Arylidene polymers XIX: Synthesis and properties of aromatic polyphosphate from diarylidenecycloalkanones

Polyphosphate esters were synthesized by interfacial polymerization of 2,5-bis(p-hydroxybenzylidene)cyclopentanone, 2,5-divanillylidenecyclopentanone, 2,6-bis(p-hydroxybenzylidene)cyclohexanone, 2,6-divanillylidenecyclohexanone or 2,7-bis(p-hydroxybenzylidene)cycloheptanone with phenyl phosphorodichloridate. The resulting polymers were characterized by elemental analysis, IR spectroscopy, solubility and viscometry measurements. The thermal properties of the polymers were evaluated by TGA measurements and correlated with their structural units. The crystallinity of all the polyphosphate esters was tested by X-ray analysis.     

New polymer syntheses VIII. Synthesis,characterization and morphology of new unsaturated copolyesters based on dibenzylidenecycloalkanones

A new interesting class of linear, unsaturated copolyesters based on dibenzylidenecycloalkanones has been synthesized by interfacial polycondensation of isophthaloyl chloride or sebacoyl chloride with 2,5-bis(p-hydroxybenzylidene) cyclopentanone I, 2,6-bis(p-hydroxybenzylidene) cyclohexanone II, 2,6-divanillylidenecyclohexanone III or 2,7-bis(p-hydroxybenzylidene)cycloheptanone IV at ambient temperature. The resulting copolyesters were characterized by elemental analyses, IR spectroscopy, and solubility. Additionally, inherent viscosities of copolyesters in the range 0·53–0·98dlg⁻¹ were determined. The thermal properties of the polymers were evaluated by TGA and DSC measurements and correlated with their structural units. The crystallinity of some copolyesters was examined by X-ray analysis. In addition, the electrical properties of the copolyesters were tested and the morphology of selected examples of the copolyesters was examined by scanning electron microscopy. © 1998 Society of Chemical Industry     

New polymer syntheses. Part 7. New unsaturated polyurethanes: synthesis and characterization†

A novel series of polyurethanes was prepared via step-growth solution polymerization, by reaction of arylidene monomers, e g 2,5 bis(4-hydroxybenzylidene)cyclopentanone ( I ), 2,5-divanillylidenecyclopentanone ( II ), 2,6-bis(4-hydroxybenzylidene)cyclohexanone ( III ), 2,6-divanillylidenecyclohexanone ( IV ) or 2,7-bis(4-hydroxybenzylidene)cycloheptanone ( V ) with diisocyanates such as toluylene diisocyanate and methylene bis(4-phenylisocyanate). To characterize these polymers, the corresponding model compounds were prepared from monomers I–V and phenylisocyanate. The polymers were characterized by reduced viscosity measurements, IR spectroscopy, ¹H NMR, solubility and determination of their crystallinity. Characterization of the model compounds was accomplished by elemental analysis, IR and ¹H NMR spectroscopy. The thermal stabilities of the polymers were evaluated by thermogravimetric analysis. The morphology of one of these polymers was examined by scanning electron microscopy. © 1999 Society of Chemical Industry     

Synthesis and photodegradation of poly[2,5-bis(dimethylsilyl)furan]

Summary Poly[2,5-bis(dimethylsilyl)furan] (V), a copolymer with alternating furan and disilyl units, has been prepared by the Wurtz coupling of 2,5-bis(dimethylchlorosilyl)furan (II) with sodium metal dispersion in toluene. Lower molecular weight poly[2,5-bis(dimethylsilyl)furan] (IV) has been prepared by a similar condensation reaction with 2,5-bis(dimethylfluorosilyl)furan (III). IV and V have been characterized by ¹H, ¹³C and ²⁹Si NMR, IR, and UV spectroscopy as well as by GPC, TGA and elemental analysis. Photolysis of V in a benzene/methanol solution results in degradation of the polymer.     

