Semicrystalline polymeric systems are a type of Shape Memory Polymer (SMP), which are more straightforward to synthesize in comparison with other class of stimulus-responsive polymers. On these systems, the shape memory is triggered by temperature and partially driven by crystallization-induced elongation, heating-induced contraction, and elastic entropy. However, a stable temporary and permanent shape through cycling is not easy to achieve. For that reason, a laminar composite made based in the encapsulation of ethylene vinyl acetate (EVA) inside a PU matrix was developed, with the aim of obtaining an actuator with a preferred deformation direction and stable change of shape. In this study, chemically cross-linked ethylene vinyl acetate copolymer (cEVA) as SMP was synthesized and functionalized as a reinforcing strip. A temperature-memory actuator composite was manufactured by the encapsulation of a shape memory programmed strip in an elastomer matrix. The shape memory properties and thermocycling assessment were evaluated using differential scanning calorimetry and dynamic mechanical analysis. Results show the ability of the actuator to bend and unbend, following multiple consecutive heating-cooling cycles. The relationship between the strip, the matrix, and the interface is critical in the bending and shape memory maintenance.

中文翻译：

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交联乙烯-醋酸乙烯酯 - 聚（氨基甲酸乙酯）温度记忆复合执行器

半结晶聚合物系统是一种形状记忆聚合物 (SMP)，与其他类别的刺激响应聚合物相比，它更易于合成。在这些系统上，形状记忆由温度触发，部分由结晶诱导伸长、加热诱导收缩和弹性熵驱动。然而，通过循环获得稳定的临时和永久形状并不容易。出于这个原因，开发了一种基于将乙烯醋酸乙烯酯 (EVA) 封装在 PU 基质内制成的层状复合材料，目的是获得具有优选变形方向和稳定形状变化的致动器。在这项研究中，化学交联的乙烯醋酸乙烯酯共聚物 (cEVA) 作为 SMP 被合成并功能化作为增强带。温度记忆致动器复合材料是通过将形状记忆编程条封装在弹性体基质中来制造的。使用差示扫描量热法和动态力学分析评估形状记忆特性和热循环评估。结果显示了执行器在多个连续加热-冷却循环后弯曲和伸直的能力。条、基体和界面之间的关系在弯曲和形状记忆保持中至关重要。经过多个连续的加热-冷却循环。条、基体和界面之间的关系在弯曲和形状记忆保持中至关重要。经过多个连续的加热-冷却循环。条、基体和界面之间的关系在弯曲和形状记忆保持中至关重要。