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Title: Preparation and Characterization of H-Shaped Polylactide
An H-polymer has an architecture that consists of four branches symmetrically attached to the ends of a polymer backbone, similar in shape to the letter “H”. Here, a renewable H-polymer efficiently synthesized using only ring-opening transesterification is demonstrated. The strategy relies on a tetrafunctional poly(±-lactide) macroinitiator, from which four poly(±-lactide) branches are grown simultaneously. 1H NMR spectroscopy, size exclusion chromatography (SEC), and matrix-assisted laser desorption/ionization (MALDI) spectrometry were used to verify the macroinitiator purity. Branch growth was probed using 1H NMR spectroscopy and SEC to reveal unique transesterification phenomena that can be controlled to yield architecturally pure or more complex materials. H-shaped PLA was prepared at the multigram scale with a weight-average molar mass Mw > 100 kg/mol and low dispersity Đ < 1.15. Purification involved routine precipitations steps, which yielded products that were architecturally relatively pure (∼93%). Small-amplitude oscillatory shear and extensional rheology measurements demonstrate the unique viscoelastic behavior associated with the H-shaped architecture.  more » « less
Award ID(s):
1901635
PAR ID:
10517560
Author(s) / Creator(s):
; ; ; ;
Publisher / Repository:
ACS Publications
Date Published:
Journal Name:
ACS Macro Letters
Volume:
13
Issue:
6
ISSN:
2161-1653
Page Range / eLocation ID:
695 to 702
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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