The limitations of celluloid led to the next major advance, known as “phenolic” or “phenol-formaldehyde” plastics.  A chemist named Leo Hendrik Baekelund, a Belgian-born American living in New York state, was searching for an insulating shellac to coat wires in electric motors and generators. Baekelund found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky mass when mixed together and heated, and the mass became extremely hard if allowed to cool and dry.

He continued his investigations and found that the material could be mixed with wood flour, asbestos, or slate dust to create “composite” materials with different properties.  Most of these compositions were strong and fire-resistant.  The only problem was that the material tended to foam during synthesis, and the resulting product was of unacceptable quality.

Baekelund built pressure vessels to force out the bubbles and provide a smooth, uniform product.  He publicly announced his discovery in 1909, naming it “bakelite.”  It was originally used for electrical and mechanical parts, finally coming into widespread use in consumer goods in the 1920s.

Bakelite was the first true plastic.  It was a purely synthetic material, not based on any material or even molecule found in nature.  It was also the first “thermoset” plastic.  Conventional “thermoplastics” can be molded and then melted again, but thermoset plastics form bonds between polymer strands when “cured,” creating a tangled matrix that cannot be undone without destroying the plastic.  Thermoplastics are tough and temperature resistant.

Bakelite was cheap, strong, and durable.  It was molded into thousands of forms, such as radios, telephones, clocks, jewelry, buttons, lamps, and, of course, billiard balls.

Phenolic plastics are still in widespread use.  For example, electronic circuit boards are made of sheets of paper or cloth impregnated with phenolic resin.

Many bakelite items are now collectors items.  Here are a few tips for bakelite collectors.  There are some simple ways to tell if an item is truly made of bakelite.  The first is smell.  Rub the item briskly with your fingers until it is warm.  You should get a formaldehyde or carbolic acid smell.  Once you are familiar with the smell, it is fairly recognizable.  Another method calls for placing “Scrubbing Bubbles” bathroom cleaner on a q-tip and touching it to the bakelite - the q tip should turn yellow.  And, yes, bakelite colors do change as they age.

Some interesting bakelite sites: The Bakelite Museum, Columbia Encyclopedia

All Goodyear had done with vulcanization was improve the properties of a natural polymer.  The next logical step was to use a natural polymer, cellulose, as the basis for a new material.

Inventors were particularly interested in developing synthetic substitutes for those natural materials that were expensive and in short supply, since that meant a profitable market to exploit.  Ivory was a particularly attractive target for a synthetic replacement.

An Englishman named Alexander Parkes developed a “synthetic ivory” named “pyroxlin,” which he marketed under the trade name “Parkesine,” and which won a bronze medal at the 1862 World’s Fair in London.  Parkesine was made from cellulose treated with nitric acid and a solvent.  The output of the process hardened into a hard, ivory-like material that could be molded when heated.

However, Parkes was not able to scale up the process to an industrial level, and products made from Parkesine quickly warped and cracked after a short period of use.  An American printer and amateur inventor named John Wesley Hyatt took up where Parkes left off.  Parkes had failed for lack of a proper solvent, but Hyatt discovered that camphor would do the job very nicely.

Hyatt was something of an industrial genius who understood what could be done with such a shapeable, or “plastic,” material, and proceeded to design much of the basic industrial machinery needed to produce good-quality plastic materials in quantity.  Since cellulose was the main constituent used in the synthesis of his new material, Hyatt named it “celluloid.”  It was introduced in 1863.

One of the first products was dental pieces.  Sets of false teeth built around celluloid proved cheaper than existing rubber dentures.  However, celluloid dentures tended to soften when hot, making tea drinking tricky, and the camphor taste tended to be difficult to suppress.

Celluloid’s real breakthrough products were waterproof shirt collars, cuffs, and the false shirt fronts known as “dickies,” whose unmanageable nature later became a stock joke in silent-movie comedies.  They didn’t wilt and didn’t stain easily, and Hyatt sold them by trainloads.  Corsets made with celluloid stays also proved popular, since perspiration didn’t rust the stays, as it would if they had been made of metal.

