Relationship between sacrificial bond content and anti-tearing properties of polyurethane elastomers

• Main Author: Chew, Min Yi
• Other Authors: Chen, Xiaodong
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2020
• Subjects: Engineering::Materials::Organic/Polymer electronics; Engineering::Materials::Testing of materials
• Online Access: https://hdl.handle.net/10356/138460
• Institution: Nanyang Technological University

Anti-tearing property of polymeric substrate materials in wearable devices is drawing great attention, as it can reduce the influence of fractures on substrates. This elongates the lifetimes of materials and hence devices. However, despite increasing researches on anti-tearing materials, the relationship between the material’s composition and its properties (anti-tearing and mechanical) has yet to be well investigated. Thus, for this project, 2 sets of polyurethane (PU) elastomers (sets A and B) were synthesised, with varying 2-ureido-4-pyrimidinone (UPy, hydrogen bond unit) content. Set A comprised of linear polymer materials while set B comprised of crosslinked polymer materials. The effects of the different UPy and crosslinking content on the anti-tearing, mechanical and energy dissipation (hysteresis) properties of the samples were studied. The PU samples underwent tensile and cyclic stretching tests, providing data of the: (1) critical strain; (2) fracture energy, (3) elastic modulus, and (4) energy dissipation. The results showed that with crosslinking, certain amounts of UPy can result in better mechanical properties, but fare weaker for anti-tearing. On the other hand, without crosslinking, increasing the UPy content caused poorer mechanical properties and antitearing properties. The revealed synergistic effect of crosslinking and hydrogen bond content can provide better recommendations regarding design of anti-tearing polymer materials with the desired mechanical strength depending on the application.