In 2013, the global market for polypropylene was around 55 million metric tons.
Invented in 1954 by Giulio Natta of Milan, Italy
It can be represented by this symbol:
Objects made of polypropylene
Electric cables
Food packaging
Plastic bottles
Carpet backing
Corrugated boards
Structure of Polypropylene
Chemical Formula: (C3H6)n
Polypropylene is a polymer* with a crystalline structure. - For the crystalline region, many monomer propylene will bond together covalently to form this rigid linear structure.
Formation of polymer side chains (crystalline region)
(n = controlled chain length of monomers)
For the diagram above, the blue lines represent the propylene monomers that are bonded tightly and orderly …show more content…
We will be talking about isotactic polypropylenes in the next few panels.
1. High melting point:
The melting point of polypropylene is 160 °C. If we compare it to similar plastics in the same weight category, polypropylene has one of the higher melting points.
Throughout the structure, mostly covalent bonds are present in between the atoms. Covalent bonds are strong and are thus difficult to break. This is why a higher temperature, which means a higher amount of energy is needed to melt polypropylene.
This makes polypropylene a suitable material to use for most products since its melting point is a lot higher than the room temperature and will stay in solid form as long as the surrounding temperature is less than 160°C.
For example, it is suitable to be used for products such as plastic water bottle, food packaging or lunch box, as these items would usually not be containing substances that is hotter than the melting point of polypropylene. For example, water’s boiling point is 100°C, which is less than the melting point of polypropylene.
2. …show more content…
as these products come in constant contact with water especially, thus the insolubility of polypropylene is crucial so as to let the products function properly.
3. Electricity insulator
In both molten and solid state, polypropylene is not able to conduct electricity. When in solid state, the carbon and hydrogen atoms are covalently bonded. Which means that the electrons of both atoms are shared between themselves. Thus, there will be no sea of delocalised electrons to act as charge carriers and conduct electricity.
When in molten state, the propylene monomers will break apart from each other. However these monomers cannot act as mobile charge carriers either. Thus, polypropylene is a very good electricity insulator in both solid and molten states.
To make use of this feature, polypropylene is often used to make wires and cables to act as a layer of insulation to protect the ones using those