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  • 1
    Electronic Resource
    Electronic Resource
    Rubber toughened polyamide 6: The influences of compatibilizer on morphology and impact properties (1993)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 33 (1993), S. 1329-1335 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: In this study, styrene-(ethylene-co-butylene)-styrene (SEBS) triblock copolymer (Kraton G-1652) was modified with maleic anhydride (MA). The maleated SEBS was used as compatibilizer for the blends of Nylon 6 (PA6) and SEBS. The morphology and impact strength of the blends were measured as functions of concentration and MA graft ratio of maleated SEBS. The compatibility and fracture mechanism of the blends were evaluated from the SEM micrographs of the xylene-etched surfaces and of fractured surfaces. Some of the blends exhibited an impact strength up to about 30 fold greater than neat PA6. The fracture involved both both cavitation and shear yielding. The mechanism of compatibilization of maleated SEBS in the ternary components blends was proposed.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760332005
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  • 2
    Electronic Resource
    Electronic Resource
    Aqueous polymerization of acrylamide initiated by cerium(IV)-amino acid chelating agent redox initiators (1993)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 31 (1993), S. 267-274 
    Details
    ISSN: 0887-624X
    Keywords: amino acid type chelating agents ; Ce(IV) redox initiators ; aqueous polymerization of acrylamide ; kinetics and parameters ; structure correlations ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Amino acid-type chelating agents such as nitrilotriacetic acid (NTA), nitrilotripropionic acid (NPA), iminodiacetic acid (IDA), and ethylenediamine tetraacetic acid (EDTA) were used in combination with cerium(IV) ammonium nitrate [Ce(IV)] as the redox initiators for the aqueous polymerizations of acrylamide (AM). The polymerization behaviors and polymer qualities were studied as functions of the concentrations of Ce(IV), chelating agent, AM, as well as temperature. The performances of the chelating agent redox systems varied with the natures of the chelating agents. The NTA-Ce(IV) initiator showed the most promising polymerization rate and conversion. The blank tests for the reactions of cerium and chelating agents were also conducted for finding mechanism of formation of free radicals and determining their complex formation constants (K) and disproportionation constants (kd). The mechanism for the polymerization was proposed and the kinetic parameters were evaluated. © 1993 John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1993.080310131
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  • 3
    Electronic Resource
    Electronic Resource
    A kinetic study on grafting of maleic anhydride onto a thermoplastic elastomer (1993)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 31 (1993), S. 3405-3415 
    Details
    ISSN: 0887-624X
    Keywords: maleated thermoplastic elastomer ; maleic anhydride ; graft ; kinetics ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Maleation of a thermoplastic elastomer, styrene-[ethylene-butylene]-styrene (SEBS) triblock copolymer, was carried out by a solution grafting reaction with maleic anhydride initiated by dicumyl peroxide. The reaction products from the graft reaction in xylene, commonly chosen as the solvent for maleation graft reactions, were identified using liquid chromatograph (LC), IR, and 13C-NMR. Side products from the graft reaction were identified by the LC analysis and, it was concluded that xylene affected the graft reaction through its active methyl groups. Reaction mechanisms were investigated by performing free radical kinetics analysis. The reaction orders and the apparent rate constant were estimated. It was concluded that a proper choice of the solvent might favor better graft efficiency. © 1993 John Wiley & Sons, Inc.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1993.080311329
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  • 4
    Electronic Resource
    Electronic Resource
    Synthesis and characterization of terminally carboxyl ethylene glycol monomethyl ethers-substituted side-chain liquid-crystalline polysiloxanes (1993)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 31 (1993), S. 2423-2436 
    Details
    ISSN: 0887-624X
    Keywords: liquid-crystalline polymer ; side-chain ; mesophase ; smectic phase ; nematic phase ; crown-ether ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Alkene monomers containing phenyl or biphenyl carboxylate benzoate ester based on a mesogenic group of varied lengths of carboxyl oligo (ethanediol) monomethyl ethers as the terminal were synthesized. They were grafted onto poly(methyl-hydrosiloxane) by the platinum-catalyzed hydrosilylation process. The thermal transition temperatures and mesophase textures of monomers and of polymers were characterized by using differential scanning calorimetry (DSC), x-ray diffraction, and polarized optical microscopy with a hot stage. The factors governing mesophase textures and thermal transition temperatures are discussed. © 1993 John Wiley & Sons, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1993.080311002
