Understanding the Low Glass Transition Temperature (Tg) of PHA: Nature's 3D FDM Printing Filament

In the world of 3D printing, understanding the properties of different filament materials is crucial for achieving the best results. One key property is the glass transition temperature (Tg), the temperature at which a polymer changes from a hard, glassy material to a softer, more rubbery state. In this blog, we"ll explore the Tg of PHA (polyhydroxyalkanoate), a unique and eco-friendly 3D printer filament from Beyond Plastic, and why it has a significantly lower Tg compared to synthetic filaments like PLA and PETG.

What is Glass Transition Temperature (Tg)?

The glass transition temperature (Tg) is a critical point for polymers. It marks the temperature range where a polymer transitions from a brittle, glass-like state to a more flexible, rubbery state. This change isn't instantaneous but occurs gradually. For instance, PLA (polylactic acid) typically has a Tg in the high 50s °C, while PETG (polyethylene terephthalate glycol) has a Tg in the high 70s °C.

To make this concept easier to grasp, think of water. Water has a Tg of 0°C. Below this temperature, water becomes solid ice. As the temperature rises above 0°C, ice begins to melt and transition back into liquid water. This melting process is gradual and becomes more rapid at higher temperatures.

Why is PHA's Tg So Low?

PHA stands out because it has a much lower Tg, around 5-6°C. This low Tg is due to its natural origin and the role it plays in the environment.

PHA is produced by bacteria as a means to store excess food, which they can later convert back into energy when needed. This conversion needs to happen efficiently at ambient temperatures typical of their environments. If PHA had a high Tg like PLA, bacteria wouldn't be able to convert it back into energy effectively, potentially jeopardizing their survival.

The average temperature of the world's oceans, for example, is around 5-6°C. This temperature is ideal for the bacterial conversion of PHA, highlighting how this polymer has evolved to suit its natural context perfectly.

Beyond Plastic's Eco-Friendly 3D Printer Filament

Beyond Plastic offers a unique brand of PHA filament that is recyclable, compostable, and biodegradable. Unlike many synthetic polymers that are designed and produced in laboratories using fossil fuels, PHA is a naturally occurring polymer that has existed for billions of years. It was discovered in 1920 and has since been recognized for its biodegradability and sustainability.

Bacteria have evolved to produce and utilize PHA efficiently, making it an excellent example of a bio-based, eco-friendly material. As the world seeks to reduce plastic waste and move towards more sustainable materials, Beyond Plastic's PHA presents a promising alternative to traditional, petroleum-based plastics.

In the context of 3D printing, Beyond Plastic's PHA filament's unique properties make it a valuable filament. Its low Tg means it can be used in a variety of ambient conditions, and its natural biodegradability ensures that printed objects have a reduced environmental impact.

However, it also means the material has the ability to crystallize at room temperature. Nearly all polymers that are petrochemically derived or even artificially polymerized, like PLA, can have their level or percentage of crystallization controlled by adding or removing heat during the printing or post-printing process. However, PHA, being a natural polymer with a low Tg, means the final printed object will crystallize to its natural state after being removed from the print bed at room temperature.

Conclusion

Understanding the low Tg of Beyond Plastic's PHA filament gives us insight into its unique properties and advantages as a 3D printer filament. Its ability to transition at lower temperatures makes it ideal for natural bacterial processes, showcasing the incredible efficiency of nature's designs. As we continue to explore and develop sustainable materials, Beyond Plastic's PHA stands out as a remarkable example of nature's ingenuity in creating environmentally friendly solutions.

For more information on Beyond Plastic and its PHA applications, stay tuned to our blog and feel free to reach out with any questions!