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  • 1
    ISSN: 1572-8935
    Keywords: Polyarylates ; Brominated polyarylates ; Interfacial polycondensation ; α,α′-Bis(4-hydroxyphenyl)-1,4(or 1,3)-diisopropylbenzene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The interfacial polycondensation technique was used for the preparation of polyarylates and brominated polyarylates. Polyarylates and brominated polyarylates were prepared by mixing a solution of diacid chloride such as terephthaloyl chloride, isophthaloyl chloride, or their mixture in dichloromethane with an aqueous alkaline solution of α,α′-bis(4-hydroxyphenyl)-1,4(or 1,3)-diisopropylbenzene or α,α′-bis(4-hydroxy-3,5-dibromophenyl)-1,4(or 1,3)-diisopropylbenzene using triethylbenzylammonium chloride as the phase transfer agent. Moderate to high molecular weight polyarylates withη inh up to 1.27 dL/g were obtained, and most of them could be cast into tough and flexible films depending on the polymer composition. In general, polymers containing more 1,3-isomer or isophthaloyl chloride moieties gave transparent and flexible films and had lower glass transition temperatures and higher solubility. Although these polymers have two isopropylidene linkages in their repeating units, they still exhibit moderately high thermal stability and show no obvious weight loss before 400 °C. The introduction of bromine on the polymer backbone caused a decrease of inherent viscosity, crystallinity, and thermal stability of the polyarylates, while causing an increase in glass transition temperature and a great enhancement of fire retardancy.
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  • 2
    ISSN: 1572-8935
    Keywords: 1,4-Bis(4-trimellitimidophenoxy)benzene ; Direct polycondensation ; Poly(amide-etherimide)s
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract An imide ring containing dicarboxylic acid, 1,4-bis(4-trimellitimidophenoxy)benzene (III), was prepared by the condensation of 1,4-bis(4-aminophenoxy)benzene and trimellitic anhydride. A series of new poly(amide-ether-imide)s were prepared by the direct polycondensation of diimide-diacid III with various aromatic diamines using triphenyl phosphite and pyridine as condensing agents inN-methyl-2-pyrrolidone (NMP) in the presence of calcium chloride. The highest inherent viscosity value of a poly(amide-ether-imide) obtained was 1.78 dL/g (inN,N-dimethylacetamide, DMAc, at 30 °C). Flexible films with excellent tensile properties were cast from DMAc solutions. Glass transition temperatures of these poly(amide-ether-imide)s were recorded in the range of 248–297 “C. These polymers do not show obvious weight loss before 400°C; the decomposition temperatures at which 10% weight loss in nitrogen and in air were observed for these poly(amide-ether-imide)s in the range of 521–564°C and 501–539°C, respectively. The polymers derived fromp-phenylenediamine or the diamines containing 1,4-bisphenoxy units exhibited a higher degree of crystallinity and higher initial decomposition temperatures but poor solubility in organic solvents.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Journal of polymer research 6 (1999), S. 141-148 
    ISSN: 1572-8935
    Keywords: Bismaleimide ; BMI ; Ortho-linked bis(ether amine) ; Thermal property
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Three bismaleimides (BMIs) each having an ortho-linked aromatic unit were prepared by condensation of maleic anhydride with 1,2-bis(4-aminophenoxy)benzene (1a), 1,2-bis(4-aminophenoxy)-4-tert-butylbenzene (1b), or 2,3-bis(4-aminophenoxy)naphthalene (1c). The molecular structures of these BMIs were confirmed by elemental, IR, and NMR analyses. The thermal behavior of the BMIs was evaluated by differential scanning calorimetry (DSC), and the thermal properties of the thermally cured BMI resins were determined by dynamic thermogravimetric analysis (TGA) and thermomechanical analysis (TMA). The effects of structure of the BMIs on the curing behavior of the BMIs and on the properties of the cured resins were investigated. The BMI of 1a had a relatively high melting point (256 °C) and immediately polymerized after having been melted. The 1b-and 1c-based BMIs with a bulkier molecular structure exhibited lower melting points (136 and 171 °C), facilitating the use of these BMIs in the molten state. The cured BMI resins did not show significant decomposition below 450 °C in air or nitrogen and did not soften below 400 °C.