Synthesis and characterization of liquid crystalline polymers containing aromatic ester mesogen and a nonmesogenic ferrocene unit in the spacer

A new series of liquid crystalline polymers containing aromatic triad ester mesogen and 1,1′‐disubstituted ferrocene as a nonmesogenic unit along with polymethylene spacer was synthesized. The polymer was synthesized by a room temperature polycondensation reaction between bis(4‐chloroformyl phenyloxy alkyl ferrocene dicarboxylate) and quinol. The alkyl groups have been varied by an even number of methylene groups with a range from two to ten groups. All the polymers were found to possess liquid crystalline properties. The identification of the mesophase is more transparent with an increase in the spacer. The thermal characteristics were studied using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The results reveal that the thermal stability of the polymers was decreased with increasing spacer length. The T_g, T_m, and T_i of the polymers decreased with increasing methylene groups. The incorporation of the ferrocene moiety also has a considerable effect on the glass transition temperature. The char yield of the polymer decreases with an increasing methylene chain length. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3494–3501, 2002     

Cyano-substituted polyester,polyurethanes, and epoxy resin derived from 2,6-bis(4-hydroxybenzylidene)-1-dicyanomethylene–cyclohexane

The condensation of cyclohexanone with 4-hydroxybenzaldehyde utilizing dry HCI as the catalyst afforded 2,6-bis(4-hydroxybenzylidene)cyclohexanone. The latter was condensed with malononitrile to yield 2,6-bis(4-hydroxybenzylidene)-1-dicyanomethylene–cyclohexane, which was used as the starting material for the preparation of a novel class of polyesters, polyurethanes, and epoxy resins. In addition, a model diester and diurethane were synthesized and their spectroscopic data were correlated with those of the corresponding polymers. It was shown that the introduction of the dicyanomethylene groups in the polymer backbone remarkably improved the polymer solubility as well as its thermal stability. The crosslinked polymers obtained upon curing the polyester and polyurethanes at 300°C for 40 h were stable up to 365–407°C in N₂ or air and afforded anaerobic char yields of 64–70% at 800°C. © 1994 John Wiley & Sons, Inc.     

Development of epoxy-cyanate ester-clay nanocomposites offering enhanced thermally stability

The preparation and characterization of blends of a series of dicyanate monomers such as 2,2′-bis(4-cyanatophenyl) propane (DCDPP), bis-4-cyanato-biphenyl (DCBP), bis-4-cyanatonaphthalene (DCN), 3,3′-bis(4-cyanatophenyl)sulphide (DCTDP), 3,3′-bis(4-cyanatophenyl)sulphone (DCDPS), and the diglycidyl ether of bisphenol A are reported. These copolymers are combined with a montmorillionite nanoclay and both epoxy-cyanate blends and epoxy-cyanate blends-nanoclay composites are all analyzed for thermal stability, thermal degradation kinetics, flame retardancy, and impact strength. The nanocomposites are further characterized by X-ray diffraction and SEM to determine morphological features, from which structure–property relationships are determined. Dispersion of the nanoclay is of paramount importance, but its inclusion serves to improve char yield and impact strength, when this is achieved. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47754.     

Ascorbate and phenolic antioxidant interactions in prevention of liposomal oxidation

Efficient prevention of membrane lipid peroxidation by vitamin E (α-tocopherol) may involve its regeneration by vitamin C (ascorbate). Conceivably, the efficacy of antioxidants designed as therapeutic agents could be enhanced if a similar regeneration were favorable; thus, a model membrane system was developed which allowed assessment of interaction of phenolic antioxidants with ascorbate and ascorbyl-6-palmitate. Ascorbate alone (50–200 μM) potentiated oxidation of soybean phosphatidylcholine liposomes by Fe²⁺/histidine-Fe³⁺, an effect which was temporally related to reduction of Fe³⁺ generated during oxidation. Addition of 200 μM ascorbate to α-tocopherol-containing liposomes (0.1 mol%) resulted in marked, synergistic protection. Accordingly, in the presence but not absence of ascorbate, α-tocopherol levels were maintained relatively constant during Fe²⁺/histidine-Fe³⁺ exposure. Probucol (4,4′-[(1-methylethylidine)bis(thio)]bis[2,6-bis(1,1-dimethylethyl)]phenol), and antioxidant which prevents oxidation of low density lipoproteins, and its analogues MDL 27,968 (4,4′-[(1-methylethylidene)bis(thio)]-bis[2,6-dimethyl]phenol) and MDL 28,881 (2,6-bis(1,1-dimethylethyl)-4-[(3,7,11-trimethyldodecyl)thio]phenol) prevented oxidation but exhibited no synergy with ascorbate. Ascorbyl-6-palmitate itself was an effective antioxidant but did not interact synergistically with any of the phenolic antioxidants. Differential scanning calorimetry revealed significant differences among the antioxidants in their effect on the liquid-crystalline phase transition of dipalmitoyl phosphatidylcholine (DPPC) liposomes. Both α-tocopherol and MDL 27,968 significantly reduced the phase transition temperature and the enthalpy of the transition. MDL 28,881 had no effect while probucol was intermediate. The potential for ascorbate or its analogues to interact with phenolic antioxidants to provide a more effective antioxidant system appears to be dictated by structural features and by the location of the antioxidants in the membrane.     

