English Successfully Used Discarded Tires To Extract Carbon Black

Recently, three British inventors extract the carbon black from discarded tires. The carbon black, which has low price, may be used as a printing ink coloring of special carbon black substitutes.

The method can be generalized as the following: Isolated from the air, getting carbon black, steel and silica mixture after pyrolysising the in the condition of high temperature 800 ℃. Baking after magnetic separation and screening, the semi-pure charcoal powder is produced. And then washing it by using hydrochloric acid and sodium hydroxide, you can get the black printing ink with carbon black (also known as Acetylene black or lamp black). Compared with conventional furnace black production process, the pyrolysis process does not emit carbon dioxide.

What Are The Effects Of Sunlight On Rubber?

In essence, the effect on rubber is one of degradation, as a result of exposure to ultraviolet (UV) rays. With the substance, the degradation comes about as a result of chemical reactions and molecular deformations, both stimulated by the UV ray exposure. There are mainly the following situations:

Degradation of Carbon Black In Tires
There’s a reason why car tires always come in black, though few stop to consider why. In order to protect against the effect of sunlight on cross-linking rubber polymers, tire type is infused with a protective material known as carbon black(CAS NO:1333-86-4), also referred to by those in the auto industry as a “competitive absorber.” The purpose of the carbon black is to absorb sunlight on the surface of the tire, and deflect it from the inner polymers of the tire.

Loss of Elasticity
The reason rubber tends to become less elastic and more cracked after long-term exposure to sunlight is a matter of molecular bonding (specifically, cross-linking bonds). UV rays from the sun have the effect of increasing the cross-linking between polymer molecules within the rubber, increasing the density of these cross-links. At a certain point, the plethora of cross-links formed–due to chemical stimulation from the rays of the sun–strengthen the rubber item, and lessen the original elasticity, making it more brittle and harder to bend or stretch. This process is also considered an oxidation of the rubber polymers.

Dry rot
Dry rot is generally referred to as the breakdown or decay in wooden materials. However, the term has been used colloquially in other fields as well, including tire deterioration, although rubber on tires does not actually rot. When cracks begin to occur within a tire’s rubber, it is said to have dry rot.

Dry rot can be caused by a number of factors. One of the major causes is excessive exposure to ultraviolet rays. One general type of UV stabilizer is called a “competitive absorber.” Competitive absorbers absorb the UV light, instead of the tire sidewall, and convert the UV rays into heat so it can dissipate. The least expensive type of competitive absorber comes in “carbon black.” This is why tires generally come in black, rather than unique colors. Eventually, though, UV stabilizers no longer offer protection to a tire, causing the tire to look gray.

While the deflection and protection abilities of carbon black extend the life of a car tire, they do not do so indefinitely. Eventually, UV rays from the sun destroy carbon black molecules, depleting the shield on the car tire surface, and giving access to the inner tire polymers. The degradation of the chemical in rubber tires explains why car tires become gray and crack as they age.

Uses of Carbon Nanotubes

Carbon nanotubes are hexagonally shaped arrangements of carbon atoms that have been rolled into tubes. They are long, thin cylinders of carbon. They were discovered in 1991 by S. Iijima. They are large molecules that have a special size and useful physical properties. What makes them so different is that nanotubes have a very broad range of electronic, thermal, and structural properties that can change.

They were developed by using nanotechnology, a relatively new field that involves building electronic circuits and devices from single atoms and molecules. Nano means one thousand millionth of a unit. A nanometer is therefore one thousand millionth of a meter. The first nanofabrication experiments occurred in 1990 when individual xenon atoms were placed on a nickel substrate and used to spell out a company logo. One primary goal of nanotechnology is to build computer chips and other devices that are thousands of times smaller than they are now.

It is the first time that carbon nanotubes have been hybridized to undergo light-induced electron transfer. Researchers say that these modified materials are the first step in building solar cells using this technology.

Carbon nanotubes have many remarkable properties which researchers are only just starting to exploit. First of all, they are extremely strong, probably one of the strongest materials that is even theoretically possible. Although nanotubes are only about a nanometer wide, they can be very long in comparison to their width, a useful property for strength.

Single-walled carbon nanotubes are excellent conductors, and many computing companies are developing ways to use them in computers. The use of them will allow the computing industry to create computers more powerful than those which can be fabricated via the conventional method of photolithography.

Carbon nanotubes are capable of ballistic electron transport, meaning they are excellent conductors in the direction of the tube. This led them to be proposed as the ideal building material for the next generation of televisions, although the improvements of LCDs, including OLCDs, makes this unlikely in the near-term future.

What’s more, scientists have long been interested in wrapping proteins around carbon nanotubes, and the process is used for various applications in imaging, biosensing, and cellular delivery, according to a study discussed in the Dec. 13 issue of “Science Daily.” Tools of this kind are useful when studying certain diseases. For example, an abnormal zinc balance is a characteristic of brain disorders, such as Alzheimer’s disease, according to the article “Applying Nanotechnology to Human Health: Revolution in Biomedical Sciences” in the “Journal of Nanotechnology.”