Fire- and heat-resistant matrix resins based on ethynyl-substituted aromatic cyclotriphosphazenes

A novel class of fire- and heat-resistant matrix resins has been synthesized by thermal polymerization of ethynyl-substituted aromatic cyclotriphosphazenes. Thermal polymerization of new tris[4-(4′-ethynylbenzanilido)phenoxy]tris(phenoxy) cyclotriphosphazene ( III ) and tris[4-(4′-ethynylphthalimido)phenoxy]tris(phenoxy)cyclotriphosphazene ( VII ) at 250°C for 1–1.5 h gave tough polymers. The thermal stabilities of the polymers were evaluated in nitrogen and in air by thermogravimetric analysis (TGA). The synthesised polymers were stable to 400–410°C and showed char yield of 78–65% at 800°C in nitrogen and of 78–69% at 700°C in air. The ethynyl-substituted polymer precursor ( III ) was synthesised by the reaction of tris(4-aminophenoxy)tris(phenoxy)cyclotriphosphazene ( I ) with 4-ethynylbenzoyl chloride. The polymer precursor ( VII ) was synthesised by a solution condensation of I with 4-ethynylphthalic anhydride followed by in situ thermal cyclodehydration at 150°C. The structure of polymer precursors was characterized using proton nuclear magnetic resonance (¹H-NMR), infrared (IR) spectroscopy, and elemental analysis. The curing of polymer precursors was monitored by differential scanning calorimetery (DSC) and IR spectroscopy. The synthesised matrix resins are potential candidates for the development of heat- and fire-resistant fiber-reinforced composites. © 1993 John Wiley & Sons, Inc.     

Heat-resistant thermosetting polymers based on a novel tetrakisaminophenoxycyclotriphosphazene

Two heat-resistant thermosetting polymers ( IX and X ) have been developed based on a new cyclotriphosphazene containing tetrakisamine. These polymers were synthesized by the reaction of tetrakisamine ( IV ) with maleic anhydride followed by in situ cyclodehydration and polymerization of the maleimides ( VII and VIII ) at 235–240°C for 1.5 h and 290°C for 0.5 h. The thermogravimetric analyses (TGA) of the developed cyclotriphosphazene containing cyclomatrix polymers showed their thermal stability up to 350°C and char yield of 71% in nitrogen at 800°C and 65% in air at 700°C. The monomer, 2,2,4,4-tetrakis(4′-aminophenoxy) -6,6-diphenylcyclotriphosphazene ( IV ), useful for producing a variety of heat- and fire-resistant polymers, has been synthesized in good yield. Its syntheses involve Friedel-Crafts reaction of hexachlorocyclotriphosphazene ( I ) with benzene followed by the reaction of 2,2,4,4-tetrachloro-6,6-diphenylcyclotriphosphazene ( II ) with potassium 4-nitrophenoxide. The reduction of the obtained 2,2,4,4-tetrakis(4′-nitrophenoxy)-6,6-diphenylcyclotriphosphazene ( III ) with molecular hydrogen in presence of PtO₂ gave the tetrakisamine ( IV ). The structure of the synthesized monomer and intermediates were characterized by FT-IR, ¹H-NMR, ³¹P-NMR, mass spectroscopy, differential scanning calorimetry (DSC), and elemental analysis. These resins are potential candidates for the development of heat- and fire-resistant composites, laminates, and adhesives, useful for space, aerospace, and electronic application. © 1993 John Wiley & Sons, Inc.     

Novel species of soluble thermally stable poly(keto ether ether amide)s: preparation,characterization, and properties

