Effect of chain extender length and molecular architecture on phase separation and rheological properties of ether-based polyurethanes

Pourmohammadi‐Mahunaki, Mohammadali; Haddadi‐Asl, Vahid; Roghani‐Mamaqani, Hossein; Koosha, Mojtaba; Yazdi, M. H.

doi:10.1007/s00289-021-03907-3

Cited by 12 publications

(5 citation statements)

References 38 publications

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“…From the stress–strain curves of PUU x elastomers, with an increase in the hard segment content, the tensile strength of PUU x increased, while the elongation at break correspondingly decreased (Figure S3), which was mainly due to the formation of more urea–carbamic ester bonds and strong intermolecular hydrogen bonds. As a result, the chain segment movement was restrained, and the T g and tensile strength of PUU x increased. , Comparatively, PUU 0.5 had superior mechanical properties, and the tensile strength and elongation at break reached 16.28 MPa and 660%, respectively. Therefore, PUU 0.5 was selected as the substrate for the preparation of the flexible strain sensor in this work.…”

Section: Resultsmentioning

confidence: 96%

Self-Healing and Degradable Polycaprolactone-Based Polyurethane Elastomer for Flexible Stretchable Strain Sensors

Yang,

Zhang,

Chen

et al. 2023

ACS Appl. Polym. Mater.

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With the rapid development of electronic skin, smart robots, etc., the past few years have witnessed explosive growth in the number of flexible sensors, and the resulting environmental contamination will be a great challenge. Herein, we propose a strategy to synthesize a polyurethane elastomer with good self-healing and controlled degradation properties for a flexible and stretchable strain sensor. First, polycaprolactone diol (PCL) and isophorone diisocyanate (IPDI) were used as monomers to synthesize the isocyanate-terminated prepolymer and further reacted with adipic dihydrazide (ADH) to obtain a polyurethane elastomer with hierarchical hydrogen bonds. By the prestretching method, a stretchable strain sensor was fabricated with carbon nanotubes as a conductive substance. The obtained elastomer exhibited high tensile strength (16.28 MPa), large stretchability (660%), superior crack tolerance, high self-healing efficiency (92.1%), and special controlled degradability (4 h in 0.5 mol/L NaOH solution). The sensor showed high sensitivity (GF = 111.4), fast response/recovery time (161/180 ms), and good repeatability (3000 stretching−releasing cycles) and was successfully applied for monitoring minute human movements. The strategy to prepare high-performance, self-healing and environmentally friendly elastomers in this work is of great significance for the sustainable development of flexible electronic devices.

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Section: Resultsmentioning

confidence: 96%

Self-Healing and Degradable Polycaprolactone-Based Polyurethane Elastomer for Flexible Stretchable Strain Sensors

Yang,

Zhang,

Chen

et al. 2023

ACS Appl. Polym. Mater.

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“…The presence of the rubbery plateau suggests that the materials are phase separated into domains and display similar behavior as thermoplastic elastomers. [49][50][51] Even though these materials displayed a substantial decrease in G' and G" as a result of losing structural rigidity, they continued to display rubbery plateaus even at temperatures significantly greater than their Tm. This indicates that a microphase separated domain structure is retained even above the Tm of the hard block, an evidence of self-assembly in the solid state.…”

Section: Rheology Measurementsmentioning

confidence: 99%

Synthesis and Self-assembly of Limonene Oxide - Lactide Block Copolymers

Dai

Valloppilly²,

Watuthanthrige

et al. 2023

Preprint

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The reaction of limonene oxide with a zirconium complex led to polymers with a molar mass up to 4.0 kDa, the largest limonene oxide homopolymer reported so far. Diblock, triblock, and tetrablock copolymers of limonene oxide and L-lactide were also prepared using a redox switchable catalyst based on the same zirconium complex; the obtained copolymers are the first-ever reported limonene oxide-lactide block copolymers. The solid-state self-assembly properties of the copolymers were characterized by small angle X-ray scattering and rheology measurements, giving a self-assembly domain radius of 11, 25, and 35 nm for the diblock, triblock, and tetrablock copolymers, respectively.

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“…[8,9] Modulation of the chemical structure and concentration of the isocyanate and chain extender provides further control over thermomechanical properties with chain extenders playing a crucial role in driving phase separation. [10,11] Chain extender symmetry, length, and composition directly correlate to phase separation behavior; critical parameters include rigidity, hydrogen bonding, and packing considerations. [10,[12][13][14][15] Conversely, flexible oligomeric polyols comprise the SS to impart flexibility, impact resistance, low temperature performance, and damping properties.…”

Section: Introductionmentioning

confidence: 99%

“…[10,11] Chain extender symmetry, length, and composition directly correlate to phase separation behavior; critical parameters include rigidity, hydrogen bonding, and packing considerations. [10,[12][13][14][15] Conversely, flexible oligomeric polyols comprise the SS to impart flexibility, impact resistance, low temperature performance, and damping properties. [16] Both of these domains are covalently bound through urethane linkages, enabling a unique combination of properties.…”

Section: Introductionmentioning

confidence: 99%

Nonisocyanate Polyurethane Segmented Copolymers from Bis‐Carbonylimidazolides

Sintas,

Bean,

Zhang

et al. 2024

Macromol. Rapid Commun.

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Bis‐carbonylimidazolide (BCI) functionalization enabled an efficient synthetic strategy to generate high molecular weight segmented non‐isocyanate polyurethanes (NIPUs). Melt phase polymerization of ED‐2003 Jeffamine®, 4,4′‐methylenebis(cyclohexylamine), and a BCI monomer that mimics a 1,4‐butanediol chain extender enabled polyether NIPUs that contain varying concentrations of hard segments ranging from 40 to 80 wt. %. Dynamic mechanical analysis and differential scanning calorimetry revealed thermal transitions for soft, hard, and mixed phases. Hard segment incorporations between 40 and 60 wt. % displayed up to three distinct phases pertaining to the poly(ethylene glycol) (PEG) soft segment Tg, melting transition, and hard segment Tg, while higher hard segment concentrations prohibited soft segment crystallization, presumably due to restricted molecular mobility from the hard segment. Atomic force microscopy (AFM) allowed for visualization and size determination of nanophase‐separated regimes, revealing a nanoscale rod‐like assembly of HS. Small‐angle x‐ray scattering confirmed nanophase separation within the NIPU, characterizing both nanoscale amorphous domains and varying degrees of crystallinity. These NIPUs, which were synthesized with BCI monomers, displayed expected phase separation that is comparable to isocyanate‐derived analogues. This work demonstrates nanophase separation in BCI‐derived NIPUs and the feasibility of this non‐isocyanate synthetic pathway for the preparation of segmented PU copolymers.This article is protected by copyright. All rights reserved

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Effect of chain extender length and molecular architecture on phase separation and rheological properties of ether-based polyurethanes

Cited by 12 publications

References 38 publications

Self-Healing and Degradable Polycaprolactone-Based Polyurethane Elastomer for Flexible Stretchable Strain Sensors

Self-Healing and Degradable Polycaprolactone-Based Polyurethane Elastomer for Flexible Stretchable Strain Sensors

Synthesis and Self-assembly of Limonene Oxide - Lactide Block Copolymers

Nonisocyanate Polyurethane Segmented Copolymers from Bis‐Carbonylimidazolides

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