This problem was given as an assignment to graduate students in preparation for writing a research proposal, a requirement for the Biosystems Engineering PhD Program at the University of Tennessee.
Senior-level students studying Biosystems Engineering were assigned a year-long project to design a new line of environmentally responsible plastic packaging. The line was to be produced by a processor that manufactured a significant volume of seedling trays used primarily by nurseries. Market research by the processor revealed that there was a growing demand for biodegradable trays as growers strive to minimize the waste.
The students’ task was to research biodegradable plastics that could be disposed of by composting without costly recycling. The class was assigned to use Knovel to quickly research the available options.
Plastic used for the production of seedling trays must be replaced with biodegradable grade so it can be fully composted in soil at the end of its commercial lifecycle.
Questions to Answer:
- Are there any plastic grades that can fully decompose in agricultural soil?
- What is the environmental impact of these plastics, and how best to assess their suitability for composting?
- What is the availability of biodegradable plastic grades, who are the manufacturers and what is the pricing?
- Check for agricultural plastics that can fully degrade when buried in soil.
- Find information on composting of biodegradable plastics and their impact on the agricultural soil.
- Get the names of the manufacturers, grades and pricing for biodegradable plastics.
Use of Biodegradable Plastics in Agriculture
The students start by searching Knovel for ‘biodegradable polymers agriculture’ (Click to run search):
On the search results page, they find Environmentally Degradable Materials Based on Multicomponent Polymeric Systems and opens Section 6.11 Other Applications:
On the next page, they read:
Checking for Degradable Plastics Used in Agriculture
Changing the query to ‘agricultural bioplastics’ (Click to run search):
In the same book, Environmentally Degradable Materials Based on Multicomponent Polymeric Systems, Section 19.3 Agricultural Mulch Films Made with Bioplastics they read two passages that describe the use of biodegradable plastics in the industry. (Click to Read 1) (Click to Read 2).
Assessing Environmental Impact
To find out about the effects of biodegradable plastics on soil, the students search for ‘soil and biodegradable polymers’ (Click to run search):
On the search results page, they find Handbook of Biodegradable Polymers and opens Section 3.1.2 Biodegradable Polymers and Soil:
Further in the book, in Section 3.5 Effects of Biodegradable Polymers on Soil Living Organisms, they read and find:
It seems that some additives in biodegradable plastics that fully decompose in soil can be toxic. The student now has a good understanding that not all biodegradable plastics are compostable.
Assessing Suitability for Composting
Next, the students must research the criteria for plastics that can decompose naturally within soil without harming the environment. They search for compostable plastic grades by using the keyword ‘compostability’ in Knovel (Click to run search):
On the search results page, they open Section 5.3.3 Compostability Norms, in the same book (Handbook of Biodegradable Polymers) where they find information on certification of compostable plastics. (Click to Read)
On the top of page 163, they find a description of test methods used for certification in different countries. (Click to Read)
Finally, in section 5.4.2 Different Certification Systems (bottom of page 173), there is a text describing certification systems used in the US:
Manufacturers, Grades and Market
Now the students have to find information on the manufacturers of biodegradable plastics and their grades. The class searches for ‘biopolymer manufacturers’ (Click to run search):
On the search results page, he finds Engineering Biopolymers – Markets, Manufacturing, Properties and Applications and opens section 8.2 The Current Price Situation containing brief description of the situation on the market.* (Click to View)
*note: current market situation may vary from that in the book
And a chart with prices for many grades of biopolymers:
An especially useful table is Table 8.1 Overview of Biopolymer Manufacturers. It can be found on pages 270–281. (Click to View)
This table is followed by contact information. (Click to View)
Appendix A: Manufacturers, Trade Names, and Material Data Sheets found in this title lists biopolymers available from various manufacturers. It has the following preface:
The graduate class has found all the general information he needs to start his research project. They compile the information into an interim report for their adviser.
The recommendation on biopolymers suitable for the application will be made on the basis of more specific information obtained directly from biopolymer manufacturers.
The student found that:
- Biodegradable plastics are used widely in agriculture and their use expands rapidly. Most widely they are used in mulching films.
- Some biodegradable plastics are especially formulated to be biodegrade in situ. Extensive studies confirm that these plastics can be safely composted in agriculture.
- Prices of biodegradable plastics are higher than those of traditional grades although some economic benefit could results from savings due to lower recycling cost and reduction in thickness and weight of the product – it does not have to be very strong if it is to be decomposed in situ.
- There is wide selection of manufacturers, grades and price levels for different types of biodegradable plastics.
A shout out to the Knovel User Who Submitted this Solution Story!
Professor Douglas G. Hayes
Douglas G. Hayes received his B.Sc. and Ph.D. in chemical engineering from Iowa State Univ. (1986) and Univ. Michigan (1991), respectively.
He currently serves as a Professor of Biosystems Engineering at Univ. Tennessee, and as Associate Editor for J. Surfactants Deterg., J. Am. Oil Chem. Soc. and Biol. Eng. Trans. (ASABE). He has coauthored over 60 research articles, book chapters, and books.
His research areas consist of complex fluids, biocatalysis, lipid chemistry, and biofuels and biobased products. To contact the author please email him directly at: firstname.lastname@example.org