What shape does plastic have? How are the different plastic products we use every day shaped ? Which polymer is best for my industrial process? If you’re racking your brains to find an answer to these questions, then this in-depth look at the plastic deformation process is for you. Ready? Let’s go!
Transforming plastic takes energy
To give an object a new shape , it is necessary to use energy. The more structured and solid this object is, the greater the concentration of energy will be necessary in order to transform it. This principle applies to all things, including plastic. Energy, however, is a vague term, because it manifests itself in many different forms. If we were all endowed with the gift of super strength, shaping an object to our liking would be very simple. Instead, most of us didn’t even join the gym in January (as he promised!) so we have to think of alternatives. For example, heat is one way energy appears. And it has the power to define modeling, that is, the deformation of plastic.
I tell my hairdresser about plastic deformation
What we commonly call “plastics” are actually groups of molecular filaments called polymers. To change the arrangement of these filaments, transforming them into objects such as caps, chairs or masterbatches, heat is exploited through complex machinery present in industrial plants. In practice, it’s a bit like when we use the hot air from the hair dryer to style our hair, giving it a more defined shape. Imagine that heat is like air moving hair: just as air acts on strands, heat acts on polymer molecules . This phenomenon is at the root of the deformation of plastic: as the temperature increases, the molecules come to life, moving more freely, just like hair moved by the current. This allows the material to arrange itself more easily, adapting to the modeling processes.
The crystallization process
This process of ordering filaments of molecules from a shapeless state, such as the liquid state, to a more complex and solid one is called crystallization. The phenomenon involves the ordering of plastic molecules into more regular and orderly, crystal-like structures. In other words, the polymer filaments align more evenly, increasing strength and improving the mechanical properties of the material. However, we must not forget that just as hair can have a different nature and therefore require specific treatments to be styled, in the same way there are also different types of plastic, each with unique characteristics and requirements. As a result, there are different processes to shape these plastic materials according to their specific properties and the needs of the end application.
Ruffled Filaments
Let’s imagine two people walking outdoors on a windy day. Both have long hair tousled by the air, the first has perfectly straight hair and the second has rebellious curly hair. When the wind drops, the straight hair of the first figure descends by the force of gravity and does not get matted. On the other hand, in the second person, curly hair still remains a bit voluminous and messy, as it is more disheveled on a congenital level. This parallel, perhaps a bit risky, can be applied to better explain the plastic deformation of polymers of different nature.
The secrets of plastic deformation come to a head
In fact, some plastics have a more marked predisposition to crystallize (straight hair), becoming rigid and orderly even when subjected to plastic deformation processes through heat (the wind that ruffles the hair). Others, on the other hand, have a more amorphous tendency (curly hair), maintaining a disordered and flexible structure, with more difficult crystallization. In other words, the thermal charge has the power to keep the molecules separate, the filaments disheveled. When, however, this energy is no longer there, the polymer molecules tend to come closer together and arrange themselves. Depending on the peculiar properties of each material, this ordering takes place in a more or less efficient and regular way.
Polyolefione vs Styrenics
In concrete terms, polyolefin plastics are semi-crystalline polymers with a tendency to crystallize during the plastic deformation process. The interactions between the positive and negative charges of the elements present within the material have an effect similar to that of gravity: the molecules tend to align and arrange themselves in a more orderly way, as does straight hair when there is no wind. On the other hand, styrenic plastics are amorphous polymers, lacking a defined crystal structure. Without the energy needed to align the molecules, as in the case of the hair dryer to style the hair, these plastics retain their messy and flexible nature. It should be noted that, in general, all polymers show a certain tendency to crystallize during plastic deformation processes, but this varies greatly depending on the type of plastic and its specific properties.
The style of my plastic
Which plastic is best to use to make my product? Why can’t I give my items the shape I want? Having read this article may have shed light on some aspects that should not be overlooked in choosing the perfect plastic for our projects. But if there are still any doubts about plastic deformation, our technical experts are at your disposal, to help you untie all the knots that have come to a head.
