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.

Hexakis(4-oxazolinophenoxy)cyclophosphazene,a multifunctional cyclophosphazene derivatives containing six pending oxazoline groups, was prepared by reacting hexachlorocyclophosphazene 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.

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.

We report our results on the miscibility and irradiation of the blends of poly(ethylene oxide) (PEO) and a phosphazene copolymer almost equimolecularly substituted with 4-benzoylphenoxy and methoxyethoxyethoxy moieties (BzMEEP). Differential scanning calorimetry (DSC) studies of the blends showed glass transitions temperatures (T-g) that increased regularly with the percentage of BzMEEP in the blend from about -50 degrees C up to -30 degrees C. Irradiation of these blends, under selected experimental conditions, leads to the absorption of the light by the benzophenone chromophore only in the copolymer, causing grafting of PEO onto the copolymer to occur concurrently with cross-linking reactions. Almost completely insoluble gellike materials were obtained. The percent of gel formed and degree of swelling of the cross-linked blends in chloroform were dependent on the amount of benzophenone, irradiation time, and molar mass of PEG.

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

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 (1H, 13C and 31P) 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.

In this paper the radical-induced solution grafting of diethyl maleate onto poly[bis(4-ethylphenoxy)phosphazene] is reported, together with the possible parameters that can influence this reaction, i.e., the maleate, molecular oxygen, and dicumylperoxide concentration in the reaction mixture, the solvent, time, and temperature of the process. A possible mechanism of this process is inferred on the basis of literature data concerning analogous grafting processes carried out onto polyolefins. The importance of the decrease of the intrinsic viscosity of the reaction mixture that takes place during the grafting reaction is also discussed in terms of chain scission and molecular weight degradation of the phosphazene macromolecule. The possible implication of the final phosphazene copolymers containing variable quantities of grafted diethyl succinate groups, poly[bis(4-ethylphenoxy)phosphazene]-g-diethyl succinate, in blending processes with commercial, carbon-backboned macromolecules (polyesters and polycarbonates) is stressed.

In this paper we highlight the general strategies established over the time for the functionalization of poly(organophosphazenes) in order to modify both the chemical structures and the chemicophysical properties of these substances. These modifications have been obtained by reacting poly(dichlorophosphazene) with difunctional nucleophiles thus introducing selected chemical functions into the polyphosphazene substrates or by carrying out suitable functionalization processes on pre-synthesized phosphazene macromolecules. Particular attention has been paid to the chemical modification of polyphosphazenes containing 2,2,2-trifluoroethoxy, phenoxy, 4-ethylphenoxy, 4-sec-butylphonoxy and 4-methoxyphenoxy substituents as these groups were attached to phosphazene homopolymers and copolymers that have been considered in the past for industrial development.

Abstract In this paper the light-induced grafting reaction of dimethyl maleate, diethyl maleate, dibutyl maleate and diethyl fumarate, onto aryloxysubstituted phosphazene polymers, to form polyphosphazene copolymers containing grafted succinate groups, is investigated by means of IR spectroscopy and the equilibrium swelling technique of polyphosphazene films. The importance of several different experimental factors that can influence the final succinate grafting yields is discussed, i.e. the type and concentration of the polyphosphazenes and of the unsaturated products, reaction time, the absence or presence of molecular oxygen or of the 1-vinyl-2-pyrrolidone monomer, and the concentration of the benzoin ethyl ether photoinitiator. Furthermore, it is shown that the overall efficiency of the lightinduced grafting process is lower than that previously measured for the reaction initiated thermally using peroxide species, and that the photochemical grafting reaction always occurs with no degradation of the ph...

In this article, the general procedure for stabilizing polyorganophosphazenes against the damage induced in these substrates by photooxidation reactions under accelerated conditions is explored. This method is based on the preventive grafting of succinic anhydride groups onto selected polyphosphazenes induced by light excitation, followed by the reaction of the functionalized phosphazene substrates with amino-terminated HALS groups. HALS moieties, in fact, are able to strongly inhibit the photooxidation ofphosphazene films under accelerated conditions even when randomly attached to the polyphosphazene materials in very low amounts.

In this paper we describe the light-induced grafting reaction of poly(vinyl acetate) onto catena-poly[bis(4-sec-butylphenoxy)-lambda(5)-phosphazene], catena-poly[bis(4-ethylphenoxy)-lambda(5)-phosphazene] and catena-poly[bis(4-methylphenoxy)-lambda(5)-phosphazene], and the successive acid- (and base-) catalyzed hydrolysis of the grafted macromolecule to poly(vinyl alcohol). The process was found to be dependent on the irradiation time, reaction temperature, relative monomer/methanol concentration in the reaction mixture, type of substituents present on the exploited phosphazene polymers, and on the crystallinity of these macromolecules. The new phosphazene grafted copolymers thus prepared have been characterized by IR spectroscopy gravimetric analysis and contact angle measurements.

