在玻璃过渡温度 (Tg) 以下的3D打印多乳酸 (PLA) 的热力学行为和应变率灵敏度
Vukašin Slavković1, Blaž Hanželič2, Vasja Plesec2
1Faculty of Engineering, University of Kragujevac, Sestre Janjic 6, 34000 Kragujevac, Serbia.
Polymers
|June 19, 2024
概括
这项研究揭示了4D打印的聚乳酸 (PLA) 表现出显著的热力学行为,其特性高度依赖于温度和拉伸率,低于其玻璃过渡温度.
科学领域:
- 材料科学 材料科学 材料科学
- 聚合物工程 聚合物工程
- 增材制造 增材制造 增材制造
背景情况:
- 4D打印的聚乳酸 (PLA) 是一个有前途的智能材料,具有形状记忆能力.
- 了解其热力学行为对于设计功能应用至关重要.
研究的目的:
- 在不同温度和拉伸率下研究4D打印PLA的热力学特性.
- 确定这些参数对机械响应和形状记忆潜力的影响.
主要方法:
- 使用张力,压缩和动态机械热分析 (DMTA) 进行表征.
- 在低于玻璃过渡温度 (Tg) 的温度下进行的热机械压缩试验,并跨越一系列拉伸率.
- 用热成像测试的adiabatic测试,以评估自我加热效应.
主要成果:
- PLA的弹性模量在玻璃 (1045.7 MPa) 和 (1.2 MPa) 阶段之间有显著的变化,这表明了形状记忆的潜力.
- 产量应力强烈依赖于拉伸率和温度,范围从110 MPa到42 MPa.
- 较高的拉伸率 (0.01-0.1 s-1) 诱导自我加热,导致材料变软.
结论:
- 4D打印的PLA表现出明显的应变率和温度敏感性,低于它的Tg (65°C).
- 该材料由于其相位过渡行为,具有显著的形状记忆潜力.
- 在高延展率下自加热会影响机械性能,因此在应用设计中需要考虑.
相关概念视频
Plastic Behavior
196
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...
196
Thermal Strain
910
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...
910
Plasticity
2.1K
Plasticity is the property where an object loses its elasticity and undergoes irreversible deformation, even after the deformation forces are eliminated. If a material deforms irreversibly without increasing stress or load, then this is called ideal plasticity. For example, when a force is applied to an aluminum rod, it changes its shape, but it does not return to its original shape once the force is removed. Plastic deformation or ductility is thus a permanent deformation or change in the...
2.1K


