Polyester: The Wonder Behind the Movie

More on Kevlar

2005-11-10T18:15:00.000-05:00

In a previous post, it was mentioned that Stephanie Kwolek discovered Kevlar, the miraculous material that was five times stronger than the same weight of steel. How exactly is this possible? One needs to examine the properties of Kevlar to find out.

Kevlar is an aramid, which is a fire resistant and strong synthetic fiber, which consists of long polymer chains that are aligned parallel to each other. Its strength lies in its strong inter-molecular hydrogen bonds (see Dr. Crane's website and accompanying picture), and aromatic stacking interactions. These interactions are much stronger than simple London Dispersion forces found in other synthetic polymers. Thus, because of these interactions, Kevlar has high mechanical strength and remarkable heat resistance.

These are some other properties of Kevlar:

High Tensile Strength at Low Weight
Low Elongation to Break High Modulus (Structural Rigidity)
Low Electrical Conductivity
High Chemical Resistance
Low Thermal Shrinkage
High Toughness (Work-To-Break)
Excellent Dimensional Stability
High Cut Resistance
Flame Resistant, Self-Extinguishing

And here are some applications of it:
Ropes that secure the airbags in the crucial landing apparatus of the Mars Pathfinder
Small-diameter, lightweight ropes that hold 22,000 pounds and help moor the largest U.S. Navy vessels
Shrapnel-resistant shielding in jet aircraft engines that will protect passengers in case an explosion occurs
Run-flat tires that allow for greater safety because they won't ruin the rim when driving to the nearest assistance
Gloves that protect hands and fingers against cuts, slashes and other injuries that often occur in glass and sheet metal factories
Kayaks that provide better impact resistance with no extra weight
Strong, lightweight skis, helmets and racquets that help lessen fatigue and boost exhilaration

Click here for more applications of Kevlar

Commercializing Nylon

2005-11-09T19:51:00.000-05:00

After DuPont discovered nylon, they wanted to make a profit from it. Of course, since the most obvious idea was to incorporate it into clothing, they decided to substitute it for silk in women's hosiery. Although this idea became a reality in 1937, there were two problems with it: breaks formed due to bubbles and extrusion holes had to be unclogged due to fouling. Fouling is the accumulation of inorganic particles, microorganisms, macromolecules, and corrosion products on a surface. Today, the bubble problem has been solved but the fouling of extrusion holes is still a big problem.
Soon after that, a pilot plant was started in Seaford Delaware, which started producing 1/10 of DuPont's expected production. It slowly increased its production, and today it produces about a million pounds a day. Another plant was authorized in Martinsville, Virginia, where DuPont's experience with cellulose based products, such as Rayon and acetate, helped them succeed in commercializing nylon.
Nylon has come a long way since Charles Stine, Vice President of DuPont, introduced nylon:

"This textile fiber is the first man-made organic textile fiber prepared wholly from new materials from the mineral kingdom. I refer to the fiber produced from nylon. . . . Though wholly fabricated from such common raw materials as coal, water, and air, nylon can be fashioned into filaments as strong as steel, as fine as a spider's web, yet more elastic than any of the common natural fibers."

For pictures of factories, advertisements, and more in-depth information on the commercialization of nylon, click here

From Space Technology to Food Wrap

2005-11-09T08:11:00.000-05:00

From space to food wrap Mylar has been there. Mylar developed out of the early 1950s compound Dracon and Cellophane of the 1960s. It showed that polyester could be oriented not only into long threads, which are woven, but also thin sheets, which are extremely strong and flexable. These thin sheets, much like long threads of polyester, have molecules aligned so that the durability of the material is increased.
The Mylar compound itself was impressive enough to be used on the lunar lander captained by Neil Armstrong. As stated in the fly and the ointment, “The lander was wrapped in a lustrous gold material.” Now a days you may find that Mylar is more commonly found wrapping food produce in the grocery market, than on our modern space shuttles. Yet, so far the polyester based Mylar has proved its usefulness, since its development back in 1960. Here you can see a thin layer of Mylar suspending a car from a crane, showing the strength of this material.

