Chapter 7
Molten Salt Conversion of Plastics
into Highly Conductive Carbon
Nanostructures
Abstract The pollution caused by the increasing accumulation of plastic wastes
in the environment is considered a serious emerging threat to our wildlife, habitats and to us. In fact, the efficient removal of plastic wastes from the environment
is challenging in the absence of a strong economic driving force. Such a driving
force can be achieved through the low-cost conversion of plastic wastes into highly
valuable outputs such as high-quality graphene materials. This chapter provides an
introduction into thermokinetic characterization of polyethylene terephthalate, the
most commonly used plastic, and then deals with the molten salt—assisted conversion of plastic bottles into graphene nanostructures with a high surface area, degree
of crystallinity and electrical conductivity.
Keywords Plastic waste · Molten salt · Carbon nanotubes · Graphene ·
Conductivity · Pyrolysis
Plastics, with an annual production of over 300 million tons, have increasingly been
used for a wide variety of applications in the modern life, owing to their unique properties including low production cost, low density, durability, high chemical resistance
and dimensional stability [1]. Polyethylene terephthalate ((C 10 H 8 O 4 ) n, PET) is considered to be the most commonly used plastic, often employed as containers for
bottled liquids and other food products due to its affordable cost, transparency and
versatile physical and mechanical properties including excellent mechanical strength,
low friction coefficient, high flexural modulus and barrier properties. Its radiationresistant properties are also accountable for applications as insulator and nuclear
track detector in nuclear plants and devices [2].
The global PET consumption experiences a grow rate of about 3.8% annually,
with an estimated market value growth from $48.1 billion to $60 billion from 2016
to 2019 [3]. The constant increasing demand for bottled water has boosted the annual
consumption of plastic bottles to somewhere around 500 billion across the world,
out of which an estimated 150 million tones accumulated in the world’s oceans [4].
While only less than 10% of virgin PET plastics can practically be recycled into
new products at the end of their first life, the majority of used PET plastics find
themselves in landfills or in the oceans. The latter is estimated to be hundreds of
millions of tones, adding up their microscopic plastic content to be ingested by
© Springer Nature Singapore Pte Ltd. 2020
A. R. Kamali, Green Production of Carbon Nanomaterials in Molten Salts
and Applications, https://doi.org/10.1007/978-981-15-2373-1_7
109
Molten Salt Conversion of Plastics
into Highly Conductive Carbon
Nanostructures
Abstract The pollution caused by the increasing accumulation of plastic wastes
in the environment is considered a serious emerging threat to our wildlife, habitats and to us. In fact, the efficient removal of plastic wastes from the environment
is challenging in the absence of a strong economic driving force. Such a driving
force can be achieved through the low-cost conversion of plastic wastes into highly
valuable outputs such as high-quality graphene materials. This chapter provides an
introduction into thermokinetic characterization of polyethylene terephthalate, the
most commonly used plastic, and then deals with the molten salt—assisted conversion of plastic bottles into graphene nanostructures with a high surface area, degree
of crystallinity and electrical conductivity.
Keywords Plastic waste · Molten salt · Carbon nanotubes · Graphene ·
Conductivity · Pyrolysis
Plastics, with an annual production of over 300 million tons, have increasingly been
used for a wide variety of applications in the modern life, owing to their unique properties including low production cost, low density, durability, high chemical resistance
and dimensional stability [1]. Polyethylene terephthalate ((C 10 H 8 O 4 ) n, PET) is considered to be the most commonly used plastic, often employed as containers for
bottled liquids and other food products due to its affordable cost, transparency and
versatile physical and mechanical properties including excellent mechanical strength,
low friction coefficient, high flexural modulus and barrier properties. Its radiationresistant properties are also accountable for applications as insulator and nuclear
track detector in nuclear plants and devices [2].
The global PET consumption experiences a grow rate of about 3.8% annually,
with an estimated market value growth from $48.1 billion to $60 billion from 2016
to 2019 [3]. The constant increasing demand for bottled water has boosted the annual
consumption of plastic bottles to somewhere around 500 billion across the world,
out of which an estimated 150 million tones accumulated in the world’s oceans [4].
While only less than 10% of virgin PET plastics can practically be recycled into
new products at the end of their first life, the majority of used PET plastics find
themselves in landfills or in the oceans. The latter is estimated to be hundreds of
millions of tones, adding up their microscopic plastic content to be ingested by
© Springer Nature Singapore Pte Ltd. 2020
A. R. Kamali, Green Production of Carbon Nanomaterials in Molten Salts
and Applications, https://doi.org/10.1007/978-981-15-2373-1_7
109