Research on polymer

In my previous post, i talked about polymer and balloons. I do not know much about it except preventing balloon's from bursting so here's my research on polymer:

A polymer is a large molecule(macromolecule) composed of repeating structural units typically connected by covalent chemical bonds. While polymer in popular usage suggests plastic, the term actually refers to a large class of natural and synthetic materials with a wide variety of properties.

Because of the extraordinary range of properties of polymeric materials, they play an essential and ubiquitous role in everyday life, ranging from familiar synthetic plastics and elastomers to natural biopolymers such as DNA and proteins that are essential for life. A simple example is polyethylene, whose repeating unit is based on ethylene (IUPAC name ethene) monomer. Most commonly, as in this example, the continuously linked backbone of a polymer used for the preparation of plastics consists mainly of carbon atoms. However, other structures do exist; for example, elements such as silicon form familiar materials such as silicones, examples being silly putty and waterproof plumbing sealant. The backbone of DNA is in fact based on a phosphodiester bond, and repeating units of polysaccharides (e.g. cellulose) are joined together by glycosidic bonds via oxygen atoms.

Natural polymeric materials such as shellac, amber, and natural rubber have been used for centuries. Biopolymers such as proteins and nucleic acids play crucial roles in biological processes. A variety of other natural polymers exist, such as cellulose, which is the main constituent of wood and paper.

The list of synthetic polymers includes synthetic rubber, Bakelite, neoprene, nylon, PVC, polystyrene, polyethylene, polypropylene, polyacrylonitrile, PVB, silicone, and many more.

Polymerization is the process of combining many small molecules known as monomers into a covalently bonded chain. During the polymerization process, some chemical groups may be lost from each monomer. This is the case, for example, in the polymerization of PET polyester. The monomers are terephthalic acid (HOOC-C6H4-COOH) and ethylene glycol (HO-CH2-CH2-OH) but the repeating unit is -OC-C6H4-COO-CH2-CH2-O-, which corresponds to the combination of the two monomers with the loss of two water molecules. The distinct piece of each monomer that is incorporated into the polymer is known as a repeat unit or monomer residue.

Polymers are studied in the fields of polymer chemistry, polymer physics, and polymer science.

The word polymer is derived from the Greek words πολυ- - poly- meaning "many"; and μέρος - meros meaning "part". The term was coined in 1833 by Jöns Jacob Berzelius, although his definition of a polymer was quite different from the modern definition.

Wow! I certainly did not know polymer was such an interesting molecule and had so much history!

The "skewer through balloon" trick

As a child, i have always watched science programmes and magic shows on television that commonly always show the trick where people would put a funny liquid on the balloon, then poking a stick that seemed like a wooden chopstick through the balloon without bursting it at the same time. Up till now, I still do not understand the science theory behind this weird trick. So now, here is my research on the trick and sharing something new and interesting i have learnt.

Just how does it actually work?
The secret is to uncover the portion of the balloon where the latex molecules are under the least amount of stress or strain. After drawing on the balloon with the Sharpie marker, you probably noticed that the dots on either end of the balloon were relatively small. You’ve just uncovered the area of least stress... the ends of the balloon. When the point of the skewer is positioned at the ends of the balloon, the solid object passes through the inflated balloon without popping it.

If you could see the rubber that makes up a balloon on a microscopic level, you would see many long strands or chains of molecules. These long strands of molecules are called polymers, and the elasticity of these polymer chains causes rubber to stretch. Blowing up the balloon stretches these strands of polymer chains. Even before drawing the dots on the balloon, you probably noticed that the middle of the balloon stretches more than either end. You wisely chose to pierce the balloon at a point where the polymer molecules were stretched out the least. The long strands of molecules stretched around the skewer and kept the air inside the balloon from rushing out. It’s easy to accidentally tear the rubber if you use a dull skewer or forget to coat the end of the skewer with vegetable oil. When you remove the skewer, you feel the air leaking out through the holes where the polymer strands were pushed apart. Eventually the balloon deflates… but it never pops.

