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Tensile strength (TS) is a measure used to describe the maximum pulling pressure a material can manage, before the cross-section begins to notably contract. The real term for tensile strength is ultimate tensile strength (UTS), but this is commonly shortened to tensile strength.

In order to determine the UTS of nylon webbing, for example, the amount of stress the webbing can withstand is measured by using machines to pull with increasing pressure. This is not necessarily based on the material’s size.

Other measures, however, do take size into account. This is generally measured as force per unit area. It is a common practice to use the unit of pounds-force per square inch (psi) or kilo-pounds per square inch, for a psi in multiples of 1000.

Some factors that can influence UTS testing are flaws or defects in the material and temperature in the testing area. Thus, it is important for testing labs to examine the material to be tested, thoroughly, for any defects or weak spots and monitor the temperature for the test.

Usually, when the test reaches close to the maximum tensile strength of the material, it is measured as a curve, called the stress-strain curve. The stress-strain curve will reach a peak of pressure withstood, before the material begins to show visible strain against the pressure. This peak is measured and listed as the ultimate tensile strength.

Did you ever stop and wonder where the belt came from? Without it, who knows how some people would keep their pants up. The buckle is not used as much as it was before the invention of Velcro, but is still used extensively in the belt and shoe industries.

The word “buckle” stems from the Latin word “buccula” which means “cheek strap” as in those used for military helmets. As far back as history can tell, some of the oldest buckles were used by the Roman soldiers to put their armor on. Also dating back to the period of 200 to 100 BC, Chinese nomads called the Xiong-nu wore belt buckles over their tunics, as an indication of status.

Later, the Romans began using the belt to strap on their swords. The belt used for this was called the “baldric.” It was worn over the right shoulder and around the left side of the waist. Made of bronze, these buckles had great strength and durability for use in battles.

Scythia and Sarmatia were ancient lands in which buckles were decorated with animal shapes. The animal motifs were mainly of animals in deadly combat. The Germans caught on to this and began importing these stylish buckles for their own use.

Through the Middle Ages, buckles in Europe were primarily ornamental in nature. But in the mid 1300s, the buckle became more of a practical matter, used in battles by knights in armor. In the 1400s, buckles began to be made with cheaper materials so that the everyday person could use buckles for clothing items. In Spain, during the 1500s, the opposite trend was seen as buckles became less of a practical matter, mainly hidden from view, and were used as a decorative fashion statement instead.

Today, the buckle continues to be worn as both a practical item and for a fashion statement. Many Americans put on their simple buckles on standard leather belts for everyday work attire. Western cowboys are famous for their decorative belts, usually rectangular or oval in shape with detailed images and decoration molded into the shiny metal. Whether for decoration or practical use, the buckle holds its place in history and seems to be one of those clothing items that never goes out of style.

Webbing is produced in two basic types: 1) Flat webbing is a solid weave used for backpack straps, seat belts, and many other applications. 2) Tubular webbing is constructed as a tube of webbing and then flattened for use. Tubular webbing is regularly used for industrial uses and climbing ropes.

Flat nylon webbing works well for situations involving more abrasion than usual. It is not recommended for use in moist environments as it absorbs water readily, leading to mildew, rot, and extra stretchiness.

Depending on the construction, flat nylon webbing generally ranges in thickness from .070 to .075 inches. It can resist intense heat, but will melt at 480 degrees Fahrenheit. 1” nylon webbing has an ultimate tensile strength of up to 6000 pounds of pressure.

Tubular webbing is often used in climbing, rescue, and other such applications because it takes to knots more readily than flat webbing and can be looped for added tensile strength. However, it has less tensile strength, without looping, than flat webbing.

Tubular webbing usually comes in thickness ranging from 0.06 to 0.09 inches. Its ultimate tensile strength (depending on the thickness) is up to 4000 pounds. When looped, the tensile strength can reach up to 6000 pounds.

The buckle has a long and extensive history. It is a device used to connect two loose ends in a temporary fashion. The buckle can be buckled and unbuckled with relative ease, making it an ideal way to keep pants up, put collars on, and secure certain types of shoes.