Part 14. Synthesis and properties of new polyketoamine polymers containing cycloalkanone moieties in the main chain

A new interesting class of polyketoamine polymers based on diarylidenecycloalkanone were synthesized by suspension polycondensation. These polymers were synthesized via polymerization of 2,5‐bis(4‐chloroacetylbenzylidene)cyclopentanone and 2,6‐bis(4‐chloroacetylbenzylidene)cyclohexanone with different aliphatic and aromatic diamines including, p‐phenylenediamine, m‐phenylenediamine, o‐phenylenediamine, 4,4′‐diaminodiphenylmethane, 4,4′‐diaminodiphenylether, 4,4′‐diaminodiphenylsulfone, hydrazine hydrate, 1,2‐diaminoethane, 1,3‐diaminopropane and 1,8‐diaminooctane. Model compounds were prepared by condensation of 2,5‐bis(4‐chloroacetylbenzylidene)cyclopentanone and/or 2,6‐bis(4‐chloroacetylbenzylidene)cyclohexanone with aniline in dry benzene, and their structure was confirmed by elemental analysis and spectroscopy. The structure of the polymers obtained was also confirmed by the same methods. Moreover, the identification of the polymers was carried out by other techniques, eg crystallinity from X‐ray spectroscopy, viscosimetry, thermogravimetric analysis; the morphological properties of selected examples were tested by scanning electron microscopy. The electrical conductivity of selected examples is about 10^?12 ohm cm^?1. The results are in accord with the structure. © 2002 Society of Chemical Industry     

The synthesis and characterization of a mesomorphic brush type polycarbosilane: poly[1,1-bis(4′-biphenyl)silabutane]

Summary Poly[1,1-bis(4-biphenyl)silabutane] (II) has been prepared by the anionic ring opening polymerization of 1,1-bis(4-biphenyl)silacyclobutane. II shows mesomorphic behavior by DSC. The¹³C NMR T₁ relaxation times have been measured. These are found to be smaller than those of poly(1,1-dimethylsilabutane)by an order of magnitude. This may result from interaction of the highly rigid biphenyl side chain moieties. The thermal stability of II is higher than that for other 1,1-disubstituted polysilabutanes.     

Synthesis and photodegradation of poly[2,5-bis(dimethylsilyl)thiophene]

Summary Poly[2,5-bis(dimethylsilyl)thiophene] (I), a copolymer with alternating thiophene and disilyl units, has been prepared by the Wurtz coupling of 2,5-bis(dimethylchlorosilyl)thiophene (IV) with sodium metal in toluene. I has been characterized by ¹H, ¹³C, and ²⁹Si NMR, IR, UV, GPC, TGA and elemental analysis. The photolysis of I in benzene/methanol solution results in degradation of the polymer. The structure of the photoproducts and possible mechanisms for their formation are discussed.     

