Synthesis and Preparation of Chitosan/Clay Microspheres: Effect of Process Parameters and Clay Type

Abstract

This work aimed to prepare chitosan/clay microspheres, by the precipitation method, for use in drug carrier systems. The influence of the process parameters, particularly two airflows of the drag system (2.5 and 10 L·min−1) on the microspheres physical dimensions and properties, such as microstructure, degree of swelling and porosity were evaluated. The samples were characterized by optical microscopy (OM), scanning electron microscopy (SEM) and X-ray diffraction (XRD). Water absorption and porosity tests were also performed. The results showed that the process parameters affected the size of the microspheres. The diameter, volume and surface area of the chitosan/clay microspheres decreased when they were prepared with the higher airflow of the drag system. The microspheres presented a porous microstructure, being the pore size, percentage of porosity and degree of swelling affected not only by the process parameters but also by the type of clay. Hybrids (chitosan/clay) with intercalated morphology were obtained and the hybrid prepared with montmorillonite clay at higher airflows of the drag system presented the greatest interlayer spacing and a more disordered morphology. Thus, it is certain that the chitosan/clay nanocomposite microspheres prepared with montmorillonite (CL clay) at higher airflows of the drag system can have good drug-controlled release properties.

The Impact of the Ionic Cross-Linking Mode on the Physical and In Vitro Dexamethasone Release Properties of Chitosan/Hydroxyapatite Beads

“…The diffraction pattern of CS, as shown in Figure 6, exhibited two major crystalline peaks at 10.8 • and 20.0 • , which confirms the partial crystallinity of the polymer, in agreement with previously reported results [55][56][57][58]. These peaks (10.8 • and 20.0 • ) are typical fingerprints of chitosan related to hydrated and anhydrous crystals, respectively [56].…”

pH-Triggered Interfacial Interaction of Kaolinite/Chitosan Nanocomposites with Anionic Azo Dye

“…Numerous researchers and their coworkers have performed several trials for developing efficient adsorbents from chitosan by incorporating different substrates such as sand [16], perlite [17], ceramic alumina [18], oil palm ash [19], calcium alginate [20], magnetite [21], polyurethane [22], cotton fiber [23], cellulose [24], polyvinyl alcohol [25], polyvinyl chloride [13], etc. However, the major focus has been on clay minerals [5][6][7][26][27][28][29][30][31][32][33]. Clay minerals are attractive immobilization/support materials for chitosan owing to their relatively large available surface areas [34].…”

Bionanocomposites based on chitosan intercalation in designed swelling high-charged micas

“…Controlling the biopolymer/nanoclay interactions can open new route to generate smart nanomaterials with interesting technological properties, such as reliable thermal stability, hydrophobicity surface, and relevant environmental applications. In fact, many authors 35,36 have expressed the need to explore parameters such as time, initial chitosan concentration, chitosan/clay ratio and type of the clay to optimize the chitosan loading. Among them, the nature of the clay, 2:1 phyllosilicate, is one of the critical parameter 35 since electrostatic attractive forces improve the controlled drug release of those bionanocomposites 37–39 .…”

“…In fact, many authors 35,36 have expressed the need to explore parameters such as time, initial chitosan concentration, chitosan/clay ratio and type of the clay to optimize the chitosan loading. Among them, the nature of the clay, 2:1 phyllosilicate, is one of the critical parameter 35 since electrostatic attractive forces improve the controlled drug release of those bionanocomposites 37–39 . Therefore, design synthetic nanoclays, that allow controlling their structural composition, can be a priceless help to obtain a deep knowledge of the bioloymer/nanoclay interaction.…”