Celluloid proved extremely versatile in its fields of application, providing a cheap and attractive replacement for ivory, tortoise-shell, and bone.  Traditional products that had used these materials were much easier to fabricate with plastics.  Some of the items made with cellulose in the 19th century were beautifully designed and implemented.  For example, celluloid combs made to tie up the long tresses of hair fashionable at the time are now jewel-like museum pieces.  Such pretty trinkets were no longer only for the rich.

Celluloid could also be used in entirely new applications.  Hyatt figured out how to fabricate the material in a strip format for movie film.  By the year 1900, movie film was a major market for celluloid.

However, celluloid still tended to yellow and crack over time, and it had another, more dangerous defect: it burned easily and spectacularly, unsurprising given that mixtures of nitric acid and cellulose are also used to synthesize smokeless powder.

Ping-pong balls, one of the few products still made with celluloid, sizzle and burn if set on fire, and Hyatt liked to tell stories about celluloid billiard balls exploding when struck very hard.  These stories might have had a basis in fact, since the billiard balls were often celluloid covered with paints based on another, even more flammable, nitrocellulose product known as “collodion.”  If the balls had been imperfectly manufactured, the paints might have acted as primer to set the rest of the ball off with a bang.

Cellulose was also used to produce cloth.  While the men who developed celluloid were interested in replacing ivory, those who developed the new fibers were interested in replacing another expensive material, silk.

In 1884, a French chemist, the Comte de Chardonnay, introduced a cellulose-based fabric that became known as “Chardonnay silk.”  It was an attractive cloth, but like celluloid it was very flammable, a property completely unacceptable in clothing.  After some ghastly accidents, Chardonnay silk was taken off the market.

In 1894, three British inventors, Charles Cross, Edward Bevan, and Clayton Beadle, patented a new “artificial silk” or “art silk” that was much safer.  The three men sold the rights for the new fabric to the French Courtald company, a major manufacturer of silk, which put it into production in 1905, using cellulose from wood pulp as the “feedstock” material.

Art silk became well known under the trade name “rayon,” and was produced in great quantities through the 1930s, when it was supplanted by better artificial fabrics.  It still remains in production today, often in blends with other natural and artificial fibers.  It is cheap and feels smooth on the skin, though it is weak when wet and creases easily.  It can also be produced in a transparent sheet form known as “cellophane.”

Plastics are polymers - long-chain carbon-based or “organic” molecules.  These chains are made up of repeating fundamental molecular elements, or “monomers.”

The term plastics covers a range of mostly synthetic or semi-synthetic organic condensation or polymerization products that can be molded or extruded into objects or films or filaments.  The name is derived from the fact the properties are in a semi-liquid state that is malleable, or has the property of plasticity.  Plastics vary immensely in temperature tolerance, hardness, resiliency.  Combined with this adaptability, the general uniformity of composition and lightness of plastics ensures their use in almost all industrial applications today.

Natural Polymers

People have been using artificial organic polymers for centuries in the form of waxes and shellacs.  A plant polymer named “cellulose” provides the structural strength for natural fibers and ropes, and by the early 19th century natural rubber, tapped from rubber trees, was in widespread use.

Eventually, inventors learned to improve the properties of natural polymers.  Natural rubber was sensitive to temperature, becoming sticky and smelly in hot weather and brittle in cold weather.  In 1834, two inventors, Friedrich Ludersdorf of Germany and Nathaniel Hayward of the US, independently discovered that adding sulfur to raw rubber helped prevent the material from becoming sticky.

In 1839, the American inventor Charles Goodyear was experimenting with the sulfur treatment of natural rubber when, according to legend, he dropped a piece of sulfur-treated rubber on a stove.  The rubber seemed to have improved properties, and Goodyear followed up with further experiments, and developed a process known as “vulcanization” that involved cooking the rubber with sulfur.  Compared to untreated natural rubber, Goodyear’s vulcanized rubber was stronger, more resistant to abrasion, more elastic, much less sensitive to temperature, impermeable to gases, and highly resistant to chemicals and electric current.

Vulcanization remains an important industrial process for the manufacture of rubber in both natural and artificial forms.  Natural rubber is composed of an organic polymer named “isoprene.”  Vulcanization creates sulfur bonds that link separate isoprene polymers together, improving the material’s structural integrity and its other properties