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Anomalous structural relaxations in PVDF rich blends with PMMA in the presence of surface functionalized CNTs

Sharma, Maya and Madras, Giridhar and Bose, Suryasarathi (2014) Anomalous structural relaxations in PVDF rich blends with PMMA in the presence of surface functionalized CNTs. In: PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 16 (42). pp. 23421-23430.

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Official URL: http://dx.doi.org/ 10.1039/c4cp03020f

Abstract

The structural relaxations in PVDF rich blends with PMMA can be quite interesting in understanding the origin of the different molecular relaxations associated with the crystalline and amorphous phases, crystal-amorphous interphase and the segmental motions. In light of our recent findings, we understood that the origin of these molecular relaxations were strongly contingent on the concentration of PMMA in the blend, crystalline morphology and the surface functional moieties on multiwall carbon nanotubes (CNTs). In addition, for the blends with concentration of PMMA >= 25 wt%, the structural relaxations often merge and are dielectrically indistinguishable. In this study, we attempted to determine the critical width in composition where the structural relaxations can be distinctly realized both in the control as well as blends with amine functionalized CNTs (NH2-CNTs). Intriguingly, we observed that in a narrow zone in composition (with PMMA concentration >= 10 wt% and <= 25 wt%), the molecular relaxations can be dielectrically distinguished and they often merge for all other compositions. Furthermore, we attempted to understand how this critical width in composition is related to the crystalline morphology using small angle X-ray scattering and polarizing optical microscopy and the crystal structure using FTIR and Raman spectroscopy. We now understand that although the formation of beta crystals in the blends has no direct correlation with the observed molecular relaxations, the amorphous miscibility and the interphase regions seem to be dictating the origin of different molecular relaxations in the blends. The latter was observed to be strongly contingent on the concentration of PMMA in the blends.

Item Type: Journal Article
Additional Information: Copy right for this article belongs to the ROYAL SOC CHEMISTRY, THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND
Department/Centre: Division of Mechanical Sciences > Chemical Engineering
Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Division of Interdisciplinary Research > Centre for Nano Science and Engineering
Depositing User: Id for Latest eprints
Date Deposited: 04 Dec 2014 04:46
Last Modified: 04 Dec 2014 04:46
URI: http://eprints.iisc.ac.in/id/eprint/50355

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