The Secret Behind Perspiration-fighting Athletic Gear

2005-11-09T00:02:00.000-05:00

Sweat-fighting athletic gear, known as “performance apparel,” is a multibillion-dollar business. Sweat cools your body when it evaporates from your skin. However, too much sweat gets soaked up by the cotton shirt, which becomes damp. Performance apparel solves this problem by absorbing the sweat and drawing it upward. How does this work? It works because of polyesters. The sweat-removing shirts. With their polyester-blended fabrics, pull sweat away from the skin and push it through the clothing’s surface, which then evaporates. The result is a comfortable and dry shirt.
Brooks Sports’ Pulse T is a shirt that comes with “moisture transfer polyester” and heat release panels in the armpits and chest. It actually works. One would receive a cold sensation when wearing that polyester shirt. These polyester shirts do absorb the sweat thus leaving an athletic with a dry comfortable shirt ready to play his game.

Biodegradable Polyester: US Entering the Race

2005-11-07T23:08:00.000-05:00

Global suppliers have commercialized a broad range of synthetic biodegradable resins, which is based on aliphatic polyesters. The demand for biodegradable polyesters is growing at a rate of 30% per year. The US is catching up with Europe and Asia in exploring the potential of biodegradable polyesters in flexibility and rigid packaging. The US is trying to find packaging applications for these materials. Synthetic polyesters are made in modified PET (mentioned in an earlier post) polymerization facilities. Polyesters, compared to other materials that take centuries to degrade after disposal, break down rapidly to carbon dioxide and water. It takes about twelve weeks to break down. Synthetic biodegradable polyesters can break up into two categories. One is highly amorphous (lacking shape), and has flexibility and clarity. The second is more rigid with properties close to that of PET. Julian Jensen, an Eastman Chemical’s business market manger, states:

"The emphasis is now on using biodegradable polyesters as specialty materials for paper coating, fibers, and garbage bags"

Companies such as Japan’s Showa Highpolymer, part of the Showa Denko group, and Korea’s SK Chemicals have small plants producing aliphatic (polybutylene succinate) and aliphatic-aromatic (polybutyrate adipate terephthalate) polyesters. It is becoming evident that polyester is indeed part of our future.

Polyester...Nylon... Now What?

2005-11-04T08:59:00.000-05:00

Chemists at DuPont were still not satisfied after they discovered nylon. They wanted yet another stiffer and tougher nylon-type of material. But this time the new material was not discovered by Carothers; instead, it was found by Stephanie L. Kwolek.

What was the new material's name? Kevlar. This miraculous new material was five times stronger than the same weight of steel. Kwolek discovered Kevlar when she developed a liquid crystal polymer that could be cold-spun. This polymer that she synthesized was known as an aromatic polymer, which means one that is spun with a solvent rather than melt spun. As a result of this, DuPont spent over $500 million towards research on this. It won the National Medal of Technology in 1996, and Forbes magazine called it "a miracle in search of a market." Thus, DuPont found a use for this material in tires at a plant in Virginia, but today Kevlar is well known as the body armor that policemen and soldiers wear.

Performance Polyester

2005-11-04T00:31:00.000-05:00

Polyester had a great run during the 70s with the infamous leisure suit era, which unfortunately ended disastrously. Yet, the wonder material is on the rise again. Since the 70s craze, polyester has evolved past the disco floor into the realm of performance athletic wear. Here, in this niche of the market, polyester has remained favorable for its heat retaining and moisture transferring properties.

DuPont has invested in its own polyester based performance wear product, which is advertised to offer superior warmth with extremely reduced weight. DuPont’s Thermolite Base delivers just what its advertisement claims. Thermolite utilizes a unique hollow structure variation of polyester thread, which maintains heat due to the air trapped inside the core.

DuPont explains that, “Hollow-core fiber technology provides the most warmth at the lightest weight.”

Due to its airway capillary design, Thermolite is one of the most breathable materials on the market. The constant flow of moisture away from the body maintains a comfortable body temperature even on the coldest days. Additionally the drying speed of this fabric beat out materials ranging from cotton and wool, to ordinary polyester and silk.

