Hülya Arslan

Synthesis and characterization of water soluble O-carboxymethyl chitosan Schiff bases and Cu(II) complexes.

In this study, mono-imine was synthesized (3a and 4a) via a condensation reaction between 2,4-pentadion and aminobenzoic acid (meta or para) in alcohol (1:1). The second-imine (CS-3a and CS-4a) was obtained as a result of the reaction of the free oxo groups of mono-imine (3a and 4a) with the amino groups on the chitosan (CS). Their structures were characterized with FTIR and (13)C CP-MAS. Then, the water soluble forms of CS-3a and CS-4a were obtained through oxidation of the hydroxide groups on the chitosan to carboxymethyl groups using monochloracetic acid ([O-CMCS-3a] · 2H2O and [O-CMCS-4a] · 2H2O). Thus, the solubility problem of chitosan in an aqueous media was overcome and Cu(II) complexes could be synthesized more easily. Characterization of the synthesized O-carboxymethyl chitosan Schiff base derivatives and their metal complexes, [O-CMCS-3a-Cu(OAc)2] · 2H2O and [O-CMCS-4a-Cu(OAc)2] · 2H2O, was conducted using FTIR, UV-Vis, TG/DTA, XRD, SEM, elemental analysis, conductivities and magnetic susceptibility measurements.

Electrospray ionisation tandem mass spectrometry of poly [(R,S)-3-hydroxybutanoic acid] telechelics containing primary hydroxy end groups

Evaluation of polymer end-capping reactions with the aid of electrospray ionisation tandem mass spectrometry techniques (ESI-MS(n)) allows characterisation of novel poly[(R, S)-3-hydroxybutanoic acid]-(a-PHB) telechelics, containing primary hydroxyl groups at both polymer chain ends. The chemical structures of individual mass-selected macromolecules of the well-defined a-PHB telechelics have been defined in this way, and fragmentation mechanisms have been proposed. Copyright 1999 John Wiley & Sons, Ltd.

Ceric ion initiation of methyl methacrylate using polytetrahydrofuran diol and polycaprolactone diol

Abstract Polymerization of methyl methacrylate (MMA) initiated by ceric ammonium nitrate in combination with polytetrahydrofuran diol (PTHF-diol) and polycaprolactone diol (PCL-diol) has been investigated in aqueous nitric acid. PMMA-b-PTHF and PMMA-b-PCL block copolymers were obtained. Block copolymer yield was increased when using tetrabutyl ammonium hydrogen sulphate as a surfactant. The effects of nitric acid and ceric ions on the block copolymer yields were investigated. Block copolymers were characterized using GPC, 1 H-NMR, DSC, TGA and fractional precipitation methods.

Ceric ion initiation of methyl methacrylate from poly(glycidyl azide)-diol

Abstract Polymerization of methyl methacrylate initiated by ceric ammonium nitrate in combination with poly(glycidyl azide)-diol was investigated in aqueous nitric acid. Poly(methyl methacrylate)-b-poly(glycidyl azide) copolymer was obtained. Block copolymer yield was increased using tetrabutyl ammonium hydrogen sulphate as a surfactant. The effect of nitric acid, ceric ions and diol concentration on the block copolymer yield was investigated. Block copolymers were characterized using GPC, 1H-NMR, FTIR, DSC, TGA and fractional precipitation methods.