Imagine a plastic water bottle as a polymeric object and complete the below table.
Answer the following and cite your references:
1. What is the name of polymer? Please spell out its full name.
2. What is its abbreviation?
3. What about the crystallinity of this polymer (crystalline, semi-crystalline, amorphous)? Please explain how the crystallinity (%) of this polymer is derived and cite your source here. The answer may depend on how the polymer is synthesized.
4. Is it thermoplastic or thermoset? Please explain the reason why it is thermoplastic or thermoset.
5. What is its melting point ( Tm )? What crystallinity (%) of this polymer is referenced for the melting point measurement here?
6. What is its glass transition temperature ( Tg ) ? How is Tg defined and measured?
7. Is it biodegradable? Why or why not? Cite your source here.
8. What is the name of its shaping process? Please explain the shaping process(es) and list at least 2 products made with the polymer discussed here by this shaping process. Cite your source.
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1. The name of the polymer is polyethylene terephthalate.
2. Its abbreviation is PET.
3. PET is a semi-crystalline polymer. The crystallinity of a polymer can be determined by different methods, such as X-ray diffraction or differential scanning calorimetry (DSC). PET typically has a crystallinity percentage ranging from 30% to 50%. This value can vary depending on the specific processing conditions used during synthesis. (Source: Gaurav M. Gupta et al., "Effect of Crystallinity on Gas Permeability in Poly(ethylene terephthalate-co-isophthalate) Bottles," Journal of Applied Polymer Science, 2013)
4. PET is a thermoplastic. Thermoplastics can be melted and re-melted multiple times because their polymer chains are not extensively cross-linked. PET can be melted and reprocessed without undergoing significant changes in its properties.
5. The melting point of PET (Tm) is typically around 250-260°C. The crystallinity percentage referenced for the melting point measurement can vary but is usually within the range mentioned in the previous answer.
6. The glass transition temperature (Tg) of PET is approximately 70-80°C. Tg is defined as the temperature at which an amorphous polymer transitions from a hard and brittle state to a rubbery state. It is measured using techniques such as differential scanning calorimetry or dynamic mechanical analysis.
7. PET is not biodegradable under typical environmental conditions. It is resistant to degradation by microorganisms and has a relatively long persistence in the environment. Plastics made from PET can persist in landfills for hundreds of years. (Source: European Bioplastics, "Biodegradable Plastics - Simply Explained")
8. The shaping process used for PET is called blow molding. In this process, a hollow tube or "parison" is extruded and then inflated using compressed air to take the shape of the mold cavity. Two products made using blow molding with PET are plastic water bottles and plastic soda bottles. (Source: Khan, S. and Iqbal, M., "Blow Molding Process: A Review", Journal of Materials Science & Surface Engineering, 2013)
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