Powder Coating

2005-11-03T18:36:00.000-05:00

TGIC (Triglycidylisocyanurate) polyester and urethane polyester are the two main groups of polyester powder coatings. They both have “flexibility and durability, including outdoor UV-resistance.” In addition, they have outstanding weathering properties.
TGIC, more specifically, is a low molecular weight epoxy (oxygen attached to two different atoms that is already united) functional cross-linker that is employed in polyester powder coatings. A cross-linker allows the polyester TGIC to have 90 plus percent resin within the binder system. Powder coating is any coating that is applied as a dry, fine solid which sticks to the substrate as a continuous film when melted and fused.
TGIC is used for the following: outdoor furniture, farm equipment, fence poles, air-conditioning units, automotive trim and accessories, and transformers. Some applications for urethane-polyester powders are fluorescent light fixtures, steel and aluminum wheels, patio furniture, chrome wheels and tires, air-conditioner cabinets, ornamental iron, electrical housing, range hoods, lawn and garden equipment, and automotive exterior trim. Research is now being done on polyester amide powders; polyester amide powders are going to be a powder coating in addition to the two primary types.

Polyester and Odorama

2005-10-27T23:03:00.000-05:00

Some may be able to recall the 1981 film Polyester, in which director John Waters pokes fun at middle class, suburban life style and culture. However, more so than the actual film, some may be surprised by the fact that it was the first movie ever coordinated with Odorama. You guessed it! Smells were incorporated into the plot of the film via the magic of Scratch and Sniff cards. Dr. Schwarcz reminisces about his experience with Polyester, stating:

“There were oven fumes, pizza, ‘new car,’ and sweaty gym sock smells, and I’ll leave it to you to guess which odor filled the theater when the number 2 appeared on the screen.” (Schwarz, 165)

Yet, how can such a variety of different smells be triggered at different times and work so effectively? Once again polyester plays a fundamental role in this product. First the chemical makeup of whatever scent, for example moldy gym socks, is devised. The next step is the most astonishing. The scent molecules are encapsulated into incredibly tiny polyester beads through the process of microencapsulation (learn more here.) The beads are then ruptured when scratched, releasing the scent. Approximately one square inch of Scratch and Sniff paper can hold up to 50 million beads. This explains why Scratch and Sniff stickers seem to never lose their scent.

Cold Drawing

2005-10-26T08:26:00.000-05:00

It was previously mentioned that Wallace Carothers discovered polyester in his Dupont factory, but soon abandoned research on it in order to concentrate on nylon. So, how exactly did he discover nylon when he was researching polyester? He did it by a process known as cold drawing.

According to About.com, cold drawing is "the process of reducing the cross sectional area of wire, bar or tube by drawing the material through a die without any pre-heating."

How was it discovered?
In 1930, Carothers wanted to form long chain polyester, by reacting diacids and diols. Since the reaction also formed water, some of the polyester reverted back to the original reactants. They invented equipment to remove this water as it was formed, and thus, produced a high molecular weight polyester. As Carothers discovered, this material could be stretched into a fiber. He also discovered that the fiber grew silkier and stronger as they stretched it more and more out. This process is known as Cold Drawing. Cold drawing made the molecules bond stronger to each other, and oriented them into a long, linear chain. However, Julian Hill, Carother's assistant had a problem: the low melting temperature was unsuitable for textile applications. But Carothers experimented a little more, and soon discovered Nylon 6, the OTHER polyester.

Experience Comfort With New Cirrasol

2005-10-25T09:36:00.000-05:00

A new multifunctional soil release agent for laundry detergents, Cirrasol PE 113, has been introduced. Cirrasol PE 113 is a hydrophilic (water-loving) detergent that offers both enhanced cleaning efficiency and long lasting comfort in wear for polyester-rich fabrics. This works by coating polyester fibers in the wash, and converting it to become water-absorbing. By changing the nature of polyester from water-repelling to water-loving fiber, Cirrasol PE 113 provides an enhanced cleansing agent to cleanse difficult to clean garments. In addition to this, the function of the polyester is changed to allow moisture to pass through the garment thus adding comfort to the wearer because the clothes can “breath.” Cirrasol enhances comfort, and reduces the graying of white polyester. Sales Development Manager states:

“Many of the traditional concerns about caring for polyester based clothing are extensively resolved, including a reduced tendency for static cling and creasing.”

