Recovering plastics in green economy: Example

BY: Dr Boniface Yeboah Antwi
Plastic pollution has become an albatros hanging on the country’s neck
Plastic pollution has become an albatros hanging on the country’s neck

The ease of processing polymers has earned them the name plastics. These plastics find applications in varied sectors of society.

A better understanding of the makeup of plastics lie in the description of a polymer, which is a large organic molecule made up of repeating units of a building block called a monomer.

For instance, the bonding of several ethylene monomer units through a polymerisation process yields the polyethylene polymer.

Literally, the molecular structure of a polymer can be compared to how a cement block wall is constructed.

The laying of several block units of the same sizes and shapes form a huge wall. The wall in this case can be considered as the polymer while the blocks become the repeating monomer units.

Conventionally, plastic granules are processed in an extruder to form plastic products like buckets, bowls, cups and so on.

These plastic products are found in different sectors of the Ghanaian economy. For instance, sectors such as, the food and beverage industry, tourism, education, banking, transport, and many more.

Grouping

The grouping of plastics, according to their responses to heat, shows some are less resistant to heat, the thermoplastics, while others resist heat to an appreciable level, the thermosets.

Thermoplastics can easily be recycled into new forms without losing their plasticity while thermosets degrade during recycling.

Chemically, the molecular chains of thermoset are highly crosslinked, which makes them harder and difficult to break.

Thermoplastics, on the other hand, are soft and easy to break under constant force due to the absence of crosslinking in the molecular chains.

Examples of thermoplastics are the polyethylenes for packaging, polypropylene for chairs and tables, and others.

Common examples of thermosets include polyurethanes for foams and mattresses, polycarbonates for sockets and switches, epoxy adhesives and so on.

We use both thermosets and thermoplastics in our daily activities. However, research shows that, thermoplastics are the common plastics in Ghana compared to thermosets due to the ease of processing and the wide application.

These have contributed to a significant amount of plastic wastes from thermoplastics.

Waste

The plastic waste are termed so because their primary functions have been exhausted by the users who discard them into dustbins or in the open.

Nonetheless, in recent years, others have found a secondary use for the single used plastics. Hence, they are no more waste, rather resources in transition.

For instance, in Ghanaian markets, some oil retailers provide a secondary function for single used plastic water bottles.

They buy the used plastic water bottles from collectors, clean, sterilise and package fresh palm oil in them for retailing.

Another reuse case is sighted at the Nelplast Ecopave Company Limited. The company reuse plastic sachets after the primary function of packaging pure water.

They reuse the material in the manufacture of plastic/sand composite blocks. The company shreds the plastic sachet into pieces and incorporates it into sand aggregates to form composite blocks for the construction of houses and pavements.

The Ghanaian company maximises the economic advantage in finding a secondary function for plastics at the end of their primary use.

This and many other companies such as Miniplast Limited, Sesa Company Limited, Trashy bags and Environment360 continue to harness