Linear low-density polyethylene colored with a nanoclay-based pigment: Morphology and mechanical, thermal, and colorimetric properties

In this study, a novel kind of hybrid pigment based on nanoclays and dyes was synthesized and characterized. These nanoclay-based pigments (NCPs) were prepared at the laboratory with sodium montmorillonite nanoclay (NC) and methylene blue (MB). The cation-exchange capacity of NC exchanged with MB was varied to obtain a wide color gamut. The synthesized nanopigments were thoroughly characterized. The NCPs were melt-mixed with linear low-density polyethylene (PE) with an internal mixer. Furthermore, samples with conventional colorants were prepared in the same way. Then, the properties (mechanical, thermal, and colorimetric) of the mixtures were assessed. The PE–NCP samples developed better color properties than those containing conventional colorants and used as references, and their other properties were maintained or improved, even at lower contents of dye compared to that with the conventional colorants.

This research was supported by the Spanish Ministry for Education and Science (contract grant number DPI2005-08999-C02-02) and, the Spanish Ministry of Science and Innovation (contract grant numbers DPI2008-06455-C02-02 and DPI2011-30090-C02-02). One of the authors (V.M.) thanks the Conselleria d’Empresa, Universitat i Ciència, for a Ph.D. grant (contract grant number BFPI/2007/038).