Bioplastic Advances Innovative, Green Architecture

How can one go back to nature and forward in technology at the same time? Or take a major industrial byproduct, use it and dispose of it without adding to the greenhouse effect? Science fiction? No, you can do it using a bioplastic called “liquid wood.”

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To start, what is bioplastic? Bioplastics (or biobased polymers) are plastics made from renewable biomass sources. The term bioplastics is generally used to distinguish them from plastics derived from petroleum. Some, but not all bioplastics are biodegradable.  Unlike biopolymers, which are produced by living organisms, bioplastics are man-made materials.

Recently an ultra-modern pavilion made of bioplastic was completed in Stuttgart, Germany. The scientists from Stuttgart University’s ITKE (Institute of Building Structures and Structural Design) designed the freeform facade using  a new bioplastic, specifically developed for use in the construction industry. According to an ITKE press release:

Collaborating materials scientists, architects, product designers, manufacturing technicians, and environmental experts were able to develop a new material for facade cladding which is thermoformable and made primarily(>90%) from renewable resources. Developed by project partner TECNARO within the framework of the research project, ARBOBLEND®, a special type of bioplastic granules, can be extruded into sheets which are further processable as needed: They can be drilled, printed, laminated, laser cut, CNC-milled, or thermoformed to achieve different surface qualities and structures and various moulded components can be produced.

The semi-finished products serve as cladding for flat or free-formed interior and exterior walls. The material can be recycled and meets the high durability and inflammability standards for building materials. The goal of the project was to develop a maximally sustainable yet durable building material while keeping petroleumbased components and additives to a minimum.

The pavilion was constructed from triangular pyramidal shapes, thermoformed from thick-walled bioplastic sheets, with the plastic waste regranulated and returned to the extruding process. According to ITKE, at the end of their useful life the façade sheets can be composted. ITKE’s conception of bioplastic facades received an award in Germany’s nationwide competition, “Landmarks in the Land of Ideas 2013/14.”

This innovative construction project used Arboform® bioplastic by Tecnaro GmbH, a German company that  has been developing and producing bioplastics for more than a decade. Arboform bioplastic material is made primarily out of lignin, an abundant natural material. Production of lignin, a byproduct of the paper industry, amounts to 50 million tons annually, with 95% of it burned for thermal energy.

Lignin is a complex polymer of aromatic alcohols. It makes up to 25-30% of a tree, forming a 3D supporting matrix for cellulose fibers. In natural wood, lignin is responsible for compressive strength, while cellulose provides tensile strength. To create Arboform, lignin is mixed with natural fibers (cellulose, flax, hemp) and additives, resulting in a bioplastic material that can be processed at elevated temperatures using conventional plastics processing machines. The composition of Arboform can be varied to adjust strength, rigidity, dimensional stability and other material properties; and just like natural wood, it can withstand combined tensile and compressive loads.

Having mechanical and thermal properties of natural wood, Arboform bioplastic materials are already used to make a variety of products, such as furniture, automotive interiors, musical instruments, jewelry, garden supplies, and more. It has passed the so-called “sucking test” for children’s toys being not only below the exposure limits, but also below the detection limit for all of the hazardous substances it was tested for.

Finally,  thermoplastic compounds based on renewable resources offer environmentally friendly alternatives to synthetic petrochemical plastics. Some bioplastics are compostable and biodegradable; others, if burned, will emit the same amount of CO2 that the plant previously used for its growth, i.e., without adding to the greenhouse effect. The bioplastic pavilion construction demonstrated the feasibility of using earth-friendly materials for architecture.

Source: Free-form semi-finished products primarily made of renewable raw materials, for use in indoor and outdoor spaces, ITKE-Stuttgart University, Germany
Source: Ecological and technical principles of ARBOFORM. Tecnaro.de
Source: ArboSkin pavilion made from bioplastic by ITKE, Dezeen magazine, November 9, 2013
Source: Compostable geometric pavilion is made out of bioplastics, Kimberley Mok, Treehugger.com, November 15, 2013
Video: ArboSkin Video Clip: Short clip about the EFRE funded bioplastic façade, ITKE on Vimeo.