Khaberni - An international research team has succeeded in discovering the secret of the exceptional strength of one of the most used materials in modern life, which is reinforced rubber.
Although we rely on this material daily in car and aircraft tires and medical equipment, and it enters an industry valued at hundreds of billions of dollars, its physical behavior remained a mystery that depended more on experimentation than understanding.
To solve the mystery, the study published in the journal "Proceedings of the National Academy of Sciences," focused on the primary material responsible for strengthening rubber, which are the black carbon particles that are added to natural rubber to transform it from a soft material to another capable of withstanding the harshest conditions.
Computer simulation reveals the truth
The research team, led by Dr. David Simmons from the University of South Florida, relied on more than 1,500 advanced molecular simulations, equivalent to about 15 years of computing, to study the interaction of hundreds of thousands of atoms within reinforced rubber, aiming to understand how black carbon particles are distributed within the rubber and their effect on its mechanical behavior.
The results showed that the main reason for the increased hardness of rubber is that black carbon prevents what is scientifically known as "Poisson's ratio mismatch."
This concept in materials science describes a state of incompatibility between the response methods of different parts within the same material when subjected to tension or pressure, where stretching any material causes it to lengthen in the direction of stretching, but at the same time, it narrows laterally, and this relationship is scientifically expressed as "Poisson's ratio."
The researchers found that when natural rubber is stretched, it expands lengthwise and narrows laterally, but the presence of black carbon prevents this natural contraction, creating an "internal conflict" within the material between expansion and resistance, making the rubber harder and more resistant to tearing, and more capable of enduring under pressure and heat.
Turning point in the history of material science
The researchers say in an official press release published by the University of South Florida, that this discovery represents a turning point in the history of materials science, because it not only provides a new explanation for the behavior of reinforced rubber, but it also rewrites the theoretical basis that the industry and science have relied on for many decades.
The researchers explain that since the early use of rubber reinforced with black carbon in the early twentieth century, development depended on trial and error without a precise understanding of the physical mechanism that grants it strength and durability, and over time, despite significant advances in engineering and material sciences, the basic question remained: Why does rubber become harder in this particular way?
They add that "this discovery closes a knowledge gap that lasted for more than a century, by clarifying that the secret lies not in one simple factor, but in a complex internal interaction that makes the material resist its natural way of stretching, this new understanding is not limited to explaining an old phenomenon, but it opens the door to a different phase in material design, where the shift from reliance on experimentation to building accurate scientific models capable of predicting the behavior of materials before manufacturing them."
