Aluminum-Magnesium Hydroxycarbonate/Azo Dye Hybrids as Novel Multifunctional Colorants for Elastomer Composites

Abstract

This study presents the preparation and characterization of new organic-inorganic pigments based on aluminum-magnesium hydroxycarbonate (LH) and azo dyes. Solvent resistance studies, XRD, SEM, and TGA confirmed the successful formation of hybrid pigments, which were characterized in terms of their physicochemical properties. The new hybrid pigments were applied in acrylonitrile-butadiene (NBR) and ethylene-propylene (EPM) rubber composites and cured with sulfur and peroxide curing systems, respectively. The mechanical properties, dispersion quality, and flame-retardant properties of the NBR/hybrid and EPM/hybrid pigment composites were determined by dynamic mechanical analysis (DMA), SEM, and microscale combustion calorimetry (MCC). Complex experimental investigations revealed that the layered nature of hybrid pigments could improve the barrier ability and flame retardancy of elastomer composites. In comparison to unmodified aluminum-magnesium hydroxycarbonate, the modified LH dye structures contributed to significantly decrease the heat release rate and the total heat release of the NBR and EPM composites, offering a new approach to imparting low flammability to elastomer materials.

Carminic Acid Stabilized with Aluminum-Magnesium Hydroxycarbonate as New Colorant Reducing Flammability of Polymer Composites

“…This is most likely associated with the deposition of carminic acid on the outer area of the LH structure. Unlike in our previous studies [36], the CA structures are not clearly distinguishable on the modified surface. This is due to the rather amorphic nature of the organic chromophore, which was also confirmed by XRD results.…”

“…This behavior can be explained by the fact that the main weight loss peaks for the CA dye were similar to those for dehydroxylation and carbonate decomposition in the LH host. These results also correspond with the observations made in our previous works [36], in which the decomposition peaks of organic chromophores incorporated in an LH matrix were covered by peaks signaling inorganic carrier decomposition.…”

“…The increase in flame resistance for the EN composite with a pure LH host was less pronounced in comparison with the EN/hybrid pigment, as evidenced by higher values of considered flammability parameters. The higher efficiency of the hybrid colorants in terms of improving flame retardance of the EN copolymer may be attributed to the presence of an organic chromophore in the LH structure and was already observed in our previous work [36].…”

Characterization of Ethylene–propylene Composites Filled with Perlite and Vermiculite Minerals: Mechanical, Barrier, and Flammability Properties

“…The air permeability of the EPM composites was determined using the manometric method. The gas transmission rate (GTR) was calculated from the equation [33]. The crosslink density of the EPM vulcanizates was determined based on the equilibrium swelling method, performed in toluene solvent at room temperature.…”

“…The air permeability of the Materials 2020, 13, 585 4 of 13 EPM composites was determined using the manometric method. The gas transmission rate (GTR) was calculated from the equation [33].…”