Multifunctional shape memory polymer composites: laboratory to reality via additive manufacturing

形状记忆聚合物(SMP)可以存储临时形状，并在施加外部刺激(如热)时恢复其原始形状。与形状记忆合金等其他形状记忆材料相比，SMP具有重要的优势。其中一些优点是重量轻、应变恢复能力相对较高、更容易裁剪性能和可制造性。它们在无人机(UAV)、变形飞机部件和生物医学支架等应用中具有巨大的潜力。它们更广泛应用的瓶颈是它们固有的低机械性能和形状恢复力(SRF)，以及对它们在实际“现场应用”中作为湿度、温度等函数的特性的基本了解。对于关键应用，这些重要方面需要详细解决和记录，这也是我们提出研究计划背后的主要动机。 大多数SMP都受到湿度的影响，因此，我们进行了详细的研究，以确定其对SMP的影响。此外，我们还研究了印刷参数对基于挤压的添加剂制造(EBAM)技术印刷的SMP性能的影响。SMP-复合材料(SMPC)是增强的SMP，与SMP相比，它具有更高的力学性能和更高的耐磨性。多年来，我的团队一直致力于EBAM技术生产的多功能SMPC的生产和表征。在我们已开发的知识和专门知识的基础上，本提案准备弥补上述缺点。 拟议研究计划的主要目标是：(A)利用EBAM生产和表征纤维增强SMPC；(B)开发预测SMPC性能的模型；(C)生产集成加热元件以便于现场激活的SMPC，并调查用于结构健康监测(SHM)能力的加热元件的阻力。 拟议计划的新颖性和意义源于它承诺对SMPC提供强有力的分析和实验理解。这不仅将为该计划提供一个大型实验数据库，而且还将为与SMPC合作多年的研究人员和工程师提供一个大型实验数据库。分析模型将是一个简单但准确的模型，遗憾的是，目前文献中没有这种模型，并打算成为该领域的开创性工作。所提出的激活技术和SHM能力将使这些新材料成为真正的多功能SMPC。因此，该提案将通过促进SMPC在上述具有战略重要性的应用中以科学知识为基础，为将这些材料从实验室转移到实际实地应用提供一条途径。该计划将为加拿大和世界各地知识的进步做出重大贡献。

Shape memory polymers (SMP) can store a temporary shape and restore their original shape upon application of an external stimulus, such as heat. SMP offer important advantages over other shape memory materials, such as shape memory alloys. Some of these advantages are lightweight, relatively higher strain recover-ability, easier tailorable properties, and manufacturability. They have the great potential to be utilized in applications, such as unmanned air vehicles (UAV), morphing aircraft components, and biomedical stents, to name a few. The bottleneck in their broader utilization is their inherently low mechanical properties and shape recovery forces (SRF), and a fundamental understanding of their properties in actual “field applications” as a function of humidity, temperature, etc. These important aspects need to be addressed and documented in detail for critical applications, and this is the main motivation behind this proposal for our research program. Most SMP are affected by humidity; therefore, we conducted detailed studies to identify its effects on SMP. Additionally, we studied the effect of print parameters on the properties of the SMP printed using extrusion based additive manufacturing (EBAM) technique. SMP-composites (SMPC) are reinforced SMP and have higher mechanical properties and SRF compared to SMP. My group has been working towards production and characterization of multifunctional SMPC produced by EBAM technique for a number of years. Building on to the knowledge and expertise we have developed, this proposal is prepared to address the aforementioned shortcomings. The main objectives of the proposed research program are: (a) to produce and characterize fiber reinforced SMPC using EBAM; (b) to develop a model to predict the properties of SMPC; (c) to produce SMPC with integrated heating elements to facilitate field activations, and to investigate the resistance of the heating elements for structural health monitoring (SHM) capability. The novelty and significance of the proposed program originate from its promise to provide a strong analytical and experimental understanding of the SMPC. This will provide a large experimental database not only for this program but also for the researchers and engineers that work with SMPC for years to come. The analytical model will be a simple yet accurate model that is unfortunately currently missing in the literature and intended to be a pioneering work in the field. The proposed activation technique and SHM capabilities will make these novel materials true multifunctional SMPC. Consequently, the proposal will provide a way forward to take these materials out of the laboratories to actual field applications by promoting scientific knowledge based use of SMPC in the aforementioned strategically critical applications. The program will make significant contributions to the advancement of knowledge in Canada and around the world.