PERSONAL DE APOYO
JUNCIEL Luis Daniel
congresos y reuniones científicas
Título:
Biodegradable polymer-clay composites produced with functionalized Patagonian bentonite precursors
Autor/es:
A. BIANCHI; L. D. JUNCIEL; G. ECHEVERRIA; I. TORRIANI
Lugar:
Santa Marta
Reunión:
Congreso; Latin American seminar of analysis by X-Ray techniques; 2012
Resumen:
BIODEGRADABLE POLYMER-CLAY COMPOSITES
PRODUCED WITH PATAGONIAN BENTONITES
A. E.
Bianchi,1 L. Junciel.2 G. A. Echeverría,3 I. L. Torriani,4 P.
Eisenberg,5 A. Botana,6 M. Mollo,7 R. M.
Torres-Sanchez8 y G. Punte9
1-3, 9 IFLP (CCT- La Plata). Departamento de Física, Facultad de Ciencias Exactas
Universidad Nacional de La Plata (UNLP) 115 y 49, 1900 La
Plata Argentina.
{bianchi@fisica.unlp.edu.ar,
junciel@fisica.unlp.edu.ar, gualech@fisica.unlp.edu.ar,
punte@fisica.unlp.edu.ar}
1-3 Facultad de Ingeniería, Universidad Nacional de La
Plata1 y 47, 1900 La Plata Argentina.
4. Instituto de Física,
Universidade Estadual de Campinas,
Cidade Universitária, Campinas, Sao Paulo
13083-970, Brazil
{torriani@ifi.unicamp.br}
5-7 National Institute of Industrial Technology,
Centre of Technological
Research for the Plastic Industry, Av. Gral.. Paz 5445 (1650), San Martin, Argentina.
{mariana@inti.gob.ar, botana@inti.gob.ar, patsy@inti.gob.ar}
5-7 Institute of Research and Environmental Engineering
(3iA),
Universidad Nacional de Gral. San
Martin, Belgrano 3563 (1650), San Martín, Argentina.
8 Centro de Tecnología de Recursos Minerales y Cerámica (CETMIC), CCT-La
Plata
Camino Centenario y 506, (1897), M.B. Gonnet,
Argentina
{rosats@cetmic.unlp.edu.ar}
Polymer composite films (PCF), based on
semicrystalline biodegradable thermoplastic polyester, polycaprolactone (PCL),
and a functionalized Patagonian bentonite were produced. The employed bentonite
is predominately sodium montmorillonite (MMT), structural formula: [(Si3.89
Al0.11) (Al1.43 Fe0.26 Mg0.30)] M+0.41,
cation exchange capacity (CEC): 174 meq/100g [1] and the organoclays had been
prepared by addition of 1 and 2 CEC of hexadecyltrimethyl-ammonium (HDTMA) and
octadecyl-trimethyl-ammonium (ODTMA) to
raw MMT diluted in deionized water and were fully characterized [2]. PCL/clay composites, with 5% of clay content in weight,
were synthesized by melt intercalation in a Brabender Plasticorder mixing
chamber at 100 °C, their thermal
behavior of the was investigated by DSC. No difference was detected between
melting point of PCL and those ones of the PCF, while a small decrease in the
degree of crystallinity for PCF coming from 2 CEC loading organoclays could be
perceived. SAXS and WAXS data analysis showed that organoclays expansion was
not lost in the PCF. However, not all PCF present the same characteristics. PCL/ODTMA1
and PCL/ HDTMA2 keep the Bragg reflections observed in the WAXS region in the
precursor organoclays and increase the proportion of clay expanded to d001=
40.8 and 39.3Å, respectively, as indicated by the noticeable Bragg peak in the
SAXS region. On the other hand, in the other PCF lower
intensity and much larger broadening of the (001) reflection in both WAXS and
SAXS regions were observed. Bragg peaks in SAXS regions were located at 53.2
and 41,3 Å
and 53,7 and 33.2 Å and for PCL/ODTMA2 and PCL/ HDTMA1,
respectively. Dielectric measurements showed that all the films present the
maximum in the dielectric constant at the lowest frequency explored, 0.1 Hz,
and a steady diminution as the frequency increases up to 1MHz. PCF showed a
dielectric constant higher than that of the PCL film up to approximately 50Hz. In PCF containing
organoclays with 1 and 2 CEC loading of HDTMA, the dielectric constant is about
double of the value found in PCL film, difference reduces to about 18% at about
1kHz. The dielectric loss is also higher in PCF than in PCL for low
frequencies. However, differences gradually decrease and PCF present values
comparables to those of PCL within the frequency range 50 Hz to 1 MHz
Keywords: nanocomposites,
SAXS, WAXS.
Acknowledgements. Ahtors
thank financial support from LNLS, Brasil, UNLP and CONICET PIP 0985, Argentina.
[1]
Magnoli. A. P. et al. (2008) Appl. Clay Sci. 40, 63?71.
[2]
Bianchi et al. ?ODTMA and HDTMA
organomontymorillonites characterization: new insight by WAXS, SAXS and surface
charge?. Sent for publication to Appl. Clay Sci.