The buckle is typically connected permanently to the leather, or other material, with its chape. The chape is a small protruding end of the belt. The chape runs from the connecting piece to the center of the belt where it is connected to a central cross-piece called the bar. The bar runs vertically from the top of the frame to the bottom.

On top of the bar is the prong. The prong is the small thin piece of metal that hooks into the appropriate hole in the belt or collar, in order to size the item to fit. Finally, the whole belt is surrounded by a frame. The frame is usually rectangular in shape.

The frame holds the prong into the selected sizing hole, once placed, to keep the prong from slipping out. The frame is also made to provide extra stability for the whole buckle.

The frame is typically the part of the buckle that is used to make a fashionable statement. While many belt buckles are relatively plain, there are also many variations in styles, colors, and forms to fit the personality or mood of the wearer.

Girls have lots of options for buckles with rhinestones or other decorations, buckles that are painted in fashionable colors, and buckles that have sayings printed on them. For men, a variety of metal types and finishes offer choices for everyday wear, but there are also wildly different styles such as those used in western wear. The buckle may often be taken for granted, but it is one of the longest lasting inventions in the human wardrobe and is still used today to make a statement.

DuPont’s chemical lab, headed by Wallace Carothers, invented nylon just before World War II. While attempting to develop the new manufactured fiber, he came across the possibility of making nylon 6, but was not able to make it work.

Using caprolactam, Carothers and his team applied a ring-opening polymerization. The goal was to take the ring-shaped caprolactam molecule and open it up into a strand. Additionally, it was to be combined with others of the same to form a stronger strand, a macromolecule.

Carothers and his team never did succeed in making nylon 6. He actually left behind a written report that nylon 6 could not be produced. But later, in Germany, Paul Schlak and his team of chemists succeeded in make nylon 6.

IG Farben, the company Schlak worked for, was thus able to compete with DuPont, with a new form of nylon no one else had. IG Farben began producing nylon 6, to be used in a variety of materials and products.

Today, science students being taught about polymerization can make nylon 6 in the school lab. Groups of students work together to initiate the chemical reaction responsible for ring-opening polymerization. Carothers, still renowned for his invention of nylon would have been surprised at the now large-scale production of nylon 6, the so-called impossible nylon.

Back in 1938, natural fibers were hard to come by. Cotton was the principle fiber used for most materials, but the military needed something better. DuPont, a chemical manufacturer, hired Wallace Carothers to lead their team of chemists to develop a manufactured fiber that was tough enough to make parachutes.

Nylon was the result of that move and it has since grown into a widely used material in military, fashion, sports, auto, and numerous other markets. Nylon webbing (found here) is found in products everywhere you look. Still the object of study today, nylon is something that chemical students learn to make in school labs.

Starting with water-based hexamethylenediamine solution, in a beaker or glass, adding sebacoyl chloride to the top makes nylon where the two layers touch. Then, with lab tweezers, the student or “home scientist” can grab the thin film of nylon and slowly pull it up and out of the glass, forming a longer and longer strand of nylon as the two solutions keep touching afresh and producing more nylon.

Here is how to do it: Gently pour the hexamethylenediamine into the bottom of the glass. Then, slowly pour the sebacoyl chloride over the top. It must be slow gentle pouring because you do not want to mix or stir the two solutions, just layer them.

Now you can reach through the sebacoyl chloride solution, with the tweezers, and grab the mid-section where the two solutions have formed a nylon “thread.” As you gently start pulling this section up, it will keep forming a thread as fast as you pull it.

Lay down the thread on some newspaper or paper towels laid over a flat surface. What you have is not really a useful form of nylon, but is definitely helpful as a teaching experience for science students of any age.

Back before the middle of the 20th century, an article was written in Time Magazine about DuPont’s development of the new manufactured fiber, nylon. It described how initially, DuPont’s nylon was used only as a fiber for women’s stockings, parachutes, surgical sutures, toothbrushes, and such.

But, on the horizon, DuPont predicted nylon’s usability in other items and products as a solid plastic. The nylon version of a solid is very heat resistant (up to 450 degrees Fahrenheit). It is also lightweight and durable.

