Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Dynamic multiphase semi-crystalline polymers based on thermally reversible pyrazole-urea bonds.

ABSTRACT: Constructing responsive and adaptive materials by dynamic covalent bonds is an attractive strategy in material design. Here, we present a kind of dynamic covalent polyureas which can be prepared from the highly efficient polyaddition reaction of pyrazoles and diisocyanates at ambient temperature in the absence of a catalyst. Owing to multiphase structural design, poly(pyrazole-ureas) (PPzUs) show excellent mechanical properties and unique crystallization behavior. Besides, the crosslinked PPzUs can be successfully recycled upon heating (~130 °C) and the molecular-level blending of polyurea and polyurethane is realized. Theoretical studies prove that the reversibility of pyrazole-urea bonds (PzUBs) arises from the unique aromatic nature of pyrazole and the N-assisting intramolecular hydrogen transfer process. The PzUBs could further broaden the scope of dynamic covalent bonds and are very promising in the fields of dynamic materials.

SUBMITTER: Liu WX

PROVIDER: S-EPMC6802193 | biostudies-literature | 2019 Oct

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Dynamic multiphase semi-crystalline polymers based on thermally reversible pyrazole-urea bonds.

Liu Wen-Xing WX Yang Zhusheng Z Qiao Zhi Z Zhang Long L Zhao Ning N Luo Sanzhong S Xu Jian J

Nature communications 20191018 1

Constructing responsive and adaptive materials by dynamic covalent bonds is an attractive strategy in material design. Here, we present a kind of dynamic covalent polyureas which can be prepared from the highly efficient polyaddition reaction of pyrazoles and diisocyanates at ambient temperature in the absence of a catalyst. Owing to multiphase structural design, poly(pyrazole-ureas) (PPzUs) show excellent mechanical properties and unique crystallization behavior. Besides, the crosslinked PPzUs ...[more]

PMID: 31628332

Similar Datasets

Dynamic urea bond for the design of reversible and self-healing polymers.

Project description:Polymers bearing dynamic covalent bonds may exhibit dynamic properties, such as self-healing, shape memory and environmental adaptation. However, most dynamic covalent chemistries developed so far require either catalyst or change of environmental conditions to facilitate bond reversion and dynamic property change in bulk materials. Here we report the rational design of hindered urea bonds (urea with bulky substituent attached to its nitrogen) and the use of them to make polyureas and poly(urethane-urea)s capable of catalyst-free dynamic property change and autonomous repairing at low temperature. Given the simplicity of the hindered urea bond chemistry (reaction of a bulky amine with an isocyanate), incorporation of the catalyst-free dynamic covalent urea bonds to conventional polyurea or urea-containing polymers that typically have stable bulk properties may further broaden the scope of applications of these widely used materials.

| S-EPMC4438999 | biostudies-literature

Photo-crosslinking polymers by dynamic covalent disulfide bonds.

Project description:A simple and general strategy to construct photo-crosslinkable polymers by introducing sidechain 1,2-dithiolanes based on natural thioctic acid is presented. The disulfide five-membered rings act both as light-absorbing and dynamic covalent crosslinking units, enabling efficient photo-crosslinking and reversible chemical decrosslinking of polydimethylsiloxane polymers.

| S-EPMC8477374 | biostudies-literature

The Continuum Approach to the Description of Semi-Crystalline Polymers Deformation Regimes: The Role of Dynamic and Translational Defects.

Project description:This paper presents a new approach to describe the mechanical behavior of semi-crystalline polymers, the plastic deformation of which is determined by their two-phase structure. To describe the plastic behavior of semi-crystalline polymers, a two-phase model is used. In the framework of this model, one phase is in a hard (crystalline) state, and the other in a soft (amorphous) state. The two-phase material is modeled by a single-phase homogeneous continuum based on the approximation of the effective medium. It is assumed that two infinitely close material points of the continuum are connected in series by elastic and viscous bonds, which corresponds to the Maxwell model. It is shown that, in this case, the Maxwell continuum is a pseudo-Euclidean space. Generalizing the definition of defects from a three-dimensional space to a four-dimensional pseudo-Euclidean space, we obtained a dynamic system of nonlinear, interrelated equations to describe the behavior of translational-type defects in the solid phase and dynamic defects in the amorphous phase. As an example of an application for these equations, the phenomenon of creep under uniaxial loading is considered. It is shown that the formalism of the proposed two-phase model makes it possible to describe creep phenomenon regularities, which correspond to both the aging theory and the flow theory.

| S-EPMC6404089 | biostudies-literature

Preparation and Characterization of Isosorbide-Based Self-Healable Polyurethane Elastomers with Thermally Reversible Bonds.

Project description:Polyurethane (PU) is a versatile polymer used in a wide range of applications. Recently, imparting PU with self-healing properties has attracted much interest to improve the product durability. The self-healing mechanism conceivably occurs through the existence of dynamic reversible bonds over a specific temperature range. The present study investigates the self-healing properties of 1,4:3,6-dianhydrohexitol-based PUs prepared from a prepolymer of poly(tetra-methylene ether glycol) and 4,4'-methylenebis(phenyl isocyanate) with different chain extenders (isosorbide or isomannide). PU with the conventional chain extender 1,4-butanediol was prepared for comparison. The urethane bonds in 1,4:3,6-dianhydrohexitol-based PUs were thermally reversible (as confirmed by the generation of isocyanate peaks observed by Fourier transform infrared spectroscopy) at mildly elevated temperatures and the PUs showed good mechanical properties. Especially the isosorbide-based polyurethane showed potential self-healing ability under mild heat treatment, as observed in reprocessing tests. It is inferred that isosorbide, bio-based bicyclic diol, can be employed as an efficient chain extender of polyurethane prepolymers to improve self-healing properties of polyurethane elastomers via reversible features of the urethane bonds.

| S-EPMC6471067 | biostudies-literature

Claisen thermally rearranged (CTR) polymers.

