Over the past years, it has become clear that the use of plastics in products not only harms the environment on planet Earth, but also harms human health, as parts of plastics are found in the soil, atmosphere, oceans, and human bodies. went. As well as astronauts willing to carry out space missions. In the future, they will need to reduce the amount of plastic they carry with them, to reduce the weight of their space flights, and the same applies to soldiers in war, because they need it. Do not carry large amounts of equipment.
As a result, scientists began looking for ways to reduce the amount of plastic made and used. An American research team has claimed that they have succeeded in this, as they were able to create a type of plastic that can be transformed into something new after its initial purpose has been exhausted. For example, a plastic bag filled with food can be turned into a fork or spoon.
In the study published in the journal Science, researchers from the University of Chicago, the US Army Research Laboratory, the National Institute of Standards and Technology and NASA's Glenn Research Center talked about the mechanism of formation of their plastic and the experiments they conducted to test it. Ability to make changes according to the purpose of use.
Determine the need.. 4 Objectives
The study was initially based on researchers' awareness of the need to reduce plastic use, with goals extending beyond Earth to space.
The need to reduce plastics on Earth arises primarily from three environmental, health and military goals and a fourth space goal which is economic in nature:
There is a need to reduce the use of plastics, as they do not decompose over time, and as a result they accumulate in landfills, waterways and oceans, polluting ecosystems and harming wildlife. Marine animals can ingest plastic debris, which can lead to their death.
Plastic waste can also disintegrate over time into smaller particles, known as microplastics, and these tiny plastic pieces can pollute soil, water, and air.
Plastic pollution can have harmful effects on human health. By consuming seafood or polluted water, humans can unknowingly ingest microplastic particles, which can lead to health problems such as inflammation, oxidative stress and the build-up of toxic chemicals.
Shape-changing plastic can help reduce the burden of carrying various equipment and tools to the battlefield. Instead of carrying multiple specialized items, soldiers can carry a single piece of shape-shifting plastic that can transform into different items as needed, thus conserving resources and reducing weight.
Soldiers can heat the new plastics using portable heat sources to create temporary barriers, camouflage materials, or custom equipment tailored to specific mission requirements.
As for the space goal, it is related to the economic aspect of space flight, which is to reduce the payload of flights, as estimates show that the cost of sending one kilogram on a future manned mission to Mars will be from 100,000 to 100,000. would be up to $500,000, and in this context comes the role played by moldable plastics, for example, in the morning, the plastic can be shaped into eating utensils, and when you finish breakfast, the fork and knife can be It can be turned into a spade for tending your Martian garden, for example, and then it can become a watering can… and so on.
3 steps that lead to achievement
Based on four goals set by the researchers, they aimed to achieve plastic through three stages that can be transformed into something new after the initial purpose is exhausted:
- First: Plastic Design
The beginning began with developing a new type of plastic with dynamic properties that allow it to change shape. It was obtained chemically by using a “thiol” substance in reaction with “benzylcyanoacetate”, a substance known as a “Michael addition”, and it helps to form cross-links within the polymer structure (plastic). This gives it dynamic properties and the ability to change shape.
“Michael addition” is a term that refers to a reaction that was first described by the German chemist Arthur Michael in 1887. To understand this reaction, we can imagine that you have two different pieces of Lego; The first is a piece with a raised part, and the second has a small hole, and when you push the piece with a raised part into the hole of the other piece, they stick together and form a new structure.
In the context of this illustrative example, a Lego block with a raised part represents “benzolcyanoacetate” and a block with a hole represents “thiol”, and after putting them together, a new compound is formed within the polymer structure. is what gives plastic its dynamic properties.
- Second: modification by “hardening”
In contrast, plastics consist of permanently linked chains of molecules, making them difficult to separate, the resulting dynamic plastic was such that it could be modified by a “tempering” process, a term in materials science and engineering terms. The concept refers to a heat treatment process. It is used to modify the properties of a material by heating it to a specific temperature and then rapidly cooling it, to achieve desired mechanical properties – such as strength, toughness and ductility. Material.
The steps of this process can be implemented in stages:
- 1- Heat: The material is heated to a predetermined temperature, usually below the melting point, but high enough to cause changes in its microstructure during heating. During this process, the material undergoes phase changes, such as rearranging the atoms depending on its structure.
- 2- Establishment: Once a material reaches the desired temperature, it is held at that temperature for a specified period of time, causing microstructural changes to occur uniformly throughout the material.
- 3- Cooling: After the holding period, the material is cooled rapidly. This rapid cooling, often achieved by quenching the material in water or air, results in the microstructure “freezing” in its changed state, thus retaining the desired properties.
The specific temperature and duration of the “hardening” process, as well as the cooling rate, depend on the material being processed and the desired properties. For example, “tempering” a high-carbon steel at a low temperature can increase its hardness and strength, while “tempering” a high-carbon steel at a high temperature can improve its toughness and ductility.
In the case of plastics described in the study, “tempering” is used as a means of changing the shape of the material. By heating the plastic to a certain temperature range and then rapidly cooling it, reversible changes occur in its molecular structure, allowing it to adopt different shapes depending on the heat treatment applied. This indicates that the versatility and adaptability of plastic makes it suitable for a variety of applications.
The researchers determined the temperature range required to heat the plastic, which is between 60 and 110 degrees Celsius, and a subsequent rapid cooling process to solidify its new shape.
- Third: content testing
Once the plastic was manufactured, researchers conducted extensive testing to evaluate its properties, including its ability to change shape through “tempering” as well as its durability and stability under various conditions.
The researchers demonstrated the shape-changing ability of the developed plastic by molding it into different objects. First, he created a spoon and then transformed it into a fork using “tempering”. They then transformed the plastic into an adhesive capable of joining the two sheets. Of glass together.
Throughout the experiment, the researchers evaluated the limits of the plastic, and found that it could only undergo the shape-changing process a limited number of times (an average of seven times) before disintegrating.
Questions and 4 conditions
For his part, Mohamed Badawi, professor of polymer engineering at Assiut University (Southern Egypt), describes the idea of a material that can possess various unique and exciting properties as “amazing”, but he also raised concerns about safety and Thought about health. Idea.
He said in a telephone interview with Al Jazeera Net: “The toxicity of this product should be determined by subsequent studies. These studies should also determine appropriate safety protocols for handling and disposing of the new plastic. It Health and environmental protection are important for human beings.”
Badawi believes the most popular applications for the new product will be under normal conditions, but to ensure the ease of the “hardening” process required to modify the shape of the plastic as it relates to combat and space situations, three different- Different situations require. , and these conditions are:
- Portability: The equipment used in the “hardening” process must be compact, lightweight, and portable to facilitate transportation and use in combat and space environments.
- energy efficiency: Equipment must be designed to operate efficiently with minimal energy consumption and rapid heating and cooling capabilities, to ensure that the “hardening” process can be completed quickly and effectively without excessive energy consumption. .
- Durability: In harsh environments such as war zones or space, equipment must be durable and flexible to withstand tough conditions. This ensures that they can withstand repeated use and retain their functionality for a long time.
- Integration: Tools should be designed to integrate seamlessly with other tools and resources available in the operational environment.
Comments of the researchers participating in the study in the press release published on the website of the University of Chicago promised further study, as they considered what had been achieved as a first step on the way.
“We believe what we have achieved is the first example of a synthetic material that exhibits multipotential behavior,” said Stuart Rowan, professor of molecular engineering and senior author of the study. “We believe what we have done paves the way.” “Toward a different way of thinking about content design.”