Dye/Clay intercalated nanopigments using commercially available non-ionic dye

摘要

Two non-ionic azo dyes: solvent yellow 14 (SY14) and solvent red 24 (SR24), and one non-ionic disperse dye: dispersed red 60 (DR60) were chemically modified into their respective cationic species, which were then subsequently ion-exchanged with Na~+-montmorillonite in an acidic medium. The dye-intercalated montmorillonite was then centrifuged, dried and milled to prepare the pigment particles. X-ray diffraction studies on the pigments showed an increase in the basal spacing in the clay layers for the SY14 and DR60 based pigments NP14 and NP60 respectively, confirming intercalation of the dyes within the clay layers giving rise to a nano-structured system. The XRD pattern of the SR24 based pigment NP24 showed a diffused shoulder with a truncated peak, suggesting the possibility of a delaminated structure after adsorption of the dye. Due to the nano-structured morphologies, these pigments were classified as nanopigments. Thermogravimetric analysis showed different thermal stabilities for different nanopigments compared to the respective original dyes: an improvement in case of NP14, no change for NP24, and an apparent deterioration for NP60. The nanopigments were subsequently mixed with polypropylene to produce coloured specimens. Bleeding tests on these coloured specimens showed a reduction in leaching in turpentine.