Synthetic zinc layered hydroxide salts intercalated with anionic azo dyes as fillers into high-density polyethylene composites: first insights

Using a co-precipitation process, we intercalated zinc layered hydroxide salts (zinc LHS) with anionic orange azo dyes (methyl orange-MO or orange II-OII), co-intercalated with chloride anions; for comparison purposes, we also intercalated zinc LHS with chloride anions only, which furnished ZHC. After XRD characterization, we filled high-density polyethylene (HDPE) with the intercalated materials and submitted them to melt compounding and injection molding. We also obtained control batches of HDPE filled with ZHC, the MO sodium salt, or the OII sodium salt. XRD, thermal (simultaneous TGA/DTA), DSC, SEM, and UV-radiation photostability analyses confirmed that homogeneous composites were obtained. HDPE filled with zinc LHS intercalated with MO (a probable more hydrophobic anionic azo dye) displayed improved mechanical properties, good interface bonding, and stability to UV photodegradation; the other fillers afforded materials with poorer mechanical properties.