With the new Cirrasol, it can resolve this issue thus making polyester more appealing to the consumers. Furthermore, Cirrasol extends the longevity of the garment. Even if one washes the garment 10 times, the garment still looks new and clean. Finally, this new product satisfies both the industry and the consumers. Cirrasol is the most efficient cleansing detergent. Also, it is very cost-effective; consumers are very sensitive to price. So next time you have a huge stain that cannot be washed, try Cirrasol and experience comfort.

Neil Armstrong's Landing and Mylar

2005-10-20T20:39:00.000-05:00

What does Neil Armstrong have to do with Polyester? Well, in The Fly in the Ointment, it stated that the lunar lander that he guided was wrapped in lustrous gold material (Schwarcz 164). That material was Mylar, a sheet of polyester. Mylar was also developed by DuPont in the mid 1950s. It is actually a simplified (market) name for biaxially-oriented polyethylene terephthalate (BOPET).
As exemplified by Mylar, polyester can be not only drawn in threads but also melted into superstrong flexible sheets. This can be made into emergency blankets such as this one. The advantage of making it out of Mylar is that the bag provides a vapor barrier, preventing heat loss by evaporation and convection. The surface will reduce the heat loss by radiation up to 90%.
Various other products are also made with Mylar, because of its shiny nature, such as these nails. And what about the material in audio and video tapes? Yes, those are made out of mylar too.

Polyester in Beer Products

2005-10-19T00:00:00.000-05:00

Nowadays, some alcohol beverage companies are changing up the ubiquitous glass bottle standard of the industry. They are now just starting to convert some of their shipments to plastic bottles. This, of course, was thought to be impractical and unrealistic due to the fact that the plastic would allow for gases to escape, and would cause the beer to go flat.
However, thanks to modern technological advancements in polyester products, this problem has been almost ruled out. Known as PET bottles, containing polyester, these plastics are coated internally and externally with barrier molecules that block out gases. These coats are so efficient that humidity and gas escape levels are well beyond acceptable for shelf life. Now the newer PET bottles have grown in appeal towards the outdoor going consumer, since the bottles are much lighter and cannot be shattered if dropped. Producers are also happy since the production of plastic bottles costs a fraction of the price of glass bottles.

Find out more about these bottles here.

Polyester Advances Digital Technology-Computer-to-Plate (CTP)

2005-10-18T18:38:00.000-05:00

Polyester plates are leading the way in the advancement of digital technology: image setters, and laser printers. At first, companies were cautious before they start to use polyester plates because companies were concerned about the print-quality, stretch, and run length. Furthermore, Dan Taxbol states:

“Polyester plates have a reputation for being difficult to handle. This has been proven wrong-polyester is different from metal-you have to get to know the material. If you want the plate to work, it will.”

However, new plates and film output options are introduced thus making polyester a more affordable choice. Polyester plates are now thicker in dimensions close to that of a metal plate. Another factor that is contributing to the popularity and growth of polyester is the new generation of small format image setters. This allows printers to duplicate their services at a fraction of the cost. The DigiPlate, which is offered in polyester and paper, can hold a 175-line screen with a three to ninety-seven percent dot. The polyester is for 25,000-plus impressions while paper is only for 10,000 impressions and below. Increasingly, polyester is proving itself useful and beneficial especially to those in the middle of the business competition. These industries are using spot and four-color work with polyester. In addition to this new novel, this transition in technology requires skilled employees.

A General Overview of the Manufacturing Process

2005-10-14T09:07:00.000-05:00

The alcohols and acids that make up most polyesters are made from petroleum. Specific details about the types of processes that manufacturers use are hard to find since companies want to keep it a secret in order to remain competitive. However, a general description of how polyester is synthesized is known:

First, the alcohols and acids obviously go through polymerization, in order to create the polymers. Then, after it hardens, it is cut into chips. The chips are dried and then put into hopper reservoirs for melting, and this process is known as spinning. It is then heated, extruded (the process mentioned in the previous post) through the spinnerets, and then cooled. The fibers must then be stretched until they are about five times their original length, and this is done in order to decrease their width. It is then made into cones or crimpled and is cut into the desired length. Click here for more details about the various phases of the process.

