Luisa Fiocca

Oxazoline-containing phosphazene derivatives. Part I: the case of hexakis(4-oxazolinophenoxy)cyclophosphazene

In this paper, the synthesis, characterization, and reactivity of a novel oxazoline-containing cyclophosphazene, hexakis(4-oxazolinophenoxy)cyclophosphazene, C-6-OXA, are reported. This product was synthesized by a two-step procedure that required first the preparation of 2-(4-hydroxyphenyl)-2-oxazoline and then the successive treatment of this compound with hexachlorocyclophosphazene in the presence of NaH (60% oil dispersion). The resulting C-6-OXA was eventually reacted with low-molecular-weight organic molecules, e.g. 4-benzoylbenzoic acid, to form highly photosensitive cyclophosphazenes, and with high-molecular-weight polymers, e.g. poly(ethylene terephthalate), PET, acting as a new type of multifunctional, phosphazene-based chain extender, to produce branched PET macromolecules showing greatly modified rheological properties.

Functionalization of poly(organophosphazenes), 10. Thermally induced grafting reactions of maleates containing oxazoline groups onto aryloxy-substituted poly(organophosphazenes)†

The functionalization reaction of aryloxy-substituted poly(organophosphazenes) with variable amounts of oxazoline groups is described as a function of different experimental parameters, such as the reaction time and temperature, the concentration of the peroxide initiator and of the oxazoline-containing maleate group, the solvent used to run the process and the type of substituents attached to the polyphosphazene skeleton. The resulting phosphazene grafted copolymers were characterized by IR and NMR ( 1 H, 13 C and 31 P) spectroscopy and by thin layer chromatography. These materials are successively reacted with poly(methacrylic acid) due to the well known reactivity of the oxazoline residues with carboxylic functions, to form new materials in which the inorganic and the organic macromolecules are linked together through genuine covalent bonds formed by ester-amide structures.

Copolymerization of bis(2-oxazoline)s, anhydrides, and diols or diamines. Reaction mechanisms and polymer properties

The preparation of linear poly(ester-amide)s from monoanhydrides, bis(2-oxazoline)s (namely 2,2′-(1,4-phenylene)bis(2-oxazoline)) and a third comonomer is discussed. The polymerization reactions were carried out in bulk between 150 and 200°C. When the third monomer is a diol, poly(ester-ester-amide)s are obtained. Diols of different structure were used: α,ω-diols having up to 12 carbon atoms, ethylene glycol oligomers (two or three repeating units), cyclic diols, etc.; glutaric, 3,3-dimethylglutaric and maleic anhydrides were used as monoanhydrides. The polymers were studied from the point of view of thermal properties, finding a substantial agreement between the structure of the monomers and the glass transition temperature of the polymers. By using primary diamines as a third comonomer, the reaction does not lead to the formation of a polymeric product. The failure of the polymerization was attributed to a competitive reaction that prevents the polymerization. After the amine group has reacted with the anhydride, cyclization of the so-formed carboxyalkylamide occurs, giving an imide derivative, unable to react further. Therefore, only a mixture of low molecular weight compounds is obtained in this case. When the diamine is secondary, the imidization reaction is not possible, and linear poly(amide-ester-amide)s are obtained.

Oxazoline-Containing Phosphazene Derivatives, Part III: Synthesis and Characterization of Novel Cyclophosphazenes Functionalized With Chiral 2-Oxazoline Groups

In this paper we describe the synthesis and the characterization of a series of cyclophosphazenes substituted with 2-oxazoline-containing moieties, with and without optical activity. These products could be obtained by reacting cyclophosphazenes containing six (hexachlorocyclophosphazene, C-6-Cl), two (2,2-dichloro-4,4,6,6-bis[spiro(2′,2″-dioxy–1′,1″-biphenyl)]cyclophosphazene, C-2-Cl) and one (pentakis(phenoxy)monochlorocyclophosphazene, C-1-Cl) chlorine atoms, respectively, with a series of 4-hydroxyphenyl-2-oxazolines, as obtained by condensation reaction of methyl-4-hydroxybenzoate with 2-aminoethanol and with chiral and racemic 1-amino-2-propanol, and successive cyclization reactions of the resulting hydroxyamides to 2-oxazoline compounds.

Poly(Organophosphazenes) Containing Oxazoline Groups

The synthesis, the characterization and the utilization of cyclo- and poly-phosphazenes functionalized with oxazoline residues are discussed.

Reactive Cyclophosphazenes Containing Oxazoline Groups: the Case of Hexakis(4-Oxazolinophenoxy)Cyclophosphazene

Hexakis(4-oxazolinophenoxy)cyclophosphazene, a multifunctional cyclophosphazene derivatives containing six pending oxazoline groups, was prepared by reacting hexachlorocyclo-phosphazene with 2-(4-hydroxyphenyl)-2-oxazoline. The resulting trimer was successively treated with carboxylic group-containing molecules (4-benzoyl-benzoic acid) and macromolecules (polyethylene terephthalate) to produce a novel photoinitiator and a polymer having higher molecular weight and improved mechanical properties, respectively.

Hexakis(4-Oxazolinophenoxy) Cyclophosphazene as a Novel Compatibilizer for Polycarbonates and Polyamides

Hexakis(4-oxazolinophenoxy)cyclophosphazene has been used to promote the compatibility between polycarbonate and polyamide-6 polymers. The resulting blends were characterized by a variety of method to assess the occurred compatibilization between the two types of macromolecules.