水性乙烯聚合物的合成和结晶:朝着创新的氧气屏障涂层
Justine Elgoyhen1, Valentina Pirela2, Alejandro J Müller2,3
1POLYMAT and Department of Applied Chemistry, Faculty of Chemistry, University of the Basque Country UPV/EHU, Avda Tolosa 72, 20018 Donostia-San Sebastián, Spain.
ACS applied polymer materials
|November 16, 2023
概括
这项研究引入了一种无启动剂的声聚合法,用于制造高固体的水性聚 (thioether) 分散物. 随后的光聚合步骤和自我核化程序显著提高了聚合物的分子量,并加速了屏障涂料的结晶动力学.
科学领域:
- 聚合物化学 聚合物化学
- 材料科学 材料科学 材料科学
- 纳米技术 纳米技术
背景情况:
- 由于提的高反应性和过早的聚合,水中提烯聚合物合成是很困难的,导致不可重复性.
- 现有的方法在水性聚乙预聚合物中难以达到高固体含量和高分子量.
研究的目的:
- 开发一种可重复的合成高固体含量,形成膜的水borne poly ((thioether) 预聚合物.
- 为了提高这些聚乙烯的分子量和结晶动力学,用于屏障涂层应用.
主要方法:
- 无启动剂的不同类型的醇和烯单体的渐进生长单聚化,固体含量为30%和50%.
- 聚合后光聚合使用水溶性光启动剂来增加分子量.
- 实施自我核化 (SN) 程序以加速结晶动力学.
主要成果:
- 合成了具有 30% 固体含量时 7 23 kDa 和 50% 固体含量时 1 9 kDa 的摩尔质量的线性聚乙烯链.
- 光聚合产生高摩尔质量链高达200kDa,这是阶段生长的多乙烯中报告的最高水平.
- 该SN程序有效地加速了所产生的半晶膜的缓慢结晶动力学.
结论:
- 通过使用声聚合和光聚合,建立了一种新的,可重复的方法来合成高固体的水性聚 ((thioether) 分散物.
- 开发的聚乙烯表现出良好的薄膜形成特性和屏障涂层的潜力.
- 自核化的成功应用显著提高了这些聚乙烯材料的可加工性和性能.
相关概念视频
02:33Preparation and Reactions of Thiols
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Thiols are prepared using the hydrosulfide anion as a nucleophile in a nucleophilic substitution reaction with alkyl halides. For instance, bromobutane reacts with sodium hydrosulfide to give butanethiol.
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03:00Preparation of Epoxides
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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...
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...
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02:44Oxidation of Alkenes: Syn Dihydroxylation with Osmium Tetraoxide
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Alkenes are converted to 1,2-diols or glycols through a process called dihydroxylation. It involves the addition of two hydroxyl groups across the double bond with two different stereochemical approaches, namely anti and syn. Dihydroxylation using osmium tetroxide progresses with syn stereochemistry.
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01:13Olefin Metathesis Polymerization: Overview
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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...
Ruthenium-based Grubbs catalyst is the most commonly used catalyst for olefin metathesis polymerization. Grubbs catalyst consists...
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02:29Ethers from Alcohols: Alcohol Dehydration and Williamson Ether Synthesis
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Overview
Ethers can be prepared from organic compounds by various methods. Some of them are discussed below,
Preparation of Ethers by Alcohol Dehydration
In this method, in the presence of protic acids, alcohol dehydrates to produce alkenes and ethers under different conditions. For example, in the presence of sulphuric acid, dehydration of ethanol at 413 K yields ethoxyethane, whereas it yields ethene at 443 K.
Ethers can be prepared from organic compounds by various methods. Some of them are discussed below,
Preparation of Ethers by Alcohol Dehydration
In this method, in the presence of protic acids, alcohol dehydrates to produce alkenes and ethers under different conditions. For example, in the presence of sulphuric acid, dehydration of ethanol at 413 K yields ethoxyethane, whereas it yields ethene at 443 K.
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02:41Formation of Halohydrin from Alkenes
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An alkene, such as propene, reacts with bromine in the presence of water to yield a halohydrin. Halohydrins contain a halogen and a hydroxyl group attached to adjacent carbons. When the halogen is bromine, it is called a bromohydrin, while a chlorohydrin has chlorine as the halogen.
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