Archaeology and the Age of Plastics: Bakelite in the Brody Dump
Take a moment to think about what kinds of materials you’d expect to find in a garbage dump from 2018. Did plastic immediately spring to mind? About 300 million tons of plastic are produced globally each year, only about 10% of which is recycled (1). Since mass production of plastic took off around 1950 an estimated 6.3 billion metric tons of plastic waste has been produced, much of which has ended up in landfills (1). We don’t encounter much plastic at the oldest sites on MSU’s campus. At sites dating to the 19th century, like Saints’ Rest and College Hall, we more frequently find glass, metal, and ceramics. At more recent sites, however, we begin to see more plastic in the archaeological record, reflecting the increased availability and use of plastic in everyday items. Several plastic artifacts were excavated at the Brody-Emmons Complex, the site of the East Lansing city landfill in the early 20th century.
Humans have long used natural substances with plastic properties, such as rubber and shellac, but man-made plastics are a fairly recent innovation. The first man-made plastic is attributed to British chemist Alexander Parkes (2). In 1856, Parkes acquired a patent for a product made from a plant material called cellulose treated with nitric acid and other chemicals. The product, called Parkesine, exhibited many useful properties: when hot it could be easily molded into various shapes, but when cool it was sturdy and durable. Unlike rubber, it could be industrially produced in large quantities (2).
Early plastics such as Parkesine and its successor, celluloid, involved the addition of chemicals to naturally occurring polymers (3). The first fully synthetic plastic wasn’t invented until 1907 when American chemist Leo Baekeland produced a plastic material through a condensation reaction of phenol with formaldehyde. He called his phenolic resin “Bakelite,” polyoxybenzylmethyleneglycoanhydride to the chemistry nerds out there. Unlike celluloid, Bakelite is thermosetting; once molded, it retains its shape even if heated again (3).
Baekeland patented Bakelite in 1909 and formed the General Bakelite Company around 1910 (3). The company adopted the infinity symbol as its logo to match its slogan “a material of a thousand uses.” In fact, Bakelite did prove to have many uses. Due to its resistance to heat and electricity, it was particularly useful in the automotive and electrical industries. The earliest commercial use of Bakelite was in insulating bushings manufactured for the Weston Electrical Instrument Corporation in 1908. During World War I, Bakelite was used in everything from electrical systems to airplane propellers. As plastic began to be incorporated in electronics such as telephones and radios, these products became cheaper and thus more widely accessible (3). There were also many decorative and aesthetic uses for Bakelite. Blocks of Bakelite could be carved to create items like pipe stems, cigarette holders, and even jewelry (3). The look, weight, and sound of Bakelite pieces struck together are similar to ivory (4). For this reason, phenolic resins are still used in items such as billiard balls, dominos, and chess pieces (3).
One of the plastic artifacts associated with the East Lansing landfill is a small hand-held mirror we suspected might be made of Bakelite. People who have handled a lot of Bakelite can make an assessment based on subtle clues like sound and feel. Since I have not handled much of it myself, I turned to some of the other “tests” for Bakelite.
First I tried the smell test. This method involves heating the object – either by running it under hot water or rubbing it vigorously–and sniffing. Bakelite gives off a telltale formaldehyde smell (4). As I wanted to avoid damaging the artifact, I tried the rubbing approach. The mirror definitely smelled “weird” to me, but it was too faint for me to discern a specific scent.
Next I decided to try one of the visual methods for testing Bakelite. These methods involve swabbing a Q-Tip or white cloth dampened with certain chemicals against the object in question. If the object is Bakelite, it will turn the Q-tip yellow (4). Other early plastics, such as Lucite, do not produce this result. Chemicals typically used for testing Bakelite are Formula 409 and Simichrome metal polish (4). I couldn’t find Simichrome at my local hardware store, so I opted to try Formula 409. After gently cleaning the mirror to remove any dirt, Campus Archaeologist Lisa Bright and I swabbed a Q-Tip sprayed with 409 against the back of the mirror. The Q-Tip turned faintly yellow, which seemed promising. After a bit of research, I discovered that some people have successfully used baking soda to test for Bakelite (5). I decided to try this method too, and added a bit of baking soda to a damp white paper towel. Voila! The paper towel turned yellow where it contacted the plastic. These tests seem to indicate that the mirror is Bakelite, which makes it the second Bakelite artifact identified in the Brody assemblage. A Sengbusch Self-Closing Inkstand with a Bakelite lid was also recovered in 2011.
Bakelite was designated a National Historic Chemical Landmark by the American Chemical Society in 1993 (3). As the world’s first synthetic plastic Bakelite is credited with ushering in the Polymer Age, also called the Age of Plastics (3). It is interesting to observe that we can see this landmark—and evidence of the dawn of the Age of Plastics —in the archaeological record of our campus.
Author: Mari Isa