuclear magnetic resonance spectroscopy to evaluate the level of clay dispersion in the nanocomposite matrices. The efficiency of the relaxation processes can be used to evaluate the nanoparticles intermolecular interactions and, consequently, the dispersion of them in the polymer matrix, the molecular dynamic of the hybrid compounds, as well as the molecular domains formation in an organic material. The determination of relaxation parameters was carried out to evaluate the organoclay exfoliation and intercalation process in the polymeric matrix, in addition to their dispersion and distribution in the matrix. The proton NMR relaxation data showed that the polymeric nanomaterials investigated presented good intermolecular interaction that promoted good nanoparticles dispersion and distribution in the hybrid materials. The proportion of 2% clay promoted a greater heterogeneity in the matrix compared to other ratios; 1% clay influenced only to the higher molecular rigidity phase; and 3% clay had a decrease in heterogeneity compared to 2% though still influenced the matrix as a whole. These results prove the efficiency of NMR technique in the evaluation of nanofillers interaction with polymer matrices, as well as their dispersion and distribution.