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  • 1
    Electronic Resource
    Electronic Resource
    Photopolymerization of methyl methacrylate with the use of bromine as photoinitiator (1973)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 11 (1973), S. 2021-2030 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Low concentrations of bromine (0.008-0.06M) were used to initiate photopolymerization of MMA in bulk and in diluted (near bulk) systems, the diluents or solvents used being benzene, toluene, dioxane, tetrahydrofuran, carbon tetrachloride, chloroform, methylene chloride, and methanol. Polymerization in bulk follows usual free-radical kinetics. Inert solvents (benzene, toluene) as well as the other solvents used enhance the rate of polymerization MMA even when used in the range of catalytic concentrations (0.04-0.4M). An initiation mechanism involving solvent molecules appears to be predominant in diluted systems.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1973.170110821
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  • 2
    Electronic Resource
    Electronic Resource
    Photopolymerization of methyl methacrylate with the use of tetrahydrofuran-bromine charge-transfer complex as the photoinitiator (1977)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 15 (1977), S. 203-218 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The polymerization of MMA was kinetically studied in the presence of visible light (using a 125-W high-pressure mercury vapor lamp with fluorescent coating, without a filter), a THF - bromine charge-transfer complex being used as the photoinitiator. The initiator exponent was 0.5 in bulk polymerization. The monomer exponent varied from about 1.2 to about 2.5, depending on the nature of the solvent used; the initiator exponent also varied in diluted systems, depending on the nature and proportion of the solvent, the variation being from a value of 0.5 in bulk system to zero or almost zero at about 25% (v/v) solvent concentration. Other kinetic parameters, viz., kp2/kt and the activation energy for polymerization, were determined and are reported. Kinetic and other evidence indicates that the photopolymerization takes place by a radical mechanism and termination is bimolecular in nature in bulk systems; in dilute systems, termination by initiator complex assumes predominance, particularly at high solvent concentrations (≥25% v/v).
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1977.170150119
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  • 3
    Electronic Resource
    Electronic Resource
    Photopolymerization of methyl methacrylate with the use of iodine as the photoinitiator (1974)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 12 (1974), S. 375-386 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Kinetics of photopolymerization of MMA at 40°C with the use of iodine as the photoinitiator was studied. At low range of iodine concentration (〈 0.0004M), the rate of polymerization was proportional to square root of iodine concentration and the monomer exponent was 2.5, while at a higher range of iodine concentration, (0.0005-0.002M) the initiator exponent and monomer exponent were zero and 3.6-3.8 (i.e., close to 4), respectively. The chain-transfer constant of iodine at 40°C was found to be 6.0. Polymerization was found to be largely inhibited in the presence of relatively high concentrations of iodine (〉 0.005M) and also in presence of hydroquinone. Kinetic and other data indicate a radical mechanism of polymerization involving complexation of monomer molecules with iodine prior to radical generation, and termination is believed to take place bimolecularly at low iodine concentrations and unimolecularly, involving reaction with iodine, at high iodine concentrations (initiator termination).