So, what was the big news? Nylon would be used for items like outdoor furniture, “lace” curtains, zippers, wire insulation, bus seats, shoes, luggage, purses, tennis racket strings, fishing lines, tubing, drapery and upholstery fabrics.

Relatively inexpensive to produce, nylon fast became a popular material of choice for these products and countless others. The material’s nearly endless availability, ease of use, and durability led to its partial takeover of many material, fiber, and plastic product markets.

Today, it is taken for granted that many of these products exist most commonly in nylon form. Nylon has worked its way into almost every manufacturing industry and will likely never be replaced with a superior product.

The new face of nylon manufacturing was recently discovered in the UK, by a team of engineers working to develop the strongest form of nylon yet. They start with materials in powdered form, melting a thin layer of the powder with a laser and then adding layer, upon layer, upon layer in a 3-dimensional laser-printing process.

The engineers have attempted this process with various materials including metal and plastic. But their nylon version, they have proclaimed, is as hard as steel. To demonstrate their laser-guided manufacturing process at its best, they made what they call the “Airbike.”

The futuristic looking bicycle is made up of six separately “printed” parts. The European Aeronautic Defense and Space Company, or EADS, produced the bike to show the versatility of their manufacturing process they have called Additive Layer Manufacturing (ALM).

Plans for ALM include making lighter-weight planes, satellites, and perhaps even products for space using nylon. Why make the switch? The process uses 90% less material and the result weighs 65% less than typical metal manufactured products. The final product is incredibly durable.

Imagine a future where robots, containing ALM printers, fight battles for us by producing more robots and weapons made of materials they find around them. Far-fetched? Probably not.

What about futuristic food? CLM Laboratories already made some edible items using ALM. For now, it seems that nylon has managed to maintain its stronghold for use in the military and throughout the world while breaking ground for future, almost unfathomable new ideas.

In the 1970s, following some tragedies with home fires, consumers demanded nonflammable sleepwear for children, carpet, and other products. Over $20,000,000 in research funds later, the manufactured fiber industry had met with success in developing surface fibers that are not flammable.

A second major challenge of this time was the energy crisis of 1973. Manufactured fiber production was big business, and absorbed big energy. Additional research went into reducing the energy needed for producing manufactured fibers.

Energy efficiency in the industry increased by 26%. And only 1% of the supply of petroleum in the United States was being used to produce about 70% of the fibers used in the nation.
Once the safety and energy concerns were dealt with, consumers began seeking ways of cleaning the fibers more easily. Soon, carpet fibers made of nylon variants olefin and polyester made cleaning a cinch. In fact, a stain could be left overnight and still easily washed out the next day.

Today, the clothing market is still dependent on manufactured fibers, and the quality of clothing has increased greatly. Nylon has expanded across industries being used in rock-climbing, surgery, diapers, space stations, and for countless other purposes. Nylon has become an American heritage and does not appear to be losing hold anytime soon.

In the days of natural fiber clothing as the only alternative, ironing was a daily drudgery for the women of America. Clothes all had to be washed, dried, and then pressed with a hot iron before they could be worn again. This time-consuming task was a great deal of work for women with families.

When manufactured fibers began to really take hold in the fiber market, this began to change. In 1952, the term “wash and wear” came out, to describe the ease of using clothes made from a cotton/acrylic blend.

Manufactured fiber research moved away from researching basic polymers and into refining the fibers already developed. This resulted in even better products produced with manufactured fibers and with manufactured fibers combined with natural fibers.

In the 1960s and 1970s, polyester-blend fabrics became the norm. Clothing dryers left this type of clothing both clean and wrinkle-free. Colors lasted longer than before and fabrics were less likely to wear out or fray than older materials. By this time about 40% of the fiber market was held by manufactured fibers.

Nylon was being used for more and more products as technology, science, and other industries expanded and developed. NASA utilized nylon in various ways. Neil Armstrong’s suit and the flag he planted on the moon contained nylon. Even rockets contained polymer products as a means of reducing weight and fuel expense while leaving the atmosphere.