02692nas a2200241   4500008004100000022001400041245011600055210006900171260009900240300001400339490000700353520173200360653002902092653004302121653003302164100002202197700002902219700001602248700002002264700002402284700001802308856012402326       2009                        eng d  a0032-386100aPreparation and nonisothermal crystallization behavior of polypropylene/layered double hydroxide nanocomposites0 aPreparation and nonisothermal crystallization behavior of polypr  aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLANDbELSEVIER SCI LTDcMAR  a1505-15150 v503 a<p>Polypropylene (PP)/layered double hydroxide (LDH) nanocomposites were prepared via melt intercalation using dodecyl sulfate anion modified LDH and maleated PP as compatibilizing agent. Evidently the interlayer anions in LDH galleries react with maleic anhydride groups of PP-g-MA and lead to a finer dispersion of individual LDH layers in the PP matrix. The nanostructure was characterized by XRD and TEM; the examinations confirmed the nanocomposite formation with exfoliated/intercalated layered double hydroxides well distributed in the PP matrix. The nonisothermal crystallization behavior of resulting nanocomposites was extensively studied using differential scanning calorimetry (DSC) technique at various cooling rates. In nonisothermal crystallization kinetics, the Ozawa approach failed to describe the crystallization behavior of nanocomposites, whereas the Avrami analysis and Jeziorny method well define the crystallization behavior of PP/LDH nanocomposite. Combined Avrami and Ozawa analysis (Liu model) also found useful. The results revealed that very small amounts of LDH (1%) could accelerate the crystallization process relative to the pure PP and increase in the crystallization rates was attributed to the nucleating effect of the nanoparticles. Polarized optical microscopy (POM) observations also support the DSC results. The effective crystallization activation energy was estimated as a function of the relative degree of crystallinity using the isoconversional analysis. Overall, results indicated that the LDH particles in nanometer size might act as nucleating agent and distinctly change the type of nucleation, growth and geometry of PP crystals. (C) 2009 Elsevier Ltd. All rights reserved.</p>10aLayered double hydroxide10aNonisothermal crystallization kinetics10aPolypropylene nanocomposites1 aLonkar, Sunil, P.1 aMorlat-Therias, Sandrine1 aCaperaa, N.1 aLeroux, Fabrice1 aGardette, Jean, Luc1 aSingh, R., P.  uhttps://library.ncl.res.in/content/preparation-and-nonisothermal-crystallization-behavior-polypropylenelayered-double-0