A new diamine containing one keto and four ether groups was prepared through a three‐step reaction: first, hydroquinone was reacted with 1‐fluoro‐4‐nitrobenzene and 4‐(4‐nitrophenoxy) phenol was obtained. The next step was reduction of nitro group to amino group in which 4‐(4‐aminophenoxy) phenol was prepared. In the final step, the new diamine named as bis(4‐(4‐(4‐aminophenoxy)phenoxy)phenyl) methanone was synthesized through reaction of the later compound with 4,4′‐difluoro benzophenone. All prepared materials were fully characterized by spectroscopic methods and elemental analysis. Novel species of poly(keto ether ether amide)s were synthesized via polymerization reaction of the diamine with different diacid chlorides including terephthaloyl chloride, isophthaloyl chloride, and adipoyl chloride. All polyamides were characterized, and their properties such as thermal behavior, thermal stability, solubility, viscosity, water uptake, and crystallinity were investigated and compared together. The glass transition temperatures of the polymers were about 204–232°C, and their 10% weight losses were in the range of 396–448°C. Polymers showed high thermal stability and enhanced solubility that mainly resulted from incorporation of the diamine structure containing keto, ether, and aromatic units into polyamide backbones. Copyright © 2014 John Wiley & Sons, Ltd.     

Heat-resistant poly(metal phthalocyanine)imide copolymers using benzenetetracarboxylic dianhydride

Novel poly(metal phthalocyanine)imide copolymers of high thermal stability have been synthesized using metal(II) 4,4′,4″,4?-phthalocyanine tetraamine (metal = copper, cobalt, and nickel); diamines: p-phenylene diamine; 4.4′-methylene dianiline and 9,9-bis(4-aminophenyl)fluorene; and 1,2,4,5-benzenetetracarboxylic dianhydride. Polymers with medium to high degree of polymerization can be prepared depending upon the metal phthalocyanine concentrations. Effects of temperature, order of addition, solvent type, and metal phthalocyanine concentrations were studied to ascertain the optimum conditions to obtain polymers having good thermal stability with a high degree of polymerization. These polymers had decomposition temperatures greater than 500°C both in air and in nitrogen atmospheres. Their anaerobic char yield at 800°C varied between 65–80%. These new copolymers have promising applications as heat resistant films, fibers, and varnishes.     

Perfluorocyclohexenyl aryl ether polymers via polycondensation of decafluorocyclohexene with bisphenols

A novel class of semifluorinated perfluorocyclohexenyl (PFCH) aryl ether homo/copolymers was successfully synthesized with high yield through the step‐growth polymerization of commercially available bisphenols and decafluorocyclohexene in the presence of a triethylamine base. The synthesized polymers exhibit variable thermal properties depending on the functional spacer group (R). PFCH aryl ether copolymers with random and alternating architectures were also prepared from versatile bis‐perfluorocyclohexenyl aryl ether monomers. The PFCH polymers show high thermal stabilities with a 5% decomposition temperature ranging from 359 to 444 °C in air and nitrogen atmosphere. These semifluorinated PFCH aromatic ether polymers contain intact enchained PFCH olefin moieties, making further reactions such as crosslinking and application specific functionalization possible. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 232–238     

Rigid-Rod benzobisthiazole polymers with reactive fluorene moieties: Synthesis and characterization

High purity 2,7-fluorenedicarboxylic acid chloride was synthesized in a multistep reaction scheme from 2,7-dibromofluorene. Subsequent polycondensation in polyphosphoric acid of 2,5-diamino-1,4-benzenedithiol dihydrochloride with terephthaloyl chloride and 2,7-fluorenedicarboxylic acid chloride led to rigid-rod benzobisthiazole polymers with reactive fluorene moieties. The proportion of fluorene in the resultant polymers was controlled through reaction stoichiometry. Soluble polymers with intrinsic viscosities as high as 33.7 dL/g (methanesulfonic acid, 30°C) were obtained if the polymerization temperature was not allowed to exceed 165°C. Insoluble, presumably crosslinked polymers were obtained at higher temperature (190–200°C). Thermal characterization of the polymers by differential thermal analysis and thermal gravimetric analysis/mass spectroscopy did not disclose any thermal transition to 450°C. Onset of weight loss in air did not occur until over 550°C.     

Bis-, tris-, and tetrakis-maleimidophenoxy-triphenoxycyclotriphosphazene resins for fire- and heat-resistant applications

Novel fire- and heat-resistant polymers was obtained by the thermal polymerization of various maleimidophenoxy-triphenoxycyclotriphosphazenes. These polymers, in which the cyclic triphosphazene structure is preserved, have thermal stability to 350°C and char yields of 82–78% at 800°C in nitrogen and 78–71% at 700°C in air. Two groups of monomers were synthesized by reacting tris(4-aminophenoxy)-tris(phenoxy)cyclotriphosphazene with maleic anhydride alone or in combination with benzophenonetetracarboxylic or pyromellitic dianhydride. The structures of cyclic phosphazene-trimeric precursors and the polymers were characterized by Fourier-transform infrared, proton nuclear magnetic resonance, and elemental analysis. The thermal stabilities of the polymers were evaluated by thermogravimetric analysis.     

