SPECTROSCOPIC CHARACTERIZATION OF RENEWABLE NANOPARTICLES AND THEIR NANOCOMPOSITES

M. A. MOSIEWICKI; N. E. MARCOVICH; M. I. ARANGUREN

Biopolymer Nanocomposites: Processing, Properties and Applications

John Wiley & Sons, Inc.

Año: 2013; p. 509 - 540

The three most abundant renewable polysaccharides in nature share rather similar building blocks, but they exhibit quite different properties because the existing differences in molecular structure lead to different arrangements and supramolecular structures. Their morphologies in nature are that of fibers in the case of cellulose and chitin and of granules in the case of starch, all of them showing crystalline and amorphous phases [1]. Besides, different treatments have been developed taking advantage of the large concentration of hydroxyl groups present in polysaccharides, an approach that can be applied for bulk and surface modifications [1]. In particular, surface modification is performed to improve interfacial compatibility and dispersion if the intended use of the nanoparticles is polymer reinforcement, or to achieve specific interactions with other material components if functional properties are required. Spectroscopic techniques, such as infrared (FTIR) and Raman spectroscopies, nuclear magnetic resonance (NMR), X-Ray photoelectron spectroscopy (XPS) and X-ray diffraction allow to investigate the chemical composition of the original materials as well as the modifications introduced to tailor specific properties. Additionally, they can also supply information with respect to the degree and type of crystallinity in the particles, being X-ray spectroscopy the technique most frequently used for this purpose. Usually, characterization by Fourier Transform Infrared (FTIR) spectroscopy is most frequently reported. Although Raman spectroscopy is less used, it does not suffer interference from water as infrared spectroscopy, which is particularly useful for the analysis of hygroscopic natural fibers. The combination of both techniques offers complementary information on the chemical nature of the particles and their composites [2].