Recycling Polymers
A Polymer is a huge molecule also known as macromolecule composed of replicating structural units linked by chemical bonds of covalent. Polymers are considered in the fields of polymer physics, polymer science and polymer chemistry. The renowned examples of polymers comprise of DNA, proteins and plastics. Though polymer in popular practice recommends plastic, the word in reality refers to a huge class of synthetic and natural materials with a range of purposes and properties.
The greater part of plastic polymers is ended up in landfills. When plastic is discarded into the landfills the decomposition procedure can take between 10 to 25 years. Recycling has thus become a sensible solution to the problem of landfill. Generally five factors are essential for making the recycling of plastic polymers a successful procedure.
First, the delivery of utilized plastic should be in bulky quantity. This bulky quantity of plastic polymers is gathered at definite areas, which is described as second step. The third step in recycling process is after the collection of plastic polymers the separating and sorting process starts. The separating and sorting process is dependent upon the form of polymers that created the plastic. For assisting the separating and sorting process the plastic products are provided codes. Reprocessing is the fourth step in recycling of plastic polymers. The reprocessing of polymers comprises of the process of melting. The process of melting can be completed if they have not been broadly cross-linked with some synthetics. It becomes difficult to stretch the polymers if the cross-linking of polymers includes loads of synthetics. The last step in recycling of plastic polymers is the production of melted plastic into fresh products.
Normally, six types of plastics are separated into two areas: polymer plastics and polyethelyne plastics. For high density polyethelyne, polyethelyne plastics are marked as HDPE and for low density polyethelyne as LDPE. The four plastic polymers that are recycled comprise of polyvinyl chloride, polystyrene, polypropylene, polyethylene terephthalate. These names though appear as confusing, are necessary in the process of recycling.
There are four kinds of processes of recycling that normally occur. They are primary, secondary, tertiary and quaternary.
Primary process of recycling is recycling of products and materials that comprise related qualities of the original product. This process is not used widely as it is feasible only with semi-clean industrial plastics scrap.
Secondary process of recycling facilitates for a superior mixture of grouping levels in plastics. When secondary recycling process is utilized it generates products for instance as fence posts and other products which can be utilized in the substitution of metal, concrete and wood. The above products are generated because of low mechanical properties of these kinds of plastics.
Tertiary process of recycling is widely used nowadays due to requirement to adapt to the waste contamination’s high levels. The real process occupies producing fuels and basic chemicals from plastic polymers.
Quaternary process of recycling utilizes the energy by burning plastic. This process is widely used and most common in recycling. This is due to high heat content of majority of plastic polymers. Mainly the incinerators utilized in this process are capable of reaching the temperature of 900 to 1000°C. For saving the environment the fresh techniques are utilized with the incinerators which have reduced the amount of air pollutants that are being released.
Now why should we worry about recycling plastic polymers?
A recent promotional program supported by the plastic industry highlights the positive contributions that are made by plastics. Plastic polymers are mainly used for packaging but as packaging has a very short lifespan they make a huge portion of the plastics into waste stream. These wastes are ended up in landfills.
Majority of consumers believe that the slow degradation of plastics is the main reason that they should be recycled. However, it has been proved by research that other waste such as wood, food wastes and paper, are also degrading very slowly in landfills. Plastic waste concerns due to additives included in plastics which is considered as more serious problem. These additives comprise of stabilizers, plasticizers and colorants which may include poisonous components such as cadmium and lead. Thus, due to all these reasons and for protecting the environment recycling of plastic polymers is necessary.
This entry was posted on Friday, July 18th, 2008 at 12:26 pm and is filed under Polymers. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.