RAFT聚合和超交叉连接 改善交叉连接均性和基于烯的多HIPEs的表面积
Amadeja Koler1, Jiři Brus2, Peter Krajnc1
1PolyOrgLab, Faculty of Chemistry and Chemical Engineering, University of Maribor, Smetanova 17, 2000 Maribor, Slovenia.
Polymers
|May 27, 2023
概括
与自由基聚合 (FRP) 相比,可逆添加-碎片化链转移 (RAFT) 聚合显著增强了乙聚合物的多孔结构. 由于更均的交叉连接,RAFT产生了更大的表面积和更大的微孔性.
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:
- 高孔性聚合物对于吸附和催化等应用至关重要.
- 控制聚合物架构,特别是孔隙性,是优化性能的关键.
- 乳液模板为创建复杂的聚合物结构提供了一条途径.
研究的目的:
- 调查聚合机制 (RAFT与FRP) 对聚合物的多孔性特性的影响.
- 分析后续超交叉连接对聚合物多孔性的影响.
- 为了将聚合方法与得到的表面积和孔径分布相关联.
主要方法:
- 使用高内部相乳液模板合成高度多孔的聚合物.
- 可逆添加碎片链转移 (RAFT) 和自由基聚合 (FRP) 方法的比较.
- 合成后的超交叉连接使用二三-丁过氧化物.
- 通过气体吸附和固态核磁共振 (NMR) 光谱学进行表征.
主要成果:
- 与FRP (2035 m2/g) 相比,RAFT聚合导致显著更高的特定表面积 (60150 m2/g).
- RAFT聚合促进了均的交叉链分布,导致 mesopore 体积增加,并在超交叉链接后增强了微孔性.
- 与FRP衍生的聚合物相比,RAFT衍生的聚合物中的微孔分数增加了多达10倍.
结论:
- 聚合机制的选择深深地影响了 styrene-divinylbenzene 共聚物的多孔结构.
- 在RAFT聚合过程中,可以对聚合物网络的同质性和多孔性发展有更好的控制.
- 来自RAFT的聚合物在需要高表面积和可访问的孔隙的应用中表现出显著改善的特性.
相关概念视频
01:14Polymer Classification: Architecture
2.8K
Polymers are classified as linear or branched on the basis of their chain architecture. The polymer chains in linear polymers have a long chain-like structure with minimal to no branching at all. Even if a polymer features large substituent groups on the monomer, which appear as branches to the skeleton, it is not considered a branched polymer. A branched polymer contains secondary polymer chains that arise from the main polymer chain. The branching occurs when the polymer growth shifts from...
2.8K
01:26Polymer Classification: Stereospecificity
2.5K
Polymerization generates chiral centers along the entire backbone of a polymer chain. Accordingly, the stereochemistry of the substituent group has a significant effect on polymer properties. Polymers formed from monosubstituted alkene monomers feature chiral carbons at every alternate position in the polymer backbone. Relative to the predominant orientation of substituents at the adjacent chiral carbons, the polymer can exist in three different configurations: isotactic, syndiotactic, and...
2.5K
02:35Free-Radical Chain Reaction and Polymerization of Alkenes
8.0K
The conversion of alkenes to macromolecules called polymers is a reaction of high commercial importance. The structure of the polymer is defined by a repeating unit, while the terminal groups are considered insignificant. The average degree of polymerization represents the number of repeating units in the polymer molecule and is denoted by the subscript n.
8.0K
01:03Step-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
01:09Radical Chain-Growth Polymerization: Mechanism
2.6K
The radical chain-growth polymerization mechanism consists of three steps: initiation, propagation, and termination of polymerization. The polymerization initiates when a free radical generated from the radical initiator adds to the unsaturated bond in the monomer. The unpaired electron of the free radical and one π electron in the unsaturated bond creates a σ bond between the free radical and the monomer. As a result, the other π electron in the unsaturated bond converts this...
2.6K
01:10Radical Chain-Growth Polymerization: Overview
2.5K
Chain-growth or addition polymerization is successive addition reactions of monomers with a polymer chain. In radical chain-growth polymerization, the reaction proceeds via a free-radical intermediate. The free radical is formed from radical initiators, which spontaneously generate free radicals by homolytic fission. Organic peroxides (such as dibenzoyl peroxide, as shown in Figure 1) or azo compounds are popular radical initiators. A low concentration ratio of radical initiator to monomer is...
2.5K