通过水-二酸盐合成途径合成的聚尿素中的化学结构和副作用
1Department of Chemical Engineering, Biotechnology and Materials, Faculty of Engineering, Ariel University, Ariel 40700, Israel.
Polymers
|September 9, 2023
概括
使用水-二酸盐路径的工业聚尿素合成产生复杂的,交联的聚合物. 分析方法显示主导的酸盐和三级的酸盐-酸盐结构,与其他合成路径形成鲜明对比.
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
背景情况:
- 工业聚尿素通过二二酸盐或水二酸盐路径合成.
- 水-二酸盐路径在工业上应用,但缺乏关于副作用和结构的详细分析数据.
研究的目的:
- 通过水-二酸盐路径合成的聚尿素中的化学结构和副作用的分析性研究.
- 为了比较由此产生的聚合物结构与来自二二酸盐路径的聚合物结构.
主要方法:
- 聚尿素合成利用水-二酸盐路径.
- 里埃变换红外光谱 (FTIR) 和固态C核磁共振 (NMR) 分析以确定化学结构.
主要成果:
- 通过水-二酸盐路径合成的聚尿素产生了高度非线性和交联的聚合物,这与理论上的线性结构相反.
- 分析显示,酸盐和三级酸盐-酸盐结构占主导地位,比例几乎相等,尿素组最小.
- 这与胺-二异酸盐路径形成鲜明对比,该路径主要产生酸盐结构.
结论:
- 水-二酸盐路径导致复杂的聚合物架构,由于其反应速度较慢,允许进一步的异酸盐组访问.
- 三级橄尿结构的形成是由这个途径的反应动力学促进的.
- 了解这些结构对于控制工业应用中的聚尿素特性至关重要.
相关概念视频
Dehydration Synthesis
133.6K
Overview
Dehydration synthesis (also called a condensation reaction) is the chemical process in which two molecules covalently link together to form a new molecule, along with the release of a water molecule. Many physiologically important compounds form by dehydration synthesis reactions, such as complex carbohydrates, proteins, DNA, and RNA.
Synthesis of carbohydrates
Sugar molecules are covalently linked together by dehydration synthesis. During the reaction, the hydroxyl (-OH) group from...
Dehydration synthesis (also called a condensation reaction) is the chemical process in which two molecules covalently link together to form a new molecule, along with the release of a water molecule. Many physiologically important compounds form by dehydration synthesis reactions, such as complex carbohydrates, proteins, DNA, and RNA.
Synthesis of carbohydrates
Sugar molecules are covalently linked together by dehydration synthesis. During the reaction, the hydroxyl (-OH) group from...
133.6K
Step-Growth Polymerization: Overview
3.5K
Step-growth or condensation polymerization is a stepwise reaction of bi or multifunctional monomers to form long-chain polymers. As all the monomers are reactive, most of the monomers are consumed at the early stages of the reaction to form small chains of reactive oligomers, which then combine to form long polymer chains in the late stages. Hence, the reaction has to proceed for a long time to achieve high molecular weight polymers.
Many natural and synthetic polymers are produced by...
Many natural and synthetic polymers are produced by...
3.5K
Hydrolysis
105.7K
Overview
Hydrolysis is a chemical reaction in which the addition of water breaks down a polymer into its simpler monomer units. For example, peptides break into amino acids, carbohydrates into simple sugars, and DNA into nucleotides. Enzymes often facilitate these processes.
Hydrolysis Reverses Dehydration Synthesis
Complex carbohydrates can be broken down by breaking the bonds between individual sugar units. The reaction breaks a glycosidic bond as water is added to the compound. The...
Hydrolysis is a chemical reaction in which the addition of water breaks down a polymer into its simpler monomer units. For example, peptides break into amino acids, carbohydrates into simple sugars, and DNA into nucleotides. Enzymes often facilitate these processes.
Hydrolysis Reverses Dehydration Synthesis
Complex carbohydrates can be broken down by breaking the bonds between individual sugar units. The reaction breaks a glycosidic bond as water is added to the compound. The...
105.7K
Cationic Chain-Growth Polymerization: Mechanism
2.4K
The cationic polymerization mechanism consists of three steps: initiation, propagation, and termination. In the initiation step of the polymerization process, the π bond of a monomer gets protonated by the Lewis acid catalyst, which is formed from boron trifluoride and water. The protonation of the π bond generates a carbocation stabilized by the electron‐donating group. In the propagation step, the π bond of the second monomer acts as a nucleophile and attacks the...
2.4K
Regioselectivity and Stereochemistry of Acid-Catalyzed Hydration
8.5K
The rate of acid-catalyzed hydration of alkenes depends on the alkene's structure, as the presence of alkyl substituents at the double bond can significantly influence the rate.
8.5K
Aldehydes and Ketones with Water: Hydrate Formation
3.3K
An oxygen-based nucleophile, like water, can undergo addition reactions with aldehydes and ketones. The reaction leads to the formation of hydrates, also referred to as 1,1-diols or geminal diols.
The formation of hydrates is a reversible reaction. Hydrate formation is influenced by steric and electronic factors accompanying the alkyl substituents on the carbonyl group: The rate of hydrate formation increases with a decrease in the number of alkyl groups attached to the carbonyl carbon. Hence,...
The formation of hydrates is a reversible reaction. Hydrate formation is influenced by steric and electronic factors accompanying the alkyl substituents on the carbonyl group: The rate of hydrate formation increases with a decrease in the number of alkyl groups attached to the carbonyl carbon. Hence,...
3.3K


