Contents
Biodegradable polymers: what are they?
This term refers to a special type of material that can be broken down by microorganisms into environmentally safe substances. During decomposition, they form biomass, carbon dioxide, and water. Biodegradable materials are environmentally friendly and recyclable. The decomposition process is accelerated by industrial composting under optimal temperature and humidity conditions.
Features of Biodegradable Plastic Production
The production of such materials is based on the processing of renewable raw materials. Sugarcane, corn, or potato starch are most commonly used. These organic substances undergo a polymerization process during production, resulting in a plastic that is flexible, hermetically sealed, and biodegradable. This is used to make biodegradable packaging used in the food and other industries.
Depending on the production process, the material is divided into types:
- RNA is produced by fermenting lipids and sugars into biopolymers;
- PLA is formed when raw materials are converted into monomer, then polymerized, resulting in the creation of a long polymer chain.
Once the polymer is formed, it is melted and extruded into pellets, shaped into other forms, and then sent to a production facility for further casting.
PET: characteristics and production stages
Polyethylene terephthalate, or PET, is a group of thermoplastic polyesters that is one of the most popular in the production of various plastic containers. It is used to make bottle preforms and caps.
PET is produced from ethylene glycol and terephthalic acid by polymerization. The raw materials undergo chemical treatment, during which a polycondensation reaction occurs under the influence of a catalyst. This results in polyethylene terephthalate and by-products, which also have industrial applications.
It is characterized by:
- lightness;
- high impact strength;
- Resistance to sunlight, water, gas, organic compounds, and oils.
PET containers are also recyclable, making the material cost-effective and economically viable for production.
Comparative characteristics of PET and biodegradable plastic
The first thing to note is the decomposition process of biodegradable polymer. In fact, its ability to break down into safe substances is rather conditional. To answer the question "how long does it take for biodegradable plastic to decompose?", it's worth clarifying the conditions right away. Industrial composting speeds up the process to 6 months. But in everyday life (home compost, trash bins), the process takes up to several years, and in natural environments (open air, water, soil) – decades.
In other words, the ability and actual decomposition of bioplastics depends on infrastructure. Without specially created conditions for industrial composting, this material offers virtually no significant advantage over PET.
To accurately determine the pros and cons of bioplastics as an alternative, we will compare the main characteristics:
|
Characteristics |
Biodegradable plastic |
Recycled PET |
|
Declared environmental friendliness |
Decomposes under certain conditions. |
It has a well-established system of disposal and recycling, generating less waste |
|
Decomposition rate |
Stated as "several months," but in the wild it can last up to decades. |
It is not biodegradable, but does not accumulate as waste, as there are collection and recycling programs. |
|
Durability |
Low thermal and mechanical strength, sensitivity to moisture, brittleness. |
High strength, texture stability, resistance to chemicals, oils, organic substances, and pressure. |
|
Economic accessibility |
Expensive, because the high cost of production is due to the high cost of raw materials, special technologies, and certification. |
Available because it is produced, among other things, through recycling. |
|
Environmental Pollution Risks |
Biodegradable plastics often contain plasticizers and various performance enhancers, the toxicity and danger of which have not yet been studied. |
The ingredients are studied, regulated, and production follows stable standards and regulations, which helps reduce environmental risks. |
It's also worth noting that polyethylene terephthalate (PET) has a wider range of applications due to its high reliability. It's used to produce PET caps and preforms for plastic bottles of various sizes. It's more practical, allowing the containers to be used in various industries: chemical, technical, and food.
Another important advantage of PET and a significant disadvantage of biodegradable plastic is that it doesn't require the use of agricultural land to obtain raw materials. PET is produced from petroleum products, thus solving the problem of their cost-effective use. Biodegradable plastic, however, requires cultivating and growing raw materials. In the context of the global economy, with global hunger at an acute stage, its production could be detrimental, especially in developing countries.