Synthesis and processing of bionanocomposites for industrial applications

LEANDRO N. LUDUEÑA; ROMINA OLLIER; JIMENA S. GONZALEZ; VERA A. ALVAREZ

Kottayam

Conferencia; Third International Multicomponent Polymer Conference (IMPC 2012); 2012

In the last decades the production of biodegradable and biocompatible polymers has attracted increasing attention owing to the environmental problems induced by the accumulation of plastic wastes1,2 and because of their potential relevance in biomedical applications. Some interesting cases of study are the Polycaprolactone (PCL), which is a biodegradable polymer that can be processed using conventional techniques3 and is suitable for a number of potential industrial applications such as packaging, disposable polymer products and automobile parts; and the polyvinyl alcohol (PVA) which has been widely used for biomedical applications4. In the case of PCL, our studies were focused on packaging applications and the production of short life-time and disposable polymer products where the main drawback until now was the relative high price and some inferior properties which have limited their large-scale production as a substitute of traditional polymers5. The use of nanoclays as fillers has been proved to be an effective and economic method to overcome this problem. In this work several commercial modified montmorillonites purchased from Southern clay products (Cloisite series) were used as reinforcement of PCL. The effect of the clay organic modifier, the processing conditions and the post-processing technique on the final properties of PCL/clay nanocomposites was analyzed. Bentonite, which is another layered silicate consisting mostly of montmorillonite, was also used. Its low price and abundance in Argentine make it a potential candidate for replacing the commercial montmorillonites. In order to improve the compatibility between bentonite and PCL and to produce an increment in the interlayer spacing of the clay, chemical treatments with ammonium and phosphonium salts at different concentrations and times of reactions were carried out. Finally we compared the thermal resistance, basal spacing and hydrophobicity of the laboratory modified bentonite with the commercial montmorillonite as well as the final properties and biodegradability of the corresponding PCL/clay nanocomposites. In the case of PVA, our works were focused on the preparation and characterization of PVA hydrogels reinforced with different kind of nanoparticles for three different biomedical applications: articular cartilage, wound dressing and drug delivery. PVA hydrogels reinforced with hydroxyapatite (HA) nanoparticles were prepared for the replacement of diseased or damaged articular cartilage due to its good physicochemical and especially tribological properties. HA nanoparticles were ?in situ? generated by freezing/ thawing (F/T) method. PVA hydrogel/bentonite nanocomposites were prepared for wound dressing where the material needs to meet the requirements to use it as artificial skin (high vapor permeation and protection of wound from infection and dehydration). PVA hydrogel/iron oxides nanocomposites were prepared in order to take the advantage of the sensitivity of this ferrogel to an external magnetic field which offers a high potentiality in the design of a targeting drug delivery system, which is considered a safe and effective way for tissue-specific release of drugs.