The objective of this project is to develop a stake base system that is biodegradable and will not impact the growth of the tree.
Sponsored by: Plantra
Team Members
Juliana Cooper Sarah Douglas Yasi Huang Ava Knaf Luke Stocker Michael Usilton
Instructor: Robert Kimel
Project Poster
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Project Video
Project Summary
Overview
Plantra’s goal is to revolutionize plant growing and crop protection to promote healthy and thriving plants. As the idea of biodegradability becomes increasingly more popular, companies are taking the initiative to modify current products with this idea in mind. For this project, the team was tasked with designing a biodegradable stake base that would allow for easy removal and reuse of the fiberglass stake in the current SunFlex Grow Tube.
Objectives
– Create a manufacturable product that allows for easy installation, good soil grip to improve stability, and is able to remain fully operational in the soil for 10 years before it begins to degrade
– Define the level of “biodegradability” and “compostability” the team would be aiming for to determine the scope of the project and what this means regarding the final product.
– Gain a full understanding of biodegradable materials and their degradation timeline through reviewing literature
– Obtain a physical model to perform quantification testing
Approach
– Meet weekly with sponsor to ensure ideas are in line with their view
– Research current material being used in biodegradable products
– Determine degradation process of materials to understand how strength would be affected and determine if byproducts would negatively impact the growth of a seedling
– Select a mixture of PLA, coconut coir fiber, and wood shavings to be used in a polymer composite matrix
– Create dog bone prototypes with varying percentages of the composite materials to determine which composition of polymers would result in the highest strength of the material
– Perform tensile testing on prototypes and analyze stress strain curves
– Create a final model using best determined polymer composite matrix
Outcomes
– From the data produced by the tensile machine, the elastic modulus, yield strength, tensile strength, and ductility of each sample were able to be calculated. The average values were then determined for each of the composites and compared against one another
– Comparing the average property values of each composite, it was determined that PLA with 5wt% coir was the best. This sample had both the largest elastic modulus and tensile strength, the third largest yield strength, and an average ductility value.
– Having a high modulus of elasticity, yield, and tensile strength indicates that the stake will be able to withstand high amounts of stress and will not be very brittle. This property is important when considering that the stake will be driven into the ground with a hammer. An average ductility is also desirable to prevent the material from completely bending and deforming under pressure.
– The components of the final stake composite are all sustainable biomaterials and will not begin to degrade until after the necessary 10 years.
– At large scale, this product would be able to be manufactured using injection molding or thermo-casting