1. The Use of Solid-State NMR to Investigate the Development of Segmental Mobility in Commercial Heterophasic Ethylene Propylene Copolymers (HEPCs).
- Author
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Botha, Linda, Sinha, Pritish, Duveskog, H., and Van Reenen, Albert J.
- Subjects
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ETHYLENE , *COPOLYMERS , *NUCLEAR magnetic resonance , *GAS phase reactions , *POLYPROPYLENE - Abstract
The effect increasing ethylene incorporation on the development of commercial heterophasic ethylene propylene copolymers (HEPCs) was previously evaluated in terms of particle morphology, chemical composition, crystallinity, and microstructure. These polymers were obtained from a commercial gas-phase process and enabled the visualization of the early development of the copolymer phase while including the effects of large-scale production processes on the resulting polymer properties. Based on the ethylene-dependent changes observed for the HEPCs as well as some semi-crystalline TREF fractions, further variable temperature solid-state 13C NMR experiments were done to observe temperature-dependent shifts in localised mobility within the bulk samples during a heating/melting profile. From these experiments, the development of amorphous polypropylene signals was observed with increasing temperature, which could indirectly be related to the introduction of ethylene defects. It was also observed that polypropylene components with high rigidity remained at high temperatures for the HEPCs but not for the homopolymer. T1ρ experiments were used to differentiate between changes in crystalline and non-crystalline phases based on ethylene incorporation as well as during melting. In this publication, the observations from the perspective of the solid-state analyses are outlined and placed in the context of the evolution of microscopic, chemical, microstructural, and mechanical properties. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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