拉伸性质和变形行为在高强度热延长聚烯的温度依赖性
1Department of Applied Chemistry, Tokyo University of Agriculture and Technology, Koganei-shi 184-8588, Japan.
Polymers
|December 31, 2025
概括
高强度的热延长聚烯 (PP) 由于片碎片化和压抑的晶体链运动而表现出增强的高温强度,导致与未延长的PP相比显著更高的产量应力.
科学领域:
- 材料科学 材料科学 材料科学
- 聚合物科学 聚合物科学
- 机械工程 机械工程
背景情况:
- 聚烯 (PP) 是一种广泛使用的热塑性塑料.
- 了解PP在高温下的机械性能对于其应用至关重要.
- 热延长加工可以显著改变聚合物形态和特性.
研究的目的:
- 在各种温度下研究热延长聚烯 (PP) 的拉伸性能和变形行为.
- 阐明PP的微观结构与其高温机械强度之间的关系.
- 了解热延长PP增强强度背后的机制.
主要方法:
- 动态机械分析 (DMA) 用于测量弹性模量 (E') 和αc-放松温度.
- 在各种温度下进行拉伸测试,以确定产应力和变形行为.
- 微角X射线散射 (SAXS) 用于分析叶片结构变化.
- 差分扫描热量计 (DSC) 用于研究热过渡.
主要成果:
- 热延长的PP显示出更高的弹性模量和αc-放松温度,表明压抑的晶体链运动.
- 在120°C时的承受应力为60MPa,比未延长的PP高7.5倍,显示出优越的高温强度.
- SAXS模式从分层转变为扩散,DSC显示融化峰值转移,这表明小菌株下的斑块碎片化.
- 观察到连接层状膜的薄晶体纤维抑制了晶体链运动.
结论:
- 热延长PP的增强高温强度归因于在小应变拉伸过程中叶片碎片化.
- 通过连接到片的薄晶纤维抑制晶链运动,有助于改善机械性能.
- 热延长加工提供了一个可行的途径,以提高聚烯的高温性能.
相关概念视频
Temperature Dependent Deformation
343
In a nonhomogeneous rod made up of steel and brass, restrained at both ends and subjected to a temperature change, several steps are involved in calculating the stress and compressive load. Due to the problem's static indeterminacy, one end support is disconnected, allowing the rod to experience the temperature change freely. Next, an unknown force is applied at the free end, triggering deformations in the rod's steel and brass portions. These deformations are then calculated and added...
343
Plastic Behavior
494
A material's elastic behavior is characterized by the disappearance of stress once the load is removed, allowing the material to return to its original state. However, when stress surpasses the yield point, yielding commences, marking the onset of plastic deformation or permanent set. This change from elastic to plastic behavior is influenced by the peak stress value and the duration before the load is removed. An intriguing observation occurs when a specimen is loaded, unloaded, and...
494
Thermal Strain
2.8K
Thermal strain is a concept that arises when we consider how temperature changes affect structures. Unlike the conventional assumption that structures remain constant under load, real-world scenarios often involve temperature fluctuations that can significantly impact these structures. Consider a homogeneous rod with a uniform cross-section resting freely on a flat horizontal surface. If the rod's temperature increases, the rod elongates. This elongation is proportional to the temperature...
2.8K
Stress-Strain Diagram - Ductile Materials
1.8K
The stress-strain relationship in ductile materials such as structural steel or aluminium is intricate and progresses through several stages. When a specimen is loaded, it initially exhibits a linear length increase, depicted by a steep straight line on the stress-strain diagram. It indicates the material is elastically deforming and will return to its original shape once unloaded. However, when a critical stress value is reached, plastic deformation begins. This stage sees substantial...
1.8K
Polymer Classification: Architecture
3.6K
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...
3.6K
Thermal expansion and Thermal stress: Problem Solving
2.0K
San Francisco's Golden Gate Bridge is exposed to temperatures ranging from -15 °C to 40 °C. At its coldest, the main span of the bridge is 1275 m long. Assuming that the bridge is made entirely of steel, what is the change in its length between these temperatures?
To solve the problem, first, identify the known and unknown quantities. The initial length (L) of the bridge is 1275 m, the coefficient of linear expansion (α) for steel is 12 x 10-6/°C, and the change in temperature (ΔT) is 55...
To solve the problem, first, identify the known and unknown quantities. The initial length (L) of the bridge is 1275 m, the coefficient of linear expansion (α) for steel is 12 x 10-6/°C, and the change in temperature (ΔT) is 55...
2.0K