Synthesis of polypropionamide-ureas from N-mesyloxysuccinimide and diamines

A series of polypropionamide-ureas was synthesized by the polymerization of N-mesyloxysuccinimide with diamines in polar aprotic solvents in the presence of acid acceptors. The polymerization proceeded through the formation of ring-opened adducts, followed by elimination and rearrangement yielding β-isocyanatopropionamide derivatives, which in turn were polymerized to afford polypropionamide-ureas. These polymers had inherent viscosities in the range of 0.1–0.2. Polymers having aliphatic chains which were fusible below 240°C were soluble in acidic solvents, whereas those with aromatic residues dissolved in polar aprotic solvents. Marked decomposition of the polyamide-ureas under thermogravimetric analysis generally occurred at around 320°C under nitrogen.     

Synthesis, characterization, thermal and optical properties of styrene derivatives having pendant p-substituted benzylic ether groups

The derivatives of styrene monomer, 4-chlorophenyl-4-vinylbenzyl ether (M1), 4-methoxyphenyl-4-vinylbenzyl ether (M2), 4-ethylphenyl-4-vinylbenzyl ether (M3) and 1-naphtylphenyl-4-vinylbenzyl ether (M4) were synthesized. The normal free radical polymerization of monomers in 1,4-dioxane were performed by using 2,2′-azobisisobutyronitrile as an initiator at 65 °C. The monomers and their homopolymers were characterized by FT-IR, NMR and elemental analyses measurements. The thermal stability of polymers was investigated by thermogravimetric and differential scanning calorimetric analysis. Thermal degradation activation energies of the polymers were calculated by the Ozawa and Kissinger methods. In addition, photo-stability tests of the polymers under near-UV irradiation were performed.     

Functionalized monomers based on N-(4-hydroxy phenyl)maleimide

N-(4-Hydroxy phenyl)maleimide (HPMI) is functionalized with acryloyl, methacryloyl, allyl, propargyl and cyanate groups and the structures of the materials are characterized by FTIR, ¹H NMR and ¹³C NMR. Thermal curing behaviours of the monomers and thermal stabilities of the polymers are studied using thermal analysis. Introduction of polymerizable groups shifts the curing exotherm to low temperatures, and the curing behaviour is dictated by the polymerizable substituent present in the aromatic ring. Polymer from acryloyl-functionalized monomer shows the highest thermal stability (402 °C), whereas the highest char value (49 % at 700 °C) is noted for the polymer obtained from propargyl-functionalized monomer. Polymers derived from functionalization of HPMI with acryloyl and methacryloyl showed better thermal stabilities. Thermosets formed by the thermal polymerization of HPMI functionalized with propargyl and cyanate groups showed higher char values at 700 °C in nitrogen atmosphere.     

Optically transparent,organosoluble poly(ether-amide)s bearing triptycene unit; synthesis and characterization

Abstract

Aromatic polyamides are famous high performance polymeric materials for their excellent thermal, mechanical, electrical properties, which now a days became a dominant platform for modern polymer chemistry area. Triptycene unit like structures in polymer directly affects the physiochemical properties of polymer, thus polyamides especially with triptycene unit in their backbone with aryl ether linkage imparts combination of properties such as better solubility, melts processing characteristics, and better thermal stability in contrast with those of polymers without an aryl-ether linkageNew triptycene-containing bis(ether amine), 1,4-bis(4-aminophenoxy), 2, 3-benzotriptycene (4a) was synthesized from nucleophilic displacement reactions of P-fluoronitrobenzene with 1,4-dihydroxytriptycene, followed by reduction, and elucidated by FTIR, ^1?H, ^13?C NMR spectroscopy and HRMS. A series of new polyamides containing pendant triptycene group and flexibilizing ether linkages was synthesized by polycondensation of diamine with commercially available aromatic diacischlorides viz., terephthalylchloride (TPC), isophthalylchloride (IPC) and varying molar mixture of TPC and IPC accordingly. Synthesized Poly(ether-amide)s were found soluble in common organic solvents such as chloroform, dichloromethane, tetrahydrofuran, DMF, DMAc, DMSO also could be cast into excellent transperent thin films. Inherent viscosities of polyamides were in the range 0.44–0.57 dL/g. Polyamides exhibited initial decomposition temperature (T_i), glass transition temperatures (T_g) and temperature at 10% wt loss (t₁₀), which was determined by TGA were noted in the range 212?°C–305?°C, 295?°C –309?°C and 587?°C–631?°C respectively with 24%–54% char yeild at 900?°C under nitrogen atmosphere, indicating its better thermal stability and moderate glass transition temperature.     

