300 research outputs found
Molecular dynamics of carrageenan composites reinforced with Cloisite Na+ montmorillonite nanoclay
[EN] Nanocomposites comprising biodegradable carrageenan and glycerol(KCg) as the host polymer, with different
contents of natural montmorillonite (MMT) as filler, were prepared by a solution casting process.
Different techniques have been used to determine the interaction/behavior among the different components
of the samples such as Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD),
Transmission electron microscope (TEM) and, mainly, Dielectric relaxation spectroscopy (DRS). FTIR indicates
hydrogen interaction between carrageenan matrix and silicate that is confirmed by the XRD data
indicating some kind of carrageenan intercalation between the MMT layers. A rather homogenous distribution
of MMT into KCg matrix were observed using transmission electron microscopy. The MMT effect
on the molecular mobility at the glass transition was studied by dielectric relaxation spectroscopy. The
MMT addition resulted in a slower relaxation and a wider distribution ofthe relaxation times. The fragility
index, m, increased upon MMT incorporation, which may be attributed to a reduction in mobility chains,
due to the MMT confinement of the KCg network. In addition, the apparent activation energy associated
with the relaxation dynamics of the chains at Tg increased with the MMT content. The modified films
developed in this paper could be used to prepare biodegradable and edible packaging films and films for
biomedical applications with improved mechanical and good dielectric response.This work was supported by the Direccion General de Ciencia y Tecnologia (DGCYT) [MAT2015-63955-R]; the Vice-Rectorate for Research of the Pontificia Universidad Catolica del Peru and the National Council of Science, Technology and Technological Innovation of Peru (CONCYTEC/FONDECYT).Sanchis Sánchez, MJ.; CarsĂ Rosique, M.; Culebras, M.; Gomez- Clari, CM.; RodrĂguez, S.; GarcĂa-Torres. F. (2017). Molecular dynamics of carrageenan composites reinforced with Cloisite Na+ montmorillonite nanoclay. Carbohydrate Polymers. 176:117-126. https://doi.org/10.1016/j.carbpol.2017.08.012S11712617
- …