Supramolecular Thermoplastic with 0.5 Pa·s Melt Viscosity

Agnaou, Réda; Capelot, Mathieu; Tencé‐Girault, Sylvie; Tournilhac, François; Leibler, Ludwik

doi:10.1021/ja505956z

Cited by 27 publications

(30 citation statements)

References 58 publications

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“…3 ) is consistent with a biphasic semi-crystalline polymer network, whereby heat-resistant nanocrystalline β-sheets embedded within an amorphous matrix exhibit viscous flow at temperatures below the melting or degradation point of the crystalline phase, with the flow resulting from chain re-arrangement in the amorphous regions. It is interesting to note that a class of supramolecular block co-polymers reminiscent of the natural design of suckerins, namely consisting of a stiff crystalline phase within a soft matrix, has recently been shown to exhibit excellent high-temperature processability 29 .…”

Section: Discussionmentioning

confidence: 99%

Multi-scale thermal stability of a hard thermoplastic protein-based material

et al. 2015

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Although thermoplastic materials are mostly derived from petro-chemicals, it would be highly desirable, from a sustainability perspective, to produce them instead from renewable biopolymers. Unfortunately, biopolymers exhibiting thermoplastic behaviour and which preserve their mechanical properties post processing are essentially non-existent. The robust sucker ring teeth (SRT) from squid and cuttlefish are one notable exception of thermoplastic biopolymers. Here we describe thermoplastic processing of squid SRT via hot extrusion of fibres, demonstrating the potential suitability of these materials for large-scale thermal forming. Using high-resolution in situ X-ray diffraction and vibrational spectroscopy, we elucidate the molecular and nanoscale features responsible for this behaviour and show that SRT consist of semi-crystalline polymers, whereby heat-resistant, nanocrystalline β-sheets embedded within an amorphous matrix are organized into a hexagonally packed nanofibrillar lattice. This study provides key insights for the molecular design of biomimetic protein- and peptide-based thermoplastic structural biopolymers with potential biomedical and 3D printing applications.

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Section: Discussionmentioning

confidence: 99%

Multi-scale thermal stability of a hard thermoplastic protein-based material

et al. 2015

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“…For example, when an appropriate stimulus is applied to a structurally dynamic polymer, the reversible bonds within the polymer architecture can be broken and reformed and/or undergo exchange. Such dynamic processes can result in a reorganization of the polymer structure and allows the material to exhibit properties, such as self‐healing, recyclability/reprocessability, and/or improved processability . Depending on the strength of the covalent bonds an external stimulus or catalyst is usually required to accelerate or initiate the dynamic character (reversible bond breakage/reformation) of the covalent bonds that are otherwise kinetically “fixed” due to their inherently slow kinetics.…”

Section: Introductionmentioning

confidence: 99%

Trapping Dynamic Disulfide Bonds in the Hard Segments of Thermoplastic Polyurethane Elastomers

Zhang

Chen

Rowan

2016

Macro Chemistry & Physics

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Dynamic covalent bonds placed within a polymer chain result in stimulus-responsive materials where the breaking/making and/or exchange of the dynamic bonds controls the response. A key attribute to access such properties is the molecular mobility of the dynamic bonds. The focus of this work is to understand how incorporating a dynamic bond, in the form of disulfide bonds, into the hard phase of a polyurethane will impact the properties of the materials. Thus, uncross-linked polyurethanes with aliphatic disulfide-containing hard segments are synthesized via a two-step protocol, using 2,2′-dithiodiethanol and/or 1,4-butanediol in the second step as the chain extenders. Thermomechanical studies show that, if the dynamic bonds are selectively placed in the hard phase of the polyurethane, the dynamic nature of the disulfide bond can be effectively "switched-off" below the melting temperature of the hard phase. As such the dynamic and mechanical properties of the materials can be controlled by tailoring the nature of the hard phase.

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“…It was envisaged that, in common with related healable structures [35,[59][60][61][62] the melting point of the crystalline regions may facilitate a dramatic reduction in tensile properties, [54] viscosity [63] and adhesion at temperatures above the melting point of the crystalline segments. [64,65]…”

Section: Scheme 1 Schematic Showing the Non-reversible Depolymerisatmentioning

confidence: 99%

Fluoride-responsive debond on demand adhesives: Manipulating polymer crystallinity and hydrogen bonding to optimise adhesion strength at low bonding temperatures

Babra

Wood

Godleman

et al. 2019

European Polymer Journal

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This paper reports the solvent-free synthesis of a series of six fluoride responsive debond-ondemand polyurethane (PU) adhesives that contain a silyl functionalised degradable unit (DU). To optimise the adhesion strength and debonding nature of the adhesives, the chemical composition of the PUs was varied according to the structure of the polyol or the diisocyanate component in the polymer mainchain. 1 H NMR spectroscopy was used to study the depolymerisation behaviour in solution state. It showed that tetra-butylammonium fluoride (TBAF) triggered the breakdown of the DU unit without fragmenting the polyol mainchain indiscriminately. On exposure to fluoride ions, the PUs underwent depolymerisation with reductions in Mn ranging from 64-90 % as measured by GPC analysis. The morphology and thermal properties of the PUs were characterised by differential scanning calorimetry (DSC), rheology and variable temperature (VT) SAXS/WAXS analysis. Each technique demonstrated the reversibility of the supramolecular polymer network under thermal stimuli. PUs containing poly(butadiene) soft segments were amorphous with glass transition and viscoelastic transition temperatures dependent on the nature of the soft segment and diisocyanate starting materials. The PU containing a polyester soft segment exhibited a defined melting point at 49 °C. Mechanical stress-strain analysis of the series of PUs showed each exhibited greater than 70 % reduction in toughness after treatment with TBAF for 30 minutes as a consequence of the chemo-responsive degradation of the polymer mainchain. The material featuring an ester-based polyol demonstrated excellent adhesion at bonding temperatures as low as 60 °C. Moreover, this material could be thermally rebonded if broken by force without loss in adhesion strength over three debond-rebond cycles. Lap shear adhesion tests showed a reduction in adhesive strength of approximately 40 % (from 11.4 MPa to 7.3 MPa) on exposure to fluoride ions.

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Supramolecular Thermoplastic with 0.5 Pa·s Melt Viscosity

Cited by 27 publications

References 58 publications

Multi-scale thermal stability of a hard thermoplastic protein-based material

Multi-scale thermal stability of a hard thermoplastic protein-based material

Trapping Dynamic Disulfide Bonds in the Hard Segments of Thermoplastic Polyurethane Elastomers

Fluoride-responsive debond on demand adhesives: Manipulating polymer crystallinity and hydrogen bonding to optimise adhesion strength at low bonding temperatures

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