The synthesis of a mesogenic poly(azine-ether) by polyetherification via cesium diphenoxides and α,ω-dibromoalkanes

The synthesis of a poly(azine–ether) via Williamson etherification using the cesium salt of 4–hydroxyacetophenone azine and 1,10–dibromodecane was carried out in N-methyl–2–pyrrolidone. The heterogeneous reaction proceeded readily at temperatures from ambient to 150°C. Polymers of varying molecular weight with essentially alkyl bromide end groups were produced either by changing the polymerization temperature or by using an excess of the organic substrate. The thermal stability of the polymers was molecular weight dependent and those with the highest DP_n exhibited monotropic nematic mesomorphism.     

Linear A–B and AA–BB polyamides with backbone aryl,alkyl, and alkenyl units

High performance linear AA–BB and A–B polyamides were generated using polymerization schemes that gave polymers in higher yields and having better performance than previous methods. Polymers were characterized with FTIR, solution and solid-state ¹³C-NMR and showed the incorporation of aryl, alkyl, and alkenyl linkages in the polymer backbone. Thermal analysis showed that a significant weight percent of the polymers remained at 1000°C.     

Polymerizable siloxane precursors having in-chain perfluoroalkyl groups

The synthesis and polymerization of several silphenylene siloxane polymer precursors containing a perfluoroalkylsegment in the backbone was carried out. The molecular weight characteristics of polymers from 1,3-bis[p(-hydroxydimethylsilyl)phenyl]hexafluoropropane and 1,3-bis[p(-dimethylaminodimethylsilyl)phenyl]hexafluoropropane were studied as a function of polymerization conditions. Polymers containing the dodecafluorohexane chain segment were also prepared. Polymers having inherent viscosities of 0.55 to 0.9 were obtained. The polymers crosslinked at room temperature to thermoset elastomers which were characterized by improved thermal and oxidative stability over dimethylsilicones. Room temperature swelling of the experimental polymers hydrocarbon solvents was also much lower than that of dimethylsilicones. The polymers containing the (CF₂)₃ and (CF₂)₆ linkages had glass transition points of ?12°C and ?34°C, respectively.     

High temperature phosphorylated or nonphosphorylated laminating resins based on maleimido-substituted aromatic s-triazines

Several new phosphorylated or nonphosphorylated maleimide or nadimide systems containing s-triazine rings were synthesized. Their synthesis was accomplished by simple methods utilizing readily available and relatively inexpensive starting materials. All polymer precursors were characterized by infrared (IR) and proton nuclear magnetic resonance (¹H-NMR) spectroscopy. They were thermally polymerized to heat-resistant laminating resins. Thermal characterization of monomers and their cured resins was achieved using differential thermal analysis (DTA), dynamic thermogravimetric analysis (TGA) and isothermal gravimetric analysis (IGA). The cured resins were stable up to 304–330°C both in nitrogen and air atmospheres and formed anaerobic char yield 49–59% at 800°C. The phosphorylated polymers showed a lower temperature of initial weight loss but afforded higher anaerobic char yield than did the corresponding nonphosphorylated polymers. The thermal properties of the polymers were correlated with their chemical structure.     

