College - Author 1

College of Engineering

Department - Author 1

Materials Engineering Department

Degree Name - Author 1

BS in Materials Engineering

College - Author 2

College of Engineering

Department - Author 2

Materials Engineering Department

Degree - Author 2

BS in Materials Engineering

College - Author 3

College of Engineering

Department - Author 3

Materials Engineering Department

Degree - Author 3

BS in Materials Engineering

Date

6-2021

Primary Advisor

Trevor Harding, College of Engineering, Materials Engineering Department

Additional Advisors

Armen Kvryan, Naval Surface Warfare Center Port Hueneme

Abstract/Summary

The US Navy utilizes PVC target balloons, known as Killer Tomatoes, that are inflated onboard a naval vessel then deployed into the ocean to calibrate a variety of weaponry. The Navy has requested the investigation of biodegradable polymers to replace the PVC in attempts to reduce ocean waste that is generated from the leftover PVC material. After communicating with American Pacific Plastic Fabricators (APPF), the current manufacturer of the Killer Tomatoes, we gained an understanding of the manufacturing process and the material requirements that would allow a new material to be integrated into their current process. Two proprietary, trial polymers were obtained from Green Dot Bioplastics, BD3001 and BD3003, who claimed both materials were marine biodegradable. The polymer pellets were extruded into thin sheets at the Cal Poly campus after being dried, cut to size, and placed into one of two twenty-gallon tanks of circulating marine-water that was obtained from the Cal Poly Pier. Two tanks were used because one was shaded from all light while the other was exposed to a full spectrum grow lamp for 12 hours each day. This method was used to test if UV radiation played a role in the degradation of the polymers. The 36 samples, 12 of each material: PVC, BD3001, and BD3003, were left in their respective tank for up to 53 days. Samples were routinely removed for testing, approximately every 7-10 days, to measure the rate of biodegradability by conducting tests on each sample that was exposed to the simulated ocean environment after the specific amount of time. Comparing the data from samples that had different exposure times to the simulated ocean environment would give insights on how the material is reacting and the degradation behavior of the material in relation to the specific environment and amount of time. Biodegradability was tested via DSC, FTIR, SEM, and gravimetry. Both BD3001 and BD3003 performed similarly throughout the biodegradability testing, as neither polymer showed definitive signs that biodegradation occurred during the testing period. The differences in light exposure also had little impact on the diminutive amount of biodegradation that took place in the samples. These results suggest that they would not eliminate the waste generated from current Killer Tomatoes. The performance was tested via radio frequency welding and tensile testing. Both polymers were able to be welded but exhibited inadequate mechanical properties that were not comparable to PVC. Therefore, both could be manufactured in the same manner as the PVC but may fail to perform the application required by the Navy, as more material would be needed to meet mechanical requirements. It is recommended that the Navy consider longer term in situ testing of prototypes for a more realistic evaluation of biodegradation and performance.

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