Jozef Luston

Unsaturated 2-Oxazoline Modification of Polyethylene Containing Carboxylic Groups

Abstract Chemical modification of terpolymer poly(ethylene-co-butyl acrylate-co-acrylic acid) with a bifunctional 2-oxazoline derivative 2-(4-allyloxyphenyl)-2-oxazoline has been performed in melt under the conditions of reactive processing and in a solution. The reaction in melt is very fast and, in spite of some modifier evaporation, it is completed in 15 minutes at 180°C. The product is a terpolymer containing thermally stable unsaturated groups bonded via amido-ester linkage to the main chain. The presence of unsaturation was proved by 13C NMR spectroscopy. The modification does not significantly change the crystallization behavior of the terpolymer.

Three isomeric forms of hydroxyphenyl-2-oxazoline: 2-(2-hydroxyphenyl)-2-oxazoline, 2-(3-hydroxyphenyl)-2-oxazoline and 2-(4-hydroxyphenyl)-2-oxazoline

Crystal structures are reported for three isomeric compounds, namely 2-(2-hydroxyphenyl)-2-oxazoline, (I), 2-(3-hydroxyphenyl)-2-oxazoline, (II), and 2-(4-hydroxyphenyl)-2-oxazoline, (III), all C9H9NO2 [systematic names: 2-(4,5-dihydro-1,3-oxazol-2-yl)phenol, (I), 3-(4,5-dihydro-1,3-oxazol-2-yl)phenol, (II), and 4-(4,5-dihydro-1,3-oxazol-2-yl)phenol, (III)]. In these compounds, the deviation from coplanarity of the oxazoline and benzene rings is dependent on the position of the hydroxy group on the benzene ring. The coplanar arrangement in (I) is stabilized by a strong intramolecular O-H...N hydrogen bond. Surprisingly, the 2-oxazoline ring in molecule B of (II) adopts a 3T4 (C2TC3) conformation, while the 2-oxazoline ring in molecule A, as well as that in (I) and (III), is nearly planar, as expected. Tetramers of molecules of (II) are formed and they are bound together via weak C-H...N hydrogen bonds. In (III), strong intermolecular O-H...N hydrogen bonds and weak intramolecular C-H...O hydrogen bonds lead to the formation of an infinite chain of molecules perpendicular to the b direction. This paper also reports a theoretical investigation of hydrogen bonds, based on density functional theory (DFT) employing periodic boundary conditions.

2-(4-Hydroxyphenyl)-4,4-dimethyl-2-oxazoline: X-ray and density functional theory study.

In the crystal structure of the title compound, C(11)H(13)NO(2), there are strong intermolecular O-H...N hydrogen bonds which, together with weak intramolecular C-H...O hydrogen bonds, lead to the formation of infinite chains of molecules, held together by weak intermolecular C-H...O hydrogen bonds. A theoretical investigation of the hydrogen bonding, based on density functional theory (DFT) employing periodic boundary conditions, is in agreement with the experimental data. The cluster approach shows that the influence of the crystal field and of hydrogen-bond formation are responsible for the deformation of the 2-oxazoline ring, which is not planar and adopts a (4)T(3) ((C3)T(C2)) conformation.

Biocompatibility and Immunocompatibility Assessment of Poly(2-Oxazolines)

Synthetic polymers are considered to be the promising materials for biomedical applications. Various polymer formulations have been employed to achieve the desired chemical, physical and biological properties. Recently, there has been much interest in the development of environmentally responsive polymers for use as biomaterials [1]. Such behavior is significant for the controlled release of drugs upon the application of a stimulus, such as pH, temperature, light or ionic strength. These mentioned properties are necessary for the utilization of polymeric materials for biomedical applications, such as drug and gene delivery, biomembrane technology and biocatalysis [2,3]. Polymer materials can be used in medicine as a part of implant, dialysis membranes, bone scaffolds or components of artificial organs. It means that polymers covers very broad range of biomedical applications. A critical point of the usage of synthetic polymers in living bodies is their utilization, accompanied with the interactions of the foreign material, with the living matter (cells, tissues etc.). The implantation of polymeric materials to a body is usually associated with the inflammation and biofouling. The inflammation is the first defense mechanism of the immune system followed by unspecific cell and protein adhesion and the formation of fibrotic tissue which leads to implant s dysfunctions. The fundamental role in the implantation of these materials is to increase the tolerance of body to implanted material and to avoid the foreign body reaction [4,5].

Synthesis of 2-oxazolines containing allyl groups by phase transfer catalysis

Several new derivatives of 2-oxazolines containing allyl groups were prepared from hydroxy derivatives under the conditions of phase transfer catalysis (PTC). Derivatives with one allyl group can be used as functional monomers or for the modification of polymers, and polyfunctional derivatives can be used for the cross-linking of polymers.