Physical Properties of Rubber
Modulus of Elasticity - and Ultimate Tensile and Yield Strength for steel, glass, ( Young's Modulus, Modulus of Elasticity) . Rubber, small strain, -and
In this article we will describe the physical properties of rubber that you will see on a physical property data sheets for elastomers that are tested to ASTM D specifications. I have described what the property is, why it is important, and how you test it. There are many more physical properties of rubber than what are described here, but, we will limit them to the most common physical properties you will see in the ASTM D standard. The results of these properties, except Hardness and Tensile Set, are from tension stress which is recorded on the stress-strain curve that is generated during a Ultimate Tensile Strength test. ASTM D and D are used to measure the stiffness modulus of rigidity of a sample while applying torsional force on a specimen chilled to a specific temperature.
We thank Mr. Thomas Young his British fellow countryman will leave his name associated to this linear behavior of many materials. In a low deformations range, materials behavior Stress relation to strain can be often compared to a straight line from the origin in red, on the following graph. This behavior range gap is traditionally called "linear elastic domain". Elastomers do not escape to this rule and for low strains we can assimilate their behaviour to a linear one. So Young's modulus is knowledge's departure point for materials.
YOUNG MODULUS FOR RUBBER
Compounds with a higher modulus are more resilient and more resistant to extrusion. Generally speaking, the harder a compound, the higher its modulus.
Tensile Modulus - or Young's Modulus alt. Modulus of Elasticity - is a measure of stiffness of an elastic material. It is used to describe the elastic properties of objects like wires, rods or columns when they are stretched or compressed. It can be used to predict the elongation or compression of an object as long as the stress is less than the yield strength of the material. More about the definitions below the table.
Young's modulus or Young modulus is a mechanical property that measures the stiffness of a solid material. It defines the relationship between stress force per unit area and strain proportional deformation in a material in the linear elasticity regime of a uniaxial deformation. Young's modulus is named after the 19th-century British scientist Thomas Young. However, the concept was developed in by Leonhard Euler , and the first experiments that used the concept of Young's modulus in its current form were performed by the Italian scientist Giordano Riccati in , pre-dating Young's work by 25 years. A solid material will undergo elastic deformation when a small load is applied to it in compression or extension. Elastic deformation is reversible the material returns to its original shape after the load is removed. At near-zero stress and strain, the stress—strain curve is linear , and the relationship between stress and strain is described by Hooke's law that states stress is proportional to strain.
High molecular weight polymers that exhibit rubber-like behavior are known as elastomers. Above the glass transition temperature, the rubber-like polymers are in a liquid-like state and the mer or repeat units change their position readily and continuously due to Brownian motion. Thus, each polymer chain takes up random conformations in a stress-free state. In an entangled or cross-linked elastomer, the chains form a loose three-dimensional molecular network. For polymers of high-molecular-weight, the network could solely consist of entanglements by molecular intertwining knots with a spacing between knots characteristic for the particular polymer; or the chains could be chemically crosslinked, that is, the chains form a permanent network, as it is the case for vulcanized rubber.