Novel organo-mineral phases obtained by intercalation of maleic anhydride–allyl ether copolymers into layered calcium aluminum hydrates

The work presented here deals with the intercalation of worm- and brush-shaped polycarboxylates (PC) into calcium aluminum layered double hydroxide (Ca–Al-LDH). The nanocomposite materials were obtained from tricalcium aluminate hydration in presence of polycarboxylate copolymers with different side chain lengths. As polycarboxylate compound, amphiphilic copolymers composed of maleic anhydride and α-allyl-ω-methoxy-poly(ethylene glycol) ether with side chain lengths of n = 7, 10, 34, 70 and 90 ethylene oxide units (EOUs) were chosen. These polymers possess a high side chain density due to strictly alternating copolymerization. Powder X-ray diffraction (XRD) of the synthesized Ca–Al–PC-LDH composites revealed that basal spacings (d-values) increase with the number n of EOUs in the side chain. An extremely high d-value of 4.85 nm was obtained for the polymer with n = 34 EOUs. According to elemental analysis data, the amounts of organic material present in the different composites were found to lie between 48 and 77 wt.%, respectively. Additionally, IR spectroscopy and thermogravimetric measurements were carried out in order to characterize the intercalates. The layered structure of the organo-mineral materials was confirmed by transmission electron microscopy (TEM).