Synthesis of phosphorus-containing dihydrazides and polyurethanes from them

From phosphonic acid esters and hydrazine hydrate, phosphorus-containing dihydrazides have been synthesized with two reactive amino groups; from them, polyurethanes have been prepared. It is shown that the introduction of phosphorus into the polyurethane molecules leads to improvement of physical and mechanical properties, to a large reduction in losses during combustion and to an improvement in capacity to absorb water.     

Preparation of phosphorus-containing polymers-xxi: Synthesis of phosphorus-containing polymaleimide-amines

The reaction of dichloromalcimides with aromatic amines was applied to the preparation of phosphorus-containing polymers, so-called polymaleimide-amines. The phosphorus-containing polymalcimide-amines were synthesized from N,N′-bisdichloromaleimido-3,3′-diphenylalkylphosphine oxides and aromatic diamines or piperazine. Some properties of the resulting polymers, such as solubility and thermal behaviour, were investigated. Most of the polymers were obtained at yields of 80% or above. The reduced viscosities of the polymers, measured at a concentration of 0.2 g/dl in DMA at 30, were 0.13–0.27 dl/g. Some of the polymers, especially those prepared from piperazine, were freely soluble in DMF, DMA, DMSO, cone H₂SO₄, formic acid etc., but all the polymers seemed to decompose in cone H₂SO₄ or formic acid. The phosphorus-containing polymaleimide-amines had poor thermal stability and little flame retardance.     

Synthesis of oligomeric phosphorus-containing borates

Boric acid was reacted with dimethyl hydrogen phosphite to obtain oligomeric products containing borate and phosphite groups. The structure of the products was studied by IR, ¹H, and ³¹P NMR spectroscopy.Translated from Zhurnal Obshchei Khimii, Vol. 74, No. 9, 2004, pp. 1460–1461.Original Russian Text Copyright © 2004 by Bondarenko, Khokhlova, Orlova, Derbisher, Tuzhikov, Dhaibe.This revised version was published online in April 2005 with a corrected cover date.     

Preparation of phosphorus-containing polymers—XVI. Synthesis of phosphorus-containing polyanhydride-imides

Phosphorus-containing polyanhydride-imides were synthesized from N,N-bis(4-carboxyphthalimido)-3,3′-diphenylalkylphosphine oxide, 3,3′-[N,N′-bis(4-carboxyphthalimido)]benzophenone and their mixtures in two steps via the diacetyl derivatives of the bisimide-carboxylic acids. The resulting polymers have reduced viscosities of 0.06–0.14 dl/g and are soluble in polar aprotic solvents such as DMA, DMF and DMSO, and conc. H₂SO₄ etc. They have good hydrolytic stability for moisture and water. Phosphorus-containing polymers have little heat-resistance and poor flame-retardance. The benefit of incorporating phosphorus in the polymers is small.     

Synthesis of a new phosphorus-containing macrocycle

Conclusions We synthesized a 15-membered organophosphorus macrocycle with twophosphine oxide groupings and polyether units, and specifically 1,2,7,8-dibenzo-3,6-diphospha-3,6-dioxo-3,6-diphenyl-15-crown-5.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1930–1932, August, 1978.     

Synthesis of a phosphorus-containing hybrid porphyrin

A phosphorus-containing hybrid porphyrin was successfully prepared via the BF3-promoted dehydrative condensation between sigma4-phosphatripyrrane and 2,5-bis[hydroxy(phenyl)methyl]thiophene. The NMR and UV-vis absorption spectra, electrochemical measurements, and DFT calculations revealed that the sigma3-P,N2,S-hybrid porphyrin exhibits high aromaticity as an 18pi-electron system in terms of both geometric and magnetic criteria. [structure: see text]     

Synthesis and properties of phosphorus-containing bio-based epoxy resin from itaconic acid

