Sorina Alexandra Garea

New polymer-halloysite hybrid materials--potential controlled drug release system.

New hybrid materials based on a natural host (halloysite), biodegradable polymer (poly(vinyl alcohol)) and diphenhydramine hydrochloride as drug were synthesized and tested as a potential controlled drug delivery system. The formation of these hybrid materials was proved using different characterization methods like Spectroscopic techniques (FTIR, XPS and UV-vis), thermogravimetrical analysis and scanning electron microscopy (SEM). The hybrid materials exhibit different features regarding the drug release. In vitro drug release tests showed that there are several factors which exhibit a strong influence on the drug release rate. Thus the initial drug concentration used at the hybrid materials synthesis, the presence of a polymer in the hybrid composition and the pH value of the release medium are the most important factors.

Epoxy-Based Nanocomposites Reinforced with New Amino Functionalized Multi-Walled Carbon Nanotubes

The aim of the work was to synthesize epoxy-based nanocomposites reinforced with multi-walled carbon nanotubes (MWNT). MWNTs were first functionalized in order to increase the dispersion degree within the polymer matrix and thus to ensure good adhesion between the two components. The functionalization process consists of two steps: first, MWNT were oxidized, and then an amidation reaction occurred with various amines using carbondiimide and succinimide as activators. Thus, new modified MWNT with benzylamine (BA) and nonylphenoxy polypropyleneoxyamine (B100) were synthesized. The nanocomposites obtained were based on diglycidyl ether of bisphenol A (DGEBA) and modified MWNT and were fully characterized by TGA, DMA, XPS, SEM, TEM, and FTIR.

Innovative approach for the synthesis of benzoxazine-modified montmorillonite

The synthesis of a benzoxazine (BZ) monomer inside the montmorillonite (MT) layers was done using a diamino-modified MT as the amine component, phenol, and formaldehyde. The formation of the BZ rings within the MT layers was investigated by thermogravimetric analysis, X-ray photoelectron spectroscopy, proton nuclear magnetic resonance spectroscopy, and X-ray diffraction, this being enhanced when dioxane was used as the solvent. The morphology of the hybrid BZ monomer was investigated by scanning electron microscopy.

Epoxy-based nanocomposites with amine modified single walled carbon nanotubes

Abstract Carboxylated Single Walled Carbon Nanotubes (SWNT-COOH) were functionalized using different types of amines as modifier agents to improve the compatibility with the epoxy matrix. Covalent attachment was proved by XPS and Raman spectroscopy. TGA showed that only long chain modifier agents improved the thermal stability of modified SWNTs. Epoxy-based composites were synthesized using diglycidyl ether of bisphenol A (DGEBA) as polymer matrix and modified SWNTs as reinforcing agent.