Elastomeric Polypropylenes from Unbridged (2-Phenylindene)zirconocene Catalysts: Thermal Characterization and Mechanical Properties
| Autor: | Mark T. Krejchi, Yirong Hu, Charles L. Myers, Chirag D. Shah, Robert M. Waymouth |
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| Rok vydání: | 1998 |
| Předmět: |
Polypropylene
Heptane Materials science Polymers and Plastics Organic Chemistry Enthalpy Nuclear magnetic resonance spectroscopy Inorganic Chemistry chemistry.chemical_compound Crystallinity Differential scanning calorimetry chemistry Tacticity Polymer chemistry Materials Chemistry Physical chemistry Thermal analysis |
| Zdroj: | Macromolecules. 31:6908-6916 |
| ISSN: | 1520-5835 0024-9297 |
| DOI: | 10.1021/ma9803990 |
| Popis: | The properties of three elastomeric stereoblock polypropylene (PP) samples made with unbridged 2-phenylindene zirconocene catalysts were investigated. One of the characteristics of these catalysts is the ability to control the structure and properties of the polypropylenes by manipulation of the reaction conditions. Samples PP1 and PP2 were prepared to have similar tacticities (as indicated by IR and NMR spectroscopy) yet different molecular weights. The molecular weight of PP2 is approximately half the molecular weight of PP1. Sample PP3 has a molecular weight similar that of PP2 but is lower in isotactic pentad content. All three samples were separated into fractions that differ in their solubilities in boiling ether and heptane. The fractionation appeared to be governed by tacticity and molecular weight. Thermal analysis by differential scanning calorimetry showed very broad melting endotherms. The broadness of the transitions and the relatively large standard deviations calculated for the enthalpy of ... |
| Databáze: | OpenAIRE |
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