Shape Memory Polymers and Their Composites: Towards Field Applications via Production, Characterization and Modelling

• Author / Creator

  Garces Arguello, Irina Tatiana

• Shape Memory Polymers (SMP) and Shape Memory Polymer Composites (SMPCs) can be used in field applications to replace mechanical actuators. They offer lightweight, ease of part manufacturing, reduced energy losses due to elimination of friction between components and a wide range of mobility. The present work focuses on production, characterization and modelling of SMPs and their composites with the ultimate goal to obtain controlled field applications. Firstly a detailed work on the properties of thermoplastic SMPs is put forward while looking at the capability to produce part manufacturing via Extrusion Based Additive Manufacturing (EBAM). To this end, a thorough characterization of different thermoplastic SMPs was done while looking at the effects of moisture on the material's mechanical performance and processability.

  Modelling is crucial to understand the basic parameters needed for engineering design, such as the shape recovery ratio, shape recovery rate and shape recovery force. Hence, a thorough literature review is provided on modelling techniques for thermoresponsive shape memory polymers. Although many great efforts have been made towards modelling, there is still a gap between modelling efforts and focus concerning engineering design. Specifically, it is necessary to provide models for the common types of loading in engineering applications. Many of the future applications for SMPs lie in soft robotics, unmanned aerial vehicles, self-assembly or self-folding structures, where bending is the most common type of load. The method of activation of the thermal shape memory effect must also be considered within engineering models. Furthermore, easy application and interpretation of models are required for first stage engineering design. Consequently, a model for SMPs under bending applications, that can be later adapted to field heating conditions, is proposed to mitigate the mentioned knowledge gap. The proposed model is a transient viscoelastic model that can predict recovery properties for flexural applications. A methodology for parameter extraction via DMA has also been presented in this thesis to explain the change of material parameters with respect to time. This model can be easily adapted to different field activation methods of the SMPs.

  Additive manufacturing of shape memory polymer composites was studied to acquire SMPCs, that can be easily formed into desired shapes and activated in out-of-laboratory conditions. As such, hybrid material SMPC structures manufactured by EBAM for field applications are proposed in this thesis. Fabrication, actuation, and characterization of the composite were done in this thesis. The proposed SMPC structure was easily manufactured and possessed great potential to be controlled and showed sensing capabilities in strain and temperature. This work has opened doors for SMPs to be used as self-sensing smart actuators in real-life engineering applications.

• Subjects / Keywords

  • Shape Memory Polymers

• Graduation date

  Spring 2021

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/r3-cbd0-v604

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.