比较一个环氧玻璃制剂的表面和散装固化过程
1State Key Laboratory of Organic-Inorganic Composites & Beijing Key Laboratory of Advanced Functional Polymer Composites, Beijing University of Chemical Technology, Beijing 100029, China.
ACS applied materials & interfaces
|March 12, 2024
概括
这项研究表明,由于交叉连接剂较少,玻璃化物表面固化比散装固化要慢. 再加工玻璃材料会降低其再加工能力和机械性能.
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
- 表面科学是一门学科.
背景情况:
- 玻璃聚合物是具有动态共价网络的先进聚合物,提供可再加工性.
- 了解表面与散装固化对优化玻璃制剂性能至关重要.
- 双甲二甲基乙烯 (DGEBA) 是一种常见的环氧树脂,用于玻璃制剂配方.
研究的目的:
- 为了研究和比较二碳酸固化DGEBA玻璃体的表面和大部分固化过程.
- 确定负责玻璃体系统中交叉链接的关键化学物种.
- 分析再加工对玻璃物质性质的影响.
主要方法:
- 基于原子力显微镜的红外光谱学 (AFM-IR) 用于化学成像.
- 纳米机械绘图 (AFM-NM) 用于表面机械表征.
- 对IR峰值进行定量分析,以评估化和固化程度.
主要成果:
- 在DGEBA系统中确定β-基作为关键的交叉链接剂.
- 表面固化比散装固化缓慢且不那么广泛,原因是功能化β-基的度较低.
- 再加工导致非可交换的形成,减少流动性和机械完整性.
结论:
- 表面固化动态与DGEBA玻璃化器中的散装固化有很大的不同.
- 在表面,纳米结构的异质性比在体积上要小.
- 由于化变化,由于重复的加工周期,玻璃材料的再加工能力和机械性能受到负面影响.
相关概念视频
Curing Methods
78
Concrete members with a small surface-to-volume ratio are cured by oiling and moistening the forms before casting the concrete member. These forms can be left in place for a prolonged period to prevent moisture loss, and can be wetted if made of a material suitable for wetting. If the forms are removed early, the concrete member is moistened and covered with polythene sheets to maintain moisture. For large horizontal concrete surfaces exposed to dry weather, a temporary covering is suspended...
78
Accelerated Curing of Concrete
133
Accelerating concrete curing is achieved by applying heat and additional moisture. This process accelerates the hydration of the cement, resulting in an earlier strength gain in the concrete. Steam curing is a method wherein the concrete products are either transported through a chamber on a conveyor belt or encased in plastic, allowing steam at atmospheric pressure to circulate freely around them. This process begins with a phase of moist curing that typically lasts between 3 to 5 hours, after...
133
Curing of Concrete
94
The hydration of cement takes place within the water-filled capillary pores. However, environmental elements can disrupt this process by evaporating water from the concrete surfaces. Sealed concrete with a water-cement ratio below 0.5 experiences self-desiccation, leading to water loss. The water loss in concrete is mitigated by curing. This technique involves keeping the concrete saturated to maintain the necessary temperature and moisture conditions, to optimally fill the spaces in the cement...
94
Fineness of Cement
131
The fineness of cement directly influences the rate of hydration, as the hydration begins at the surface of the cement particles. In addition to hydration, the fineness of cement is vital for various properties of concrete including workability, gypsum requirement, and long-term behavior. The fineness of cement is represented in terms of the specific surface of cement which is typically measured in square meters per kilogram, with several methods available for this determination.
Direct...
Direct...
131
Porosity in Cement Paste
132
The porosity of concrete is a measure of the void spaces within its structure. These spaces impact its strength and durability significantly. When water and cement interact, a chemical reaction called hydration creates a semi-solid paste. This paste includes combined water, making up approximately 23% of the cement's dry mass, and gel water, which fills minuscule voids known as gel pores, accounting for about 28% of the cement gel volume.
The balance of water to cement in the mix is...
The balance of water to cement in the mix is...
132