Synthesis and properties of conjugated polymers containing 3,9‐carbazolylene and silylenevinylene moieties in the main chain

Novel conjugated polymers containing 3,9‐carbazolylene and silylenevinylene moieties were synthesized by the hydrosilylation polymerization of 1,4‐bis(3‐ethynyl‐9‐carbazolyl)benzene ( 1 ) with various bis(hydrosilane)s or dihydrosilanes using a rhodium catalyst. Polymers with weight‐average molecular weights ranging from 5400 to 20,000 were obtained in 55–97% yields by the polyaddition with a rhodium catalyst in toluene at 25 °C for 24 h. All the polymers were soluble in CHCl₃ and THF, and had predominantly trans‐structures. The polymers exhibited λ_max at a longer wavelength region than 1 , and emitted fluorescence in 14–50% quantumn yields. The polymers were oxidized and reduced in the region of 0.4–1.6 V, and thermally stable up to 200 °C under air. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1815–1821, 2010     

Polymerization of fluorinated diacetylenes

Perfluoroalkylene diacetylenes, HC?C? (CF₂)_n? C?CH, underwent thermal polymerization at 250–350°C to give glassy polymers stable to 450°C. Partial polymerization of the volatile monomers gave oligomers that are processable at atmospheric pressure. Polymers with similar thermal stability were obtained by transition-metal-catalyzed polymerization of the monomers at moderate temperatures.     

Aromatic polyethers,polysulfones, and polyketones as laminating resins. VI. Polymers from 2,5-dicyanoterephthalic acid

Aromatic poly(keto ether sulfones) containing various amounts of pendant cyano groups were synthesized from 1,4-bis(p-phenoxybenzoyl)-2,5-dicyanobenzene, 1,3-bis(p-phenoxybenzenesulfonyl)benzene, and isophthaloyl chloride by a Friedel-Crafts type polymerization. These polymers softened at 160–190°C and had inherent viscosities of 0.44–0.61 in hexamethylphosphoric triamide. Crosslinkings were made by heating the polymers alone or in the presence of zinc chloride at 360–370°C to give black resinous materials that were insoluble in hexamethylphosphoric triamide in which the original polymers dissolved quite readily.     

Synthesis and characterization of novel polybenzimidazoles bearing pendant phenoxyamine groups

A novel aromatic diacid, 3, 5‐dicarboxyl‐4′‐amino diphenyl ether, containing pendant phenoxy amine group was synthesized. Homo‐ and co‐polybenzimidazoles containing different content of pendant phenoxyamine groups were synthesized by condensation of 3,3′‐diaminobenzidine with this acid and a mixture of this acid and isophthalic acid in different ratio in polyphosphoric acid. Copolybenzimidazoles with structural variations were also synthesized based on this acid and pyridine dicarboxylic acid, terephthalic acid, adipic acid, or sebacic acid. The polymers have good solubility in polar aprotic solvents and strong acids and they form tough flexible films by solution casting. The polymers were characterized by different instrumental techniques (FTIR, TGA, DSC, XRD, etc.) and for solvent solubility, mechanical properties, inherent viscosity, and proton conductivity. The inherent viscosities of the polymers vary in the range of 0.62–1.52 dL/g. They have high thermal stability up to 475–506 °C (IDT) in nitrogen, high glass transition temperatures (T_g) ranging from 313 to 435 °C and good tensile strength ranging from 58 to 125 MPa. Proton conductivity of homo polymer is 3.72 × 10^?3 S/cm at 25 °C and 2.45 × 10^?2 S/cm at 200 °C © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 5776–5793, 2008     

Synthesis and properties of polyketones containing thiophene links

A series of polyketones containing thiophene links was synthesized by the Friedel-Crafts polymerization of these dithienylalkanes with aromatic diacid chlorides or dicarbonyl chlorides comprising thiophene links with diphenyl compounds. The resulting polymers had inherent viscosities in the range of 0.11–0.27 dL/g and showed poor solubilities to common organic solvents except strong acids. These thiophene-based polyketones exhibited fairly good thermal stabilities. The TGA data revealed 5% weight losses at 375–450°C and residual weights at 500°C were 43–79% under nitorgen. It was found that the thermal stabilities of these polymers were superior to those of polymides or polysulfonamides containing thiophene links and almost comparable to common aromatic polyketones