Naslov
Modification of montmorillonite with liquid crystalline diols

Autori
Huskić, Miroslav ; Brnardić, Ivan ; Ivanković, Marica ; Žigon, Majda

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
SLONANO 2004 / Mihailovič, Dragan - Ljubljana : Institute "Jožef Stefan", 2004

Skup
3rd Slovenian workshop on nanoscience and technology "SLONANO 2004"

Mjesto i datum
Ljubljana, Slovenija, 21.10.2004. - 22.10.2004

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Nije recenziran

Ključne riječi
Montmorillonite; Modification; Liquid crystalline diol

Sažetak
Modification of montmorillonite with liquid crystalline diols M.Huskić, 1 I.Brnardić, 2 M.Ivanković, 2 M.Žigon1 1 National Institute of Chemistry, POB. 660, 1001 Ljubljana, Slovenia 2 University of Zagreb, Fac. Chem. Engn. & Technol, HR-10001 Zagreb, Croatia Montmorillonite (MMT) is a layered silicate with an excess of negative charges within the silicate structure. The negative charge, which appears on the surface, is compensated by the adsorption of cations, usually Natrium or Calcium. They can be exchanged by organic cations in an aqueous solution. Quaternary ammonium salts (QAS) having long alkyl chains are most frequently used for MMT modification. [1-3] Modified MMT can be used for the preparation of polymer nanocomposites by in-situ polymerization, solvent casting or melt intercalation. [4] In present work liquid crystalline (LC) hydrochlorides based on diethanolamine were used for MMT modification. The synthesis of liquid crystalline diols and diol hydrochlorides is described elsewhere. [5, 6] The hydrochlorides differ in the length of the spacer (n=6 or 8 CH2 units). The reaction is depicted in Scheme1. Scheme: The synthesis of LC diole hydrochlorides. The cation exchange capacity (CEC) of a montmorillonite was determined by ammonium acetate method to be 83.9 meq/100g. To modify montmorillonite, stoichiometric amounts of liquid crystalline hydroclorides (calculated from the CEC) were used. Montmorillonite and organically modified montmorillonite were characterized by X-ray diffraction analysis (XRD). [7-10] The basal spacing of unmodified montmorillonite, determined by XRD, was 1.236 nm. After modification with liquid crystalline diol hydrochloride having 6 and 8 CH2 units it increased to 1.845 and 1.976 nm respectively. These diffraction patterns reveal the exchange of cations in between the montmorillonite layers with the liquid crystalline hydroclorides. The modified MMT as well as pure MMT were analysed by TGA in air. The weight loss on heating to 1050oC was 22% and 13% respectively. The MMT modified with DN-8-HCl was used for the synthesis of liquid crystalline polyester and the influence of the MMT content on liquid crystalline properties was determined. The presence of MMT increases the crystallization and melting temperature and slightly decreases isotropization temperature of polyester. The X ray diffraction shows the increase of interlayer distance of MMT indicating that intercalated nanocomposites were formed. Literature 1. Z.Klapyta, T.Fujita, N.Iyi, Appl. Clay Sci., 19, 5, 2001 2. H.Favre, G.Lagaly, Clay Miner. 26, 19, 1991 3. M.Kozak, L.Domka, J.Phys.Chem.Solids, 65, 441, 2004 4. S.Sinha Ray, M.Okamoto, Prog.Polym.Sci. 28, 1539, 2003 5. M.Brecl, T.Malavašič, J.Polym. Sci.:Part A:Polym. Chem. 35, 2871, 1997 6. M.Huskić, M.Žigon, Liq. Cryst. 29, 1217, 2002 7. C.S.Triantafillidis, P.C.LeBaron, T.J.Pinnavaia, J. Solid State Chem. 167, 354, 2002 8. T. Lan, P.D.Kaviratna, T.J.Pinnavaia, J. Phy. Chem. Solids 57, 1005, 1996 9. J.Lü, Y.Ke, Z.Qi, X.-S.Yi, J. Polym. Sci. Part B: Polym. Phys. 39, 115, 2001 10. X.Kornmann, H.Lindberg, L.A.Berglund, Polymer 42, 1303, 2001

Izvorni jezik
Engleski

Znanstvena područja
Kemijsko inženjerstvo

POVEZANOST RADA