Hemp Plastics

Soft Secrets
21 Jun 2011

When compared with other bioplastics crops, such as soy and corn, hemp has many advantages.


Some of the first plastics ever made were bioplastics: in 1869, John Wesley Hyatt Jr. created a cotton cellulose derivative to replace ivory in billiard balls. He went on to produce cotton celluloid and cellophane, both of which can also be synthesized from hemp. As ever, murky legality has hindered research here, as prices are high and supplies are inconsistent. Yet when compared with other bioplastics crops, such as soy and corn, hemp has many advantages. The bast fibers, when mixed into a composite form with glue or resin, are extremely strong, durable and flame-retardant. Cellulose, the basis of around 77% of all plastics, constitutes as much as 85% of the hurds, according to some sources. Cotton contains percentages reaching the high nineties, but cultivation requires very specific climatic conditions and many fertilizers and pesticides. Hemp has few such requirements and flourishes in all manner of habitats. Corn, which contains around 45% cellulose and is very damaging to the environment when intensively farmed, prevails as the favored crop for bioplastics - against all logic. Outside of the US, the movement is experiencing some ongoing success in the effort to legitimize hemp. Funding from the European Regional Development Fund (ERDF) has been available since 2008 for initiatives to use locally-produced hemp in car parts for the UK firm Lotus. A $2.13m grant from the Australian Commonwealth Scientific and Industrial Research Organization (CSIRO) for New South Wales company Biofiba to further develop their 100% natural and biodegradable hemp fiber and natural starch composite was approved in April this year. Vancouver-based Hemptown Clothing received government funding to the tune of $1.45 million as early as 2005, to develop their natural fiber Crailar, primarily used in textiles but also useful for creating advanced composites. Funding has also been awarded to other participants in the hemp industry, from primary producers to initiatives specializing in textiles; industrial materials such as insulation, hemp concrete and isochanvre; and producers of hemp oils and foodstuffs. Most hemp plastics so far produced have been composites, where fiber is mixed with synthetic thermoplastics (such as polyesters or natural resins) to form rigid, durable materials similar to fiberglass. Even the resin used to bind the fibers can be produced from hemp-seed oil. These composites are suitable for injection molding, and can be thermoplastic or thermosetting. They are very diverse in application, but colors have so far been limited, and appearances often somewhat rudimentary. This is now changing, and as more is learned about the mechanical properties of fiber in different hemp varieties, techniques are set to undergo rapid evolution. Cellulose, a natural polymer (or long-chain, structurally repeating molecule) of glucose, can be isolated and modified to form many kinds of 100% hemp plastics, without the need for any resins or glues. The processes involved are often much more expensive and final costs are therefore much higher than for composites. They are remarkably attractive and versatile, however. Hemp stone is an extremely strong blend of cellulose and water used to make musical instruments and other durable items. Hemp cellophane is significant, although the process to produce it involves highly toxic chemicals. The potential to replace traditional plastics in packaging is very significant, as the percentage of all plastic currently produced for this purpose is estimated at up to 56%. Bioplastics for packaging are usually designed to rapidly biodegrade, making them safer for the environment. However, they remain more expensive than standard petrochemical-based synthetics. In the categories they are most useful for, hemp plastics have started to gain a reasonable - and growing - market share and the expected pattern of cost reduction and streamlining of production has begun. New formulas are being developed continually, and an increasing amount of new applications are being discovered. Hemp Plastic (UK), established in 1996, last year released their highest performance composite yet, and also manufacture high-end 100% hemp plastics. With the capability to produce plastic tailor-made to their customers requirements, they are in the process of developing specific compounds for several multinational electronics corporations keen to enhance their green credentials. Currently, the most well-known proponents of hemp plastic are in the automobile industry. Companies in Canada, Germany and Austria are acknowledging hemp composite plastic's many qualities as a fiberglass substitute, and its contribution to overall emissions reductions in the sector. Hemp is lighter, and very encouragingly, 20% cheaper than fiberglass. This is very significant when one considers the variety of products (sporting goods, boats, suitcases, flat roofing, piping, and many more) for which fiberglass is in widespread use, and we may see the biggest market advances of all being made in these sectors. As ever, in the US our biggest obstacle is the illegality of domestic production, which forces businesses to import from Canada or the EU. There are companies that use imported hemp, but the practice is far from widespread. In 2004, Stanford University discovered that hemp fibers fused with polyhydroxy-butyrate (PHB), a natural resin, formed the strongest synthetic wood substitute out of all tested combinations. This composite can be molded into heavy-duty flooring and building materials, or bottles and other lightweight plastic items. This is encouraging, but we need to invest further in bioplastics research in order to not fall far behind globally. The time is ripe for the domestic market to take advantage of such research and push for more. To innovate further with hemp plastic we need a consistent, affordable supply. It must be reiterated - we have a potential goldmine awaiting us if we legislate for hemp. As we've stated in previous articles, many states have approved industrial hemp production and license applications have been made to the DEA, which have simply taken the fees then denied the requests. On April 28th of this year, the Presque Isle County Board of Commissioners in Michigan approved a resolution to relax restrictions on industrial hemp, with a specific request for state control of licenses that would effectively bypass federal obstructions. This may represent a legal precedent for other would-be hemp activists to follow, but whether they are successful remains to be seen. In the meantime, we and many like us are going to keep on piling up the evidence for hemp, because, sooner or later, the world just has to pay attention.
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