Hemp was the first plant known to have been domestically cultivated. The oldest relic of human history is hemp fabric dated to 8,000 BC from ancient Mesopotamia, an area in present-day Turkey. The paintings of Rembrandt, Van Gogh, Gainsborough, etc., were primarily painted on hemp canvas, as were practically all canvas paintings. Hemp sails and ropes carried the European settlers to America for hundreds of years – 1492 to the advent of steamships in the early 1800s. Cannabis hemp was legal tender (money) in most of the Americas from 1631 until the early 1800s. You could pay your taxes with cannabis hemp throughout America for over 200 years. You could even be jailed in America for not growing cannabis during several periods of shortage, e.g., in Virginia between 1763 and 1767.
In 1942, after the Japanese invasion of the Philippines cut off the supply of manila (Abaca) hemp, the U.S. government distributed 400,000 pounds of cannabis seeds to American farmers from Wisconsin to Kentucky, who produced 42,000 tons of hemp fiber annually for the war effort until 1946. In 1942–43 farmers were made to attend showings of the USDA film Hemp for Victory, sign that they had seen the film and read a hemp cultivation booklet. Farmers from 1942 through 1945 who agreed to grow hemp were waived from serving in the military, along with their sons; that’s how vitally important hemp was to America during World War II.
In thermoset production the natural fibers are soaked with binders such as epoxy resin or polyurethane, placed in the desired form, and allowed to harden through polymerization. Hemp has also been used in other types of thermoplastic applications, including injection molding. The characteristics of hemp fibers have proven to be superior for production of molded composites.
One of the most significant developments for the North American hemp industry was investment in hemp products by Anita and Gordon Roddick, founders of The Body Shop, a well known international chain of hair and body care retailers. This was a rather courageous and principled move that required overcoming American legal obstacles related to THC content. The Body Shop now markets an impressive array of hemp nutraceutical cosmetics (Fig. 39), and this has given the industry considerable credibility. The Body Shop has reported gross sales of about a billion dollars annually, and that about 4% of sales in 2000 were hemp products.
It has been contended that hemp is notably superior to most crops in terms of biomass production, but van der Werf (1994b) noted that the annual dry matter yield of hemp (rarely approaching 20 t/ha) is not exceptional compared to maize, beet, or potato. Nevertheless, hemp has been rated on a variety of criteria as one of the best crops available to produce energy in Europe (Biewinga and van der Bijl 1996). Hemp, especially the hurds, can be burned as is or processed into charcoal, methanol, methane, or gasoline through pyrolysis (destructive distillation). As with maize, hemp can also be used to create ethanol.
Today, hemp is fully legal in North America. and businesses are beginning to turn to the plant more and more for innovative production techniques, although some restrictions are still incredibly tight.