Video Experimental Relacionado
Updated: Jan 5, 2026
09:16
Synthesis of Terpolymers at Mild Temperatures Using Dynamic Sulfur Bonds in PolyS-Divinylbenzene
Published on: May 20, 2019
8.1K
Metátesis directa de éter de silicio para vitrímeros con una estabilidad térmica excepcional
Chase A Tretbar1, James A Neal1, Zhibin Guan1
1Department of Chemistry , University of California , Irvine , California 92697 , United States.
Journal of the American Chemical Society
|October 12, 2019
Resumen
Una nueva reacción de metástasis de éter silílico permite la creación de vitrímeros avanzados. Estos nuevos materiales poliméricos exhiben una excelente estabilidad térmica y capacidad de reprocesamiento, ofreciendo una química covalente dinámica robusta para termofijos mejorados.
Área de la Ciencia:
- Química de los polímeros
- Ciencias de los materiales
Sus antecedentes:
- Los vitrímeros combinan la resistencia a la resistencia térmica con la capacidad de reprocesamiento termoplástico.
- Existe la necesidad de químicos covalentes dinámicos robustos para los vitrímeros térmicamente estables.
Objetivo del estudio:
- Descubrir y utilizar una nueva química covalente dinámica para la síntesis de vitrímeros.
- Desarrollar vitrímeros con una estabilidad térmica y una reprocesabilidad excepcionales.
Principales métodos:
- Descubrió una reacción de metástasis de éter silílico para el intercambio covalente dinámico.
- Vitrímeros preparados por siliciado de polietileno-co-vinilo-alcohol (PEOH) y enlazado con un éter bisilílico.
- Propiedades investigadas del vitrimero, incluida la reciclabilidad y la relajación del estrés.
Principales resultados:
- Los motivos de éter de silicio se someten a un intercambio catalizado en condiciones anidras.
- El vitrimero resultante basado en PEOH demostró una estabilidad térmica excepcional.
- El material era reprocesable a 150 °C y mostraba una buena resistencia al deslizamiento.
Conclusiones:
- La metatesis de éter de silicio es una nueva y robusta química covalente dinámica para los vitrímeros.
- Esta química imparte plasticidad, reprocesamiento y reciclabilidad a los termofijos.
- Los vitrímeros desarrollados ofrecen una prometedora combinación de resistencia y procesamiento.
Videos de Conceptos Relacionados
01:13Olefin Metathesis Polymerization: Overview
2.5K
Recently, the development of olefin metathesis polymerization advanced the field of polymer synthesis. Simply put, the reorganization of substituents on their double bonds between two olefins in the presence of a catalyst is known as the olefin metathesis reaction. The use of metathesis reaction for polymer synthesis is called olefin metathesis polymerization.
Ruthenium-based Grubbs catalyst is the most commonly used catalyst for olefin metathesis polymerization. Grubbs catalyst consists of a...
Ruthenium-based Grubbs catalyst is the most commonly used catalyst for olefin metathesis polymerization. Grubbs catalyst consists of a...
2.5K
00:53Olefin Metathesis Polymerization: Acyclic Diene Metathesis (ADMET)
2.2K
Acyclic diene metathesis polymerization or ADMET polymerization involves cross-metathesis of terminal dienes, such as 1,8-nonadiene, to give linear unsaturated polymer and ethylene. As ADMET is a reversible process, the formed ethylene gas must be removed from the reaction mixture to complete the polymerization process.
Similar to cross-metathesis, ADMET also involves the formation of metallacyclobutane intermediate by [2+2] cycloaddition of one of the double bonds of a terminal diene with...
Similar to cross-metathesis, ADMET also involves the formation of metallacyclobutane intermediate by [2+2] cycloaddition of one of the double bonds of a terminal diene with...
2.2K
01:16Olefin Metathesis Polymerization: Ring-Opening Metathesis Polymerization (ROMP)
3.1K
Ring-opening metathesis polymerization or ROMP involves strained cycloalkenes as starting materials. The mechanism of ROMP proceeds by reacting cycloalkene with Grubbs catalyst to give metallacyclobutane intermediate which undergoes a ring-opening reaction to form new carbene. The new carbene reacts with another molecule of cycloalkene. Repetition of these steps leads to the formation of an unsaturated open-chain polymer product. All these steps are reversible, however, relieving the ring...
3.1K
![[3,3] Sigmatropic Rearrangement of Allyl Vinyl Ethers: Claisen Rearrangement](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2Ffiles%2Fmedia%2Fscience-education%2Fscience-education-thumbs%2F13097.jpg&w=3840&q=75)
01:24[3,3] Sigmatropic Rearrangement of Allyl Vinyl Ethers: Claisen Rearrangement
2.7K
The Claisen rearrangement is a [3,3] sigmatropic rearrangement of allyl vinyl ethers to unsaturated carbonyl compounds. The rearrangement is a concerted pericyclic reaction proceeding via a chair-like transition state.
2.7K
01:17Thermal Electrocyclic Reactions: Stereochemistry
2.5K
The stereochemistry of electrocyclic reactions is strongly influenced by the orbital symmetry of the polyene HOMO. Under thermal conditions, the reaction proceeds via the ground-state HOMO.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
2.5K
03:00Preparation of Epoxides
9.0K
Overview
Epoxides result from alkene oxidation, which can be achieved by a) air, b) peroxy acids, c) hypochlorous acids, and d) halohydrin cyclization.
Epoxidation with Peroxy Acids
Epoxidation of alkenes via oxidation with peroxy acids involves the conversion of a carbon–carbon double bond to an epoxide using the oxidizing agent meta-chloroperoxybenzoic acid, commonly known as MCPBA. Since the O–O bond of peroxy acids is very weak, the addition of electrophilic oxygen of peroxy acids to...
Epoxides result from alkene oxidation, which can be achieved by a) air, b) peroxy acids, c) hypochlorous acids, and d) halohydrin cyclization.
Epoxidation with Peroxy Acids
Epoxidation of alkenes via oxidation with peroxy acids involves the conversion of a carbon–carbon double bond to an epoxide using the oxidizing agent meta-chloroperoxybenzoic acid, commonly known as MCPBA. Since the O–O bond of peroxy acids is very weak, the addition of electrophilic oxygen of peroxy acids to...
9.0K