Synthesis of epoxidized poly(ester carbonate)-b-polyimide-b-poly(ester carbonate): reactive single-walled carbon nanotube dispersants enable synergistic reinforcement around multi-walled nanotube-grafted carbon fibers

File Description SizeFormat 
Manuscript_ submitted_v2.pdfFile embargoed until 17 January 20201.97 MBAdobe PDF    Request a copy
Supporting_information_submitted_v2.pdfFile embargoed until 17 January 2020943.94 kBAdobe PDF    Request a copy
Title: Synthesis of epoxidized poly(ester carbonate)-b-polyimide-b-poly(ester carbonate): reactive single-walled carbon nanotube dispersants enable synergistic reinforcement around multi-walled nanotube-grafted carbon fibers
Authors: Liu, B
Liu, C
De Luca, H
Raman Pillai, SK
Anthony, DB
Li, J
Bismarck, A
Shaffer, M
Chan-Park, MB
Item Type: Journal Article
Abstract: Polyimides (PI) generally have a high affinity for single-walled carbon nanotubes (SWNTs), but they suffer from poor solubility in most low boiling point organic solvents and low compatibility with common resins (such as epoxy) used in composites, limiting their suitability as dispersants. PI block copolymer systems containing reactive poly(ester carbonate)s have not yet been reported and are expected to act as effective reactive dispersing agents of SWNTs. Herein, PI-derived block copolymers are synthesized via ring-opening copolymerization of lactide (LA) (a control monomer) and allyl-bearing 2-methyl-2-(allyloxycarbonyl)-propylene carbonate (MAC) from the OH-terminal ends of the PI block to produce PLA-PI-PLA (TB1, a control) and PMAC-PI-PMAC (TB2). The allyl pendant group of TB2 allows further facile functionalization to form a third series of epoxidized (EP) derivatives, i.e. PMACEP-block-PI-block-PMACEP (TB3). TB3 copolymer when mixed with a conventional structural epoxy resin forms blends that do not show inferior tensile properties compared with the epoxy, which is unusual. Furthermore, the mixing solvent tetrahydrofuran (THF) can be readily evaporated off after forming the blends. TB3-dispersed (2 wt%) SWNTs added to epoxy increased the tensile strength, modulus, and elongation at break of the resulting nanocomposite films by 40%, 34%, and 26% respectively, compared to the baseline epoxy resin. Furthermore, when TB3b triblock-dispersed SWNTs in epoxy were combined with fuzzy carbon fibers, i.e. carbon nanotube-grafted-carbon fibers (CNT-g-CF), a synergistic interfacial strength reinforcement was observed, together with shifting of the failure mode from the matrix interphase to the carbon fiber-grafted nanotube interface. The ultimate interfacial shear strength between the TB3-dispersed SWNT-epoxy matrix and the fuzzy carbon fibers (i.e., fibers having carbon nanotubes grown on them) measured via single fiber pull-out tests was 100 MPa, which was ca. 11% improvement over the baseline unsized carbon fiber in neat epoxy. To our knowledge, this is the first evidence of a synergistic enhancement in interfacial properties when fuzzy carbon fibers are combined with a SWNT-reinforced epoxy using the new epoxidized TB3 nanotube dispersing agent that forms a strong covalent TB3–epoxy interface. The new functionalizable TB3 synthesis route introduced here is generalizable to other PI-based copolymers with diverse functionalities and solvent compatibilities.
Issue Date: 17-Jan-2019
Date of Acceptance: 11-Jan-2019
URI: http://hdl.handle.net/10044/1/67118
DOI: https://dx.doi.org/10.1039/c8py01465e
ISSN: 1759-9954
Publisher: Royal Society of Chemistry (RSC)
Journal / Book Title: Polymer Chemistry
Copyright Statement: © The Royal Society of Chemistry 2019
Keywords: 0303 Macromolecular And Materials Chemistry
Publication Status: Published online
Embargo Date: 2020-01-17
Online Publication Date: 2019-01-17
Appears in Collections:Faculty of Engineering
Chemistry
Faculty of Natural Sciences



Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.

Creative Commonsx