Paper is the ubiquitous and lightweight product we all know and love. It can be made to absorb stains for cleaning purposes or watercolors for generating art. It is used to write love letters, folded to create envelopes, or rolled to inhale various substances. It can hold our tea, hygienically dispose our wastes, and document our laws and literature (the good, the bad, and everything in between).
Paper was a historical achievement and the kind of use it had for documenting conveniently would not have been possible if it did not spread openly. Its long and eventful history was also open to many mechanical inventions and chemical discoveries.
Paper was invented in China almost two millennia ago. In the eighth century, the Arabs learned to make paper from the Chinese, who then passed it to Europe in the eleventh century. Eventually it spread to North America and the rest of the world.
The first Chinese papers were made using the fibrous material found in the bark of trees, and old scraps of cloth. These ingredients were soaked and beaten. The resulting pulp was stirred in a barrel of clean water. A spoonful of this mix was spread over a screen of stretched woven cloth within a frame, usually made from bamboo. This screen acted like a mold and provided a surface over which each layer of interlocking fibers in the mesh was converted into a sheet of paper as the excess liquid escaped from below.
This transformation process works because of the hydrogen bond, a type of molecular glue that is characteristic of vegetative matter, and critical to the construction of paper. This fundamental chemical bond allows softened cellulose fibers to attach via hydroxyl (contains hydrogen and oxygen atoms) groups as the water is removed. The fibers are attracted to each other because the fiber-to-fiber hydrogen bonds replace fiber-to-water hydrogen bonds. This is why paper can be defined as a composite sheet-like material formed from individual fibers by removing water.
However, this definition gives a deceptively simple image of the history of papermaking, which was more of an art form in its early stages due to the lack of technology and resources. For example, as the demand for paper drastically increased, papermakers vigorously sought after cotton and linen rags as a source of fiber to prepare an appropriate pulp. This hunt for suitable fibers engrossed papermakers for five centuries.
In theory, paper can be fabricated from any plant; however, the difference lies in the quantity and quality of the fibers. Cotton and linen rags were the most popular but they were in limited supply. Therefore, efforts were made to manufacture paper without using these rags.
Matthias Koops, an experimenter, proposed alternative ways to produce paper. Information was also exchanged via trade publications such as the Paper Trade Journal. Jacob Christian Schäffer, an eighteenth-century scientist, produced one of the most important books in the literature of papermaking; it is a six-volume account of his experiments with different vegetable fibers. He recognized the revolutionary observations of the entomologist, René-Antoine Ferchault de Réaumur, whose study of insects eventually led to the use of ground wood pulp in making paper. However, this transition from cotton to wood as a source of fiber was not immediate. Though the potential for using ground wood had been acknowledged, it took a century to practically apply it.
The modern aspects of papermaking were finally established when the technology caught up with the existing conclusions of the old but groundbreaking experiments and observations. This led to the production of mechanical wood pulp using a process patented by Friedrich Gottlob Keller in 1845. This was combined with water and fed into a papermaking machine called the Fourdrinier, which could make rolls of paper. The principle of this machine involves forming paper on a continuous woven-wire cloth that retains the bonded fibers while water gets pulled by suction; it is still used for all modern papermaking machines. Another noteworthy historical machine is the Hollander beater, a mechanical processor that enhanced the refinement of fiber.
Nonetheless, the three fundamentals of the papermaking process remained the same during the journey of paper from China to the rest of the world: clean water, cellulose fiber, and a mold.
The open exchange of information and ideas is vital to the progression of all sciences. The modern manufacture of paper was certainly no exception. It started with the Chinese discovery of hydrogen bonds, was assisted by the French study of wasps, aided by published observations and patented mechanical inventions, and ultimately made its way to its modern form.