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  • 1
    Electronic Resource
    Electronic Resource
    Factors affecting the nascent structure and morphology of polyethylene obtained by heterogeneous ziegler-natta catalyst - III. Crystal morphology and growth mechanism
    Amsterdam : Elsevier
    Journal of Crystal Growth 48 (1980), S. 250-258 
    Details
    ISSN: 0022-0248
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0022-0248(80)90214-6
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  • 2
    Electronic Resource
    Electronic Resource
    Kristallstruktur und Morphologie von Polymeren aus Reaktionen im Festzustand (1977)
    Springer
    Colloid & polymer science 255 (1977), S. 824-824 
    Details
    ISSN: 1435-1536
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01664565
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  • 3
    Electronic Resource
    Electronic Resource
    Lösungspolymerisation von 1,3,5-Trioxan und 1,3,5,7-Tetroxocan. 2. Mitt. Morphologie der so erhaltenen Polyoxymethylen-Kristalle (1978)
    Springer
    Colloid & polymer science 256 (1978), S. 305-305 
    Details
    ISSN: 1435-1536
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01550720
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  • 4
    Electronic Resource
    Electronic Resource
    Fracture morphology and mechanical properties of thermocatalytically polymerized MMA-impregnated mortar (1978)
    Springer
    Journal of materials science 13 (1978), S. 301-310 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Mortar mixes with different water-cement ratios and consistency were impregnated with methyl-methacrylate monomer and polymerized thermally under water using the free radical initiatorα, α′-azobis (isobutyronitrile). Results on drying, impregnation and polymerization are presented. It is shown that a considerable amount of polymer remained strongly adhered or chemically inserted in the inorganic matrix. The molecular weight of the inserted polymer is higher than that obtained in the solvent extracted polymer and this is also higher than the polymer molecular weight obtained by bulk polymerization under the same conditions. The compressive and flexural strength of the impregnated mortar were found to be a function of the amount of polymer in the composites. Fracture behaviour under load, and polymer distribution inside the composites were examined by scanning electron microscopic techniques (SEM). It was observed that the polymer acts in two ways, first as a filler of porous and microcrack voids, secondly forming an anisotropic irregular network improving the bond characteristic of the interface between aggregate and matrix. Furthermore, due to the the adhesion of the polymer to both phases, it acts as a reinforcement and improves the mechanical properties, in particular the flexural strength.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00647774
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  • 5
    Electronic Resource
    Electronic Resource
    Degradation and stabilization of high molecular weight polyethylene in solution (1987)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 25 (1987), S. 2469-2477 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The changes in the molar mass of high molecular weight polyethylene, in o-dichlorobenzene, with time are examined using viscometry. The results show that the molar mass decreases with time and that the observed decay can be satisfactorily explained by a simple degradation model. Commercial antioxidants can inhibit the degradation process if the appropriate concentration is chosen. Thus, at very low concentrations a polynuclear phenol shows good antioxidant behavior but this decreases with an increase in concentration due to direct oxidation of the inhibitor. Conversely, zinc dimethyldithiocarbamate shows the best stabilizing activity which increases with concentration. The results are explained on the basis of the established mechanistic action of these compounds and show that viscometry is not an accurate method for measuring the molar mass of high molecular weight polyethylene samples unless the appropriate conditions are chosen. Even with the best inhibitor, some degradation is still observed.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1987.080250912
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  • 6
    Electronic Resource
    Electronic Resource
    A theoretical study of the comonomer effect in the ethylene polymerization with zirconocene catalytic systems (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 1157-1167 
    Details
    ISSN: 0887-624X
    Keywords: zirconocene catalysts ; ethylene ; 1-hexene ; copolymerization ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The PM3(tm) semiempirical method has been used to optimize the structures for the reactants and transition states of the first and second ethylene insertion processes into zirconocene catalytic systems. The results obtained for these reactions are compared with calculations published in the literature performed at different ab-initio theoretical levels. The agreement between our calculations and those reported in the literature is satisfactory. Taking advantage of the reduced computational effort required in semiempirical calculations two additional processes related with the so-called comonomer effect were also studied: ethylene/1-hexene copolymerization, and chain termination reaction, both in the homopolymerization and in copolymerization of ethylene with 1-hexene comonomer. The calculated activation energies support some experimental findings such as the higher polymerization activities in the presence of comonomers and also the molecular weight reduction of the copolymers due to the more favorable β-elimination reactions. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1157-1167, 1998
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    The role of coupling agents on the mechanical properties of polymer-impregnated mortars (1982)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 27 (1982), S. 2151-2165 
    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: An investigation has been carried out for determining the effect of coupling agents on the mechanical properties of polymer-impregnated mortars. Mortar specimens were impregnated with methyl methacrylate (MMA) monomer and α, α-azobis-isobutyronitrile initiator, and polymerized thermally in water. Three titanate coupling agents, KR-33CS, KR-55, and KR-138s, and one silane coupling agent, the A-174, were used for the investigation. Varying amounts of coupling agent were used in impregnating the mortars in situ or in pretreating the mortars with a solvent system. Bulk polymerization of MMA shows no appreciable influence of the coupling agents in the reaction kinetics; however, with the exception of KR-138S, all polymers obtained in the presence of coupling agents came out as insolble. Similar results were obtained for polymers extracted with acetone from mortars. The mechanical property results show an improvement of properties in mortars containing 5.0 vol% of KR-33CS and A-174 after impregnation in situ. A slightly better improvements of mechanical properties were obtained by pretreating the mortar specimens with acetone or toluene/xylene containing coupling agents. Microscopic observation of the fracture surface showed no noticeable difference in the surfaces prepared with and without coupling agents.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1982.070270626
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  • 8
    Electronic Resource
    Electronic Resource
    A study of wood-plastic combinations based on low-density woods (1976)
    Springer
    Journal of materials science 11 (1976), S. 1711-1724 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Six low-density tropical woods were impregnated with various vinyl monomers and polymerized by irradiation with a60Co source. The wood-plastic combinations were subjected to standard tests of mechanical properties, and their fracture surfaces were studied by scanning electron microscopy. It was found that, even though most mechanical properties are enchanced by addition of plastics, the properties of wood-plastic combinations fall below those of high-density natural woods on a per unit weight basis. The direct observation of fracture surfaces gave indications of non-uniform penetration of the plastic and little bonding between the polymer and cellulose fibres. Although the wood-plastic combinations produced by the present methods may not be recommendable for applications where increased strength is desired on the basis of cost/ quality considerations, they may be suitable for uses where increased abrasion resistance, dimensional stability and lower anisotropy of compressional properties are primary considerations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00737527
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  • 9
    Electronic Resource
    Electronic Resource
    Lösungspolymerisation von 1,3,5-Trioxan und 1,3,5,7-Tetroxocan. 1. Mitt. Polymerisationsgeschwindigkeit, Charakterisierung und Schmelzverhalten des so erhaltenen Polyoxymethylens (1978)
    Springer
    Colloid & polymer science 256 (1978), S. 305-305 
    Details
    ISSN: 1435-1536
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01550719
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  • 10
    Electronic Resource
    Electronic Resource
    Synthese von Übergangsmetalle enthaltendem Polystyrol (1978)
    Springer
    Colloid & polymer science 256 (1978), S. 723-723 
    Details
    ISSN: 1435-1536
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01784562
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