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.     

Curing kinetics and thermal stability of epoxy blends containing phosphorous-oxirane with aromatic amide-amine as curing agents

This article describes the synthesis of a series of aromatic amide-amines and their potential use as epoxy hardeners. These amines were synthesized by the reaction of L-phenylalanine（PA） with diamines of different structures i.e.1,4- phenylene diamine（PD）,1,5-diamino naphthalene（N）,4,4’-（9-fluorenyllidene）-dianiline（F）,4,4’-diaminodiphenyl sulphide （DS） and 3,4’-oxydianiline（O） in a stoichiometric ratio（1:1）.Structural characterization of synthesized amide-amines was done with the help of elemental analysis and spectroscopic techniques viz.FT-IR,¹H-NMR and ¹³C-NMR.An epoxy blend was prepared by mixing tris（glycidyloxy） phosphine oxide（TGPO） with conventional epoxy i.e.diglycidyl ether of bisphenol-A（DGEBA） in an equivalent ratio of 2:3 to incorporate phosphorous into the main chain.The curing kinetics of the epoxy blend with synthesized aromatic amide-amines was investigated by non-isothermal DSC technique using multiple heating rate method（5,10,15 and 20 K/min.）.The activation energies were determined by fitting the experimental data into Kissinger and Ozawa kinetic models.The activation energies obtained through Ozawa method were slightly higher than those of Kissinger method but were comparable.However,both the energies were found to be dependent on the structure of amines.The thermal stability and weight loss behavior of isothermally cured thermosets were also investigated using thermogravimetric analysis（TGA） in nitrogen atmosphere.All the samples showed improved thermal stability in terms of char yield than using only amines as hardeners.     

Synthesis, characterization, and cure properties of phosphorus-containing epoxy resins for flame retardance

An organophosphorus compound, 10-(2,5-dihydroxyl phenyl)-9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DHPDOPO), was synthesized through the reaction of 9,10-dihydro-9-oxa-10-phosphaphnanthrene-10-oxide (DOPO) and p-benzoquinone, and characterized by elemental analysis, Fourier transform infrared spectrum (FTIR), and ¹H-NMR and ³¹P-NMR spectroscopes. Consequently, the phosphorus-containing epoxy resins with phosphorus content of 1 and 2 wt.% were prepared via the reaction of diglycidyl ether of bisphenol-A with DHPDOPO and bisphenol-A, and confirmed with FTIR and gel permeation chromatography (GPC). Phenolic melamine, novolak, and dicyanodiamide (DICY) were used as curing agents to prepare the thermosetted resins with the control and the phosphorus-containing epoxy resins. Thermal properties and thermal degradation behaviors of these the thermosetted resins were investigated by using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Phenolic melamine-cured resins exhibited higher glass transition temperatures than the other cured resins due to the high rigidity of their molecular chain. TGA studies demonstrated that the decomposition temperatures of the novolak-cured resins were higher than those of the others. A synergistic effect from the combination of the phosphorus-containing epoxy resin and the nitrogen-containing curing agent can result in a great improvement of the flame retardance for their thermosetted resins.     

Arylidene Polymers. XVII. Cyclization of Aromatic Poly[dibenzylidenecyclopentanone-Hydrazide] as a Route to Polyheterocyclic 1,3,4-Oxadiazole and 1,2,4-Triazole

A new interesting class of thermal stable arylidene polymers containing 1,3,4-oxadiazole and 1,2,4-triazole moieties in the main chain have been synthesized from aromatic polyhydrazide I. Cyclization of I at 250°C in the absence of solvent was found to be the best pathway for the inclusion of the 1,3,4-oxadiazole moiety in the main chain. Heating of I with aniline, cyclohexyl amine, or 3-amino pyridine at 180°C for 30 h gave the corresponding 1,2,4-triazole polymers III. The introducing effect of different aromatic, cycloalkyl, and heterocyclic amines in III_a-c and IV_a-c on thermal stability behavior was studied by TGA analysis. Moreover, all the polymers were characterized by elemental and spectral analyses, solubility, and viscometry measurements. X-ray diffractograms of the synthesized polymers showed they had less crystallinity than the polyhydrazide precursors.     

