水作用对热过渡和分子流动性在克桑糖多糖
Sokratis N Tegopoulos1, Aristeidis Papagiannopoulos2, Apostolos Kyritsis1
1Physics Department, National Technical University of Athens, Iroon Polytechneiou 9, Zografou Campus, Athens, 15780, Greece. akyrits@central.ntua.gr.
Physical chemistry chemical physics : PCCP
|January 11, 2024
概括
赞坦口香糖的使用方法
科学领域:
- 聚合物科学 聚合物科学
- 生物物理学的生物物理.
- 材料科学 材料科学 材料科学
背景情况:
- 赞坦 (XG) 是一种多用途的多糖化合物,在各种行业中都有应用.
- 了解其热和动态特性对于优化其使用至关重要.
- 补水显著影响了多糖的行为.
研究的目的:
- 通过广泛的水分水平来研究香甘的玻璃过渡和分子移动性.
- 为了确定克桑系统中冰形成的关键水分.
- 为了阐明水对放松过程的影响,并在香中进行充电运输.
主要方法:
- 差分扫描热量计 (DSC) 用于热分析.
- 宽带介电光谱 (BDS) 用于分子动力学和电荷传输.
- 水分 (0~0.70) 和温度的系统变化.
主要成果:
- 确定了大约0.35的冰形成的关键水分.
- 观察到水作为塑化剂,降低玻璃过渡温度 (Tg) 到0.35水分.
- 检测到对水敏感的二次放松过程,归因于侧链或主链动态.
- 解决了两种不同的远程电荷传输机制:一种是通过冰结构,另一种是通过不结冰的水的键网络.
- 观察到一种类似于Vogel-Tammann-Fulcher (VTF) 的过程,与在水分较高的情况下相互连接的水群中的电荷流动性有关.
结论:
- 这项研究提供了第一个全面分析使用DSC和BDS在多种水化水平上对丹的玻璃过渡和分子流动性.
- 水在塑化香中起着至关重要的作用,并影响其放松动态和电荷传输特性.
- 这些发现为化香丹的结构性质关系提供了基本的见解,这与材料设计和应用有关.
相关概念视频
01:21Polymer 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
01:08Molecular Weight of Step-Growth Polymers
2.2K
Step growth polymerization involves bi or multifunctional monomers. Bifunctional monomers react to form linear step growth polymers, whereas multifunctional monomers react to form non-linear or branched polymers.
As the step-growth polymerization involves step-wise condensation of monomers, the molecular weight also builds up eventually. Consequently, high molecular weight polymers are obtained at the late stages of the polymerization, where 99% of monomers have been consumed.
The extent of the...
As the step-growth polymerization involves step-wise condensation of monomers, the molecular weight also builds up eventually. Consequently, high molecular weight polymers are obtained at the late stages of the polymerization, where 99% of monomers have been consumed.
The extent of the...
2.2K
02:57Surface Tension, Capillary Action, and Viscosity
27.8K
Surface Tension
The various IMFs between identical molecules of a substance are examples of cohesive forces. The molecules within a liquid are surrounded by other molecules and are attracted equally in all directions by the cohesive forces within the liquid. However, the molecules on the surface of a liquid are attracted only by about one-half as many molecules. Because of the unbalanced molecular attractions on the surface molecules, liquids contract to form a shape that minimizes the number...
The various IMFs between identical molecules of a substance are examples of cohesive forces. The molecules within a liquid are surrounded by other molecules and are attracted equally in all directions by the cohesive forces within the liquid. However, the molecules on the surface of a liquid are attracted only by about one-half as many molecules. Because of the unbalanced molecular attractions on the surface molecules, liquids contract to form a shape that minimizes the number...
27.8K
02:39Enthalpy of Solution
24.9K
There are two criteria that favor, but do not guarantee, the spontaneous formation of a solution:
24.9K
02:19Physical Properties Affecting Solubility
22.7K
Solutions of Gases in Liquids
As for any solution, the solubility of a gas in a liquid is affected by the attractive intermolecular forces between solute and solvent species. Unlike solid and liquid solutes, however, there is no solute-solute intermolecular attraction to overcome when a gaseous solute dissolves in a liquid solvent since the atoms or molecules comprising a gas are far separated and experience negligible interactions. Consequently, solute-solvent interactions are the sole...
As for any solution, the solubility of a gas in a liquid is affected by the attractive intermolecular forces between solute and solvent species. Unlike solid and liquid solutes, however, there is no solute-solute intermolecular attraction to overcome when a gaseous solute dissolves in a liquid solvent since the atoms or molecules comprising a gas are far separated and experience negligible interactions. Consequently, solute-solvent interactions are the sole...
22.7K
01:21Factors Affecting Dissolution: Polymorphism, Amorphism and Pseudopolymorphism
310
Polymorphism refers to the existence of a drug substance in multiple crystalline forms, known as polymorphs. Recently, this term has been expanded to include solvates (forms containing a solvent), amorphous forms (non-crystalline forms), and desolvated solvates (forms from which the solvent has been removed).
Some polymorphic crystals possess lower aqueous solubility than their amorphous counterparts, leading to incomplete absorption. For instance, the oral suspension of Chloramphenicol, which...
Some polymorphic crystals possess lower aqueous solubility than their amorphous counterparts, leading to incomplete absorption. For instance, the oral suspension of Chloramphenicol, which...
310