特殊な熱安定性を持つヴィトリマーのための直接シリルエーテルメタテシス
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
まとめ
新しいシリルエーテルメタテシス反応により,高度なガラスの生成が可能になる. これらの新しいポリマー材料は,優れた熱安定性および再処理性を示し,強化された熱固体のための堅固なダイナミック共性化学を提供します.
科学分野:
- ポリマー化学
- 材料科学
背景:
- ガラスの材料は,熱性強度と熱可塑性再処理性を組み合わせています.
- 熱的に安定したガラスのための強固なダイナミック共性化学が必要である.
研究 の 目的:
- ビトリマー合成のための新しいダイナミックな共性化学を発見し,利用する.
- 特殊な熱安定性と再処理性を有するガラスを開発する.
主な方法:
- ダイナミックな共性交換のためのシリルエーテルメタテシス反応を発見した.
- ポリエチレンコビニールアルコール (PEOH) をシリアリングし,ビシリルエーテルで交結することによって,準備されたビトリマー.
- リサイクル可能性とストレス緩和を含むヴィトリマーの性質を調査した.
主要な成果:
- シリルエーテルモチーフは無水状態で触媒交換を受けます.
- その結果,PEOHベースのビトリマーは,例外的な熱安定性を示した.
- 材料は150°Cで再処理可能であり,良質のクリープ抵抗性を示した.
結論:
- シリルエーテルメタテシスは,ガラスのための新しい,堅固な動的共性化学です.
- この化学反応により 耐熱材料は 柔軟性があり 再処理可能で 再利用可能になります
- 開発されたガラスは,強度と処理性の有望な組み合わせを提供します.
関連する概念動画
Olefin 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
Olefin 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
Olefin 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
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
Thermal 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
Preparation 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


