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Polymer Structure

Plastics can be classified into two main categories based on their polymer structure: thermoplastics and thermosetting plastics.


Thermoplastics


Recyclability: 

High. Thermoplastics can be melted and remolded multiple times without undergoing significant chemical changes. This makes them generally easier to recycle. Examples include PET, HDPE, PVC, LDPE, PP, and PS.


Examples:

  1. PET (Polyethylene Terephthalate)Commonly used in beverage bottles and food containers.

  2. HDPE (High-Density Polyethylene)Found in milk jugs, detergent bottles, and piping.

  3. PVC (Polyvinyl Chloride)Used in plumbing pipes, electrical cable insulation, and medical devices.

  4. LDPE (Low-Density Polyethylene)Used in plastic bags, squeeze bottles, and film wrap.

  5. PP (Polypropylene)Found in packaging, textiles, and automotive parts.

  6. PS (Polystyrene)Used in foam products like Styrofoam, disposable cutlery, and CD cases.


Thermosetting Plastics


Recyclability: 

Low. Thermosetting plastics undergo a chemical change when heated, making them rigid and unable to be remelted and reshaped. This makes recycling these plastics more challenging. Common examples include epoxy resins, phenolic plastics, polyurethane, and melamine formaldehyde.


Examples:

  1. Epoxy ResinsUsed in adhesives, coatings, and composite materials.

  2. Phenolic PlasticsFound in electrical components and heat-resistant objects.

  3. PolyurethaneUsed in foam products, coatings, and adhesives.

  4. Melamine FormaldehydeUsed in kitchenware, laminates, and adhesives.

References:


Polymer Structure:

Andrady, A. L., & Neal, M. A. (2009). "Applications and societal benefits of plastics." Philosophical Transactions of the Royal Society B: Biological Sciences, 364(1526), 1977-1984. Link

Hopewell, J., et al. (2009). "Plastics recycling: challenges and opportunities." Philosophical Transactions of the Royal Society B: Biological Sciences, 364(1526), 2115-2126. Link

Polymer structure drawing:

Recycling of Plastics:

Geyer, R., Jambeck, J. R., & Law, K. L. (2017). "Production, use, and fate of all plastics ever made." Science Advances, 3(7), e1700782. Link

Ragaert, K., et al. (2017). "Recycling of multilayer plastic packaging materials: A review." Waste Management, 69, 24-58. Link

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