Plastic industry is growing with the growing population of the world. This growth rate of polymer industry concerns the environmentalist authorities rightfully. Because, the waste of plastics are very harmful for nature. because of degradation of general plastics is very hard. So recycling of plastics is very important but also very hard compared with other kinds of materials such as metals etc.
Why Recycling Of Plastics Is Hard?
The first reason of it, general polymer materials include additives, dyes and fillers to obtain specific properties. And decomposition of these additives is very hard and requires various kinds of processes in recycling phase of polymers.
The second reason, if we consider the amount of metals that recycled, they are much more higher in tonnage compared with plastics. Metals that are used in big structures such as bridges, ships etc. recycling of them is much more profitable because of higher tonnage. But recycling of plastics is not profitable compared with metals, because gathering same types of plastics to recycle is much more hard. Products produced from plastics are smaller than metals to be recycled generally.
An another important reason for this, the plastics that they came for recycling can have various kinds of chemical structures, which makes them very hard to mix, fuse to obtain a new product. For example, recycling of glass waste is much more easy compared with plastics, because all the glass products depend on silicon dioxide.
How To Cope With This Situation In Recycling Of Plastics?
We stated that there are different kinds of thermoplastic polymers, and because of that, decomposition of different kinds of polymers is hard. To overcome this situation, Society of Plastics Industry developed Plastic Identification Code(PIC) which refers the type of thermoplastic of produced plastic products to separate them in same groups to recycle them. You can see this code on plastic products in the shape of triangle that corners are arrows. And inside these arrows, there is a number states the type of that thermoplastic.
With this code, people can separate the plastic parts into same types. Here we give the meaning of these numbers to separate the thermoplastics;
- 1: Polyethylene terephthalate that used in beverage containers.
- 2: High density polyethylene that is generally used in shopping bags and milk containers.
- 3: Polyvinyl chloride that used in juice beverage bottles and PVC pipes.
- 4: Low-density polyethylene which has acronym of LDPE used in compressible bottles and container lids.,
- 5: Polypropylene which is generally used in yogurt containers and margarine containers.
- 6: Polystyrene used in disposable plates, egg cartons, and cups, and as foamed packing materials.
- 7: Other: such as ABS or polycarbonate.
This system makes decomposition of plastics much more easy. Despite this system to decompose thermoplastics, use of recycled thermoplastics is around 6% in United States.
This separation system is valid for only thermoplastics. Recycling of thermosettings and elastomers is almost impossible. Because of cross-linked molecular structure in elastomers and thermosettings, melting of these materials to recycle them is not easy. But they can be recycled as filler material for other applications. Also recycled elastomers can be used as granules, chunks and nuggets in various applications.
These are the general aspects of recycling of plastics. Do not forget to leave your comments and questions below about recycling of plastics below. Your precious feedbacks are very important for us.