One of the most important materials that we use today is rubber. There are so many things that are made of rubber: gloves, tires, plugs, rubber boots, raincoats, earplugs, balloons.
In this lesson, we are going to learn about RUBBER, as one of the most used materials. We are going to find out:
Rubber is an incredibly versatile, all-purpose material that is used across a huge range of domestic and industrial applications.
Rubber is a naturally soft and flexible material, which can stretch and shrink, and remains durable with extended use. It is a polymer (a long, chain-like molecule that contains repeating subunits), and can be produced from natural sources or can be synthesized on an industrial scale. This material is a renewable resource and is biodegradable ensuring that landfill waste is kept to a minimum.
Rubber is a material that has been commonly used for over 1000 years, once came entirely from natural sources. But, today, because we can't produce enough natural rubber to meet all our needs, rubber products are just as likely to be made artificially in chemical plants. And that is because rubber is very useful.
Natural rubber is also known as caoutchouc, India rubber, latex, and other names.
The natural color of rubber is white. Rubber is made black by adding various chemicals, such as carbon black. This isn't just for cosmetic reasons, but because adding chemicals like carbon black to the rubber drastically increases the desirable qualities of the rubber.
The two main types of rubber are:
Natural rubber is the original and the first kind of rubber to be used by man. Natural rubber is made from a runny, milky white liquid called latex that oozes from certain plants if you cut them. Latex is an emulsion of polymer microparticles in water and can be found in 10% of all flowering plants. Over 99 percent of the world's natural rubber is made from the latex that comes from a tree species called Hevea brasiliensis, widely known as the rubber tree. The rubber trees are generally found in regions that are hot and moist, that is:
Natural rubber is entirely nontoxic and free of petroleum or heavy metals. The material is a renewable resource and is biodegradable.
Other than natural rubber, all the other types of rubber are synthetic or manmade. Synthetic rubber is a man-made rubber created by synthesizing it from petroleum and other minerals at manufacturing plants. It is any artificial elastomer. An elastomer is a polymer with both viscosity and elasticity, and with weak intermolecular forces. In simple words, elastomers can be stretched out and will return to their original shape let gone. Today 70 percent of the rubber used in manufacturing processes is synthetic. Synthetic rubber is used as a substitute for natural rubber in many cases. Depending on the chemicals added and the properties associated with it, synthetic rubber can be hard, soft, resilient, and so on.
The process of making rubber starts with gathering latex from the rubber trees. This process is called rubber tapping. The latex gathered from many trees then goes through the process of filtration and washing, and then is reacted with acid to make the particles of rubber stick together. After these processes, the rubber is pressed into slabs or sheets and then dried. After this, it is ready for the next stages of production.
Further processes are used to turn the rubber into a much more versatile material. The first one is known as mastication. During this process, the rubber will become softer, more sticky, and easier to work. Then, for improvement of some of the properties, extra chemical ingredients are mixed in. Then, the rubber is squashed into shape by rollers or squeezed through specially shaped holes to make hollow tubes.
The final process is vulcanization. During this process, the rubber is vulcanized (cooked). Sulfur is added and the rubber is heated to about 140°C (280°F) in an autoclave. An autoclave is a kind of industrial pressure cooker. Before vulcanization, rubber is soft and pliable. After this treatment, it becomes strong and hard. Most rubber products in the world are vulcanized.
Rubber in general is:
The largest consumers of rubber are tires and tubes, followed by general rubber goods. Other significant uses of rubber are hoses, belts, matting, flooring, medical gloves, and much more. Rubber is also used as adhesive in many products and industrial applications.
Some common objects made from rubber are dishwashing gloves, medical gloves, toys, jar seals, tires, rubber boots, raincoats, pond liners, balloons, mattresses and cushions, pillows, grips on garden tools, rubber mattress pads, bathtub plugs, doorstops, earplugs, hot water bottles, rug backings and many more.
