Analysis of mould-making materials

• Main Author: Poh, Yong Kang
• Other Authors: Aravind Dasari
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2023
• Subjects: Engineering::Materials
• Online Access: https://hdl.handle.net/10356/168244
• Institution: Nanyang Technological University

Epoxy resins are essential materials used widely for artistic applications and has become a popular choice of material for sculptors to create art. Epoxy resin compounds with different viscosities are commercially available at high costs to suit different artistic applications. Most artists often purchase ready-made products from companies to suit their specific needs, which end up being very costly. However, these properties can be replicated by adding easily obtainable fillers to the epoxy resin bases. With proper knowledge of the fillers’ effects on the properties of the epoxy resin, the base resin can be tuned to suit many different purposes such as laminating, brush-up, fairing and kneadable compounds, all of which require varying levels of viscosities. These viscosities differ based on the amount of filler added into the epoxy resin. Five types of fillers were used in the testing, namely talcum powder, fumed silica, kaolin, class F fly ash and Q-Cel, a filler consisting of hollow glass microspheres. This project defines four viscosity thresholds, or “viscous states”, namely the laminating compound, the brush-up compound, the fairing compound and kneadable epoxy. The apparent viscosities corresponding to the different viscous states were measured using a rheometer using fly ash as a filler. Differential scanning calorimetry (DSC) was used to determine the crosslink density of the epoxy compounds containing fillers, in an attempt to find out if fillers were affecting the curing mechanics. The curing behaviour was also monitored with the use of a thermocouple to determine if the fillers had any effects on the curing time of the resin. It showed that some fillers decreased the cure time by reacting away the epoxide groups. Viscosity measurements yielded inconsistent values for the same viscous states for different fillers, showing that apparent viscosity was not an appropriate measurement to numerically define the viscous states. The mechanical testing showed that the increase of fillers increased the resulting material’s stiffness, while decreasing the toughness. Most samples showed a very slight increase in flexural strength with increasing filler content. Additionally, the use of Q-Cel as a filler in epoxy resins resulted in a decrease in the flexural strength with little change in stiffness.