Thermal stability and degradation kinetics of novel organic/inorganic epoxy hybrid containing nitrogen/silicon/phosphorus by sol-gel method

Hybrids containing silicon, phosphorous and nitrogen were prepared by the sol-gel method and compared with pure epoxy. The silicon, phosphorous and nitrogen components were successfully incorporated into the networks of polymer. Thermogravimetric analysis (TGA) was used for rapid evaluation of the thermal stability of different materials. The integral procedure decomposition temperature (IPDT) has been correlated the volatile parts of polymeric materials and used for estimating the inherent thermal stability of polymeric materials. The IPDT of pure epoxy was 464 °C and the IPDTs of hybrids were higher than that of pure epoxy. The thermal stability of hybrids increased with the contents of inorganic components. The inorganic components can improve the thermal stability of pure epoxy.Two methods have been used to study the degradation of hybrids containing silicon, phosphorous and nitrogen hybrid during thermal analysis. These investigated methods are Kissenger, Ozawa's methods. The activation energies (E_a) were obtained from these methods and compared. It is found that the values of E_a for modified epoxy hybrids are higher than that of pure epoxy. The hybrids of high activation energy possess high thermal stability.     

Synthesis, curing behavior and thermal properties of fluorene containing benzoxazines

A series of difunctional fluorene-based benzoxazine monomers were synthesized from the reaction of 9,9-bis-(4-hydroxyphenyl)-fluorene with formaldehyde and primary amines including aniline, o-toluidine, n-butylamine, and n-octylamine. Their chemical structures were confirmed by FT-IR, ¹H and ¹³C NMR analyses. The curing behaviors of the precursors were monitored by differential scanning calorimetry (DSC) and FT-IR. The thermal properties of cured polymers were evaluated with DSC and thermogravimetric analysis (TGA). The fluorene-based polybenzoxazines show the typical curing characteristic of oxazine ring-opening for difunctional benzoxazines centred at 231-250 °C, and remarkably higher glass transition temperature and better thermal stability ascribed to the high rigidity, high aromatic content, and intermolecular and intramolecular hydrogen bonding. The thermal decomposition temperature and char yield of aromatic amine-fluorene-based polybenzoxazines are much higher than those of aliphatic amine-based polybenzoxazines.     

Preparation, characterization and curing properties of epoxy-terminated poly(alkyl-phenylene oxide)s

A series of dihydroxyl telechelic poly(alkyl-phenylene oxide)s (1) have been synthesized by oxidative polymerization of alkylphenols with various aromatic diols using manganese or copper amine catalysts. The novel telechelic derivatives (1) were epoxidized with epichlorohydrin yielding a series of new epoxidized poly(alkyl-phenylene oxide)s (EPPO, 2) and the structures, properties were studied by nuclear magnetic resonance spectroscopy (NMR), differential scanning calorimetry (DSC), thermo gravimetric analysis (TGA) and gel permeation chromatography (GPC). The 1:1 blends of diglycidyl ether of bisphenol-A (DGEBA) with EPPO resins were cured with three curing agents and the effects of chemical structure change on thermal property of the curing matrixes were discussed. Incorporation of EPPOs to DGEBA epoxy system resulted in a significant increase in its glass transition temperature (T_g), thermal stability and flame resistance. The T_g values and char yields arising from a DDM-cured epoxy resin are usually higher than those of dicyandiamide (DICY) or 2-methylimidazole (2-MI) analogues and the reactivity of epoxy blends with three curing agents presents an increase in the order of 2-MI, DDM and DICY. In general, the tetramethylbisphenol-A (TMBPA)-derived polymer exhibits the lowest T_g, char yield and dielectric constant among PPO derivatives whereas the biphenol polymers usually results in higher T_g and char yield due to its rigid rod structure.     