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  • 5
    Electronic Resource
    Electronic Resource
    Aqueous polymerization of acrylamide initiated by cerium (IV)-ethylenediamine tetraacetic acid redox system (1992)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 30 (1992), S. 2459-2466 
    Details
    ISSN: 0887-624X
    Keywords: EDTA-Ce(IV) redox initiator ; aqueous polymerization ; acrylamide ; rate dependence ; mechanism ; kinetic parameters ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ethylenediamine tetraacetic acid (EDTA) terminated polyacrylamide was obtained by using the EDTA-cerium(IV) ammonium nitrate [Ce(IV)] redox initiator in the aqueous polymerization of acrylamide. The polymerization behaviors as a function of the concentration of Ce(IV), EDTA, and acrylamide as well as temperature were studied. The consumption rate of cerium(IV) depends a first-order reaction on the ceric ion concentration ([Ce(IV)]). The complex formation constant (K) and disproportionation constant (kd) of Ce(IV)-EDTA chelated complex are 1.67 × 104 and 3.77 × 10-3, respectively. The rate dependences of polymerization on monomer concentration and EDTA concentration both follow a second-order reaction in the run of initial monomer concentration ([M]i) equal to 0.2 mol dm-3. The number average molecular weight increases linearly with the ratio of [M]i/[Ce(IV)]i. The mechanism and kinetics for the polymerization was proposed. The kinetic parameters involved were determined. © 1992 John Wiley & Sons, Inc.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1992.080301120
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  • 6
    Electronic Resource
    Electronic Resource
    Study on aqueous polymerizations of vinyl monomers initiated by metal oxidant-chelating agent redox initiators (1993)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 31 (1993), S. 3213-3222 
    Details
    ISSN: 0887-624X
    Keywords: redox initiators ; chelating type reductants ; metal oxidants ; mechanism ; characterization of kinetic parameters ; aqueous polymerizations of vinyl monomers ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In this study, a series of chelating type reductants containing redox pairs were tested as the initiator for aqueous polymerizations. The redox pairs consist of Ce(IV) or several first-row transition metals coupled with chelating agents of amino acids, dibasic acids, or diamine. The initial rates and limiting conversions of acrylamide polymerization initiated by those redox pairs were determined. The reductive reactivity of the chelating agents with Ce(IV) and the oxidative half-wave potential of Ce(III)-chelating agent/Ce(IV)-chelating agent were measured to evaluate the feasibility of these redox pairs as initiators. After the evaluation, the redox pairs other than Ce(IV)-amino acid type chelating agent were precluded to be promising initiators for aqueous polymerizations. Those Ce(IV)-amino acid type chelating agent redox pairs which could form at least two five- or six-membered rings were found to be potential initiators. The Ce(IV)-NTA pair was the most promising one. The mechanism of initiation of the redox pairs was proposed and further confirmed by the 13C- and 1H-NMR spectra of NTA-terminated polyacrylamide. The complex formation constants (K) and disproportionation constants (kd) of the Ce(IV)-amino acid type chelating agent redox initiators for acrylamide polymerization were evaluated. The factors governing the parameters of chelated complexes and the performance of polymerizations were discussed. These redox pairs were also used as the initiators for aqueous polymerizations of acrylic acid and acrylonitrile. © 1993 John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1993.080311307
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  • 7
    Electronic Resource
    Electronic Resource
    The effect of sodium methacrylate on the soapless emulsion copolymerization of methyl methacrylate and n-butyl acrylate (1991)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 29 (1991), S. 709-718 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The soapless emulsion polymerization of methyl methacrylate (MMA) and n-butyl acrylate (BA) containing various concentrations of sodium methacrylate (NaMA) or methacrylic acid (MMA) is studied. The hydrosoluble yields in final latexes are not larger than 1.3-5%, depending on the concentration of NaMA used. Below 25% conversion, the change of conversion with reaction time follows the square rule and the particle size is proportional to the 2/3 power of time. Above 25% conversion, serious gel effect occurs, and the conversion follows the seventh power on time and the growth of particle diameter obeys the 2.5 power on time. The multiple glass transition (Tg) occur below 20% conversion, where monomer droplets exist. NaMA added induces more Tgs. The effect of molecular weight of the copolymers obtained on Tg (even the molecular weight distributions were shown to be shouldertype bimodal) is estimated to be insignificant. Thus, the heterogeneity of copolymer compositions for multiple Tgs is ascribed to be caused from neither the molecular weight heterogeneity nor the shifts in compositions due to the difference of the monomer reactivity ratios. Referring to the results mentioned, we assume the sublayer surrounding the particle, rich with SO4- and COO- groups, and the concentration gradients of monomers in particles to illustrate particle morphology. In addition, the relatively hydrophilic sublayer is proposed to be closely relative with the occurrence of the composition heterogeneity in particles.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1991.080290513