Manufacturing of Polyester Products

2005-10-14T07:09:00.000-05:00

Ever wonder about the manufacturing process of polyester products? Did you know that the shine or resistance to stains is dependent on the manufacturing process? Just how are these solid polymer chips transformed into neatly weaved materials?

Most of these processes involve the method of “extrusion,” in which the polymer chips are melted and then squeezed through small holes, positioned somewhat like a showerhead, as a viscous liquid. This causes thin strands of melted polyester to strain downward. The strains are then hit with cold air, which solidifies the strands. Then for increased strength the strands are stretched.
This process is explained more in depth at fibersource.com.

Dr. Joe Schwarcz states that, “Quite often I would have to tear loose a polyester thread from the material, which turned out to be quite easy when done quickly, but much tougher when done slowly.” Again this anomaly occurs because the molecular chains align themselves along the fiber axis.

The cross-sectional shape that the polyester is twined into determines its qualities, such as Trilobal-shaped fibers, which give clothing a shine and sparkle. Other standard shape designs include round, pentagonal, and octagonal cross-sections.

Polyester's Emergence into the Public

2005-10-13T10:28:00.000-05:00

Since it was previously mentioned that Carothers discovered that alcohols and carboxyl acids could be combined to form fibers, the question remains as to how polyester was made public. Well, the truth is, Carothers stopped doing research on polyester when he discovered nylon. So, a few British scientists - J.R. Whinfield, J.T. Dickson, W.K. Birtwhistle, and C.G. Ritchie - continued where Carothers left off. In 1941, they created Terylene and DuPont soon bought the legal rights for it from the scientists in 1946, and named it Dacron.

In 1951, polyester was introduced to America as a miracle fiber that could be worn for 68 days straight without ironing, and still look presentable. Soon after that, in 1958, another polyester fiber called Kodel was developed by Eastman Chemical Products, INC. The market for polyester kept getting bigger. Since it was inexpensive and durable, numerous mills were created in order to produce polyester clothes. People were going crazy over polyester! However, the craze died down in the 1970s, and sales went down. Although, polyester is simply thought of as a cheap fiber today, its image is changing since polyester luxury fibers are starting to be made.
A more in-depth look at the history of polyester and its emergence can be found by clicking here.
Note: The link is a .pdf file

Under Appreciated

2005-10-07T07:02:00.000-05:00

What substance can save your life in the cold, has brought you your favorite VHS videos, keeps your soda bottles from exploding, and has been to the Moon? Stumped? Well you’re not the only one. It seems today that the wonders of polyester are simply little known and under appreciated. Although during the 60s and 70s polyester did make quite an entrance in the form of leisure suits. You have probably seen John Travolta sporting a polyester suit in Saturday Night Fever. Even then the polyester suits had some cool features: easy to clean, no need to iron. Polyester presented its true scientific contributions though, way back when a chemist Wallace Carothers and his assistant Julian Hill in 1930 noted that stressing polyester fibers made the substance extremely durable.

According to the Wonders of Polyesters, “Subjecting a fiber to such stress causes the long polyester molecules to orient themselves along the axis of the filament, leading to enhanced strength.”

This discovery led to the production of polyester based sheets and plastics, which were not only extremely hard to tear, but also heat resistant.

Poly+Ester=Polyester!

2005-10-06T17:22:00.000-05:00

Look at the word Polyester very closely. You can see in the name “polyester’ the word “ester;” hence, polyester is made out of esters. Esters are functional group with –COOR where R is the methyl group. A more concise definition of polyester is a polymer (a chain of repeating units) where ester linkages hold the individual units together. Polyester is a man-made fiber. Polyester is very popular these days. Terylene, or also known as dracon, is popular brand of polyester today.
Esters are formed when a carboxylic acid reacts with an alcohol. With polymerization reaction, esters can be formed into long chain molecules.