Low relative dielectric permittivities of polyimides and copolyimides derived from non-coplanar diamines and 4,4′-(hexafluoroisopropyl)diphthalic anhydride

Abstract

Two series of polyimides and copolyimdes were solution cast into transparent, flexible and tough films. The glass transition temperatures T _g obtained from dynamic mechanical analysis were moderate compared with commercial polyimides such as Dupont Vespel®. The T _gs for the majority of polymers derived from monomer 1 (2′,5′-bis(p-aminophenoxy)-[1,1′;4′,1≥]terphenyl) (1A-F) were higher than those of polymers derived from monomer 2 (2,5-bis(p-aminophenoxy)biphenyl) (2A-F). The thermal expansion coefficients of the two series of polymers were moderate and comparable. The maximum elongations and moduli of polymers 2A-F were larger than those of polymers 1A-F possibly because polymers 2A-F were more flexible than polymers 1A-F. The relative dielectric permittivities of both series of polymers were measured and exhibited a low value from 2 49 to 3 01 at 100 kHz. In contrast, the relative permittivities calculated using the Clausius-Mosotti relationship were higher. Incorporation of non-coplanar diamines into the polymer chain causes an increase in free volume, which may account for the decrease in relative permittivities.     

Synthesis of some new polyers and copolymers from 2,2-bis (4-chlorophenyl) 1, 1, 1-trichloro ethane (DDT)

DDT (I) was polycondensed with 2,2-bis(4-hydroxy phenyl)- propane (bisphenol-A) to form polyether. The following monomers were synthesised from DDT: 2,2-bis(4-chloro-phenyl)1, 1-dichloroethylene(II), 2,2-bis(3-nitro-4-chlorophenyl)ethane (III) and 2,2-bis (3-nitro-4-chloro-phenylethylene (IV) and polycondensed with bisphenol-A. They were also copolymerised with bis(4-chlorophenyl)sulphone and bisphenol-A in several molar ratios. The polymers and copolymers were characterised by various techniques. The results obtained show that the DDT has a low reactivity, but nitration and dehydrochlorin-ation increases its reactivity to a significant extent.     

The Synthesis and Characterization of a Novel Ternary Polymer Bisphenol A-4,4’-Difluorobenzophenone-bis(p-hydroxylphenyl)-1,4,5,8-naphthalenetetracarboxylic Diimide Monomer

Summary A novel bis(p-hydroxylphenyl)-1,4,5,8-naphthalenetetracarboxylic diimide (NTDA–OH) monomer was prepared through the condensations of 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTDA) with p-aminophenol. A series of ternary copolymers derived from NTDA–OH were further synthesized by the nucleophilic substitution reactions. Both the monomer and the ternary copolymers were characterized by FT–IR, ¹H NMR, and inductively coupled plasma (ICP). The characterization results showed that, the imide groups were successfully introduced into the prepared monomer. The differential scanning calorimetry (DSC) and the thermal gravimetry analysis (TGA) were further performed on the produced polymers. The thermal stability of the polymer increased with the content of the NTDA–OH increasing.     

Erosion of poly(anhydride-co-imides): A preliminary mechanistic study

A new class of biodegradable polymers that show promising characteristics for orthopedic applications was investigated. This study examines aspects underlying the polymer erosion of poly[trimellitylimidoglycine-co-1,6-bis(carboxyphenoxy)hexane] and poly[pyromellitylimidoalanine-co-1,6-bis(carboxyphenoxy)hexane].Copolymer degradation was studied by examining the anhydride bond hydrolysis and copolymer composition by IR and NMR spectroscopy. Hydrolysis of the anhydride bonds occurred much faster than did the dissolution of the hydrolyzed products, leading to the formation of two distinct erosion zones. The two erosion zones were observed by light and scanning electron microscopy with erosion originating at the surface and moving to the center of the polymer samples. © 1996 John Wiley & Sons, Inc.     

