Fracture of model polyurethane elastomeric networks
| Autor: | Paul A. M. Steeman, Alba Marcellan, Antonella Cristiano, Bert J. Keestra, Costantino Creton |
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| Rok vydání: | 2010 |
| Předmět: |
Toughness
Materials science Polymers and Plastics Fracture mechanics 02 engineering and technology Strain rate 010402 general chemistry 021001 nanoscience & nanotechnology Condensed Matter Physics Elastomer 01 natural sciences Viscoelasticity 0104 chemical sciences chemistry.chemical_compound Fracture toughness Polypropylene glycol Natural rubber chemistry visual_art Materials Chemistry visual_art.visual_art_medium Physical and Theoretical Chemistry Composite material 0210 nano-technology |
| Zdroj: | Journal of Polymer Science Part B: Polymer Physics. 49:355-367 |
| ISSN: | 0887-6266 |
| Popis: | Fracture properties of model elastomeric networks of polyurethane have been investigated with a double-edge notch geometry. The networks were synthesized from monodisperse end-functionalized polypropylene glycol precursors and a trifunctional isocyanate. All reagents were carefully purified and nearly defect-free ideal networks were prepared at a stoichiometry very close to the theoretical one. Three networks were prepared: an unentangled network of short chains (Mn = 4 kg mol−1), an entangled network of longer chains (Mn = 8 kg mol−1) and a bimodal network with 8 kg mol−1 and 1 kg mol−1 chains. The presence of entanglements was found to increase significantly the toughness of the rubber, in particular at room temperature, relative to the bimodal networks and to the short chains network. Fracture experiments were carried out at different strain rates and temperatures and showed for all three networks a marked decrease in fracture toughness with increasing temperature and decreasing strain rate which mirrored reasonably well the rate and temperature dependence of tan δ, the dissipative factor. However the proportionality factor between tan δ, and GIC was very material dependent and the shift factors obtained for the master curves of the viscoelastic properties could not be used to build fracture energy master curves. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2010 |
| Databáze: | OpenAIRE |
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