Feasibility of recycling styrofoam with acetone

• Main Author: Lim, Jin Feng
• Other Authors: Heng Kok Hui, John Gerard
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2023
• Subjects: Engineering::Mechanical engineering
• Online Access: https://hdl.handle.net/10356/167315
• Institution: Nanyang Technological University

Styrofoam, otherwise known as expanded polystyrene (EPS), is a petroleum-based plastic widely used in the transportation industry given its light weight and excellent insulation properties. However, only 2% of the Styrofoam used worldwide is recycled as the recycling process involves great complexities in breaking down the material safely. A potential alternative to recycling the material is to ‘dissolve’ Styrofoam through a simple reaction with organic solvents. This experiment can be conducted at standard room conditions to form a hard plastic material (termed EPS-A for ease of reference). However, this process comes with its own set of challenges as the drying duration and porosity of the final product varies greatly from specimen. Should the production of EPS-A be more consistent and controlled, it could prove an affordable and accessible way to repurpose Styrofoam for further use. The aim of this project was to identify variables which could have an effect on the drying duration and porosity of the Styrofoam-acetone compound: drying temperature, stirring duration, mass ratio of Styrofoam to acetone. Another aim of the project was to investigate if changes to these variables affect the tensile and elastic strength of the final product. Since there are no official parameters to abide by for the experiments conducted in this project, different procedures and standards were crafted using available devices to minimise human and experimental errors. The drying duration is set as the time frame from the instant the EPS-A test specimen was left to dry and when it can be first removed from the mould. The specimens are left to dry for two hours and followed by removal attempts made at 15-minute intervals till successful extraction. Drying temperatures were varied by heating the specimens in an oven or cooled in a refrigerator over a 60-minute period before continuing the drying process at room temperature. Lastly, a tensile test machine was used to record the readings for tensile and elastic strength. Five test specimens were made to test each variable and the three most consistent data sets were used for further analysis of each physical property. Overall, some of the identified factors proved effective and improved the usability and durability of EPS-A. However, the EPS-A specimens tend to have lower elastic modulus than Styrofoam and would fracture under load to produce plastic fragments, which could pose as an environmental threat if the fragments are not properly contained. Hence, further studies are needed to optimize the ductility of the compound in order to eliminate excessive fragmentation from occurring during material failure.