What Are The Advantages & Disadvantages of Using Hemp For Making Plastic?
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What Are The Advantages & Disadvantages of Using Hemp For Making Plastic?
Hemp plastic is probably the unsung hero of industrial development, because there is usually no fanfare about it.
The lack fanfare and media mileage is due to the fact that industrial hemp is derived from a variety of Cannabis sativa plant, which is more commonly known as marijuana.
In terms of chemistry, the difference between hemp and cannabis in popular usage is that hemp has higher levels of CBD, which is incredibly medicinal, compared to cannabis which is cultivated for its high THC content. In today’s post, we are going to talk about the advantages and disadvantages of using hemp for making modern plastics.
Find out the pros and cons of industrial hemp and bioplastics in the 21st century. Hemp plastic is probably the unsung hero of industrial development, because there is usually no fanfare about it.
Could Southwest farmers benefit from commercial hemp production? Will state lawmakers ever approve hemp as a lawful crop?
The argument for and against commercial hemp production continues to rage across the country, but since the 2014 farm bill cleared the way for the legal research and testing of hemp production under controlled circumstances, interest in growing hemp, at least as an alternative crop, has increased considerably.
While valid arguments could be made supporting and opposing the idea of hemp as a legal crop, overall, the agricultural community seems to view the potential of commercial hemp in a positive light. As research continues, a number of advantages to growing hemp are becoming clear.
From an economic standpoint, hemp does not currently offer itself as one of the most profitable crops to grow. Demand for raw hemp, while substantial, is much less than for most commodity crops.
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The Hemp Industries Association reports that Americans bought about $625 million worth of hemp products last year, including clothing, building materials, food made with hemp seeds, and assorted other hemp-related products, according to Eric Steenstren, the association’s executive director.
Potential exists for growth
It is not the current demand that makes hemp a potentially attractive cash crop but the new and diverse uses of hemp currently under research and in some case in early development stages.
At a recent North American Industrial Hemp Council (NAIHC) annual meeting these developing uses were showcased and offered a look into hemp’s potential uses. According to analysts, if only a percentage of these applications were to be successfully developed, they would greatly enhance the value of hemp as an agricultural crop.
Some of the more promising hemp-related projects include:
Hemp Fiber Supercapacitors
David Mitlin, Professor, Clarkson University, Potsdam, New York
Researchers seek to transform natural precursors to value-added materials such as industrial polymers. Mitlin seeks to utilize natural and abundant materials and to this end has found and patented a process to create a cheap analogue to graphene from hemp.
Graphene is a high value, honeycomb lattice of carbon derived from naturally occurring graphite. It has many prospective uses but is too expensive for most applications. It can be used in capacitors and energy storage, has a high surface area, high conductivity versus copper, is inert, will not corrode or dissolve and has a firm crust making it stable. Materials with some of these properties and costs include: activated carbon, $25 to $50 per kilogram, carbon fiber $22 to $26/ per kilogram, and graphene $2,000 per kilogram.
Mitlin’s process to make a graphene substitute from hemp costs about $1 to $1.50 per kilogram. His process involves separating three strands (layers) of bast fiber (S1, S2, and S3), the layered structure of microfibers and digested to dissolve the S1 and S3 layers, winding up with carbon nanosheets. These are punched (honeycombed) chemically, bonded with magnesium oxide for structural support, and then layered into cells. The product has very high conductivity and potential use in electric auto batteries, water desalinization, wind/solar power storage, and more. It benefits from hemp’s unique structure.
Mitlin indicated that negotiations are in process to commercialize the technology.
Biorefining Industrial Hemp
Ed Lehrburger, CEO, PureVision Technology
This company, formed in 1992, has developed a machine they have named Biorefinery, which can be used for numerous fibrous field materials like cornstalks and wheat straw. Lehrburger sees a valuable application for industrial hemp and has formed a subsidiary, Pure Hemp Technology, and has constructed a pilot plant biorefinery at Ft. Lupton, Colorado. This project has been funded by a single “global client,” implying that a major company has been attracted to the technology.
