Structure modification of isotactic polypropylene through chemical crosslinking: Toughening mechanism
Autor: | F. J. Baltá Calleja, M. E. Cagiao, Djafer Benachour, S. Bouhelal |
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Rok vydání: | 2006 |
Předmět: |
chemistry.chemical_classification
Organic peroxide Crosslinking Materials science Polymers and Plastics technology industry and agriculture Concentration effect Izod impact strength test macromolecular substances Reactive blending General Chemistry Polymer Surfaces Coatings and Films Interpenetrating networks chemistry.chemical_compound Crystallinity Differential scanning calorimetry chemistry Tacticity Materials Chemistry Ductile–brittle transition Lamellar structure Composite material |
Zdroj: | Digital.CSIC. Repositorio Institucional del CSIC instname |
ISSN: | 1097-4628 0021-8995 |
DOI: | 10.1002/app.25406 |
Popis: | Reversibly crosslinked isotactic polypropylene (iPP) was prepared in the presence of dicumyl peroxide. The effects of the peroxide oxy-radicals in the melt were investigated in relation to the modification of the polymer. The dynamic rheology analysis of the crosslinking process was carried out by using a plastograph. The crosslinking reaction was evaluated by the Monsanto method. The resulting structure of the modified samples was studied by means of differential scanning calorimetry (DSC), wide-angle X-ray scattering (WAXS), microhardness, and mechanical properties. The degree of crystallinity of the modified iPP, derived from DSC and WAXS, remains almost unchanged, i.e., the crystalline structure is unaffected, though the lamellar thickness slightly decreases. The impact strength of the crosslinked iPP is greatly improved with reference to that of the unmodified material. A transition from brittle to ductile behavior appears in the modified iPP for all the crosslinking agents studied. |
Databáze: | OpenAIRE |
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