Bruce H. Maddock
A pioneer in adapting extrusion to thermoplastics. His contributions include achieving greater heating, mixing and metering capacities and coating of wire with extruded thermoplastic insulation.
Bruce Maddock, who died in November 1996, shortly after being selected for induction into the Plastics Hall of Fame, pioneered the adaptation of extrusion to thermoplastics. When he began this work in 1936, the process was used only for thermoset rubber.
Extrusion experts cite his contributions to:
- Redesign of the single-screw extruder to achieve the greater heating, mixing, and metering capacities required for thermo-plastics.
- Methods for coating wire with thermoplastics.
- Techniques for extruding film, sheet, pipe, and other products from thermoplastics.
- Establishing a systematic body of knowledge about how productivity and product quality are affected by temperature, pressure, flow, mixing, and other process variables, making possible today's computer modelling of extrusion.
Maddock is also credited with these inventions:
- The "push-out" or "screw-freeze" technique for analyzing the extrusion process by stopping the machine, rapidly cooling molten polymer containing colored tracers, removing the filled screw from the barrel, and unwrapping the plastic helix, which serves as a specimen for studying process variables.
- Addition to the screw of a barrier mixing section, called the Maddock Mixer or the Union Carbide Mixing Head, that improved product quality while increasing throughput.
Born and raised in Wyandotte, Michigan, Bruce H. Maddock received a bachelors degree from the University of Michigan in 1934 and joined Bakelite Company in 1936. The company was acquired by Union Carbide Corp. in 1939, and from then until his retirement in 1974, with the exception of a three-year interval, he worked at Carbide, which he left with the title of Corporate Fellow.
From 1942 to 1945, as chief engineer with Intelin Division of Federal Telephone and Radio Corp., he was responsible for the design and manufacture of thermoplastic-insulated coaxial cables needed for radar equipment during World War II.
Maddock produced many groundbreaking technical papers on extrusion. He was active in the Society of Plastics Engineers (SPE) and in 1957 helped found its Extrusion Division. He received SPE's Engineering and Technology Award in 1982, and its highest honor, the International Award, in 1988.
Maddock was living in Lakewood, NJ, at the time of his death at the age of 85. His wife, Dorothea, died in 1984. He is survived by two daughters.