II - CONTEXTUALIZATION¶
As I already explained in the concept area, I want to design a machine that allows us to convert plastic bottles into textile fibers.
To do this, in this chapter I will talk more about the chemical and physical properties of working with PET bottles. I will also talk about the collection that was done locally at Unifranz University where we encouraged students to separate their plastics and thus be able to have a good number of bottles that allow us to experiment in different ways.
Chemical fo PET plastic bottles.¶
A little introduction:
PET (Polyethylene Terephthalate) is a plastic polymer that is obtained through a process of polymerization of terephthalic acid and monoethylene glycol. It is a linear polymer, with a high degree of crystallinity and thermoplastic in its behavior, which makes it suitable to be transformed by extrusion, injection, injection-blow molding and thermoforming processes. Its main features are:
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It is completely recyclable
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Crystallinity and transparency, although it accepts dye loads
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Good behavior in the face of permanent efforts
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High wear resistance
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Very good coefficient of sliding
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Good chemical resistance
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Excellent barrier to CO2, acceptable barrier to O2 and humidity
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Compatible with other barrier materials that overall improve the barrier quality of the packaging and therefore allow its use in specific markings.
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Approved for use in products that must be in contact with food products The physical properties of PET and its ability to meet various technical specifications have been the reasons why the material has reached a relevant development in the production of fibers textiles and in the production of a wide variety of packaging, especially in the production of bottles, trays, straps and sheets.
Properties¶
| Properties | |
|---|---|
| Chemical Formula | (C10H8O4)n |
| Monomers | Terephthalic acid, Ethylene glycol |
| General properties | Transparency to visible light and microwave. Very good resistanceto ageing, wear and heat. Lightweight, impact and shatter resistant. Good gas and moisture barrier properties |
• Chemical resistance: PET is known for its excellent chemical resistance.expand_more It's unreactive to most common chemicals, including acids, bases, and oils.expand_more This makes it suitable for storing a variety of beverages and food products
• Low moisture absorption: PET doesn't readily absorb water, which is important for keeping packaged goods dry and fresh.
• Thermal stability: PET has a high melting point (around 250°C) and good thermal stability.expand_more This allows it to withstand high temperatures without deformation and makes it suitable for applications like hot beverage containers.
• Insoluble in water: PET is practically insoluble in water.expand_more This means it won't leach chemicals into water-based contents. Overall, these chemical properties make PET a versatile and reliable material for various packaging and container applications.
CHEMICAL RESISTANCE/ LOW MOISTURE ABSORPTION/ THEMAL STABILITY/ INSOLUBLE IN WATER
References:
•Anatomy of a Bottle - Berlin Packaging Specialist
•What Is PET Packaging?- The plastek group
•Why Use PET Plastic For Packaging Food And Beverage? - Sailor Plastic Bottles
•THE SCIENCE BEHIND PET- Petra pet resin Association
Anatomy fo PET plastic bottles.¶
In this process we can use the entire body of the bottle, even the hardest parts such as
- Neck
- Base
Collect¶
After start I need to collect bottles.
It takes place in Santa Cruz - Bolivia at the Unifranz university. Within this University there is a cafeteria called "el breik", where students eat and order drinks that mostly come in plastic containers, which is why a special trash can was placed for collection.
Totalle collected in 1 week: 10kg
Wash and prepare¶
As you know, a normal bottle comes with a label and a lid, which is made up of different plastics such as PVC. It is necessary to remove these elements so that we can only be left with the PET.
After those steps we are ready to experiment.