The machine, defined as a Continuous Countercurrent Reactor, separates the three prime constituents of hemp stalk: cellulose, hemicellulose, and lignin. Lehrburger states that the traditional Kraft method of pulping fiber for paper products requires a four-hour chemical cycle which can be replaced by a four-minute cycle using his biorefinery. It further results in a pure lignin, which can be used for plastics, specialty chemicals, coatings, binders, and adhesives.
Hemp Grain Production
David Williams, PhD, agronomist at the University of Kentucky
Williams reported on the extensive work at his department on the progress of hemp production in his state. He believes hemp must become a commodity like other large volume crops, with a sustainable supply chain, so that farmers can reasonably expect profitable planting.
He presented a slide demonstrating that hemp grain can be competitive with corn and soybeans.
Williams also showed a slide comparing the results of various seed sources used in the 2015 field trials; the best performer for grain yield was a seed of Polish origin. He stated, as well, that 2015 was a difficult year for hemp in Kentucky, due to unusual rainfall during the normal planting season. For a look at the UK hemp program, see http://hemp.ca.uky.edu.
Opponents argue they fear that since hemp is genetically related to marijuana, it could make it difficult to distinguish between a growing crop of hemp marijuana. Some also fear that legalization of hemp represents an in-road to the legalization of marijuana.
While those concerns may not be entirely without merit, supporters argue that hemp can not be used as a psychotropic drug because it hardly has any THC content. THC is the ingredient necessary to create the high one gets from marijuana. They also point out that a trained eye can easily tell the difference between a hemp plant and a marijuana plant.
Supporters of commercial hemp production say that hemp fibers are longer, stronger, more absorbent and more mildew-resistant than cotton, and are ideal for generating a cash crop to be used in the textile industry. Fabrics made of at least one-half hemp block the sun’s UV rays more effectively than other fabrics.
They also point out that over 30 industrialized democracies do distinguish hemp from marijuana. International treaties regarding marijuana make an exception for industrial hemp.
Currently, most hemp used in the United States is imported from Canada and China, places where hemp farming is a profitable and stable industry.
But perhaps the greatest argument in favor of commercial production are new developments just coming to light. Researchers seem to agree that hemp could provide relatively high profits and raising it in a rotation with other crops could improve soil health and fight weeds, insects and crop disease.
In the end, researchers and policy makers say it will be the decision of each farmer and local elected officials whether hemp is a good crop to grow. That is if a bill currently before Congress makes commercial hemp production legal at the federal level. But overall, they say, reviewing the facts and ignoring the myths related to hemp farming should serve as a guide to making the right decision.
Below is a listing of some of those facts:
• Hemp can be grown as fiber, seed or a dual-purpose crop. The interior of the stalk has short, woody fibers called hurds; the outer portion has exceptionally strong and durable bast fibers. Seed are smooth and one-eighth to one-fourth of an inch long.
• Hemp uses include food, cosmetics, nutritional supplements, fabrics, paper and construction and insulation materials, among many others. Global market is estimated at more than 25,000 products.
• The U.S. sales value of hemp-based products is pegged at over $600 million annually and growing.
• Virtually all hemp processed in the U.S. is imported, primarily from Canada and China.
• Hemp grows in a wide variety of climates and soil types. The biggest advantage for farmers could be that it grows rapidly and chokes out competing weeds.
• It was widely grown in the U.S. from colonial times into the mid 19th Century. The Declaration of Independence was written on hemp paper.
• It was treated the same as any other farm commodity by the U.S. Department of Agriculture well into the 20th Century. U.S. Department of Agriculture compiled statistics on hemp and helped farmers grow and distribute it.
• U.S. production peaked in World War II, when supply of imported industrial fibers needed for rope and other wartime products was largely cut off.
• Production plunged after World War II because of new anti-drug laws and competition from synthetic fibers.
Americans bought about $625 million worth of hemp products last year, including clothing, building materials, food from hemp seed, and assorted other products.