GOALI: Mechanical Activation of Amorphous Shape Memory Polymers

本研究项目的目的是阐明形状记忆聚合物在机械活化过程中的性能控制机制。 无定形形状记忆聚合物可以通过施加变形和冷却到低于玻璃化转变温度来编程以存储临时形状。 当再加热到转变温度以上时，材料恢复永久形状。聚合物结构可以定制以满足广泛的机械和生物学要求。 这使得它们在生物医学设备行业的应用中具有吸引力;但由于它们的恢复时间慢，它们尚未获得更广泛的接受。 在机械活化中，除了温度之外还施加机械功以加速形状恢复。本研究将探讨两种机制的重要性，分子取向和结构松弛，对机械活化的力的要求。 将测量形状记忆编程条件和物理老化对机械性能的影响。本构模型将用于研究材料特性、温度和载荷条件对机械激活的影响，该研究将有助于为机械激活器件开发更精确的编程和更有效的制造策略。 所开发的模型将有助于表征这些器械在其预期有效期内的安全性和性能，这可能会导致生物医学器械行业更广泛的接受。学生研究人员将通过在形状记忆聚合物医疗器械的领先公司进行暑期实习获得行业经验。 这项研究将被整合到课程中，包括智能聚合物的力学。

The research objective of this Grant Opportunity for Academic Liaison with Industry (GOALI) project is to elucidate the mechanisms controlling the performance of shape memory polymers during mechanical activation. Amorphous shape memory polymers can be programmed to store a temporary shape by applying deformation and cooling below the glass transition temperature. The material recovers the permanent shape when reheated above the transition temperature. The polymer structure can be tailored to meet a broad range of mechanical and biological requirements. This makes them attractive for applications in the biomedical device industry; yet they have not gained wider acceptance because of their slow recovery times. In mechanical activation, mechanical work is applied in addition to temperature to accelerate shape recovery. The research will investigate the importance of two mechanisms, molecular orientation and structural relaxation, on the force requirements for mechanical activation. The effect of shape memory programming conditions and physical aging on mechanical behavior will be measured. Constitutive models will be developed to investigate the effect of material properties and temperature and loading conditions on mechanical activation.The research will enable the development of more precise programming and more efficient manufacturing strategies for mechanically activated devices. The developed models will help to characterize the safety and performance of these devices throughout their intended shelf life, which can lead to a wider acceptance in the biomedical device industry. Student researchers will gain industry experience through summer internships at a leading company for shape memory polymer medical devices. The research will be integrated into courses to include the mechanics of smart polymers.