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Monday, March 29, 2021

Unremarkable Cellophane

In 1900, a Swiss gentleman named Jacques E. Brandenberger was sitting at a table in a restaurant. He didn’t know it but his life was going to change. Brandenberger noticed a customer spilt wine onto the tablecloth. As the waiter replaced the cloth, Brandenberger got the idea to develop a material that would repeal liquid instead of absorbing it. His first step was to spray a waterproof coating onto fabric and he opted for viscose. The resulting coated fabric was far too stiff and the clear film easily separated from the backing cloth. He abandoned his original idea as the possibilities of the new material became apparent. Brandenberger was awarded the Franklin Institute’s Elliott Cresson Medal in 1937. His estimated net worth at the time of his death in 1954 was around $10 Million.

The original Cellophane material was made from wood cellulose. Cellophane is thus initially a bioplastic. Nowadays much of what we refer to as “Cellophane” is actually plastic wrap derived from petroleum. PVC has been used since the 1960s and polypropylene since the 1980s. For many years after World War I, cellophane was the only flexible, transparent plastic film available for use in such common items as food wrap and adhesive tape.

In the 1950's, DuPont's then-revolutionary product, Cellophane, became very popular. The see-through plastic allowed consumers to see what they were buying, and it would keep food fresher for longer periods of time. DuPont ran a series of ads through the 1950's extolling the benefits of its product. Cellophane became so widely used that the name, originally trademarked by DuPont, is now used for any clear plastic film.

Saturday, March 20, 2021

The Unremarkable Spring

On the first day of Spring, let's take a look at The Unremarkable Spring. Fundamentally there are two types of springs. The flat or stretched spring and the coiled spring - also known as the spiral spring.

***The stretched spring*** The best example of a stretched spring is the bow and arrow. The bow itself is made of a flexible material - typically wood - and the bow-string is attached to each end of the bow. By pulling the string back you create tension on the bow (spring) and the energy of the spring (kinetic energy or movement energy) is transferred to an arrow or similar, when you let go of the string.

***Leaf springs from the time of Tutankhamen*** A more advanced type of spring can be traced all the way back to the Egyptian pharaoh Tutankhamen, who used leaf springs on his carriages. The leaf springs provided a more comfortable drive and also increased the durability of the carriage. Years later, leaf springs were also used on two-wheeled Roman vehicles. Centuries after Tutankhamen’s chariot used leaf springs, Henry Ford was to use these same springs for a very similar purpose on his iconic Model T Ford.

***Leonardo Da Vinci*** In 1493 Leonardo Da Vinci, engineer, architect, sculptor and much more (he also painted the famous painting Mona Lisa) invented a spring for guns. The small spring made it possible to shoot with just one hand, which was revolutionary for this type of weapon.

***Spiral springs*** The coil spring is probably the greatest step in the history of the spring In 1763 R. Tradwell secured a patent for the invention of the first version of the coil spring. This was a great step in the history of the spring, as the coil spring - in comparison to the thus far used leaf springs - did not require the same maintenance. A leaf spring often had to be separated to be lubricated. In 1857 the first coil spring made of steel wire was produced. This was a spring for use in an armchair.

***Regardless of the size, shape or purpose, the principle behind the spring is the same.