Rhodamine 6G Intercalated Montmorillonite Nanopigments-Polyethylene Composites: Facile Synthesis and UltravioletStability Study

Bright red pigments, based on montmorillonite (MM) intercalated with rhodamine 6G (R6G) have been developed for the purpose of pigmenting polyethylene‐based polymers. The cationic dye R6G was intercalated into NH4+‐saturated MM in a slightly acidic medium. The resultant inorganic–organic MM complex was characterized using X‐ray diffraction, thermogravimetric analysis, Fourier transform infrared (FTIR) spectra, diffused reflectance, and color measurements. Expansion in basal spacing from an initial 11.3 to ∼15.8 Å was detected in the X‐ray profile, confirming clay intercalation with R6G. The average particle size of the intercalated clay was 35 nm as measured by photon scattering. Frequency shifts of the C–H bending vibration from 724 to 744 cm−1 and that of the carbonyl (>C=O) stretching vibration from 1647 to 1666 cm−1 have been observed as a result of intercalation in FTIR spectra. Improvement in thermal stability for the intercalated MM was indicated by results from thermal analysis. The intercalated colored polyethylene‐pigment showed enhanced stability under exposure to ultraviolet radiation of wavelength of 200–400 nm. The values for color coordinates were a*=53.45 and b*=9.62 from the color measurements.