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1974.170120210
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  • 4
    Electronic Resource
    Electronic Resource
    Polymerization of methyl methacrylate using isatoic anhydride-bromine donor-acceptor complex as the photoinitiator (1993)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 31 (1993), S. 1007-1012 
    Details
    ISSN: 0887-624X
    Keywords: photopolymerization ; isatoic anhydride-Br2 ; kinetics ; free-radical ; nonideal ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Isatoic anhydride (IA) alone did not initiate photopolymerization of methyl metacrylate (MMA) at 40°C when exposed to visible light for about 180 min. But IA, when used in combination with bromine (Br2) as the initiator, initiated the photopolymerization of MMA readily under the same conditions. This behavior was explained by the formation of a donor-acceptor type of complex between IA and Br2 in the presence of MMA. The polymerization was found to proceed via a free radical mechanism and the radical generation process was considered to follow an initial complexation reaction between the initiator components and monomer. The complex initiator showed nonideal kinetics for the present system (initiator exponent 〈 0.5) and was analyzed. The monomer exponents varied from 0.83 to 1.15 normally depending on the nature of solvent used. Initiator-dependent chain termination was significant as well as the bimolecular mode of chain termination. © 1993 John Wiley & Sons, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1993.080310422
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  • 5
    Electronic Resource
    Electronic Resource
    Role of solvent in the compatibility of a vinylchloride-vinylacetate-maleic acid terpolymer and nitrocellulose blends (1991)
    New York, NY : Wiley-Blackwell
    Polymers for Advanced Technologies 2 (1991), S. 191-196 
    Details
    ISSN: 1042-7147
    Keywords: Solution blending ; phase morphology ; Polymer-polymer interaction ; Donor number of solvents ; Taft-β value of solvents ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The compatibility of cast films of a vinylchloride-vinylacetate-maleic acid terpolymer (VMCH) and nitrocellulose (NC) blends is influenced by solvents. Transparent films of VMCH/NC blends are obtained when cast from solvents such as tetrahydrofuran or cyclohexanone, whereas hazy films are obtained when cast from solvents such as acetone or ethylacetate. Visible spectroscopy and phase morphology were used to analyse the compatibility-incompatibility of the blend. Differential scanning calorimetry (DSC) studies demonstrate that the transparent film is compatible, but the hazy film is incompatible. Fourier transform infra-red (FTIR) studies establish that a greater interaction is observed between the polymer pair in case of the compatible blend than in the case of the incompatible blend.A solvent dependency of blend compatibility is reflected in this study. The conformational state of the polymers in solution, which is responsible for the compatibility phenomena, may depend on the donor number and/or Taft-β value of the solvent. The greater the donor number and/or the Taft-β value, the higher may be the level of interaction between the solvent and the polymer molecules, which in turn may give a compatible blend after removal of the solvent.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pat.1991.220020404
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  • 6
    Electronic Resource
    Electronic Resource
    Mechanical behavior and tensile fractography of compatible vinylchloride-vinylacetate-maleic acid terpolymer and nitrocellulose blends (1993)
    New York, NY : Wiley-Blackwell
    Polymers for Advanced Technologies 4 (1993), S. 502-508 
    Details
    ISSN: 1042-7147
    Keywords: Solution blending ; Modulus ; Brittle and ductile failure ; tensile fractography ; craze formation ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Vinylchloride-vinylacetate-maleic acid terpolymer (VMCH) and nitrocellulose (NC) were blended at 10% (W/V) concentration is cyclohexanone at different weight fractions. Compatible blends were obtained at all weight fractions. This paper reports the mechanical behavior of solvent cast blend films of VMCH and NC. The films were prepared by solution blending and subsequent casting on a mercury surface. Depending on the composition, the tensile behavior ranged from brittle to ductile. The effect of the blend ratio on the properties shows that within the Hookeian region the modulus and strength have a positive deviation from linearity, whereas the elongation has a negative deviation. The effect of the blend ratio on the ultimate properties of the materials shows a positive deviation in strength up to 63 wt% VMCH composition and a negative deviation in elongation and toughness. The tensile fractography of the pure VMCH and VMCH/NC blends shows the presence of peaks, foldings of fibrils along with cavities or voids, which indicate a ductile mode of failure with craze-initiated fracture. Fractography of the pure NC Indicates a brittle mode of failure wit h craze-initiated fracturing.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pat.1993.220040804
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  • 7
    Electronic Resource
    Electronic Resource
    Flexural behavior of unidirectional polyethylene-glass fiber-PMMA hybrid composites (1995)
