Hydrogel fracture experiment: from different stimuli to delayed fracture study (C)

• Main Author: Ng, Wei Qiang
• Other Authors: Li Hua
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2023
• Subjects: Engineering::Mechanical engineering
• Online Access: https://hdl.handle.net/10356/168418
• Institution: Nanyang Technological University

Hydrogel is widely utilized in various applications and developments such as the delivery of medicines, tissues regenerative scaffolding and contact lenses. This is due to its great mechanical properties like great biocompatibility and biodegradability, especially in the relevance of biomedical industries. From this report, the influence of water content on polyacrylamide hydrogels with regards to fracture mechanics is explored. Experiments relating to fracture mechanics is carried out to accomplish the above mentioned, mainly fast fracture for samples with and without any pre- cut, through subjecting samples to monotonic loading and, also on the study of delayed fracture, whereby samples with pre- cut will be subjected to static loading. Water content varying from the maximum swelling percentage, original percentage of the as prepared hydrogel, and variation from 80% down to 50% will be utilized as test samples for the experiments mentioned. The theory of energy release rate relating to fracture toughness and fracture energy is applied in this report. The effect of pre- cut length concerning crack tip sensitivity is also being studied. It is observed through the experiments conducted that at higher water content, the critical energy release rate is considerably low, but with the reduction of water content displayed, the higher the critical energy release rate. Thus, indicating that water content in polyacrylamide hydrogels does indeed have a significant effect on the mechanical properties like the fracture energy and fracture toughness.