Flame retardation of polyurethanes by means of 1,4-bis[(dialkoxyphosphinyl)hydroxymethyl]benzene

New phosphorus-containing homopolyurethanes were synthesized by reacting various diisocyanates such as tolylene diisocyanate, methylenebis(4-phenylisocyanate) and hexamethylene-1,6-diisocyanate with 1,4-bis[(dialkoxyphosphinyl)hydroxymethyl]benzene (BDAB). In addition, copolyurethanes containing approximately 3% phosphorus were prepared by copolymerization of these diisocyanates with an equimolar amount of BDAB—hydroquinone mixture. BDAB was less reactive towards diisocyanates than hydroquinone due to the electron-withdrawing inductive effect of the phosphinyl groups. The polymers synthesized were characterized by inherent viscosity measurements as well as by proton nuclear magnetic resonance (¹H-NMR) and infrared (IR) spectroscopy. The spectroscopic examination of polymers did not provide evidence for crosslinking by allophanate groups. Differential thermal analysis (DTA) studies of polymers revealed that the incorporation of BDAB in polyurethanes altered their thermal decomposition mode by increasing the exothermicity due to pyrolysis. Thermogravimetric analysis (TGA) of polymers showed that the phosphorus-containing homopolyurethanes and copolyurethanes were thermally less stable than the corresponding common polyurethanes but afforded higher char yields. Determination of the limiting oxygen index (LOI) values showed that the phosphorus-containing copolyurethanes exhibited a higher fire resistance than that of common polyurethanes.     

Thermally stable polymers containing 1,3,4-oxadiazole units obtained from Huisgen reaction

Thermally stable polymers containing 1,3,4-oxadiazole units have been synthesized through Huisgen reaction of the aromatic/aliphatic bis-tetrazole compounds with the aromatic/aliphatic bis-acid chlorides in pyridine as solvent.The obtained polymers are insoluble or slightly soluble even in polar aprotic solvents such as DMSO and DMF.Relatively high inherent viscosity values（0.61-1.33 dL/g,in 0.125%H₂SO₄ at 25℃） were observed for these compounds.Thermal analyses of the polymers using DSC and TGA techniques showed that the polymers have improved thermal stabilities.The glass transition temperature has not been observed in the fully aromatic polymers,but the polymers obtained from 5-[6-（1H-tetrazol -5-yl）hexyl]-lH-tetrazole（Ⅳ） showed very clear T_g.A model reaction was also investigated and the resulting bis-1,3,4-oxadiazole compound was characterized by conventional spectroscopy methods.     

Preparation of phosphorus-containing polymers—XV. Preparation of phosphorus-containing polyamide-imides from N,N′-bis(4-carboxyphthalimido)-3,3′-diphenylalkylphosphine oxide and aromatic diacetamides

Phosphorus-containing polyamide-imides were prepared from N,N′-bis(4-carboxyphthalimido)-3,3′-diphenylalkylphosphine oxide and aromatic diacetamido derivatives by acidolysis; the reaction conditions are discussed. The resulting polymers were fairly soluble in DMA, DMF and conc. H₂SO₄; the reduced viscosities of polymers in DMA or cone. H₂SO₄ (0.2 g/dl) at 30° were 0.19–0.32. The phosphorus-containing polymers have good thermal stability, and are self-extinguished immediately after the flame is removed. Most of the i.r. absorption bands of polymers vanished on heating at above 600°.     

Thermal degradation mechanism of flame retarded epoxy resins with a DOPO-substitued organophosphorus oligomer by TG-FTIR and DP-MS

A novel phosphorus-containing oligomeric flame retardant, poly(DOPO substituted hydroxyphenyl methanol pentaerythritol diphosphonate) (PDPDP) was synthesized and applied to flame retarded epoxy resins. The thermal degradation behaviors of flame retarded epoxy composites with PDPDP were investigated by thermogravimetric analysis (TGA), thermogravimetric analysis/infrared spectrometry (TG-FTIR) and direct pyrolysis-mass spectrometry (DP-MS) techniques. The identification of pyrolysis fragment ions provided insight into the flame retardant mechanism. The results showed that the mass loss rate of the EP/PDPDP composites was clearly lower than pure EP when the temperature was higher than 300 °C in air or nitrogen atmosphere. The results also suggested that the main decomposition fragment ions of the EP/PDPDP composite were H₂O, CO₂, CO, benzene, and phenol. The incorporation of PDPDP can reduce the release of combustible gas and induce the formation of char layer, hence the fire potential hazard was reduced.     

