Self-healing characterizations of polyurea/polyurethane coating & its formulation optimization

• Main Author: Sim, Celine (Shen Silin)
• Other Authors: Dong Zhili
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2021
• Subjects: Engineering::Materials::Material testing and characterization
• Online Access: https://hdl.handle.net/10356/149284
• Institution: Nanyang Technological University

In midst of the global rising cost of corrosion, solutions such as application of protective coating and employing regular maintenance work have been put in place. All these efforts made primarily to aim for the lifetime extension of what is being protected. To further reduce need for regular maintenance, the area of self-healing materials is explored. Self-healing materials, especially self-healing polyurea/polyurethane, to replace traditional coating has been of increasing interest in the past decade. The frequency of regular maintenance work can also be reduced as the coating is capable of forming bonds at ruptured sites. This reduces the cost of maintenance and the risk involved in workers engaging in maintenance work. Polyurethane has always been the more popular coating among other polymers because of its lower cost of raw materials, easy fabrication and fast curing time. Although polyurea is known to cost more, it has even shorter curing time. The extremely short curing time of polyurea coating could potentially outweigh the cost due to its short down time. With high self-healing efficiency, self-healing polyurea could be the ultimate choice of protective coating. This report aims to find the optimum formulation for fabrication of polyurea with high self-healing efficiency. This is conducted by changing the composition of components chose for formulation of polyurea. The choice of isocyanate and amine is varied to explore its impact on chain mobility and microphase separation, which are important factors affecting self-healing efficiency. A series of characterisation including ATR-FTIR, DSC, optical microscope and mechanical tester is used to analyse the factors affecting the self-healing efficiency of polyurea fabricated and eventually determine the best formulation. The ideal formulation of TDI-P1000 polyurea managed to achieve self-healing of 42%. Further studies could be done to include multiple healing mechanisms at different area of polyurea to boost its self-healing efficiency after repeated healing.