Oh, just to prove your point, try pushing the skewer through the middle part of an inflated balloon. Well, at least you went out with a bang!

This facts and experiments' success is all thanks to the properties of POLYMER!!!

"Thermite reaction"

I found a "thermite reaction" video on YouTube and decided to do some research on "Thermite"s since I did not know anything about it at all. ( I did not even know that there was such and thing and thought it was a fraud.)
Not to be confused with termite, Termit (disambiguation), or Thermalite. We should try not to mix "Thermite" up with the above terms i mentioned like i did at first. :)

Basically, Thermite is a pyrotechnic composition of a metal powder and a metal oxide, which produces an aluminothermic reaction known as a thermite reaction. Most varieties are not explosive, but can create short bursts of extremely high temperatures focused on a very small area for a short period of time.

Thermites can be a diverse class of compositions. The fuels are often aluminium, magnesium, calcium, titanium, zinc, silicon, and boron. The oxidizers can be boron(III) oxide, silicon(IV) oxide, chromium(III) oxide, manganese(IV) oxide, iron(III) oxide, iron(II,III) oxide, copper(II) oxide, and lead(II,III,IV) oxide. All these I have just learnt recently during science for elements and compounds!

The most common thermite is aluminium-iron(III) oxide.

Thermite Reaction:

The aluminium reduces the oxide of another metal, most commonly iron oxide, as aluminium is highly reactive:

Fe2O3 + 2Al → 2Fe + Al2O3 + heat
The products are aluminium oxide, free elemental iron, and a large amount of heat. The reactants are commonly powdered and mixed with a binder to keep the material solid and prevent separation.

The reaction is used for thermite welding, often used to join rail tracks. Other metal oxides can be used, such as chromium oxide, to generate elemental metal. Copper thermite, using copper oxide, is used for creating electric joints in a process called cad welding:

3CuO + 2Al → 3Cu + Al2O3 + Heat
Some thermite-like mixtures are used as pyrotechnic initiators such as fireworks.

Thermites with nanosized particles are described through a variety of terms, such as metastable intermolecular composites, superthermite, nanothermite, and nanocomposite energetic materials.

A mixture of thermite and sulfur produces thermate which lowers the melting point of the iron it contacts when reacting by forming a eutectic system. This is useful in cutting through steel.

History of Thermite:

The thermite (thermit) reaction was discovered in 1893 and patented in 1895 by German chemist Hans Goldschmidt. Consequently, the reaction is sometimes called the "Goldschmidt reaction" or "Goldschmidt process". Dr. Goldschmidt was originally interested in producing very pure metals by avoiding the use of carbon in smelting, but he soon realized the value in welding.

The first commercial application was the welding of tram tracks in Essen, in 1899. Evonik, formerly Degussa, a corporate descendant of Goldschmidt's firm, is still today one of the world's largest producers of welding thermite.

"All together now-for fun ... and science"

Recently around august I came across this very interesting article about 1500 of Punggol Secondary School's students, teachers and parents, under the eye of A*Star, NTU and the Singapore Science Centre attempting to get into the Singapore Book of Records for the "Most number of famous Cola-Mentos Geysers created at once." It was an act done part of the school's National Day celebrations and this year's Singapore Science Festival.
After I read the interesting and cool but thought-provoking article, I began to think, "How does this thing work actually and why is it so famous with large numbers of people experimenting this "Chemical Trick". And then, I wanted to find out how this whole thing actually worked.
This is actually a reaction of Diet Coke and mint Mentos candies. Diet cokes are usually the preferred choice as it tends to react better. By dropping some Mentos into bottle of Diet Coke causes the Diet Coke to foam at a rapid rate and spew into the air. Mint-flavored Mentos are also the preferred choice of mints to use, as fruit-flavored mentos have a smooth coating which slows down the reaction. Because of the spectacular nature of this physical and chemical reaction and the easy availability of the recipe, the chemical reaction which causes the eruption is a popular subject for several Internet videos which can also be found on websites and mostly on YouTube. The bigger the bottle of Diet Coke, the bigger the spectacular explosion.
After this trick was created, it gained lots of support from around the world and eventually led to several videos on demonstrations for cola geysers, tv shows about it, guinness world records of the reaction explosion height and number of simultaneous explosions, and even competitions!!!
This is the reason behind the chemical reaction: The physical structure of the Mentos is the most significant cause of the eruption due to nucleation. The surface of the mint Mentos is littered with many small holes, allowing CO2 bubbles to form very rapidly and in great quantity, in turn causing the jet of foam.

