调节聚乙烯玻璃过渡温度,通过改变芳香环/+相互作用的水合水平来调节
Sze Yuet Chin1, Yunpeng Lu2, Weishuai Di3
1NTU Center of High Field NMR Spectroscopy and Imaging, Nanyang Technological University, 21 Nanyang Link, 637371, Singapore. kai.xue@ntu.edu.sg.
Physical chemistry chemical physics : PCCP
|October 11, 2023
概括
离子兴奋剂通过结合水分子来改变聚合物的特性. 这项研究提供了强+/水结合的光谱证据,以及其对聚钢侧链包装和玻璃过渡温度的影响.
科学领域:
- 材料科学 材料科学 材料科学
- 聚合物化学 聚合物化学
- 固态物理 固态物理
背景情况:
- 聚合物属性可以通过离子兴奋剂调整,影响与水等分子的相互作用.
- 在固态聚合物中,离子 (Li+) 和水 (H2O) 结合的强度的直接证据很少.
- +对聚合物侧链包装和动态的影响仍未得到充分探索.
研究的目的:
- 为了研究Li+和H2O在固态聚乙烯系统中的结合相互作用.
- 阐明水合+对聚钢侧链的包装和动态的影响.
- 确定+兴奋剂如何影响聚钢的玻璃过渡温度 (Tg).
主要方法:
- 固态核磁共振 (NMR) 光谱,包括质子检测的NMR.
- 确定Li+和H2O质子之间的二极合.
- 密度函数理论 (DFT) 模拟.密度函数理论 (DFT) 模拟.
主要成果:
- 在Li+和H2O质子之间测量了11.4kHz的显著双极合,证实了强大的结合.
- 通过电荷亲和力将Li+与H2O结合被确定为一个关键的相互作用.
- 化+被证明会改变聚钢侧链的包装和动态,影响能量屏障.
- 实验数据和DFT模拟与Li+添加和水合与玻璃过渡温度变化相关联.
结论:
- 固态NMR提供了在聚合物中强大的Li+/H2O结合的直接证据.
- 化+显著影响聚合物侧链包装,动力学和玻璃过渡温度.
- 这项研究提供了对离子合聚合物系统的见解,以定制材料特性.
相关概念视频
Polymer 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
Polymer Classification: Architecture
2.7K
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...
2.7K
Polymer Classification: Crystallinity
2.9K
Unlike ionic or small covalent molecules, polymers do not form crystalline solids due to the diffusion limitations of their long-chain structures. However, polymers contain microscopic crystalline domains separated by amorphous domains.
Crystalline domains are the regions where polymer chains are aligned in an orderly manner and held together in proximity by intermolecular forces. For example, chains in the crystalline domains of polyethylene and nylon are bound together by van der Waals...
Crystalline domains are the regions where polymer chains are aligned in an orderly manner and held together in proximity by intermolecular forces. For example, chains in the crystalline domains of polyethylene and nylon are bound together by van der Waals...
2.9K
Variables Affecting Phosphorescence and Fluorescence
513
Fluorescence and phosphorescence are essential phenomena in fields like analytical chemistry, biological imaging, and materials science, where they detect molecular properties and visualize cellular structures. Understanding the variables that influence these luminescent behaviors is crucial for maximizing accuracy and efficiency in their applications. These variables can broadly be grouped into chemical structure, solvent properties, and external conditions, each playing a distinct role in...
513
Olefin Metathesis Polymerization: Ring-Opening Metathesis Polymerization (ROMP)
2.6K
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...
2.6K
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


