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Basal Distance (basal + distance)
Selected AbstractsRelaxation map of PETg-montmorillonite composites: Nanofiller concentration influence on , and , relaxation processes,POLYMER ENGINEERING & SCIENCE, Issue 5 2009H. Couderc Samples of polyethylene-1.4-cyclohexylenedimethylene terephthalate glycol (PETg) with different filler contents were prepared by a master batch process. The intercalated dispersion state of montmorillonite (MMT) was characterized using X-Ray Diffraction. Two different sample series are put in evidence with different basal distances (3.31 and 3.48 nm). The influence of nanofiller on , and , relaxations was studied by Dielectric Relaxation Spectroscopy and Differential Scanning Calorimetry. The use of these two techniques allowed us to determine accurately the fragility index m at the glass transition temperature Tg. For Tg, m, the Kauzmann temperature TK, and the relaxation time at Tg ,(Tg), we showed a decrease of the values more important for 3.48 nm basal distance than for 3.31 nm. The , did not seem affected in its apparent activation energy Ea by the MMT addition. POLYM. ENG. SCI., 2009. © 2008 Society of Plastics Engineers [source] Effect of intercalating agents on clay dispersion and thermal properties in polyethylene/montmorillonite nanocompositesPOLYMER ENGINEERING & SCIENCE, Issue 8 2008Karen Stoeffler Alkyl pyridinium, 1-vinyl alkyl imidazolium, 1,3-dialkyl imidazolium, and tetraalkyl phosphonium bromides were successfully used as intercalants for the preparation of highly thermally stable organophilic montmorillonites. Nanocomposites of linear low density polyethylene (LLDPE) and linear low density polyethylene grafted with maleic anhydride (LLDPE/LLDPE- g -MAH) were prepared from those organoclays. The micro- and nano-dispersions were analyzed through X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM): intercalation and/or partial exfoliation were found to occur only for formulations based on organoclays having an initial basal distance higher than 20 Å, suggesting the existence of a critical interfoliar distance for the delamination of silicate layers in a noninteracting polymer matrix. The properties of the nanocomposites were analyzed through differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and oscillatory rheometry. The dynamic crystallization of LLDPE was not significantly affected by the presence of clay. TGA in oxidative atmosphere proved to be very sensitive to the dispersion state of the organoclay: the thermal stability was drastically enhanced for intercalated and partially exfoliated formulations. However, the inherent thermal stability of the organoclay did not appear to influence significantly the overall thermal stability of the composite in the range of temperatures investigated (160,230°C). POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers. [source] The influence of layered compounds on the properties of starch/layered compound compositesPOLYMER INTERNATIONAL, Issue 6 2003Helena-M Wilhelm Abstract Glycerol-plasticized starch films were modified by addition of various layered compounds as fillers, two being of natural origin (kaolinite, a neutral mineral clay, and hectorite, a cationic exchanger mineral clay) and two synthetic (layered double hydroxide, LDH, an anionic exchanger, and brucite, having a neutral structure). The effects of the filler type and the plasticizer were analyzed by X-ray diffraction, dynamic mechanical analysis and thermogravimetry. The storage modulus was higher for kaolinite > brucite > hectorite than for LDH starch composites. However, only the hectorite filler presented a shift of the interplanar basal distance to higher values, which represents the intercalation of glycerol molecules between the clay layers. The glycerol intercalation is minimized in plasticized,oxidized starch films where the oxidized starch chains are preferentially intercalated. Copyright © 2003 Society of Chemical Industry [source] Relaxation map of PETg-montmorillonite composites: Nanofiller concentration influence on , and , relaxation processes,POLYMER ENGINEERING & SCIENCE, Issue 5 2009H. Couderc Samples of polyethylene-1.4-cyclohexylenedimethylene terephthalate glycol (PETg) with different filler contents were prepared by a master batch process. The intercalated dispersion state of montmorillonite (MMT) was characterized using X-Ray Diffraction. Two different sample series are put in evidence with different basal distances (3.31 and 3.48 nm). The influence of nanofiller on , and , relaxations was studied by Dielectric Relaxation Spectroscopy and Differential Scanning Calorimetry. The use of these two techniques allowed us to determine accurately the fragility index m at the glass transition temperature Tg. For Tg, m, the Kauzmann temperature TK, and the relaxation time at Tg ,(Tg), we showed a decrease of the values more important for 3.48 nm basal distance than for 3.31 nm. The , did not seem affected in its apparent activation energy Ea by the MMT addition. POLYM. ENG. SCI., 2009. © 2008 Society of Plastics Engineers [source] | ||||||||||