Nylon and PET | Chemistry for Grade 11 (IGCSE) PDF Download

Plastics & their Disposal

• Synthetic polymers, including nylon, terylene, and lycra, are produced in factories.
• Nylon, categorized as a polyamide, is utilized in the manufacturing of clothing, fabrics, nets, and ropes.
• PET, also known as Terylene, is a polyester formed by linking monomers through ester links.
• PET is extensively used in the textile industry and is often blended with cotton to create clothing.

Non-biodegradable plastics

• These plastics are non-biodegradable or degrade very slowly, leading to significant environmental pollution.
• Plastic waste, particularly, is entering oceans and seas, causing extensive harm to marine ecosystems.
• In landfills, these polymers occupy valuable space without decomposing, accelerating the filling of landfill sites.
• When polymers are incinerated, they release considerable heat energy and emit carbon dioxide, a greenhouse gas contributing to global warming.
• Incomplete combustion of polymers can generate carbon monoxide, a toxic gas that interferes with oxygen transport in the blood.
• While polymers can be recycled, separating different types of polymers for recycling is a challenging and costly process.

PET Re-polymerisation

• PET, which stands for polyethylene terephthalate, is a commonly used polymer for producing items like plastic bottles.
• This polymer is a type of polyester known as a condensation polymer, comprised of recurring ester units, similar to terylene.
• A significant challenge in recycling polymers is the harsh conditions required to break them down, such as high temperatures and pressures, which can damage the monomers, rendering them unsuitable for re-polymerisation.
• PET is notably straightforward to convert back into its original monomers.
• Depolymerisation of PET can be accomplished through enzymatic processes or chemical methods.
• Microbial enzymes play a role in breaking down PET into its initial monomers, a process that can also be replicated using solvents, a catalyst, and gentle heating.

• The monomers are reclaimed and can be reprocessed into fresh PET through polymerization.
• This conservation method helps conserve resources and energy, thereby diminishing the carbon footprint associated with the manufacturing procedure.