Preparation, characterization and studying the physico-chemical and mechanical properties of some natural and synthetic blends and their nano-composites with silica and montmorillonite nanoparticles.

Abstract

In the recent year’s significant progress has been achieved in the field of blending some natural polymers with and without synthetic polymers for various industrial applications from the environmental, health and safety points of view. The blending process is one of the various methods which are used for improving physico-chemical and physico-mechanical properties and thermal stability of the blend from environmental and economic aspects. In the present study we reported the preparation of a new series based on blending chitosan (CS) with poly vinyl alcohol (PVA) or with polyethylene glycol (PEG) in presence of nano-montmorillonite (MMT) or nano silica in different concentrations to get hybrid organic/inorganic nanocomposites of enhanced physico-mechanical and thermal properties and having biodegradable properties. 1. Preparation of chitosan / poly vinyl alcohol casted films (AB)

Chitosan solution (A) was added to PVA solution (B) in different ratios [70:30, 50:50, 30:70], the casted dry films of the different ratios of polymers blend named AB1, AB2 and AB3 respectively.

2. Preparation of hybrid chitosan-PVA/montmorillonite (MMT) nanocomposite films (C)

To a blends of (10 ml) chitosan solution (A) and (10ml) of PVA solution (B) was added different ratios [4%, 5% and 6%] ofnano MMT respectively, the three composite films named (C4, C5 and C6) were prepared for various testing and characterization experiments.

3. Preparation of hybrid chitosan -PVA / silica nanocomposite films (D):

To a blends of (10 ml) chitosan solution (A) and (10ml) of PVA solution (B) were added different ratios [4% and 6%] of nano silica respectively, the two composite films named (D4 and D6) were obtained. 4. Preparation of chitosan / poly ethylene glycol (PEG) films (AE): Add from prepared chitosan solution (A) to PEG solution (E) in different ratios [70:30, 80:20, 90:10], the three hydrogel ratios are obtained AE1, AE2 and AE3. 5. Preparation of chitosan - polyethylene glycol /nano montmorillonite (nano MMT) blended films (F): To (10 ml) of chitosan solution (A) add PEG solution (E) (10ml) then add nano MMT in different ratios [4%, 5% and 6%] respectively, the three blended films (F4, F5 and F6) are obtained respectively. 6. Preparation of chitosan -polyethylene glycol /nano silica blended films (G): To solution of a mixture of chitosan solution (A) (10 ml) and PEG solution (E) (10 ml) add nano silica in different ratios [4%and 6%]. the two blended films (G4 and G6)are obtained respectively. The casted films of chitosan, PVA, PEG and their hybrid composites with either nano montmorillonite or withnano silica were subjected for investigation using spectroscopic methods of analysis FT-IR, XRD and morphological properties using transmition electron microscope (TEM) in addition to thermal analysis via TGA and DSC. The mechanical properties were measured using tensile testing machine (tensile strength, elongation) and investigating the degradation properties of the hybrid composite films.

X-Ray diffraction • The x-ray diffraction patterns are expressed as simply mixed patterns of chitosan and PVA with the same ratios as these for mechanical blending.