Question: Boots that rise to the knee and were originally made of leather, can be made of a synthetic rubber that exhibits good chemical stability, and is produced by the polymerization of what? 
Context: Samuel Emmett Horne Jr. (July 26, 1924 –February 4, 2006) was a research scientist at B. F. Goodrich noted for first synthesizing cis-1,4-polyisoprene, the main polymer contained in natural tree rubber, using Ziegler catalysis.  Earlier attempts to produce synthetic rubber from isoprene had been unsuccessful, but in 1955, Horne prepared 98 percent cis-1,4-polyisoprene via the stereospecific polymerization of isoprene.  The product of this reaction differs from natural rubber only slightly.  It contains a small amount of cis-1,2-polyisoprene, but it is indistinguishable from natural rubber in its physical properties. Polybutadiene [butadiene rubber BR] is a synthetic rubber.  Polybutadiene rubber is a polymer formed from the polymerization of the monomer 1,3-butadiene.  Polybutadiene has a high resistance to wear and is used especially in the manufacture of tires, which consumes about 70% of the production.  Another 25% is used as an additive to improve the toughness (impact resistance) of plastics such as polystyrene and acrylonitrile butadiene styrene (ABS).  Polybutadiene rubber accounted for about a quarter of total global consumption of synthetic rubbers in 2012.  It is also used to manufacture golf balls, various elastic objects and to coat or encapsulate electronic assemblies, offering high electrical resistivity. 4-"tert"-Butylcatechol (TBC) is an organic chemical compound which is a derivative of catechol.  It is added as a stabilizer and an inhibitor of polymerization to butadiene, styrene, vinyl acetate and other reactive monomer streams.  It is 25 times better than hydroquinone at 60 °C for polymerization inhibitory effect.  Also used as a stabilizer in the manufacture of polyurethane foam.  It also can be used as an antioxidant for synthetic rubber, polymers and oil derivatives.  It can be used as purification agent for aminoformate catalysts.  TBC is available in a form of a solid crystal and 85% solution in methanol or water. Neoprene or polychloroprene is a family of synthetic rubbers that are produced by polymerization of chloroprene.  Neoprene exhibits good chemical stability and maintains flexibility over a wide temperature range.  Neoprene is sold either as solid rubber or in latex form, and is used in a wide variety of applications, such as laptop sleeves, orthopedic braces (wrist, knee, etc.), electrical insulation, liquid and sheet applied elastomeric membranes or flashings, and automotive fan belts. Butyl rubber is a synthetic rubber, a copolymer of isobutylene with isoprene.  The abbreviation IIR stands for isobutylene isoprene rubber.  Polyisobutylene, also known as "PIB" or polyisobutene, (CH), is the homopolymer of isobutylene, or 2-methyl-1-propene, on which butyl rubber is based.  Butyl rubber is produced by polymerization of about 98% of isobutylene with about 2% of isoprene.  Structurally, polyisobutylene resembles polypropylene, having two methyl groups substituted on every other carbon atom.  Polyisobutylene is a colorless to light yellow viscoelastic material.  It is generally odorless and tasteless, though it may exhibit a slight characteristic odor. Knee-high boots are boots that rise to the knee, or slightly thereunder.  They are generally tighter around the leg shaft and ankle than at the top.  Originally made of leather, versions made of a synthetic rubber (PVC, Neoprene, etc.), they are used by fishermen, dairy workers, stable hands, duck hunters, clammers, etc. to protect the feet from water, mud, manure, etc. and to provide traction on slippery surfaces.  Most slip on, but there are varieties with buckles and those that lace up. Dayco was founded in 1905 as Dayton Rubber Manufacturing Co.  The company initially made products such as garden hoses out of natural rubber.  In 1908, the company hired John A. MacMillan, and began creating his product, the airless tire.  The company also produced the first whitewall tires in 1913.  Beginning in the early 1920s, the company entered a diversification period when it radically increased the variety of its products.  Dayco would eventually make many different rubber parts, as well as some textiles.  It also pioneered some synthetic rubber products, including developing the first synthetic rubber tire.  The company would be a valuable supplier of military products during World War II.  The company officially changed its name to the DAYCO Corporation in 1960. Ivan Ivanovich Ostromislensky (Russian: Иван Иванович Остромысленский , also Iwan Ostromislensky) (9 September 1880 – 16 January 1939) was a Russian organic chemist.  He is credited as the pioneer in studying polymerization of synthetic rubber as well as inventor of various industrial technologies for production of synthetic rubber, polymers and pharmaceuticals. Ray P. Dinsmore was an internationally recognized rubber scientist, known for pioneering the use of rayon as a reinforcing material in auto tires.  In 1928, Dinsmore patented the first water-emulsion synthetic rubber in the United States.  The material later became a staple of the rubber industry during the World War II shortage of natural rubber.  Dinsmore worked for the Goodyear Tire and Rubber Company and developed Chemigum, an early synthetic rubber.  Dinsmore served as Chairman of the Rubber Division of the American Chemical Society in 1927.  He received the 1947 Colwyn medal and was named the 1955 Charles Goodyear Medalist. A synthetic rubber is any artificial elastomer.  These are mainly polymers synthesized from petroleum byproducts.  About 15 e9kg of rubbers are produced annually, and of that amount two thirds are synthetic.  Global revenues generated with synthetic rubbers are likely to rise to approximately US$56 billion in 2020.  Synthetic rubber, like natural rubber, has uses in the automotive industry for tires, door and window profiles, hoses, belts, matting, and flooring.
Answer: chloroprene