Some properties of Polyesters include:
1) Polyester fibers are strong due to their long chain of polymers.
2) Polyesters are very elastic for they can regain their original shape quickly. Even after repeated use, they do not loose their shape.
3) Polyesters absorb little water or moisture.
4) Fibers made of polyesters do not wrinkle easily (hence John Travolta and his white polyester suit).
5) Polyester fibers can withstand wear, tear, and/or abrasions much better. Due to their long chain, polyesters are not affected by chemicals hence they are long-lasting.
6) Polyesters are more resistant and light in weight.
7) Polyesters can be made very thin thus, the texture can be very fine and smooth.

Some Advantages of Polyester:
1) Rigid, resilient to chemical and environmental exposures, corrosion resistant, and flame retardant
2) Relatively cheap
3) Easily processed in low cost equipment
4) Polyester material is light weight as well as strong.
5) Polyester materials have good elastic properties.
6) They are also strong and long lasting

Disadvantages of Polyester
1)Moisture absorbent
2) Toxic
3) non-recyclable
4) long processing times
5) odor and potential health hazards

Some Products made out of polyesters include:
1) Boat hulls
2) Shower stalls
3) Electrical components
4) Appliances
5) Recreation vehicles
6) Automotive body panels
7) Floor pans
8) Bowling balls
9) Simulated wood furniture

Special Post!

2005-10-03T10:41:00.000-05:00

Dr. Chem here. I just found 5 links about Polyester that I thought I would share with you. This will clarify many questions about Polyester. I will explain them as we go further into this discussion. I am looking foward to your questions and comments. I will be back Saturday night. See you then.

This is about the history of Polyester which we have covered.
http://inventors.about.com/library/inventors/blpolyester.htm
Some general facts abouts Polyester.
http://www.fibersource.com/f-tutor/polyester.htm
New Polyester Products Perform Better and Are Easy to Recycle
http://www.vtnews.vt.edu/archives/1999/99118.html
Polyester Products:
http://www.shopmaninc.com/polyprod.html
Chemical Formula-The Chemistry of Polyester
http://www.chemindustry.com/apps/chemicals?m=s&t=Polyester

Oh, and I found this extremely smart guy (maybe even smarter than me?). His name is Dr. Crane and he teaches at Bergen County Academies. Check out his blogspot:
http://advchembca.blogspot.com

First Question

2005-10-01T19:27:00.000-05:00

Hello everyone and welcome to the polyester on-line discussion board. We have our first question today. Before we start, let me start with an introduction. I have a PhD. in Chemistry. I graduated from MIT undergrad and Harvard graduate school. I am currently a professor. I am more than happy to answer any questions about polyester. Let me start with a few interesting things. Remember John Travolta from Saturday Night Live? Well, he wore a white polyester suit. He did not have to worry about creases or perspiration stains for polyester is easy to clean. This was in the 1960s and 1970s. Since then, polyester has come a long way.

Thank you everyone for all those e-mails we received. You may send your questions to matoh@bergen.org or you may simply ask the question on-line.

Our first question is very basic: What is the history behind polyester?
One must know this before I jump into the more advanced. Polyester was the world's synthetic fiber. Wallace Carothers and his assistant Julian Jill who both worked at DuPont chemical company found this. It began with a controversy, in the 900s, within the chemical research community. Germany's Hermann Staudinger suggested that small molecules, called "monomers" could be joined together to form long chains called "polymer." Others kept the old assumption that polymers were just monomers packed together somehow. Carothers was ready to solve this mystery. He decided to tie small molecules together by using known chemical reactions hoping to get polymers as a result. He knew that alcohols and carboxylic acids formed compounds called “esters.” He created molecules with alcohol and functions on both ends, to create "polyesters."
The history behind polyester is very interesting. I would click here to find out more. This ends tonight questions. Feel free to comment and ask questions.

Coming Soon.

2005-09-26T22:33:00.000-05:00

Welcome to Ask Dr. Chem about Polyester!

You may submit questions for Dr. Chem regarding Polyester.
Every Saturday Night, Dr. Chem will be answering questions in person.

Join us!