Polymers are substances that consist of repeating units of carbon and hydrogen. Some polymers that occur naturally may include proteins, latex and even cellulose. These materials are commonly referred to as plastics. Some of the polymers are synthetic and are produced from industrial processes.
Polymerization refers to the degree in which repeating components form one outstanding unit. High strength polymers are those that have high level of polymerization, whereas those with one type of repeating units are homopolymers. Those with several and different repeating units are co-polymers. The mode of classification that is in use for classifying polymers is the method used in their formation. There are two types of polymers which include additional polymers and condensation polymers. Additional polymers are formed from the combination of many monomers while condensation polymers where the combination of monomers leads to the loss of a water molecule.
The vital elements that form the polymers are carbon and hydrogen, although sulfur, oxygen, nitrogen may also be included. Natural polymer is believed to have originated from South Africa from the trees called Heave and Castile. Its origin dates back from 1735 when natural rubber was first described by French geographic expedition to South Africa. One of the first pioneers in the application of polymers was Joseph Priestley who in 1770 made a remarkable discovery that led to the use of natural rubber as an eraser.
Then in 1909, this synthetic rubber was introduced publicly. 1922 German chemist Hermann Staudinger came up with his macromolecular hypothesis, giving a suggestion that the polymers are actually large molecules formed by the permanent joining of uncountable tiny molecules. Through his experiments, he proved this hypothesis to be true and earned himself a Nobel Prize in 1953. There are a number of ways in which polymers are used. Such ways include: In agriculture and agribusiness, polymers can be used to promote plant growth. They can also be used to improve aeration in soil.
(Emsley,5). In medicine, polymers are used to replace heart valves. These polymers include Teflon and Dacron. Polymers can act as a substitute for natural cotton. In industrial market, they can be used to make pipes, matrix for composites, insulation or even windshields in fighter planes. They are also used to replace natural materials such as ivory and woods. They can be used in cars and planes with reduced amount of fuel to be used due to their light weight.
In consumer science, polymers are used to replace traditional containers. This is because they are light in weight and are also economical. In sports, they are used in making protective helmets, balls of different varieties and other playground equipment.
Biopolymers are biodegradable polymers. The raw materials for their production may be renewable or synthetic. These types of polymers are not produced widely due to their high cost. Such kinds of polymer include: Polyhdroxyalkanoate: compostable in an industrial facility.
These are produced from a range of bacterial action, which act carbon storage materials. They also act like energy storage materials. They form a stable latex suitable in paper surface finishes and coating and sizing.
Polylactic acid: 100% compostable at 60oc in an industrial facility.
Biodegradable plastics are those that will decompose in landfill (environment). Biodegradable plastics can be produced from organisms in the environment. Micro-organisms can produce renewable raw materials or petroleum based plastics. Since these plastics are made from materials that are natural, for example, cellulose and starch, they decompose easily when in contact with oxygen or even water and sunlight. Micro-organisms use enzymatic break down of the points of glycoside linkage to bring about decomposition of these biopolymers.
(Scott,93). Polymers have varying environmental impacts. Such impacts include: Some monomers are said to be toxic or even to some level said to be carcinogenic. Burning of plastics produces emission that lead to production of green house gases for example, carbon dioxide.
This gas is also a major source for global warming. There is also production of methane gas, a product of anaerobic digestion, together with carbon dioxide emitted from decomposition of biodegradable polymer. Non-biodegradable plastics are buried in landfills.
These plastics occupy space that would otherwise have been occupied by other biodegradable plastics. This will result to the same lasting in landfills for a longer period of time, even up to hundreds of years. Improper composition of plastics also has its impacts to the environment. In regions of the north pacific, there is a floating island of plastics that have been discarded hence bring about the danger to the aquatic life and the birdlife. Many coast areas, as well as the inland, may contain plastics.
Glass is a solid object with non-crystalline properties. It is amorphous in nature and occurs in various forms. It is principally made up of silica (SiO2) which makes up a substantial percentage about 75% of its components; other components include lime (calcium oxide), magnesium oxide and aluminium oxide each of which add to its long lasting nature. Sodium carbonate may be an additive, however it is not preferred as it makes its ability to be converted to the liquid state easily attainable. Huge debates have risen as to the physical state of glass i.
e. whether it is a solid or a liquid but in essence glass is a liquid in a super cooled state. This means that it has rigidity and is static however it does not lose its molecular state. Glass comes in a variety of forms and used in varied applications as it ranges from clear glass to tinted glass and lastly tempered glass. It is believed that glass has been in existence since time immemorial with natural glass dating back to 5000 BC, in ancient Rome, as an accidental finding by Syrian merchants and the man-made glass tracing its roots in Mesopotamia in 3500BC as the outcome of a coincidental mixture of calcified sand and soda being mixed in a kiln. Since its advent glass has improved man’s way of living significantly.
Uses range from home-use to industrial use. Compared to polymers glass is the appropriate material for producing storage equipment due to its hygienic nature. It is essentially absent of toxic components and is quite inert thus its effect on the environment is minimal. Resistance to wear and tear is an additional feature and the little quantities of glass like lime and silica are constituents of mineral water. The inert nature is evident in its slow conversion to silicates when released to the environment and this property can be utilized in making environmentally dangerous material inert.
Recycling, which is, the ideal waste management strategy can easily be implemented when using glass due to its non-biodegradable nature. A particular glass bottle can be used infinitely as it can be melted and re-melted without losing its properties. (Walker,22). This is ecologically friendly as it: – Cuts down on disposal and transport expenses. Minimizes environmental damage. Minimizes production costs by reducing the amount of primary materials, especially calcium carbonates and silicates and by extension minimizing quarry exploitation of these resources. Reduces amount of energy that is consumed in production as a ton of glass re-melted spares a similar amount of the same raw materials and even more energy. Reduces the greenhouse effect that would arise from carbon dioxide production that would have arisen, as a result, carbonate decomposition in case of primary materials.
However, there are also negative attributes to glass being in the environment such as:- Glass dust has detrimental health risks to humans and other forms of human life. Physical trauma can be incurred from glass particles hanging in the environment. It therefore goes without saying that the use of polymers in the production of storage equipment has much more negative attributes as compared to the use of glass especially in the detrimental effects that they have on the environment. Recycling is the most efficient ecologically friendly way of management of waste.
Polymers: the environment and sustainable development. New York: John Wiley and Sons,2003. Scott, Gerald. Polymers and the environment. England: Royal Society of Chemistry, 1999. Walker, Kate. Recycle, reduce, reuse, rethink .
New York: Black Rabbit Books, 2005.