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  • 8
    Electronic Resource
    Electronic Resource
    Study on the continuous loop tubular reactor for emulsion polymerization of styrene (1990)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 30 (1990), S. 187-192 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A continuous loop tubular reactor (CLTR) with a Bodenstein number of 100 and a recycle ratio of 0.992 (obtained under the conditions of a mean residence time of 25.0 to 59.95 min and a stirring rate of 418 rpm) was used for studying the emulsion polymerization of styrene (St). The recipe used in the study is 76.8 g St/l-water, 3.73 g sodium lauryl sulfate (SLS)/l-water, and 2.30 g potassium persulfate (KPS)/l-water. The effects of the mean residence time on the performance of emulsion polymerization were studied. The overshoots in the monomer conversion and the particle number concentration were found to be higher as the mean residence time increased. The overshoots diminished at about 3 times the mean residence time. The steady state particle number concentration was independent of the mean residence time, while the steady state monomer conversion increased with increasing mean residence time.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760300308
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  • 9
    Electronic Resource
    Electronic Resource
    The performance of the emulsion polymerization of styrene in a continuous loop tubular reactor (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992), S. 198-205 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The emulsion polymerization of styrene in a continuous loop tubular reactor (CLTR) has been used to study the process kinetics under eigth levels of sodium lauryl sulfate (SLS) concentration, eight levels of potassium persulfate (KPS) concentration, and three levels of styrene monomer (St) concentration. A critical surfactant concentration for the overshoot phenomenon in the monomer conversion exists between 8.02 and 12.40 g-SLS/1-water. Overshoot was not eliminated by changing concentrations of the initiator and monomer. The overshoot in the number concentration of polymer particles was observed in all the polymerizations studied. The dependences of the rate of polymerization and the number concentration of particles in the steady state on the SLS and KPS concentrations are presented. The growth of the average cumulant diameter of particles shows a transient period followed by a steady state. The dependences of the volumetric growth rate of polymer particles on diameter are of the order of 1 for the lower SLS concentration and 0.5 for the higher SLS concentration, respectively. The steady state cumulant diameter depends on an order of -0.24 for the SLS concentration.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760320306
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  • 10
    Electronic Resource
    Electronic Resource
    Dimerizations of acrylate monomers with sodium hydroxymethanesulfinate and characterization of the products (1994)
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 195 (1994), S. 1493-1502 
    Details
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The reactions of sodium hydroxymethanesulfinate (sodium formaldehyde sulfoxylate, SFS) with various monomers, including acrylates, methacrylates, styrene and vinyl acetate, were studied. The reaction products formed depended on the molecular structure of the monomers and acidity of the reaction solution. Among the monomers studied, acrylates with resonance stability values Q between 0,38 and 0,45 produced diacrylate sulfones in neutral conditions. The other monomers or reaction conditions did not result in a dimer. The obtained diacrylate sulfones were characterized by elemental analysis, mass spectrometry, IR spectra, normal 1H and 13C NMR, CHn (n = 1, 2 and 3) subspectra by Distortionless Enchancement by Polarization Transfer at θ = 3π/4, as well as by 1H- 13C 2D-NMR spectra using Correlated Spectroscopy and Heteronuclear Multiple Bonding Correlation methods. A possible reaction mechanism for the formation of dimers is suggested. The morphology and thermal properties of these diacrylate sulfones were determined.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1994.021950504
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