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Boston Society of Architects

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Organic chemistry

Searching for a natural cure to the plastic plague

Organic Chemistry header

Magic Circle Variation 5 (detail), by Rogan Brown, 2015. Hand-cut paper “embodies paradoxical qualities in nature: fragility and durability”; 39 × 40 × 8 inches.

Photo: Courtesy Rogan Brown

Plastic has an endurance problem. The material lasts—but not in a good way. Long after its useful life as a product is over, plastic lives on in a degraded state, filling landfills and clogging seas. This combination of durability and decay makes it a kind of undead material, a substance that lives on in a deteriorating condition. Despite the problems with old plastic (or perhaps because of them), our demand for new plastic grows: Approximately 300 million tons of polymers are produced annually. Of this quantity, only 30 million tons will be recycled, and about 7 million tons will end up in the ocean.

The root of the problem is plastic’s general lack of biocompatibility. Longevity is a problem only insofar as the material exerts a detrimental influence as it ages. Certainly, some plastics are biocompatible in a medical sense—meaning that they do not produce measurably adverse anatomical effects. However, most polymers made from petroleum consist of synthetic chemicals that resist biodegradation or reintegration with nature. When these substances do eventually break down into smaller pieces, they remain incompatible with ecosystem processes. Many plastics also leach toxins that impair the health of living organisms.

Now Australia-based entrepreneur Alf Wheeler has created a compelling alternative to plastic called Zeoform. Unlike petroleum-based polymers, Zeoform is made from two simple, nontoxic ingredients: cellulose and water. The material is completely biodegradable and compostable. According to Zeoform inventor and chief technologist Martin Ernegg, Zeoform is even edible throughout its life cycle—thus exhibiting true biocompatibility. The material is a durable, industrial-grade substance that may be manufactured in various densities, ranging from Styrofoam to ebony, based on the desired application. Zeoform also functions as a carbon dioxide–sequestration vehicle, “banking” carbon from repurposed feedstock materials that would otherwise release it into the atmosphere.

How is such a compelling material made? Zeoform’s process is designed to accept a wide range of feedstocks. In their Zeo prototype factory in Mullumbimby, south of Brisbane, Wheeler and Ernegg use a variety of wood- and fabric-based materials—such as paper, jute, bamboo, hemp, and agricultural biomass—in both virgin and recycled states, grinding and mixing them with water to create a pulpy substance resembling wet dough. In terms of equipment, Zeo relies primarily on a paper disk refiner for feedstock preparation in combination with custom steam explosion and enzymatic processing methods. “The process transforms the right matrix of fibers into a porridgy pulp which can be poured, pressed, sprayed, sculpted, and molded,” says Wheeler. Once hardened and dried, the material can be used as a functional substitute for many commercial-grade petroleum-based resins including acrylic; polyvinyl chloride, or PVC; and nylon.

The Zeoform process aspires to create materials as nature does, using the most prevalent organic substance on the planet—cellulose—which comprises approximately one-third of all plant matter. Technically speaking, the manufacture aims to optimize the surface area of cellulose fibers in order to develop hydroxyl bonding, a chemical phenomenon in which glucose chains form a strong adhesion with neighboring chains. Both hydroxyl bonding and entanglement bonding—where the cellulose fibers form tight knots—generate significant strength and resilience, as seen at a microscale in the cell walls of plants.

Zeoform may be combined with various natural compounds like dyes, substrates, minerals, and reinforcing fibers to achieve particular results relating to aesthetic and/or mechanical performance. Some samples resemble petroleum-based plastic while others are reminiscent of stone, metal, or wood. High-density variants of Zeoform are intrinsically water and fire resistant, and the company is developing new coatings capable of resisting harsh environmental conditions.

Zeoform may be processed in a variety of ways. “It can be spray-molded, pressed, compression-molded, poured, sculpted and—when dry—worked like wood,” says Wheeler. “It can be sanded, routed, laser cut, engraved, and polished.” It does not thermoform like plastic, however. When in doubt, fabricators should consider Zeoform more like wood than plastic, as it permits the use of standard woodworking tools.

Significantly, the material requires much less energy to make than petroleum-based plastic; even recycled plastics cannot compete.

Listed among the “top materials for 2014” in Engineering Materials magazine, Zeoform has been used to create various products including furniture, musical instruments, and surfboards. Wheeler is keen on expanding the material’s reach into building construction, citing Zeoform’s ideal strength-to-weight ratio, durability, safety, and customizability as fundamental attributes for architectural applications. Zeo identifies three types of uses for future building product lines: flat panels, tubes, and molded components. Flat panels are appropriate for interior and exterior uses such as façade cladding, flooring, doors, ceilings, counters, and interior wall facings. Tubes are particularly suitable as the material tends to prefer curvature, according to Ernegg, and include rail, framing, and handle applications. Molding, in this case, refers to small items like switch plates and knobs.

One of the most compelling potential applications for Zeoform is additive manufacturing. 3-D printing is rapidly becoming a pervasive, accessible, and cost-effective method of producing finished products as well as working prototypes. Plastic is the most common 3-d printing material, and although digitally fabricated plastic contributes less waste than con­ven­tional manufacturing, it still bears high embodied energy and water characteristics. Given Zeoform’s versatility and environmental benefits, it represents an ideal feedstock for additive manufacturing. In the future, “the ideal feedstock for a fabricator would be some renewable, recyclable, pollution-free goop whose material qualities—tensile strength, color, insulation, resistance to heat — are all specifiable on command,” argues author Bruce Sterling in Shaping Things, a far-reaching speculation on the future of products. “Materials like that don’t yet exist.”

Ah, but now they do.

Another future application could be the multilayered envelope. In nearly every case, the contemporary building façade consists of multiple materials and assemblies, each of which is installed by a different trade. It is commonly known that a building envelope performs only as well as its weakest material, and a single connection failure can lead to catastrophic problems.

However, an envelope assembly could be fabricated entirely out of Zeoform—a multifunctional sandwich with an insulation-grade material in the middle, dense and envi-ronmentally resistant material on the outside, and various channels and piping provided as needed for integral building services. (Even windows could be produced this way, as Zeoform can be translucent when formed very thin.) Interlocking composite panels with such a configuration could be produced via 3-d printing using a single feedstock with tunable additive materials and printing densities. The result would be a prefabricated façade system that could be quickly constructed onsite and would exhibit strength, water resistance, fire safety, and longevity—all out of a single material. (“Zeoform can be applied externally, as can timber — both require protection from the elements by way of roof eaves and/or water- and ultraviolet-resilient coatings,” claims Wheeler.)

Will Zeoform become the preferred building material of the 21st century? Despite its seemingly improbable combination of positive attributes, Zeo has only begun to license its methods and scale its manufacturing process to meet the demands of commercial markets. The economic viability of Zeo’s business plan is still to be determined; however, the material has extraordinary potential—not to mention possibilities for revitalizing struggling industries. “There is opportunity to create jobs and reinvigorate towns once dependent on papermaking,” says Wheeler. “There are also possibilities to explore utilizing ‘blue economy’ principles in which all parts of a crop—for example, industrial hemp—are utilized, and the waste streams cascade into systems for new value-added raw materials, ensuring nothing is wasted.”

Perhaps decades from now, petroleum-based plastic will be in decline—replaced by a significantly more environmentally responsible, versatile substitute made entirely from cellulose and water. Zeoform products, furnishings, and even building façades may become commonplace, substantially reducing society’s environmental footprint. Inevitably, as the new material is discarded and winds up in unanticipated contexts (such as the ocean), it will disintegrate into its original, natural components—nutrients for future ecological processes.