Materials Science Forum Vol. 722

Abstract: Nano-capsules with organic-inorganic composite PMMA-SiO2 as the shell and paraffin as the core have been largely and rapidly synthesized by the cooperative reaction of interfacial hydrolysis and polymerization. Ammonium persulfate as the initiator and catalyst was used to make the polymerization and hydrolysis process occurring simultaneously and to improve the uniformity and controllability of capsule morphology. The prepared homogeneous core-shell structures of capsules with the grain size around 100 nm have small volume change and stable thermodynamic characteristics. The cooperative reactions of polymerization and hydrolysis process provide a convenient and efficient method for preparing homogeneous and stable organic-inorganic composite capsules.

Abstract: The effects of carbon nanotubes (CNTs) on the thermal stability of CNT/polymer nanocomposites are discussed using CNT/silicone composites as a model compound. Pristine CNTs can improve the thermal stability of polymer composites due to the high thermal stability of CNTs, their network structure and free radical scavenging capabilities. However, impurities such as metal catalyst residues and defects such as carboxylic acid functional groups in CNTs can lead to decreased thermal stability of CNT/silicone nanocomposites. Acid purification is an efficient way to remove metallic impurities and can enhance free radical scavenging capabilities. However, controlling the amount of oxidation is important to avoid acid catalyzed thermal degradation induced by carboxylic acid groups on CNT surfaces.

Abstract: Nanoparticular chitosan-dye nanocomposites were prepared by a facile ionotropic gelation, which show a much improved stability against UV and ozone attack. The nanocomposites do not contain any toxic material. Also, as natural occurring biopolymeric chitosan is used as the matrix material, the nanocomposite is biocompatible and biodegradable with high bioaffinity. After suitable bioconjugation, the developed luminous chitosan-dye nanocomposites can be used as target biolabels in various medical and biomedical applications.