Andrew R. McLauchlin

Preparation and characterization of organoclays based on an amphoteric surfactant

The uptake of the amphoteric surfactant, cocamidopropyl betaine (CAB) by a sodium montmorillonite clay was studied with respect to concentration and pH. A series of organoclays was prepared in which the basal spacings were found to depend on both parameters. Adjusting the solution pH during preparation influenced the adoption of either 1.8 or 2.0 nm spacing, whereas the 3.9 nm spacing in the same sample was unaffected. The presence of the carboxyl group in the CAB molecule enabled dispersion of the clay at higher pH by which means pure organoclays of high spacing could be obtained, whereas, without dispersing the clay, mixed populations were obtained. The results indicate the optimum parameters for preparing organoclays of desired spacings for use in clay-reinforced nanocomposites.

Biodegradable polymer nanocomposites

Abstract: Fossil carbon reserves are used to produce items whose durability was considered either to be an advantage or irrelevant depending on the application. Economic and environmental concerns are propagating interest in polymers that either are derived from alternative sustainable sources such as biomass or are biodegradable so that the risks of plastic residues in the environment are reduced or removed. Nanocomposite technology can engineer polymers to provide new materials, which is significant because of increasing legislative pressure and consumer demand for biodegradable high-performance materials, particularly in the packaging, biomedical and automotive sectors. This chapter introduces the most significant biodegradable polymers and reviews both methods of production and the physical properties of biodegradable nanocomposites.