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Effect of Spacer Stiffness on the Properties of Hyperbranched Polymers

Perala, Suresh Kumar and Ramakrishnan, S (2017) Effect of Spacer Stiffness on the Properties of Hyperbranched Polymers. In: MACROMOLECULES, 50 (21). pp. 8536-8543.

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Official URL: http://dx.doi.org/10.1021/acs.macromol.7b01401

Abstract

A series of peripherally clickable hyperbranched polyesters were prepared wherein the stiffness of the spacer segment between branching junctions was systematically varied. Three different four-carbon spacers were studied: one was fully saturated (HBPC4-S), another bears a double bond (HBPC4-DBc), and a third carries a triple bond (HBPC4-TB); in the case of the sample with a double bond c indicates cis-rich isomer. The glass transition temperatures of the HB polyesters were seen to increase with the stiffness of the spacer segment from 27 to 60 degrees C. Furthermore, when the peripheral propargyl groups of the HB polyesters were quantitatively clicked with a crystallizable docosyl (C-22) azide, all the derivatives exhibited sharp melting/crystallization peaks in the DSC traces, indicative of segregation and colocalization of the peripheral segments. WAXS data confirmed the crystallization of the alkyl segments in a paraffinic lattice, while SAXS profiles revealed the formation of a lamellar morphology; the interlamellar spacing reflected the compactness of the HB polymeric core and also the adaptability of the core toward the self-segregation. Whereas the effect of such structural variations in linear polyesters has been examined extensively, this represents the first study that reveals the implications chain stiffness and geometry on the properties of hyperbranched polymers.

Item Type: Journal Article
Additional Information: Copy right for this article belongs to the AMER CHEMICAL SOC, 1155 16TH ST, NW, WASHINGTON, DC 20036 USA
Department/Centre: Division of Physical & Mathematical Sciences > Instrumentation Appiled Physics
Depositing User: Id for Latest eprints
Date Deposited: 26 Dec 2017 05:58
Last Modified: 26 Dec 2017 05:58
URI: http://eprints.iisc.ac.in/id/eprint/58435

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