High Performance Poly(ether-amide)s Derived from 1,1-Bis[4-(4-carboxy methylene phenoxy)-3-methyl phenyl] Cyclopentane and Aromatic Diamines

A series of new methyl substituted poly(ether-amide)s were synthesized by using direct Yamazaki’s phosphorylative polycondensation of novel diacid 1,1-bis[4-(4-carboxymethyl phenoxy)-3-methylphenyl] cyclopentane (BCMMP) with various aromatic diamines. These polymers were characterized by FTIR spectroscopy. Inherent viscosities of these polymers were in the range 0.25 to 0.42 dL/g indicating moderate molecular weight built-up. These polymers exhibited excellent solubility in various polar aprotic solvents such as NMP, DMSO, DMAc, DMF, pyridine, and were insoluble in THF, DCM and chloroform. X-Ray diffraction pattern of polymers showed that incorporation of methyl substituent on aromatic backbone and cardo cyclopentylidene moiety containing ether linkage and methylene spacer would disturb the chain regularity and packing, leading to amorphous nature. Thermal analysis by TGA showed excellent thermal stability of polymers. The glass transition temperature T_g were in the range 195–210°C. The structure-property correlation among this poly(ether-amide)s was studied, in view of these polymer’s potential applications as high performance polymers.     

The synthesis and characterization of some new vic-dioximes and their transition metal complexes

In this study, three new vic-dioximes, [L¹H₂], N-(5-chloro-2-methoxyphenyl)amino-1-acetyl-1-yclohexenylglyoxime, [L²H₂],N-(3-chloro-4-methoxyphenyl)amino-1-acetyl-1-cyclohexenylgly-oxime and [L³H₂], N-(3-chloro-2-methoxyphenyl)amino-1-acetyl-1-cyclohexenylglyoxime were synthesized from 1-acetyl-1-cyclohexeneglyoxime and the corresponding substituted aromatic amines. Metal complexes of these ligands were also synthesized with Ni(II), Cu(II) and Co(II) salts. The structures of these new compounds (ligands and complexes) were characterized with FT-IR, magnetic susceptibility measurement, molar conductivity measurements, mass spectrophotometer measurements, thermal methods (TGA), ¹H NMR and ¹³C NMR spectral data and elemental analyses.     

New heat stable and processable poly(amide-ether-imide)s derived from 5-(4-trimellitimidophenoxy)-1-trimellitimido naphthalene and various diamines

New aromatic diimide-dicarboxylic acid having flexible ether linkage, 5-(4-trimellitimidophenoxy)-1-trimellitimido naphthalene, was synthesized by the reaction of trimellitic anhydride with 5-(4-aminophenoxy)-1-naphthylamine. Then, a series of novel aromatic poly(amide-ether-imide)s were prepared by the phosphorylation polycondensation of the synthesized monomer with various aromatic diamines. A model compound was synthesized by the reaction of the monomer with aniline. The resulting polymers with inherent viscosities of 0.43-0.70 dl/g were obtained in high yield. All new compounds including the naphthalene-based monomer, model compound, and the resulted polymers were characterized by FT-IR and NMR spectroscopic methods. The ultraviolet λ_max values of the poly(amide-ether-imide)s were also determined. The resulted polymers exhibited a good solubility in a variety of high polar solvents such as N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), N-methyl-2-pyrrolidone (NMP), and pyridine. For some of the polymers obtained the crystallinity behavior was estimated by means of wide-angle X-ray diffraction (WXRD) method, and the resulted polymers exhibited nearly an amorphous nature. Thermal stability of the obtained polymers was determined by thermogravimetric analysis (TGA/DTG), and the 10% weight loss temperatures of the one-step degraded poly(amide-ether-imide)s were found to be in the range between 528 and 551 °C in nitrogen. From differential scanning calorimetric (DSC) analyses, the polymers showed T_gs between 276 and 307 °C. Cyclic voltammetry (CV) measurements of a typical polymer showed that they are also electrochemically stable.     

