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Bio PE – Extruding the Renewable Polymer

Last year saw a huge surge in the varieties of different 3D printing materials. However, with the world’s focus on saving the environment, not many are coming from biological sources. Even though 3D prints can be recycled into other 3D prints, it is not a zero-sum outcome. With the increase in biological materials though, the end result would be just carbon dioxide and water. In this article we focus on one of these biological materials – Bio PE – and if it can be extruded using our Next filament extruder.

Bio PE Summary

By definition, bio-plastics and biopolymers are the type of plastics and polymers which come from renewable biomass sources. These sources include: vegetable oils, sugarcane, starch and wheat grain. Depending on the products; the global bio-plastics market includes bio-PET, starch blends, PLA, bio-PA, bio-PE and others. Bio PE, or biopolyethylene, is simply polyethylene made out of ethanol. After a dehydration process, it becomes ethylene using these biomass sources. The final product is polyethylene, which properties mimic those of conventional polyethylene.

Applications

The main application for biopolymers is packaging, which makes up around 28% of the total volume shown in 2016. This includes shopping bags, food packaging, bottles and many other uses. Other uses include blow-molded hollow parts such as automotive fuel tanks, injection molded parts, tubes and other applications used in the automotive and consumer-goods industries.

Advantages & Disadvantages

sugarcane field

According to Braskem, the world-leading supplier of bio-PE, a production rate of 200 kilo ton/year of bio-PE would require approximately 450 million liters of ethanol. This would utilize 65 million hectares of Brazilian sugar cane land to produce enough sugar to enable Braskem’s production capacity. This represents 0.02% of the Brazilian arable land.  Clearly, the impact to the sugar cane food supply is quite small.

Another great advantage is that the chemical structure, applications, and recycling are identical to fossil-fuel based PE. Also do not forget that Bio PE is 100% recyclable.

All these advantages do come with one main drawback. Currently, the price of bio-PE is about 50% higher than fossil-fuel PE. In upcoming years though it should see a decrease in price when volumes increase.

Extruding Bio PE + TMP + MAPE

Here at 3devo we were able to acquire some Bio Polyethylene (PE) SHD 7255 LSL, including 20% thermomechanical pulp (TMP) and 6% maleated polyethylene (MAPE). Take note this is just a short summary of our testing. More information can be found here.

Preparation and Extrusion

Cleaning the Next filament extruder has been very important. Either a purging compound or HDPE can be used. Drying the materials was also critical. After 7 hours of drying the material doubled in moisture content over 48 hours (stored in a closed container with silica gel), it was finally ready. Three tests were conducted, using various temperatures and settings. It was interesting to see how quickly the material heated up, and fast fan cooling was vital it to handle more stress. Low temperatures also helped improve the results.

The end result of the extrusion tests

Extrusion Summary

After multiple tests, we conclude that Bio PE + TMP + MAPE combination can be successfully extruded with the Next. Some issues include the TMP particles causing the material to get easily torn apart and the ease at which the material heats up. Cleaning also determines the best results for the final filament.

Conclusion

In the end, bio-plastics and biopolymers are definitely something to focus on in the future of 3D printing. Their unique characteristics make it great for sustainable development. Also now that extruding materials like this is possible, it will be great to see what upcoming projects will be rolling out in the years ahead.