The light-induced grafting reaction of acrylate monomers containing hindered piperidine groups (HALS) onto poly[bis(4-benzylphenoxy)phosphazene] is described as a function of several different experimental parameters, i.e., type of photoinitiator (benzophenone or benzoin ethyl ether), monomer concentration, solvent composition, light intensity, and swelling of the polyphosphazene films. The obtained phosphazene-g-HALS-containing acrylate-grafted copolymers, irradiated with light of wavelength longer than 300 nm under accelerated photooxidative conditions to test the photostabilizing ability of the grafted HALS groups, showed that the hindered piperidine groups grafted onto the polyphosphazene matrix are able to considerably depress the damage caused to the poly[bis(4-benzylphenoxy)phosphazene] films during light exposure. The efficiency of this process seems to be related to the amount of HALS residues grafted onto the phosphazene substrates. © 1996 John Wiley & Sons, Inc.

The radical-induced grafting reaction of maleic anhydride on to poly[bis(4-methylphenoxy)-phosphazene] is described and the different experimental parameters able to influence this process (maleic anhydride and peroxide concentrations, reaction time and temperature, molecular oxygen and solvent) are evaluated. The obtained poly[bis(4-methylphenoxy)phosphazene]-graft-succinic anhydride grafted copolymers show an enhanced reactivity toward air moisture, alcohols and amines with respect to the pristine phosphazene macromolecule. These substrates, in fact, are reacted with several organic substances containing free -OH and -NH2 functionalities to obtain new functionalized phosphazene copolymers showing interesting scientific and technological potential.

In this paper we describe the solution functionalization reaction of six phenoxy-substituted poly(organophosphazenes) with maleic anhydride and the effect of the phosphazene substituents on the overall grafting yield of anhydride moieties. It was found that the phosphazene polymer substituted with 4-ethylphenoxy groups is the most reactive of the whole series of exploited materials, while that bearing 4-t-butylphenoxy groups is the most inert one. This experimental reactivity trend observed in the grafting process is accounted for on the basis of both thermodynamic and steric factors.

The synthesis of hexakis(4-carboxyl-3-O-acetylphenoxy)cyclophosphazene starting from hexachlorocyclophosphazene is described.

In this paper we describe the free-radical-promoted grafting of maleic anhydride onto poly[bis(4-ethylphenoxy)phosphazene] carried out in solution under variable experimental conditions. It was found that this reaction depends on several different experimental parameters, i.e. the percentage of maleic anhydride in the system, the type and the thermal stability of the exploited peroxide initiators, the solvents used to run the grafting experiments, the amount of molecular oxygen present in the reaction medium, the heating time, and the reaction temperature. The grafting of maleic anhydride onto poly[bis(4-ethylphenoxy)phosphazene] induces profound modifications both in the physical (viscosity and glass transition temperature) and in the chemical (reactivity) properties of the phosphazene polymer and opens up unexpected perspectives to further; functionalization reactions and compatibilization processes for the phosphazene polymer.

In this paper we describe a method for the functionalization of catenapoly[bis(4-hydroxyphenoxy)-lambda(5)-phosphazene] with diazonium salts to form new, deeply-coloured, phosphazene copolymers containing variable amounts of azo dyes attached to the polyphosphazene skeleton. The degree of functionalization in these substrates is regulated in order not to exceed 20% of the sites available in the pristine polyphosphazene and to maintain a high percentage of unreacted, free, hydroxy groups, in the final, coloured copolymers. These species are still very reactive and able to undergo further functionalization reactions.

An overview of the grafting reactions of organic substrates onto poly(organophosphazenes) is presented. It was found that the type of phosphazene substrate used in the reactions, the swelling properties of the polymeric films, the characteristics of the photoinitiators and the composition of the reaction media are the major factors that influence the light-induced grafting of organic macromolecules onto polyphosphazene matrices. When the thermal grafting of maleic anhydride onto poly(organophosphazenes) is considered, the nature of the polymer, the reaction temperature, and the peroxide concentration are of importance.

In this paper we report the light-induced grafting copolymerization of N,N'-dimethylacrylamide onto four poly(organophosphazene) films i.e. poly[bis(4-isopropylphenoxy)phosphazene], poly[bis(4-s-butylphenoxy)phosphazene], poly[bis(4-benzylphenoxy)phosphazene] and poly[bis(2,2',2''-trifluoroethoxy)phosphazene]. The process was carried out in N,N'-dimethylacrylamide/methanol mixtures in presence of benzophenone as sensitizer.The yield of the grafting process was evaluated as a function of the phosphazene structure, of the relative amounts of N,N'-dimethylacrylamide and methanol in the reaction mixtures, and of the swelling capability of the polymer films. The obtained polyphosphazene-g-poly-N,N'-dimethylacrylamide copolymers were characterized by i.r. spectroscopy, both ATR and transmission, and by contact angle measurements.