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Journal of polymer research 7 (2000), S. 205-213 
    ISSN: 1572-8935
    Keywords: Polyamides ; Terephthalic acid ; Isophthalic acid ; Ether-diamines ; Structure-property relationships
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Aromatic polyamides containing different numbers of p-oxyphenylene groups and different catenated positions in the benzene rings were prepared from terephthalic acid (TPA) and isophthalic acid (IPA) with various aryloxy-containing diamines by means of the phosphorylation polycondensation reaction. Most of the polyamides were moderately to highly crystalline, as indicated by X-ray diffraction and DSC measurements. Polyisophthalamides were readily soluble in polar amide-type solvents such as N-methyl-2-pyrrolidone (NMP) and N,N-dimethylacetamide (DMAc). Some non-crystalline polyamides could afford tough films by solution casting. Most polyisophthalamides revealed discernible glass transition on their DSC curves, and their Tg values were recorded in the range of 215–238 °C. No discernible glass transitions were observed for the polyamides of TPA by DSC. The thermal stability of these polymers did not show clear dependence on the structure of the diacid or the diamine. In addition, a series of polyamides having pendant groups was synthesized from the polycondensation of TPA and IPA with 1,4-bis(4-aminophenoxy)benzene and its derivatives with methyl, tert-butyl, or phenyl substituent on the central benzene ring. In most cases, the incorporation of pendant groups generally resulted in an enhanced solubility and a decreased Tg and crystallinity.
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  • 5
    ISSN: 1572-8935
    Keywords: Poly(amide-imide)s ; Polycondensation ; Phosphorylation ; Aromatic diamines ; 1,3-bis(4-aminophenoxy)benzene ; 1, 3-bis(4-trimellitimidophenoxy)benzene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract A diamine, 1,3-bis(4-aminophenoxy) benzene (II), was synthesized in two steps; fist from the condensation of resorcinol with p-chloronitrobenzene in the presence of potassium carbonate, producing I ,3-bis(4-nitrophenoxy) benzene (I), followed by hydrazine hydrate/Pd-C reduction. A two imide rings-preformed dicarboxylic acid, 1,3-bis(4-trimellitimidophenoxy)benzene (III), was prepared from the condensation of diamine II and trimellitic anhydride in 1:2 molar ratio. A series of structurally new polyamide-imides (Va-p) were directly synthesized from the diacid III and various aromatic diamines (IVa-p). The resultant polyamide-imides had inherent viscosities between 0.56–1.39 dl/g. All polymers, except some derived from diamines with p-phenoxy structure, showed excellent solubility. Some polymer resulted in tough or flexible transparent films. Dynamic TG data indicated that all polymers possess excellent thermal stability with no significant weight loss up to the temperature of approximately 450 °C in nitrogen, and their 10% weight loss temperature was recorded in the range of 489–577 °C. Measurements of wide-angle X-ray diffraction revealed that some polymers derived from p-phenoxy group-containing diamines showed crystalline patterns.
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Journal of polymer research 3 (1996), S. 31-37 
    ISSN: 1572-8935
    Keywords: Bismaleimides ; Thermal properties
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Aromatic bismaleimides (BMIs) were prepared by the condensation of malefic anhydride with multiring diamines containing ether bridges. The thermal behavior of the bismaleimides was investigated by differential scanning calorimetry (DSC). Thermogravimetric analysis (TGA) and thermomechanical analysis (TMA) were utilized to characterize the thermal properties of the cured resins. The effect of the structures of bismaleimides on their thermal behavior and the thermal properties of the cured resins is discussed. Increasing molecular weight between reactive endgroups lowered melting points of BMIs, leading to a large temperature range between their melting point and the initial polymerization temperature. The introduction of ether bonds together with other flexible partners to bismaleimide resins decreased the glass transition temperatures or softening temperatures and the brittleness of the cured bismaleimide resins without extreme loss of their thermal stability. The cured bismaleimides were stable up to 450°C in both air and nitrogen.
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Journal of polymer research 3 (1996), S. 247-256 
    ISSN: 1572-8935
    Keywords: Aromatic polyamides ; Isopropylidene ; Hexafluoro-isopropylidene ; Direct polycondensation ; Triphenyl phosphite
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Two multiring, flexible dicarboxylic acids, 4,4'-[isopropylidenebis(1,4-phenylene)dioxy] dibenzoic acid (3) and 4,4'-[hexafluoroisopropylidenebis(1,4-phenylene)dioxyldibenzoic acid (3-F), were synthesized through the nucleophilic fluorodisplacement ofp-fluorobenzonitrile by the dipotassium bisphenolates of the corresponding bisphenol precursors followed by alkaline hydrolysis. Two series of aromatic polyamides 5a–k and 5a–k-F containing both ether and isopropylidene or hexafluoroisopropylidene linkages between phenylene units were prepared by direct polycondensation of diacids 3 and 3-F, respectively, with various aromatic diamines using triphenyl phosphite and pyridine as condensing agents in aN-methyl-2-pyrrolidone (NMP) solution containing dissolved calcium chloride. The resulting polyamides of 5 and 5-F series have inherent viscosities of 0.92–1.29 dL/g and 0.60–0.92 dL/g, respectively. Most of these polymers are amorphous in nature, are soluble in polar solvents such as NMP,N,N-dimethylacetamide (DMAc), andN,N dimethylformamide (DMF), and can afford tough and flexible films by solution casting. Differential scanning calorimetry shows Tgs ranging from 175 to 239 °C for the 5 series polyamides and ranging from 172 to 267 °C for the 5-F series polymers. Both classes of polyamides show good thermal stability, with the 5-F series polyamides being more stable.