Tuesday, September 14, 2010"China out to conquer the ocean depths"

I came across this somewhat "attention-drawing" article and decided to share it here on my science blog.
Three Chinese scientists plunged to the bottom of the South China Sea in a tiny submarine early this summer. They did not only simple plant their country's flag on the dark seabed, but during the 3000m descent in a craft the size of a small truck, they also signalled Beijing's intention to take the lead in exploring remote and inaccessible parts of the ocean floor, which are rich in oil, minerals and other resources the Chinese would like to mine. But, many of these areas are actually where the country has clashed with its neighbours over territorial claims. The mineral nodules are apparently worth trillions of dollars, and china are in a perfect position to go after these.
A small craft that made the trip-JiaoLong, meaning sea dragon in Chinese, was unveiled publicly late august after eight years of secretive development. It is designed to go deeper than any other craft in the world and it gives its owners access to 99.8% of the ocean floor. Technically the JiaoLong is a submersible as it differs from submarines in their size, their need for a mother ship on the surface of the water and their ability to dive extraordinarily deep under the waves despite the darkness and crushing pressure. These types of craft are extremely rare with only a few existing in the whole world. The JiaoLong is able to go the deepest ever depth of 7000m, deeper than many other Japanese, Russian, french and US crafts.

"Motorists get a message: Don't leave the engine on"

I read an article about motorists getting complaints after leaving their engines on and at the same time, infringing a little-known law. I also found some scientific concepts behind this article and would like to share them.
Why do up to 3000 people complain about this inconsiderate and illegal act?
Little of the "law-breakers" have learnt their lesson as only a handful of them have been let of with a warning and $70 fine.
These motorists keep their engines and air-conditioners running in this hot and humid climate to cool themselves down in this type of weather but end up bringing harm to the environment as well at the same time.
Not only does the noise and fumes produced annoy people, but the Co2 it emmits also brings harm to the Earth's well-being. I hope that these people would stop this acts and try to play a better part in protecting the earth.

NewsPaper Article on "SPILL FALLOUT IN CHINA"

"'Severe threat to sea life' as slick spreads". Little did I know what this title meant until I started to read the article. The largest ever oil spill china reported occured at around late July this year and it was double the size of the previous oil spill, and its current size was about 430sq km. The oil spill caused nearby beaches to be closed down and more importantly, it prompted an official to warn of a "severe threat" to sea life and water quality.
When I finished the article, I felt that this article had many scientific concepts behind it, and it also very clearly displayes the consequences of many of our actions and this is also partially related to the hotly discussed global warming.
The scientific concepts are: The pollution caused by the oil spill in the water will kill many marine life and intefere the aquatic food chain. There would also be chemical re-actions when the petrol in the water decomposes after a while. The petrol also does a part in polluting the sea.
Although the amount of oil spill was still unclear, more importantly, this incident highlights the severe consequences which we have to face if we mankind do not play our parts in protecting the environment and preserving the Earth.

Science questions on density.

1)Salt has a higher density than water , and when salt was added to the normal water, it increased the water's density, thus the salt water's density was higher than normal water.

Science questions on density.

2)Salt has a higher density than water, and objects float better in substances with a higher density. Thus, when salt was added to the water, it increased the density of the substance, thus enabling the egg to float in the salt water. The egg could float in salt water as it had a higher density but not in the normal water as the normal water had a lower density.