A new tris-spiro-(3,4-dioxybenzaldehyde)cyclotriphosphazene [PNCHO] was synthesized from the condensation of hexachlorocyclotriphosphazene with 3,4-dihydroxybenzaldehyde in the presence of strong base. Further reaction of the trialdehydic cyclotriphosphazene based molecules [PNCHO] with three different dianilines (benzidine, 4,4'-methylenedianiline and 4,4′-Sulfonyldianiline) resulted in creation of a new poly(tris-spiro-3,4-dioxbenzene)cyclotriphosphazenes with Schiff-base groups [PNSB1-3]. The structures of [PNCHO] and the polycyclotriphosphazenes-schiff base derivatives were characterized by means of FTIR, 1H, 13C NMR and C.H.N elemental analysis. Differential scanning calorimetery (DSC) revealed a relatively high glass transition temperature (135−175°C) of obtained polymers. Thermal gravimetric analysis (TGA) exhibited their good thermal stability (up to 375oC). The char yield was about 36-42% at 700°C. All polymers were self-extinguishable as the LOI (Limiting Oxygen Index) values were above 26% and this meets with the V-0 and V-1, classification (UL-94). No fumes, soot, or toxic gases emission were observed during burning. The polymers obtained can be used as environmentally friendly, flame-retardant materials.
Four cyclolinear poly(aryloxycyclotriphosphazenes) derived from poly[4,4 0 -(isopropoylidene)diphenoxytetrachlorocyclotriphosphazene]and poly[4,4 0 -(hexafluoroisopropylidene)diphenoxytetrachlorocyclotriphosphazene] were synthesized from the reaction of hexachlorocyclotriphosphazene (HCP) with 4,4 0 -(isopropylidene)diphenol (bisphenol A) or 4,4 0 -(hexafluoroisopropylidene)diphenol (bisphenol AF) in molar ratio 1 : 1 via a one-step condensation polymerization. Subsequent reaction of the resulted chlorine-bound polymers with adequate amount of the sodium salts of 4-methoxycarbonylphenoxide or 4-propoxycarbonylphenoxide yielded the corresponding chlorinefree polymers, [poly(tetra-4-methoxycarbonylphenoxy)-4,4 0 -(PBACP), [poly(tetra-4methoxycarbonylphenoxy)-4,4 0 -(hexafluoroisopropylidene)diphenoxycyclotriphosphazene] (MBAFCP), [poly(tetra-4propoxycarbonylphenoxy)-4,4 0 -(hexafluoroisopropylidene)diphenoxycyclotriphosphazene] (PBAFCP), respectively. The chemical structures were characterized by Fourier transformer infrared, 1 H, and 13 C-NMR. Thermal properties of polymers were investigated using DSC and TGA analysis. The obtained polymers were thermoplastic, having moderate T g values in the range of 26-78 C and good thermal stability up to 350 C in N 2 and O 2 gases. The thermal decomposition of the isopropylidene-containing polymers is a one-step process, while that of hexafluoroisopropylidene-containing polymers is a two-step process. However, presence of the latter group in the polymers backbone showed negligible effects on the thermo-oxidative stability. The adhesive strength was measured by lapshear strength test on glass-glass bonded joint and found to be in the range of 1.78-2.62 MPa, this property may be attributed to the physical interactions between glass-glass interfaces and the polar-pendant units present at the polymers backbone. The products showed high optical transparency when they applied between two glass surfaces, the adhesive layers were colorless, with the UV cut-off wavelength of 300-302 nm, and the maximum transparency of about 90% was observed within the wavelengths range of 400-700 nm. Because of their properties, the cyclolinear poly(aryloxycyclotriphosphazenes) synthesized in this study are recommended as potential candidates for high thermally stable, transparent adhesives required in industrial applications.
New homo-and block copolymers composed of polyacrylate and epoxy resin with hexafunctional cyclotriphosphazene core were synthesized and characterized by FT-IR and 1 H-, 13 C-, and 31 P-NMR. The first homopolymer, PN-polyacry was prepared from the direct condensation of 2-hydroxyethylacrylate with acyl chloride of hexakis(4-carboxyphenoxy)cyclotriphosphazene, PN-acyl. The second homopolymer, PN-Ep, was prepared in a direct reaction of catalyzed carboxyl groups of hexakis(4-carboxyphenoxy)cyclotriphosphazene PN-COOH with epoxy resin via an oxirane ring opening re action. The block copolymer, PN-Ep/polyacry, was prepared from the partial coupling of 2-hydroxyethyl acrylate with the PN-acyl, followed by the reaction of unreacted carboxyl groups with epoxy resin. Differential scanning calorimetry (DSC) analysis of the PN-Ep/polyacry copolymer exhibited good compatibility between polyacrylate and cured epoxy resin. Thermal gravimetric analysis (TGA) revealed that the prepared polymeric systems accumulate 30-38 wt % char at elevated temperatures, compared to neat polyacrylate and cured epoxy resin, which accumulate negligible char at 700 °C. The limiting oxygen index (LOI) exhibited significant enhancement of fire retardant properties of the prepared polymeric systems. A scanning electron microscopy (SEM) morphology study revealed that PN-polyacry and PN-Ep/polyacrylate produced intumescent char residues while PN-Ep produced solid dense char with a nonporous surface.
Poly acrylate cyclotriphosphazene (poly PN-A) was successfully synthesized by polymerization reaction using benzoyl peroxide as an initiator in dry 1,4-dioxane to form poly PN-A. After that the blended polymer with poly(methyl methacrylate) (PMMA) were prepared for synthesized polymer (poly PN-A) by using ratio 10:1 per weight of synthesized polymer to PMMA hence they were mixed using dioxane. Many techniques were used to characterize the chemical structures of synthesized material. Infrared spectroscopy was used to identify the functional groups within the chemical structure of the compounds. Three types of nuclear magnetic resonance (1H NMR, 13C NMR, and 31P NMR) were used to confirm the chemicals structures of the products. 31P NMR was used because all units and their polymers have phosphine atoms in their chemical structures. Thus, all used spectra confirmed the chemical structure of synthesised materials with high percentage of purity
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