A phosphorus-containing bio-based epoxy resin (EADI) was synthesized from itaconic acid (IA) and 9,10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide (DOPO). As a matrix, its cured epoxy network with methyl hexahydrophthalic anhydride (MHHPA) as the curing agent showed comparable glass-transition temperature and mechanical properties to diglycidyl ether in a bisphenol A (DGEBA) system as well as good flame retardancy with UL94 V-0 grade during a vertical burning test. As a reactive flame retardant, its flame-resistant effect on DGEBA/MHHPA system as well as its influence on the curing behavior and the thermal and mechanical properties of the modified epoxy resin were investigated. Results showed that after the introduction of EADI, not only were the flame retardancy determined by vertical burning test, LOI measurement, and thermogravimetric analysis significantly improved, but also the curing reactivity, glass transition temperature (T _g), initial degradation temperature for 5% weight loss (T _d(5%)), and flexural modulus of the cured system improved as well. EADI has great potential to be used as a green flame retardant in epoxy resin systems.     

Synthesis of phosphorus-containing polyurethanes without use of isocyanates

Phosphorus-containing polyurethanes were synthesized by reacting phosphonic acid diesters (RO)₂P(O)X (X = H, CH₃, Ph) with hydroxycarbamates. These phosphorus-containing polyurethanes were characterized by a combination of molecular-weight determination (GPC) and NMR spectroscopy. The thermal stability of the polymers was evaluated by a combination of TGA and DTA techniques. These polymers are readily soluble in highly polar solvents like DMF and DMSO. The phosphorus-containing polyurethanes are water soluble. © 1996 John Wiley & Sons, Inc.     

Synthesis and performance of cyclic phosphorus-containing flame retardants

A series of organo-cyclic phosphorus compounds were synthesized in an attempt to find an efficient flame retardant (FR) for acrylonitrile-butadiene-styrene (ABS). The success of synthesis was confirmed by ¹H and ³¹P NMR. Thermogravimetric analysis (TGA) results reveal that cyclic phosphorus compounds synthesized in this study show almost one step degradation between 250 and 400 °C and are believed to work in the vapour phase rather than in the condensed phase. From UL-94 test, V-0 rating was achieved at 15-35 wt% loading of cyclic or cyclic alkyl phosphonate FR and no rating at 35 wt% loading of cyclic phosphate for ABS. On the other hand, a much lower loading (7.5%) was needed to obtain V-0 rating for polycarbonate when 3,9-diphenyl-3,9-dioxa-2,4,8,10-tetraoxa-3,9-diphosphaspiro-5,5-undecane (PBPP) was added as FR. All the results show that the flame retarding effect is strongly dependent on the P content of the FR incorporated. The flame retardant mechanism of cyclic phosphorus compounds is also discussed.     

Flame-retardant polyurethanes from phosphorus-containing isocyanates

Phosphorus-containing polyurethanes are synthesized by reacting phosphorus-containing diisocyanates, bis (4-isocyanatophenoxy) phenyl phosphine oxide (BIPPO) and bis (3-isocyanatophenyl) phenyl phosphine oxide (BIPPPO), with various diols. The chemical structures of the obtained monomers and polymers are characterized by IR, ¹H- and ³¹P-NMR spectroscopy. Thermal analysis of the phosphorus-containing polyurethanes reveals that incorporating phosphorus into the polymers increases exothermicity during their decomposition. According to these results, the phosphorus-containing polyurethanes are less thermally stable than conventional polyurethanes. Char yield and LOI measurements demonstrate that incorporating phosphorus into polyurethanes markedly improves their flame retardancy. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 1769–1780, 1997     

Amorphous polyacrylonitrile: Synthesis and characterization

Amorphous polyacrylonitrile was successfully synthesized with bis(pentamethyleneimino)magnesium in heptane at 70°C. The amorphousness of the polymer increased with rising polymerization temperature and was favored by the nonpolar solvent. The polymer showed regular head-to-tail sequences which were confirmed by converting the polymer into polyacrylic acid and polymethylacrylate. The amorphous PAN produced a broad x-ray diagram with a maximum at 2θ = 16.1° and a less intense halo at 2θ = 27.5°. This pattern did not change after heat treatment. The synthesis of amorphous PAN strongly supports Imai's hypothesis that polyacrylonitrile consists of paracrystalline and amorphous phases. The amorphous PAN also tends to support Minami's assignment of the two absorptions in the temperature dependence of the dynamic loss tangent; the absorption at the lower temperature (110°C) is due to molecular motions in the paracrystalline phase and the absorption at the higher temperature (160°C) is attributed to the molecular motions in the amorphous region.     