Project description:Thermally rearranged (TR) polymers, which are considered the next-generation of membrane materials because of their excellent transport properties and high thermal and chemical stability, are proven to have significant drawbacks because of the high temperature required for the rearrangement and low degree of conversion during this process. We demonstrate that using a [3,3]-sigmatropic rearrangement, the temperature required for the rearrangement of a solid glassy polymer was reduced by 200°C. Conversions of functionalized polyimide to polybenzoxazole of more than 97% were achieved. These highly mechanically stable polymers were almost five times more permeable and had more than two times higher degrees of conversion than the reference polymer treated under the same conditions. Properties of these second-generation TR polymers provide the possibility of preparing efficient polymer membranes in a form of, for example, thin-film composite membranes for various gas and liquid membrane separation applications.

| S-EPMC4966881 | biostudies-other

Nitric oxide-releasing semi-crystalline thermoplastic polymers: preparation, characterization and application to devise anti-inflammatory and bactericidal implants.

Project description:Semi-crystalline thermoplastics are an important class of biomaterials with applications in creating extracorporeal and implantable medical devices. In situ release of nitric oxide (NO) from medical devices can enhance their performance via NO's potent anti-thrombotic, bactericidal, anti-inflammatory, and angiogenic activity. However, NO-releasing semi-crystalline thermoplastic systems are limited and the relationship between polymer crystallinity and NO release profile is unknown. In this paper, the functionalization of poly(ether-block-amide) (PEBA), Nylon 12, and polyurethane tubes, as examples of semi-crystalline polymers, with the NO donor S-nitroso-N-acetylpenicillamine (SNAP) within, is demonstrated via a polymer swelling method. The degree of crystallinity of the polymer plays a crucial role in both SNAP impregnation and NO release. Nylon 12, which has a relatively high degree of crystallinity, exhibits an unprecedented NO release duration of over 5 months at a low NO level, while PEBA tubing exhibits NO release over days to weeks. As a new biomedical application of NO, the NO-releasing PEBA tubing is examined as a cannula for continuous subcutaneous insulin infusion. The released NO is shown to enhance insulin absorption into the bloodstream probably by suppressing the tissue inflammatory response, and thereby could benefit insulin pump therapy for diabetes management.

| S-EPMC6246781 | biostudies-literature

Programming a crystalline shape memory polymer network with thermo- and photo-reversible bonds toward a single-component soft robot.

Project description:The need to support the two most basic functions [three-dimensional (3D)-shaped support and actuation] independently for a typical robot demands that at least two components should be used in its construction. Therefore, component assembly is unavoidable despite the ultimate dream of creating assembly-free robots. We devise a strategy that uses a programmable crystalline shape memory polymer with thermo- and photo-reversible bonds to create a single-component robot. The global 3D-shaped structural support is fabricated via a plasticity-based origami technique enabled by the thermo-reversible bonds. More critically, precisely controlled localized actuation can be programmed into the 3D origami via spatially defined reversible shape memory using the photo-reversible bonds. The overall result is that a polymer thin film can be programmed into various soft robots including a 3D crane and an elephant. Besides reversible shape memory, other types of actuation mechanisms can be potentially introduced via a similar principle. Thus, our strategy represents a general method to create single-component soft robots.

| S-EPMC5787381 | biostudies-literature

Dynamic interconversion of amorphous microparticles and crystalline rods in salen-based homochiral infinite coordination polymers.

Project description: Not available

| S-EPMC2532983 | biostudies-literature

Hydrolyzable polyureas bearing hindered urea bonds.

Project description:Hydrolyzable polymers are widely used materials that have found numerous applications in biomedical, agricultural, plastic, and packaging industrials. They usually contain ester and other hydrolyzable bonds, such as anhydride, acetal, ketal, or imine, in their backbone structures. Here, we report the first design of hydrolyzable polyureas bearing dynamic hindered urea bonds (HUBs) that can reversibly dissociate to bulky amines and isocyanates, the latter of which can be further hydrolyzed by water, driving the equilibrium to facilitate the degradation of polyureas. Polyureas bearing 1-tert-butyl-1-ethylurea bonds that show high dynamicity (high bond dissociation rate), in the form of either linear polymers or cross-linked gels, can be completely degraded by water under mild conditions. Given the simplicity and low cost for the production of polyureas by simply mixing multifunctional bulky amines and isocyanates, the versatility of the structures, and the tunability of the degradation profiles of HUB-bearing polyureas, these materials are potentially of very broad applications.

| S-EPMC4277771 | biostudies-literature

One-Dimensional Mercury Halide Coordination Polymers Based on A Semi-Rigid N-Donor Ligand: Reversible Structural Transformation.

Project description:Four one-dimensional (1D) mercury(II) halide coordination polymers have been synthesized by using a semi-rigid N-donor ligand, 2,2'-(1,4-phenylene)-bis(N-(pyridin-3-yl)acetamide) (1,4-pbpa). While [Hg(1,4-pbpa)Cl₂·CH₃OH]n, 1, forms a sinusoidal chain, the complexes [Hg(1,4-pbpa)X₂]n (X = Cl, 2; Br, 3; I, 4) are helical. The sinusoidal 1 undergoes reversible structural transformation with helical 2 upon removal and uptake of CH₃OH, which was accompanied with the conformation adjustment of the 1,4-pbpa ligand from trans anti-anti to trans syn-anti. Pyridyl ring rotation of the 1,4-pbpa ligand that results in the change of the ligand conformation is proposed for the initiation of the structural transformation.

| S-EPMC6473486 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data