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).

Nanocomposite materials were obtained from tricalcium aluminate hydration in presence of maleic anhydride–allylether copolymers. The brush and star shaped polycarboxylates possessing high side chain density intercalate in between [Ca2Al(OH)6]+ layers. X-ray diffraction revealed increased basal spacings of the composites with increasing side chain lengths. Elemental analysis, thermogravimetry, IR spectroscopy and TEM confirm the formation of the organo-mineral phases.Figure optionsDownload as PowerPoint slide