ART
BEAUTY & WELLNESS
CRAFT
CULTURE & HISTORY
ENTERTAINMENT
ENVIRONMENT
FOOD & DRINKS
REVERSE ENGINEERING
SCIENCES
SPORTS
TECHNOLOGY
WEARABLES
Butyl Rubber
Polyisobutylene was a soft, sticky material that could not be vulcanised - it had no double bonds left for sulphur to bridge. At Standard Oil in 1937 William Sparks and Robert Thomas added a few percent of isoprene to the isobutylene, just enough double bonds to cure it, and polymerised the mix far below freezing. The result held air better than any rubber before it, and inner tubes have been made of it ever since.
**US 2,356,128**, "Mixed olefinic polymerization process and product", Thomas and Sparks, assigned to Jasco, filed 20. October 1939, granted 22. August 1944: an isoolefin with a small amount of diolefin, polymerised below 0 °C (down to about -160 °C) with aluminium chloride; it describes "a low, controlled, chemical unsaturation, capable of being cured with sulfur".
**You measure the two properties that made its name**: it barely bounces, and it barely leaks.
Beginner
1 hour plus a week of readings
Instructions
1
1
Make a butyl pad
Make a butyl pad
Cut 80 mm pieces from a bicycle inner tube and flatten them. Stack three (six walls) and tape the edges so it is about as thick as the natural rubber sheet.
Materials for this step:
Inner Tube1 piece
Masking Tape1 rollTools needed:
Scissors2
2
Drop and watch
Drop and watch
Tape a metal ruler upright beside each pad on a solid floor. Drop the steel ball from 500 mm, five times per pad, and read the top of the first bounce. Filming at eye level makes it easier.
Materials for this step:
Natural Rubber Sheet1 pieceTools needed:
Steel Ball Bearing
Metal Ruler3
3
Inflate the leak test
Inflate the leak test
Pump the rest of the tube just until it is round - do not stretch it. Blow up a latex balloon to about the same firmness and tie it. Mark where you will measure each with tape.
Materials for this step:
Balloons1 packTools needed:
Bicycle Floor Pump4
4
Measure for a week
Measure for a week
Each day at the same time measure the balloon round its middle and the tube round its cross-section at the mark. Note the room temperature.
Tools needed:
Tape Measure
Room Thermometer5
5
Bounce and leak
Bounce and leak
Loading Jupyter Notebook...
6
6
History & Context
History & Context
**What the patent specifies:** isobutylene with a little conjugated diolefin, polymerised below 0 °C with aluminium chloride in an alkyl halide, then sulphur-cured. **Modern build (derived):** a commercial butyl inner tube.
Butyl became a strategic wartime rubber, then the air-holding liner inside every tubeless tyre, plus pond liners, roof membranes and engine mounts. Its limits: it is slow to vulcanise, does not bond well to other rubbers, and swells in oil and petrol.
Materials
4- 1 piecePlaceholder
- 1 rollPlaceholder
- 1 piecePlaceholder
- 1 packPlaceholder
Tools Required
6- Placeholder
- Placeholder
- Placeholder
- Placeholder
- 1 vendor sell this, none ship to you yetPlaceholder
- Placeholder
Related Blueprints
These blueprints share knowledge with this one — techniques, materials, or principles that connect them in the learning graph.
CC0 Public Domain
This blueprint is released under CC0. You are free to copy, modify, distribute, and use this work for any purpose, without asking permission.
Support the Maker by purchasing products through their Blueprint where they earn a Maker Commission set by Vendors, or create a new iteration of this Blueprint and include it as a connection in your own Blueprint to share revenue.