    New York, NY : Wiley-Blackwell
    Polymers for Advanced Technologies 6 (1995), S. 637-642 
    Details
    ISSN: 1042-7147
    Keywords: hybrid composite ; poly(methyl methacrylate) ; flexural behavior ; interlaminar shear strength ; mode of failure ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Unidirectional hybrid laminates based on glass fibers (GF) and high performance polyethylene fibers (PEF) were prepared with a partially polymerized methyl methacrylate (MMA) matrix at room temperature followed by heating at 55°C for the stipulated time (well below the softening point of PEF). The ultimate flexural strength (UFS), flexural modulus (FM) and interlaminar shear strength (ILSS) of the composites were determined and analyzed. An interesting observation of the study was the change in flexural behavior, which was largely dependent on the position of GF and PEF ply/plies in the compression and tension sides. When the ply/plies of PEF were at the tension side, the UFS and FM showed a higher value than that when GF plies were in the tension side of the hybrid composites. The ILSS also follows the same trend regarding the position of the GF and PEF plies.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pat.1995.220061001
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  • 8
    Electronic Resource
    Electronic Resource
    Photograft copolymerization of methyl methacrylate on viscose fiber using titanium(III) chloride-potassium persulfate redox initiator in a limited aqueous system (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 46 (1992), S. 1879-1885 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    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 graft copolymerization of methyl methacrylate (MMA) onto viscose fibers were studied under photoactive conditions with visible light using titanium(III) chloride - potassium persulfate as redox initiator in a limited aqueous system. Polymerization carried out in the dark at 40 ± 1°C produced little graft copolymer whereas that in the presence of light at 40 ± 1°C produced significant grafting. Percent grafting, percent total conversion, and grafting efficiency (%) were studied by varying time, initiator concentration, monomer concentration, solvent composition, and pH of the medium. High percent grafting (∼ 200%), high grafting efficiency (∼ 98%), and percent total conversion (∼ 47%) were obtained with little homopolymer formation. A suitable mechanism for grafting has been discussed and also the characterization of the grafted fibers were studied by Fourier transform infrared (FTIR) spectroscopy, thermogravimetry and scanning electron microscopy (SEM). © 1992 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1992.070461101
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  • 9
    Electronic Resource
    Electronic Resource
    Dynamic mechanical study on unidirectional polyethylene fibers-PMMA and glass fibers-PMMA composite laminates (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 60 (1996), S. 657-662 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    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: Unidirectional (UD) composite laminates based on glass fibers (GF) and high-performance polyethylene fibers (PEF) were prepared with partially polymerized methyl methacrylate (MMA) at room temperature and then heated at 55°C (well below the softening point of PEF) for 2 hrs. The viscoelastic behavior of the composite was studied through dynamic mechanical analysis at different volume fractions of fibers. Several parameters such as storage modulus (E′), loss modulus (E″), and loss factor or damping efficiency (tan ∂) were determined to be between 40 and 160°C in a resonant frequency mode. All the properties were compared between the two composite laminates. It was found that the shift of the glass transition temperature (Tg) due to incorporating fibers was higher in the case of a PEF-reinforced composite than that of a GF-reinforced composite at the same volume fraction of fibers. It was also observed that the efficiency of both the composites decreases with the increase in the volume fraction of fibers. © 1996 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
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  • 10
    Electronic Resource
    Electronic Resource
    Impact behavior of unidirectional polyethylene-glass fibers: PMMA hybrid composite laminates (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 62 (1996), S. 1193-1197 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    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: Unidirectional (UD) hybrid laminates based on glass fibers (GF) and high performance polyethylene fibers (PEF) were prepared with partially polymerized methyl methacrylate (MMA) at room temperature followed by heating at 55°C (well below the softening point of PEF) for 2 h. Izod impact strength of the composites was then measured. An interesting observation of the study was the change in impact strength that was largely dependent on the position of GF and PEF ply/plies present within the hybrid laminates. When the ply/plies of PEF were at the impacted surface, the impact strength showed a higher value than that of the case when GF ply/plies were at the impacted surface of the hybrid laminates. © 1996 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
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