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Journal of polymer research 3 (1996), S. 239-245 
    ISSN: 1572-8935
    Keywords: Aromatic polyamides ; 4,4′-Oxydibenzoic acid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract A series of aromatic polyamides were synthesized by direct polycondensation of 4,4′-oxydibenzoic acid with various aromatic diamines inN-methyl-2-pyrrolidone (NMP) solution containing dissolved calcium chloride, using triphenyl phosphite and pyridine as condensing agents. The resultant polyamides had inherent viscosities of 0.21-1.48 dL/g. Most of the polymers were organo-soluble and could be solution-cast into flexible and strong films. The glass transition temperatures (Tgs) of most polyamides could be determined with the help of differential scanning calorimetry (DSC) traces, which were recorded in the range of 170–275 °C. Thermogravi metric data of these polymers indicated that most of the polyamides showed no significant weight loss before 450 °C in either air or nitrogen atmospheres.
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Journal of polymer research 5 (1998), S. 193-198 
    ISSN: 1572-8935
    Keywords: Polyimides ; Ether-sulfone-diamines
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Two diamine monomers, 4,4′-[sulfonylbis(1,4-phenyleneoxy)]dianiline (III a ) and 4,4′-[sulfonylbis(2,6-dimethyl-l,4-phenyleneoxy)]dianiline (III b ), were prepared by an aromatic nucleophilic substitution of 4,4′-sulfonyldiphenol (I a ) and 4,4′-sulfonylbis(2,6-dimethylphenol) (I b ) with p-chloronitrobenzene in the presence of potassium carbonate, followed by hydrazine catalytic reduction of the intermediate dinitro compounds. The diamines III a and III b were used as monomers with various aromatic tetracarboxylic dianhydrides (IV a–f ) to synthesize polyimides. The polymerization was conducted in two steps via the formation of a poly(amic acid) precursor followed by thermal cyclodehydration. The poly(amic acid)s had inherent viscosities above 0.87 and up to 2.56 dL/g. Most poly(amic acid)s could be coated and thermodehydrated into flexible and transparent polyimide films. The polyimides derived from the dianhydrides containing-O-and-SO2-or-C(CF3)2-bridging groups between the phthalic anhydride units were soluble in some organic solvents such as N,N-dimethylacetamide (DMAc) and N,N-dimethylformamide (DMF). The glass transition temperatures (Tg) of the polyimides were in the range from 254 to 300 °C. The methyl-substituted polyimides exhibited slightly higher solubility and higher Tg compared to the corresponding unsubstituted polyimides. Thermogravimetric analysis (TG) showed that the polyimides containing methyl substitutents started to lose weight around 450 °C and the unsubstituted ones started to lose weight around 550 °C.
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  • 10
    Electronic Resource
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    Springer
    Journal of polymer research 5 (1998), S. 243-248 
    ISSN: 1572-8935
    Keywords: Polyamides ; Poly(amide-imide)s ; Ether-sulfone-diamines ; Methyl substituent ; Solubility ; Tgs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract A series of polyamides and poly(amide-imide)s were prepared by the direct polycondensation of 4,4′-[sulfonylbis(1,4-phenyleneoxy)]dianiline or 4,4′-[sulfonylbis(2,6-dimethyl-1,4-phenyleneoxy)]dianiline with aromatic dicarboxylic acids and phthalimide unit-bearing dicarboxylic acids in a N-methyl-2-pyrrolidone (NMP) solution containing dissolved calcium chloride using triphenyl phosphite and pyridine as condensing agents. The inherent viscosities of the resulting polymers were above 0.45 dL/g and up to 1.70 dL/g. Except for the polyamides derived from terephthalic acid and 4,4′-biphenyldicarboxylic acid, all the other polyamides and all poly(amide-imide)s were readily soluble in polar organic solvents such as NMP, N, N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and m-cresol, and afforded transparent and tough films by solution-casting. Most of the polymers showed distinct glass transition on their differential scanning calorimetry (DSC) traces and their glass transition temperatures (Tg) stayed between 140–264 °C. The methyl-substituted polymers showed higher Tgs than the corresponding unsubstituted counterparts. The results of the thermogravimetry analysis (TGA) revealed that all the methyl-substituted polymers showed lower initial decomposition temperatures than the unsubstituted ones.
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