Studies of heterocyclic polymers. V. poly (1, 3′-benzobis (iminopyrrolenones))

The synthesis of dimethyl-2, 5-dicyanoterephthalate from 2,5-dibromo-p-xylene and its conversion to 1,3′-benzobis (iminopyrrolenone) are reported. 1,3 -Benzobis (N-phenyliminopyrrolenone) was prepared by reaction of 1,3′-benzobis (iminopyrrolenone) with aniline. The product was a bright yellow crystalline solid which was also formed when dimethyl-2,5-dicyanoterephthalate was condensed with aniline under suitable conditions. Poly (1,3′-benzobis (iminopyrrolenones)) were synthesised by the condensation of 1,3′ -benzobis (iminopyrrolenone) with aromatic diamines and with 1,6-diaminohexane at high temperatures in dimethyl sulphoxide. The degrees of polymerisation of the polymers obtained were low, as judged by the completeness of the condensation reaction. Thermogravimetric analyses of these polymers in air showed that they have 10% weight-loss temperatures in the range 420 to 520°C, for the polymers prepared from aromatic diamines, and of 350°C for the polymer derived from 1,6-diaminohexane. The insoluble, intractable nature of these polymers precluded a thorough study of their structure.     

Polyimides from a Novel Monomer 3,6-Bis(dimethylamino)acridine(p-cymene)dichlororuthenium(II) for a Catalytic Application

Tricyclic heteroaraomatic dye-based monomer containing NMe₂ units, 6-bis(dimethylamino)acridine(p-cymene)dichlororuthenium (II), was used to prepare novel polyimides via a one-stage solution polycondensation due to their stability under a variety of oxidative and reductive conditions. The Ru(II) complex monomer was synthesized starting from [RuCl₂(p-cymene)]₂ and 3,6-bis(dimethylamino)acridine. A series of stable polyimides was synthesized from the Ru(II) complex of 3,6-bis(dimethylamino)acridine and various aromatic dianhyrides. The polymers had inherent viscosities ranging from 1.72 to 2.11 dL/g and were soluble in polar solvents. The glass transition temperatures were 192–278 °C, and the 10% weight loss temperatures were above 503–635 °C. Ruthenium-substituted polyimides were tested for catalytic activity in the furan formation reaction of (Z)-3-methylpent-2-en-4-yn-1-ol. The polymeric catalyst was added to (Z)-3-methylpent-2-en-4-yn-l-ol without a solvent and the pure furan was isolated by distillation under reduced pressure. The conversion of the starting, enynol, was determined by gas chromatography (GC).     

Organometallic polymers. II. Crosslinking of ferrocenylene–methylene-type polymers

Poly(ferrocenylene-methylmethylene) (PFMM) was prepared and subsequently crosslinked by the aid of either 1,1'-bis(α-hydroxyethyl)ferrocene or polyfunctional ferrocene polymers, containing reactive-CH₂OH or-CH(CH₃)OH groups. The thermal behavior of both the primary polymer and the thermoset was investigated. The solubility parameter of PFMM was determined and the degree of crosslinking was studied by solvent swelling and sol fraction measurements. Various thermosetting structural composites were prepared and subjected to mechanical testing.     

Synthesis and properties of poly(dioxynaphthyleneisophthaloyl)s with various isomeric naphthylene links

Summary By condensation of 1,4-, 1,5-, 1,6-, 2,3-, 2,6-, and 2,7-naphthalenediol (ND) isomers with a isophthaloyl chloride six aromatic polyesters were prepared, and after removal of low molecular weight materials by extraction with acetone their properties were investigated. Effects of the isomerism of the naphthylene units on the properties of the polyesters were discussed. All the polyesters except one derived from 2,7-ND were soluble in a mixed solvent of phenol/p-chlorophenol/1,1,2,2-tetrachloroethane (TCE). Weight-average molecular weight of the polymer derived from 2,3-ND having the lowest inherent viscosity of 0.10 dL/g was measured to be 12,200 g/mol in TCE by means of a laser light scattering spectrometer. Polydispersity of this sample was determined to be 1.59 by a gel permeation chromatography with o-chlorophenol at 100°C. Glass transition temperatures of the polymers ranged from 144 to 195°C, depending on their molecular weight and chain structure. The polyesters derived from 1,6- and 2,3-NDs were amorphous and all the others were crystalline. Melting temperatures (T_m) of the polymers range from 341°C to 417°C and the polymer derived from 2,6-ND showed the highest T_m. All the polymers had initial decomposition temperature higher than 400°C and showed residue more than 50 wt% at 600°C.