The Effects of UV Degradation on Polycarbonate Plastics Under Dynamic Compressive Loading

Author

Hannah BradfordFollow

Date of Award

Spring 5-9-2024

Document Type

Undergraduate Thesis

Department

Mechanical Engineering

First Advisor

Damian Stoddard

Second Advisor

Arunachalam Raj Rajendran

Third Advisor

Shan Jiang

Relational Format

Dissertation/Thesis

Abstract

The objective of this experiment was to analyze the dynamic properties of polycarbonate plastics subjected to accelerated ultraviolet (UV) exposure. This was done by subjecting rods of polycarbonate plastic to UV degradation in a QUV accelerated weathering machine for 375, 750, and 1500-hours. These rods were then tested under dynamic compression using a Split-Hopkinson Pressure Bar at an average strain rate of 1600/s. The Split-Hopkinson pressure bar works by rapidly compressing a sample between 3 axial rods sending an elastic wave through the sample. The strain gauges on the incident rod and the transmission rod transformed the elastic wave deformation into a voltage change that was then converted to stress and strain values. This allowed for an analysis of the dynamic response of the samples under compressive conditions. The samples were compared with a control group of polycarbonates to better understand the effects of UV degradation.

The results of this experiment showed little change in the material response for the control, 375, and 750-hour UV exposure sample groups. This indicates that 750 hours of accelerated UV exposure was not significant enough to cause changes in the Polycarbonate sample properties. 1500-hour sample groups showed an increase in plateau strength as compared to the other sample groups with a value of 169.03 MPa which was 35.5% more than the control group plateau stress. The energy density of the samples described the amount of energy absorption per unit volume of the sample and the trend was the same as for the plateau strength. The changes in properties were indicated by the 32.6% increase in energy density for the 1500-hour samples with a value of 37.54 kJ/m³.

Recommended Citation

Bradford, Hannah, "The Effects of UV Degradation on Polycarbonate Plastics Under Dynamic Compressive Loading" (2024). Honors Theses. 3111.
https://egrove.olemiss.edu/hon_thesis/3111

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