GOALI: Mechanical Activation of Amorphous Shape Memory Polymers

GOALI项目的研究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。通过在玻璃化转变温度以下进行变形和冷却，非晶态形状记忆聚合物可以被编程为存储临时形状。当材料在转变温度以上重新加热时，会恢复永久形状。聚合物结构可以定制，以满足广泛的机械和生物要求。这使得它们对生物医学设备行业的应用具有吸引力；然而，由于恢复时间较慢，它们没有得到更广泛的接受。在机械激活中，除了温度外，还应用机械功来加速形状恢复。这项研究将探讨分子取向和结构松弛两种机制对机械激活所需的力的重要性。将测量形状记忆编程条件和物理老化对机械行为的影响。将开发本构模型来研究材料特性、温度和加载条件对机械激活的影响。该研究将使机械激活器件的编程更精确、制造策略更高效。开发的模型将有助于表征这些设备在预期保质期内的安全性和性能，这将导致生物医学设备行业的更广泛接受。学生研究人员将通过在一家领先的形状记忆聚合物医疗设备公司的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.