In the experiment, all components were is filled
one by one into the opening of a standard hot glue gun.
With an app, the Foam community can share their results with each other.
The foam gun reaches a higher temperature than conventional hot glue guns.
Standard hot glue guns don’t reach the right temperature
to melt PHB, therefore a candle is used to help.
UNDER PRESSURE
a foam gun for the individual use of PHB foam
This project dealt with foaming of the bioplastic polyhydroxybutyric acid (PHB). With the aim of generating a more sustainable and non-toxic alternative to the conventional construction foam. I investigated the industrial foaming processes in order to make its properties more accessible to individuals. Eventually, I modified a hot glue gun to make this industrial method available for individual households. In the future, it could thereby by possible to foam the PHB according to different needs and to use it in a variety of applications.
| student: | Theresa Voigt |
| project: | full circle |
| year: | 2020/21 |
| examined bioplastic: | Polyhydroxybutyric acid (PHB) |
| material expert support: | Dr. Gundela Peschel Hans-Knöll-Institut |
full concept text
The aim of this project was to make PHB available for home-use and open up new fields of application. Using a modified hot glue gun, it is possible to melt the PHB granules and foam them by adding a foaming agent. Experimentally, I filled in the granules and the foaming agent individually into the opening. In the future, the material can be provided with a foaming agent integrated and extruded into the correct size during a compounding process. Standard hot glue guns do not reach the sufficient temperature, therefore some enhancements had to be made. However, first experiments showed that it is possible to create a strong enough PHB foam to connect materials like wood. The material proves to also be detachable when needed (in terms of repairs or artistic measures).
The PHB is synthesized by the bacteria Ralstonia eutropha as a storage medium. Since these bacteria preferably digest plant based sugars, no fossil resources are being used. In addition, PHB is completely biodegradable, which also allows long-lasting use with subsequent composting.
Taking these aspects into account, the cycle for “Under pressure” was created. The material and the foam gun are supplied either to hardware stores or directly to customers. Once the foam gun is heated up, it can be used for a variety of things: the versatile applications include reversible or irreversible repairs, for example, to fill cracks or holes. It is also possible to foam up small objects, like a light bulb holder on the wall, hooks or small book shelves. The system allows for quick creating and enables the user to form individual objects. An app is part of the concept where the Foam community can share their projects and thereby make them accessible to others.
The recycability of the resulting products is very limited or lacking all in all. Since the PHB foam is applied for a long life span, I can justify the complete biodegradability of the material at the end of the cycle.
In order to be able to produce PHB foam, more research is needed. Then, PHB foam could be a useful alternative to conventional construction foam.