Gabrielle Charlotte Chitanu

Potential drug delivery systems from maleic anhydride copolymers and phenothiazine derivatives

New functionalized derivatives of phenothiazine containing amino or hydroxy groups with potential pharmacological properties were synthesized and characterized. They were reacted with maleic anhydride copolymers in order to obtain conjugates which can be used as controlled-release systems.

Efficient solvent-free microwave phosphorylation of microcrystalline cellulose

Environmentally friendly microwave phosphorylation of microcrystalline cellulose is herein described for the first time. Microwave irradiation is found to offer an efficient solvent-free procedure for cellulose modification without its pre-treatment (swelling in appropriate solvent).

Analysis and Characterization of Maleic Anhydride Copolymers. II. Some Aspects of Thermo-oxidative Decomposition

Abstract Six binary and ternary maleic anhydride copolymers with vinyl acetate, methyl meth-acrylate and styrene, useful as plastics, adhesives coatings, additives, etc., have been synthesized. Thermo-oxidative behavior under dynamic conditions of heating has been studied to test the possible changes during thermal treatments. The four or five thermo-oxidative steps of weight loss are characteristic for the studied copolymers. The characteristic temperatures, weight losses and overall kinetic parameters have been determined, and information about physical and/or chemical processes involved has been obtained.

Specific biofunctional performances of the hydroxyapatite-sodium maleate copolymer hybrid coating nanostructures evaluated by in vitro studies.

The nanohybrid structures consisting of hydroxyapatite (HA) and sodium maleate-vinyl acetate copolymer (MP) deposited by Matrix Assisted Pulsed Laser Evaporation (MAPLE) technique on Ti surfaces were investigated for specific biological qualities required in bone implantology. The data from in vitro studies demonstrated that human primary osteoblasts (OBs) firmly adhered to Ti coated with HA–MP as indicated by cytoskeleton and vinculin dynamics. OBs spread onto biomaterial surface and formed groups of cells which during their biosynthetic activity expressed OB phenotype specific markers (collagen and non-collagenous proteins) and underwent controlled proliferation.

Hybrid HAp-Maleic Anhydride Copolymer Nanocomposites Obtained by In Situ Functionalisation

The aim of the work is to establish if maleic anhydride copolymer acts as a grain growth modulator and/or as a biocompatible functionalisation agent for hydroxyapatite. Experimental work was developed in three directions: nanocomposites synthesis, nanocomposites characterization and citotoxicity tests on nanocomposites. Maleic anhydride copolymer – HAp nanocomposites were prepared by in situ functionalisation in hydrothermal conditions and were characterized by chemical quantitative analysis, XRD, FT-IR, SEM, specific surface area and picnometric densities. Chemical bonding between the copolymer carboxyl groups and calcium ions of HAp induced a peak of 1577 cm-1 on the FT-IR analysis. Following the evolution of this characteristic peak with the hydrothermal synthesis conditions (different temperatures and pressures) and corroborates the results with XRD and SEM analysis it was pointed out the copolymer grain growth modulator behaviour. Citotoxicity studies in vitro on mice fibroblast cultures were performed. The results proved the biocompatibility of new hybrid –polymer nanocomposites.

Comparative Study of In Situ Interactions between Maleic Anhydride Based Copolymers with Hydroxyl Apatite

A comparative study of the in situ interactions between different maleic anhydride based copolymers and calcium phosphates is presented in this paper. The ability of functional groups of the organic polymers to form under high pressure and low temperatures chemical bonds with the inorganic phase leading to improved properties of hybrid nanostructured material is discussed. The open challenges of new hybrid nanocomposites in the field of biomedical materials are evaluated. The challenge to use these nanostructured materials in medical field was evaluated by mapping the interface reactions between hybrid active layers and cells.

Self-assembled LbL opto-electronics from maleic anhydride copolymers

The layer-by-layer technique was applied to the fabrication of non-linear optical films. Poly(maleic anhydride-methyl methacrylate) was first modified with disperse red 1. This chromophore-containing polymer was assembled into multilayer thin films by electrostatic interaction with a polycation. Regular film growth during absorption cycles was proved by means of UV spectroscopy. Optical second-harmonic generation (SHG) was clearly observed from the films prepared using maleic acid copolymer containing DRl. The SHG signal increased with the number of chromophore-containing polymer layers up to 5 layers, while further assembly reduced the signal.

Analysis and Characterization of Maleic Copolymers—III. Differential Scanning Calorimetry Study

Abstract Endothermic physical processes and transition temperatures below 220°C of several binary and ternary copolymers of maleic anhydride with vinyl acetate, methyl methacry-late and/or styrene were studied by differential scanning calorimetry and infrared spectroscopy. To improve resolution of differential scanning calorimetry peaks and allow correct assignment of the chemical and physical processes in the studied temperature range, multiple heating-cooling or isothermal treatments were performed. The recycliza-tion of hydrolyzed maleic acid units to maleic anhydride units, occurring around 160–190°C, was confirmed by infrared spectra.