Hemp plastics represent an alternative to conventional plastics. They are resistant, durable, lightweight, biodegradable and their production has a low environmental impact.
What is hemp?
Hemp is a plant belonging to the Cannabis Sativa species. It is native to Asia, where it has been cultivated for centuries. Its THC content is very low, so it does not produce psychoactive effects, unlike its cousin, marijuana. Basically, the varieties with high concentrations of THC are called “Marijuana” and hemp to those where the concentration is low.
Today it is cultivated to be used for its medicinal properties, but it also has other applications, perhaps unknown to many. It can be used to create food products, personal care products, paper, textiles, construction materials, biofuels and plastics. The list is extensive and seems to be growing every year.
What are hemp plastics?
Hemp plastics are not a modern invention, quite the contrary. Hemp as a raw material has been used since ancient times, but we can cite one of the most famous cases. In 1941 Henry Ford, using a special formula of 70 % hemp fibers, straw and sisal, created the body of a new prototype car. In an effort to promote its cultivation and encourage farmers to try the plant.
In 1942 hemp cultivation was supported by the U.S. government under war propaganda during World War II. Because it was needed to manufacture ropes, fire hoses, shoe soles, parachutes, among others. But after the end of the war, hemp was criminalized and demonized as “Marijuana”. Meanwhile, the plastic and synthetic fiber industry began to take off.
Types of hemp plastics
Hemp plastics are not only presented as an environmentally friendly alternative, they also allow to improve the quality of products, for example, hemp fiber has replaced several materials, such as fiberglass, because it is lighter, more flexible and resistant. The resulting products will have better characteristics and will be more environmentally friendly.
Among some types and uses of hemp plastics, we can mention the following:
Hemp cellulose: Cellulose is part of the cell walls of plants, it is the most abundant organic polymer on the planet. In general, cellulose is used in the manufacture of paper, it is also used to manufacture plastics such as cellophane, celluloid and rayon.
Celluloid: It is a thermoplastic, dense and resistant. It is characterized by being easily moldable when heated.
Cellophane and rayon: Both are regenerated cellulose fibers, their industrial process is the same. They are used to manufacture cellophane film and rayon fiber respectively.
Nanocellulose: It is a viscous gel that can change to a liquid state when agitated or subjected to tension. It is a pseudoplastic, used to reinforce plastics. It has a powerful absorbent power, indispensable for cleaning up oil spills. It is also used as a low-calorie food stabilizer.
Hemp composite plastics: Composite plastics are made of polymers (natural or synthetic) and reinforcing fibers. Hemp fibers reinforce these materials, giving them greater strength and durability.
Biocomposites made from hemp: Hemp fibers can be subjected to various physical or chemical processes to obtain strong, attractive, soft and resistant biocomposites.
Benefits of hemp plastics
The benefits of hemp plastics are little known to many, as they go beyond just being environmentally friendly. It represents an effective solution to many real problems facing modern society.
Biodegradable: Ordinary plastics can take up to a thousand years to degrade, but before that they cause environmental disasters. In contrast, hemp-derived plastics take only 3 to 6 months to fully degrade.
Recyclable or compostable: 70% of the plastics used by a person end up in landfills or worse, in our seas. One of the great benefits of hemp plastics is that they can be reused in an indefinite recycling cycle. They can also end up in a compost where it degrades without polluting.
It lacks toxins: Petrochemical plastics contain toluene, benzene or bisphenol A, the latter is responsible for several endocrine, cardiac, metabolic and reproductive diseases, as it causes infertility. With hemp derivatives there is no such risk.
Environmentally friendly: Hemp crops absorb carbon dioxide from the atmosphere (For every ton of hemp harvested, one and a half tons of carbon is removed from the air), prevent soil erosion, absorb heavy metals, decrease water pollution. It is a rotation crop, perfect for improving the yield of other plant species, because it enriches the soil.
Stronger and lighter: When compared to other plastics, hemp is 5 times more rigid and 2.5 times more resistant. It is also very resistant to heat.
Disadvantages of hemp plastics
Among so many benefits, it is hard to believe that there are some disadvantages to hemp plastics. One of the biggest obstacles farmers face is the cost of seeds and legal restrictions.
These two aspects work against them, preventing cultivation from being brought to a large scale. On the other hand, hemp cultivation needs large amounts of fertilizer, because it requires a lot of nitrogen for its growth.
For the manufacture of hemp plastics, large amounts of energy are needed and the costs are high compared to the manufacture of conventional plastics. This makes it difficult to compete in the market.
Hemp plastics have great potential for the future. Although more research and innovation is still needed in the field. The advances obtained so far show that it is a sustainable alternative to replace plastics that have done so much damage to our planet.