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  • 1
    Digitale Medien
    Digitale Medien
    s.l. : American Chemical Society
    Macromolecules 23 (1990), S. 502-509 
    ISSN: 1520-5835
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie , Physik
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Journal of polymer research 3 (1996), S. 89-95 
    ISSN: 1572-8935
    Schlagwort(e): Thermotropic ; Poly(ester-amide)s ; Direct polycondensation ; DPCP ; Nematic
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Abstract Thermotropic Poly(ester-amide)s containing triethyleneglycol bis(4-carboxyphenyl) ether (PEG3), o-Tolidine (OT) and various aromatic diols such as hydroquinone (HQ) and 4,4′-biphenol (BP) were synthesized by direct polycondensation with DPCP (diphenyl chlorophosphate) as direct condensation agent in the presence of pyridine and LiCl. The polymer structures were characterized by infrared spectroscopy and elemental analysis. The influence of structure, substituents and contents of various aromatic diols on the phase transitions were studied by Differential Scanning Calorimetry (DSC) and Polarized Optical Microscopy. These revealed that the structure and substituents of diols affected the mesophase while most of the synthesized polymers exhibit nematic mesophase. Addition of HQ decreased the melting temperature of the polymers, but, in contrast to others diols, did not affect thermal resistance.
    Materialart: Digitale Medien
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  • 3
    ISSN: 1572-8935
    Schlagwort(e): Surface reconstruction ; Adhesion ; Silicone ; Polyurethane ; FTIR-ATR
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Abstract A new class of hydroxyl-functionalized polydimethylsiloxane-block-hydroxyl graft acrylate prepolymer (PDMS-b-HGAP) copolymers was synthesized. The copolymers were characterized using Fourier transform infrared spectroscopy as well as 1H and 13C nuclear magnetic resonance spectroscopy. The hydroxyl groups of the HGAP were reacted with the chlorine terminal in the PDMS to yield a triblock copolymer consisting of two segments of PDMS linked to a HGAP segment. The induced surface reconstruction of silicone rubber (SR)by blending polysiloxane reactants with bifunctional PDMS-b-HGAP copolymers and curing using mold materials having high critical surface tension such as polyethyleneterephthalate was attempted to improve the adhesion between chemically-inert SR and polyurethane (PU). Surface characterization using Foruier transform infrared-attenuated total reflectance indicated that the surface of the SR was enriched with HGAP. The increased content of surface HGAP was suggested to account for the improved adhesion between SR and PU.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Journal of polymer research 7 (2000), S. 115-123 
    ISSN: 1572-8935
    Schlagwort(e): Latex ; Polymeric surfactant ; Alkali soluble resin ; Emulsion polymerization ; Retarding effect
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Abstract In this work, alkali soluble resin (ASR) was evaluated as a surfactant in the emulsion polymerization of butyl methacrylate (BMA). Kinetic analysis indicated that the ASR surfactant retarded the reaction rate and reduced the average number of radicals per latex particle. Since the particle nucleation period proceeds until the disappearance of droplets, Interval II does not exist in this system. Experimental results show that the particle number depends on the 0.31 and 0.51 powers of the ASR and KPS concentration, respectively. The particle size distribution of the latex becomes broad with the increase of the ASR concentration in the emulsion polymerization. This phenomenon explains why the period of the particle nucleation is proportional to the ASR concentration used in the reaction.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Journal of polymer research 1 (1994), S. 273-284 
    ISSN: 1572-8935
    Schlagwort(e): Polyarylate ; Liquid crystal polymer ; Naphthalene dicarboxylic acid ; Kinky monomer ; Anisotropy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Abstract A series of copolyarylates primarily based upon 2,6-naphthalene dicarboxylic acid, hydroxybenzoic acid and 4,4′-biphenol were prepared by slurry-melt polymerization with Santotherm 66 as a heat exchange medium. The frequently used kinky monomer, resorcinol or isophthalic acid, was introduced into these copolyarylates to modify the chemical strcture. The relationship of the thermal behavior and the crystalline structures for these copolymers was studied by means of DSC and wide angle X-rays diffraction. The amount of mcorporated kinky modifier was found to produce a significant effect on the liquid crystalline phase and the melting temperature of the copolyarylates. All of these liquid crystal polymers exhibited nematic textures; shreaded and/or Schlieren type, depending upon the incorporated kinky monomer. The liquid crystal polymers modified by isophthalic acid (up to 40 mole % of 2,6-naphthalene dicarboxylic acid replaced by isophthalic acid) possessed shreaded texture however high the temperatures of the polymer melts were. The liquid crystal polymers modified by resorcinol (60 to 100 mole % of 4, 4′-biphenol replaced by resorcinol), however, would have two types of nematic textures: the shreaded texture occurred when the temperature of the polymer melt was between the melting temperature and the anisotropic transition temperature; the Schlieren texture existed when the temperature of the polymer melt was high above the anisotropic transition temperature. The Schlieren texture formed only when a liquid crystal polymer revealed good flowability and lower rigidity. The polydomain concepts could be utilized to explain the observed textures of these copolyarylates clearly.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Journal of polymer research 5 (1998), S. 77-84 
    ISSN: 1572-8935
    Schlagwort(e): Block copolyetheresters ; Poly(trimethylene 2,6-naphthalenedicarboxylate) ; Segments ; Thermal transitions ; X-ray diffraction ; Thermal stimulated current
