Thermal and Mechanical Properties of Chitosan/SiO₂ Hybrid Composites

Abstract

Chitosan-silica (CSSi) hybrid films have been fabricated by sol-gel process using tetraethoxysilane (TEOS) as precursor. The structure of the resulting hybrid has been characterized by Fourier transform infrared spectroscopy (FTIR). Fracture surface has been revealed through a field emission-scanning electron microscopy/energy dispersive spectrometer (FE-SEM/EDS) to probe the dispersion degree and the size ofSiO2particle. Study of morphology using a SEM micrograph and the High Resolution Transmission Electron Microscopy (HRTEM) images of the nanocomposite films suggests that theSiO2nanoparticles are within the range of 2–7 nm in diameter and are uniformly dispersed in the polymer matrix. Thermal properties of these composite materials have been studied as a function of silica, indicating that thermal stability of the chitosan film is enhanced. Dynamical mechanical thermal analysis (DMTA) has been carried out to measure the shift in the glass transition temperature (Tg) of the composites from the maxima of theαtransition curves. The glass transition temperature and the storage modulus show an increase with increasing silica content. The maximum increase in theTgvalue, that is,159.37∘C,is seen with 30 wt% silica. A gradual increase of 3.0 GPa in the modulus relative to the pure polymer is observed.

Chitosan/siloxane hybrid polymer: synthesis, characterization and performance as a support for immobilizing enzyme

“…27 Other characteristic bands were observed at 950 cm -1 (Si-O-Si axial deformation), 810 cm -1 (Si-O-Si axial deformation) and 600 cm -1 (Si-O-Si angular deformation).…”

“…In this range of temperature probably occurred the dehydration of the saccharide rings, depolymerization and decomposition of the units of the organic polymer as well as the inorganic part of the hybrid. 30,27 The higher temperature values for the first stage of decomposition observed for support compared to the first stage decomposition temperature of the pure chitosan (60 ºC), 31 indicates that the formation of the hybrid of SiO 2 -chitosan was successful.…”

“…The initial weight loss (26%) was observed around 155 °C and can be attributed to loss of adsorbed water on the surface of chitosan and side product of subsequent condensation of Si-OH groups. 27 The second weight loss (29%) was observed at 275 ºC due to the decomposition of low molecular weight species. Thermal decomposition was marked in the region of 275 ºC up to 800 ºC (around 40%).…”

Optical Sensor for the Determination of Lead(II) Based On Immobilization of Dithizone onto Chitosan-Silica Membrane

“…2) according to Al-Sagher and Salim [17], indicated hydrogen bonds formed between amide group of chitosan and silanol. Other interactions were ionic bonds between amino group and silanol and also covalent bonds which were possible to be formed due The characterization of the membrane by FTIR (Fig.…”

3d Nanocomposite Chitosan/Bioactive Glass Scaffolds Obtained Using Two Different Routes: An Evaluation of the Porous Structure and Mechanical Properties

“…The interactions between the chitosan and the TEOS reveal the formation of hydrogen bonds between the amide groups on chitosan and the ionic silanol groups, connections between the amines from chitosan and the silanols and covalent bonds generated after the esterification of the hydroxyl groups on chitosan and the networked silanol groups on the silica. 25 …”