Synthesis of phosphorus-containing polyurethanes from oligoethers prepared from bis(chloromethyl) methylphosphine oxide and glycols

Oligoethers with hydroxyl end-groups were prepared in boiling toluene from bis(chloromethyl)methylphosphine oxide and glycols used as monosodium glycolates. From these oligoethers and diisocyanates (hexamethylenediisocyanate and 2,4-toluene-diisocyanate), phosphorus-containing polyurethanes were synthesized.     

Synthesis of ultra-high-molecular-weight polyacrylonitrile by anionic polymerization

The anionic polymerization of acrylonitrile in DMF initiated by lithium 1,2-bis(diethylamino)-2-oxoethanolate in the range ?60 to 0°C has been studied. The initiator efficiency at low temperatures (?60 to ?40°C) is 2–6%; it remains nearly invariable with conversion owing to the associated state of the initiator. The low concentration of growing active centers is constant throughout the process; as a result, polymers with M > 3 × 10⁵ are produced. The polymers are characterized by a narrow molecular-mass distribution, M _w/M _n = 1.3–1.6, and contain insignificant amounts of low-molecular-mass fractions. It has been shown that controlled polymerization processes can be carried outat moderately low temperatures (?30 to 0°C), and experimental conditions for freezing of polymerization and its recommencement have been ascertained. Optimum conditions for the synthesis of a high-molecular-mass polyacrylonitrile with M > 3 × 10⁵ have been established, and the method for preparing polymers with M = (6.50–8.5) × 10⁵ on an enlarged scale using high concentrations of the monomer has been developed.     

Synthesis of phosphorus-containing polycyclic derivatives by phosphorylation of hydroxyl-containing diimines

Russian Journal of General Chemistry -     

Synthesis and properties of phosphorus-containing epoxy resins by novel method

Novel phosphorus-containing epoxy resins (1–3% phosphorus content) were synthesized by the reaction of 9,10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide (DOPO) and the diglycidyl ether of bisphenol A and then cured with 4,4′-diaminodiphenyl sulfone or phenol novolac. Differential scanning calorimetry, high performance liquid chromatography, and epoxide equivalent weight titration were used to trace the reaction between the DOPO and the epoxy. The thermal stability and flame retardancy were checked by thermal gravimetric analysis, the limiting oxygen index, and the UL-94 vertical test. The glass transitions were measured by dynamic mechanical analysis. The relation between these properties (thermal stability, flame retardancy, and glass transition) and the DOPO contents (phosphorus content) were discussed. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 3903–3909, 1999     

Preparation of phosphorus-containing polymers—XX. Synthesis of phenoxaphosphine-containing polyesters

New polyesters containing phenoxaphosphine rings were prepared from 2,8-dichloroformyl-10-phenylphenoxaphosphine 10-oxide (I) and bisphenols by interfacial polycondensation. The investigations of polymerization conditions using (I) and bisphenol A showed that addition of quarternary ammonium salts was effective in the preparation of polyesters. The highest viscosities were obtained when tetrabutylammonium chloride was used as accelerator. Some of the resulting polyesters had reduced viscosities of 0.85–1.92 dl/g in DMA of m-cresol and they dissolved in chloroform, m-cresol and nitrobenzene. These polymers melted in the range of 288–355′, hardly degraded below 400′ and were self-extinguishing. They appeared to have better thermal stability than linear open-chain phosphorus-containing polyesters.