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Abstract Block copolyetheresters with hard segments of poly(trimethylene 2,6-naphthalenedicarboxylate) and soft segments of poly(tetramethylene oxide) were prepared by melt polycondensation of dimethyl 2,6-naphthalenedicarboxylate, 1,3-propanediol and poly(tetramethylene ether)glycol (PTMEG) of molecular weights of 650, 1000 and 2000. The block copolyetheresters were characterized by FTIR, 1H NMR, DSC, X-ray diffraction, TSC (thermal stimulated current), DMA and TGA. It was found that the thermal transitions were dependent on the composition. As the charge molar ratio of PTMEG to dimethyl 2,6-naphthalenedicarboxylate, x, increased, the Tm and ΔHm of the polyester segments decreased, which has been also confirmed by the X-ray diffraction data. The polyether segments of the block copolyetheresters derived from PTMEG2000 could crystallize after cooling, but those of the block copolyetheresters derived from PTMEG1000 and PTMEG650 could not crystallize. The DSC, TSC and DMA results show consistent Tg data of the polyether segments. Based on the shift in Tg of the polyether segments, the amorphous parts of the polyether segments and the amorphous parts of the polyester segments were immiscible for the block copolyetheresters derived from PTMEG2000, but became partially miscible for the block copolyetheresters derived from PTMEG1000 and PTMEG650. The TGA results indicated that composition had little effect on thermal degradation under nitrogen.
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 190 (1989), S. 1413-1423 
    ISSN: 0025-116X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: DSC, X-ray diffraction and solid-state 13C NMR were used to investigate the crystallization properties of block copolyarylates prepared via two-step interfacial polycondensation. The block copolyarylates obtained from 1,1,2,2-tetrachloroethane solution were found to have low crystallinity. This could be explained as the influence of amorphous blocks on the crystalline blocks. When the block copolyarylates were redissolved in dichloromethane, the annealed, cast films exhibited considerably higher crystallinity. It was concluded that the crystallization behavior of block copolyarylates is very much dependent on their sample history.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 8
    Digitale Medien
    Digitale Medien
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 193 (1992), S. 2477-2486 
    ISSN: 0025-116X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: Two smectic main-chain liquid-crystalline polyesters containing biphenyl as mesogen and spacers with 8 and 18 methylene carbon atoms were prepared, and their transition kinetics were investigated by means of differential scanning calorimetry (DSC). The isothermal liquid-crystallization was analyzed using the Avrami equation. The Avrami exponent n was found to be 2 to 4 indicating that the liquid-crystallization of these two smectic polyesters would be a process of two-to three-dimensional growth rather than of one-dimensional growth as for nematic liquid-crystalline polymers. The nonisothermal liquid-crystallization and crystallization were also analyzed by means of DSC. The crystallization from the smectic phase was found to be a very fast process and the supercooling of crystallization was small. Thus, the smectic phase might nucleate crystallization. The transition kinetics of these two smectic polyesters are considerably different from those of nematic liquid-crystalline polymers due to the different orders of the liquid-crystalline phases.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
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  • 9
    ISSN: 0025-116X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: A model imide with a tricyclic structure was synthesized by reacting 3-phenyltricyclo[6.2.2.02,7]-2,11-dodecadiene-5,6 : 9,10-tetracarboxylic dianhydride with aniline. The thermogravimetry curve showed that it degraded at about 300°C, and its differential scanning calorimetry curve was found to be similar to that of its corresponding polyimides. The thermal curing of this model imide was studied in detail. A curing mechanism was proposed based on the analysis of the cured product using NMR and mass spectroscopy. The results show that the curing mechanism started with a reverse Diels-Alder reaction, forming an intermediate which either dehydrogenated or further decomposed into 1,1-diphenylethylene, and N-phenylsuccinimide. The 1,1-diphenylethylene and N-phenylsuccinimide would either polymerize or become hydrogenated to form 1,1-diphenylethane and N-phenylsuccinimide, respectively.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
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  • 10
    Digitale Medien
    Digitale Medien
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 193 (1992), S. 1537-1550 
    ISSN: 0025-116X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: Polyimides were prepared by the condensation of 3-phenyltricyclo[6.2.2.02,7]-2,11-dodecadienne-5,6:9,10-tetracarboxylic dianhydride with diamines. Thermal curing of these polyimides was studied using thermogravimetry, infrared spectroscopy, nuclear magnetic resonance spectroscopy, mass spectroscopy and elemental analyses. The results were compared with those of a model imide compound and a neat dimaleimide. It is proposed that the thermal curing mechanism is controlled by a reverse Diels-Alder reaction, a three-dimensional polymer network being formed following the degradation of the polymer. Based on these studies, a three-dimensional structure is proposed if the curing temperature was over 330°C. The weight loss of isothermal thermogravimetry studies was tentatively used to determine the composition of the crosslinked structure and elemental analyses confirmed the results.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
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