Phosphorus-containing polybenzimidazoles prepared by reaction of bis(p-carboxyphenoxymethyl)methylphosphine oxide with aromatic tetramines

Two types of polybenzimidazoles (phosphorus- and phosphorus and chlorine containing) are synthesized from bis(p-carboxyphenoxymethyl)methylphosphine oxide or its chlorine-containing analogue and aromatic tetramines in polyphosphoric acid. The structures of the new polybenzimidazoles are determined with the aid of model compounds and i.r. and u.v. spectroscopy. The polymers possess comparatively high thermal stability and resistance to ignition.     

Synthesis and characterization of multifunctional polymers via atom transfer radical polymerization of N‐(ω′‐alkylcarbazolyl) methacrylates initiated by Ru(II) polypyridyl chromophores

A series of poly(N‐(ω′‐alkylcarbazoly) methacrylates) tris(bipyridine) Ru‐centered bifunctional polymers with good filming, thermal, and solubility properties were synthesized and characterized. Atom transfer radical polymerization (ATRP) of N‐(ω′‐alkylcarbazoly) methacrylates in solution was used, where Ru complexes with one and three initiating sites acted as metalloinitiators with NiBr₂(PPh₃)₂ as a catalyst. ATRP reaction conditions with respect to polymer molecular weights and polydispersity indices (PDI) of the target bifunctional polymers were examined. Electronic absorption and emission spectra of the resultant functional polymers provided evidence of chromophore presence within a single polymeric chain. The thermal properties of all polymers were also investigated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), and these analyses have indicated that these polymers possess higher thermal stabilities than poly(methyl methacrylate) (PMMA) obtained via free radical polymerization. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 6057–6072, 2005     

聚芳亚胺的合成、结构与性能

以不同的二碘化合物和芳香二胺为单体,通过两种不同的方法经缩聚反应得到了系列高分子量、低分布的聚芳亚胺。其结构由FT-IR, 1H NMR1和元素分析表征。由DSC和TG测定结果可知,该系聚合物具有较高的玻璃化转变温度(Tg＞150℃)和良好的热稳定性(TD＞400℃)。另外,该系聚合物还表现出良好的溶解性能。     

Aromatic-aliphatic copolyesters—I. Synthesis and characterization

Copolyesters have been synthesized by interfacial polycondensation of 2,2-bis(4-hydroxyphenyl)-propane or phenolphthalein as aromatic diol and ethylene glycol or polyethylene glycol as aliphatic diol in various mole ratios with terephthaloyl or isophthaloyl chloride. Chemical compositions, dilute solution viscosities and solubility behaviours of these polymers have been investigated. The introduction of aliphatic diol in aromatic polyesters influences T_g, softening point, chemical resistance and thermal stability.     

Synthesis and characterization of crosslinkable polyimides

A series of copolyimides were prepared from benzophenone-3,3′,4,4′-tetracarboxylic dianhydride (BTDA) and various aromatic diamines which contain a fluorenyl group and/or alkyl substituents in ortho position to the amine groups. The effect of the chemical composition on the glass transition temperature (T_g), thermal stability as well as on the dielectric constant of these polymers was studied. High T_g polymers (T_g ranging from 260 °C to 370 °C), withstanding temperatures as high as 400 °C for 10 h and having a low dielectric constant (from 2.6 to 3.1) were successfully synthesized. All these polymers were able to crosslink under UV or thermal treatments.     

Synthesis and properties of a phosphorus-containing flame retardant epoxy resin based on bis-phenoxy (3-hydroxy) phenyl phosphine oxide

A reactive phosphorus-containing compound, bis-phenoxy (3-hydroxy) phenyl phosphine oxide (BPHPPO) was first successfully synthesized to produce the phosphorus-containing flame retardant epoxy resin (BPHPPO-EP). The chemical structures were characterized from FTIR, MS, NMR spectra and elemental analyses. Thermal degradation behaviors and flame retardant properties of the cured epoxy resins were investigated from the thermogravimetric analysis (TGA) and the limiting oxygen index (LOI) test using 4,4′-diaminodiphenylsulfone (DDS) as curing agent. The high char yields and the high limiting oxygen index values were found to certify the great flame retardancy of this phosphorus-containing epoxy resin.