INIQUI   05448
INSTITUTO DE INVESTIGACIONES PARA LA INDUSTRIA QUIMICA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Characterization of HDPE/polyamide 6 nanocomposites using scanning and transmission electronic microscopy. Comparison
Autor/es:
E. ERDMANN; M. LOPES DIAS; V. J.R.R PITA; H. DESTÉFANIS; F. MONASTERIO; D. ACOSTA
Lugar:
Río de Janeiro - BRASIL
Reunión:
Workshop; POLYCHAR 15; 2007
Institución organizadora:
IMA/UFRJ, IQ/UERJ, SEPOL/UENF, INT/RJ, IT/UFRRJ, CENPES/PETROBRAS
Resumen:
Nanocomposite synthesis by conventional polymer processing operations requires strong interfacial interaction between the polymer matrix and the clay to generated shear forces of sufficient strength. This is readily achieved with high surface energy polymers such as polyamides, where polarity and hydrogen-bonding capacity generates considerable adhesion between the polymer and clay phases. However, low-energy materials such as polyethylene interacts only weakly with mineral surfaces, making the synthesis of polyolefin nanocomposites by melt compounding considerably more difficult1,2. Interest in polyolefin nanocomposites has emerged due to their promise of improved performance in packing and engineering applications. On the other hand, most polymers are incompatible when blended and thus they generally form multiphase morphologies, polyethylene and nylon 6 are typically incompatible and form an unstable morphology when blended3,4. The main objective of this work was to study the interfacial adhesions and morphologies of high density polyethylene (HDPE)-nylon 6/modified clay nanocomposites with a scanning electron and transmission electron microscope (SEM, TEM) and an X-ray diffractometer. Thus the ability of nylon 6 in dispersing clays provided by Nylodur was used to prepare a modified delaminated clay and then it was mixed with HDPE from Polisur S.A. Mixing was performed using melt compounding processing in a Haake Rheocord 9000 torque rheometer equipped with roller rotors, operating at 240oC for 10 min and 60 rpm with a 3% fill factor. An Argentinean montmorillonite from Minarmco S.A. was used for preparing the silicate layers and two modified clays were prepared: Montmorillonite was intercalated with ƒÃ-caprolactam this specimen was named MMTArInt5, the second modified clay, the MMTArHDTAM, was prepared  using a Genamin quaternary alkyl ammonium salt, hexadecyl trimethyl ammonium bormide (HDTAM-CTAC) according Valenzuela6 technique. The morphologies of the nanocomposites were investigated using an SEM (JSM-5600, JEOL) and TEM (TEM-1210, JEOL) using an accelerated voltage of 60 kV. The fractured surfaces of the nanocomposites for SEM imaging were prepared by cryogenic fracturing in liquid nitrogen and then sputter-coating with Au. To get precise information about domain sizes, the samples were etched in boiling toluene in order to remove PE component, or etched in formic acid at room temperature in order to remove nylon 6 domains. Besides ultrathin sections of the composites with a thickness of approximately 50 nm for TEM were prepared in a Reichert ultramicrotome Ultracut S50 equipped with a diamond knife and the samples were analyzed without any staining. XRD patterns show that the nylon 6 is a great factor in the substantial reduction in the intensity of the diffraction peak and that the position of the (001) peak shifts to lower angle. This result is due to the investigated organoclays have more affinity to nylon 6 than HDPE. The TEM analyses confirmed the typical structure of the nanocomposites. The phase-separated domains were studied and the obtaining of nanocomposites was proven. [1] H.R. Dennis, D.L. Hunter, D. Chang, S. Kim, J.L. White, J.W. Cho and D.R. Paul, Polymer 2001, 42, 9513-9522. [2] T.G. Gopakumar, J.A .Lee, M. Kontopoulou and J.S. Parent, Polymer 2002, 43, 5483-5491. [3] A. HalldeLn, M. Deriss, B.WessleLn, Polymer 2001, 42, 8743. [4] M. Y. Gelfer, H. H. Song, L. Liu, B. S. Hsiao, B. Chu, M.Rafailovich, M. Si, V. Zaitsev, J. of  Polym. Sci., Part B: Polym. Phy. 2003, 41, 44. [5] Y. Kojima, A. Usuki, M. Kawasumi, A. Okada, T. Kurauchi and O. Kamijaito, J. Polym. Sci., Polym. Chem. 1993, 31, 983-986. [6] F. Valenzuela Diaz, Key Engineering Materials 2001, 189 (191), 203-207.