Reasons for changes in storage modulus

What is a storage modulus?

The storage modulus is a measure of how much energy must be put into the sample in order to distort it. The difference between the loading and unloading curves is called the loss modulus, E ". It measures energy lost during that cycling strain. Why would energy be lost in this experiment? In a polymer, it has to do chiefly with chain flow.

What is the difference between loss modulus and storage modulus?

At lower frequency, the storage modulus is lesser than the loss modulus; it means viscous property of the media dominates the elastic property. As the frequency increases, the storage modulus increases; it shows the abrasive media has the capacity to store more energy, and it crosses loss modulus at a point called cross-over point.

How does temperature affect storage modulus?

The storage modulus generally increases with increase in the percentage of secondary constituent (polymer as blend, fillers/reinforcement to make composite), while it decreases dramatically with increase in temperature, and a complete loss of properties is observed at the Tg, which is generally close to 40 °C.

How does storage modulus affect material removal?

The developed media behave like an elastic solid as because of G'>G" at different temperatures with a varying frequency that is best suitable for the finishing process. Storage modulus is solely responsible for the maximum material removal because it decides the radial force exerted by abrasive grain on the work surface.

How does storage modulus improve the efficiency of the media?

Studies conducted by Davies and Fletcher (1995), Kar et al. (2009a, 2009b), and Sankar et al. (2011) describe the improvement in the storage modulus and reduction in the free space between the polymer chains increases the efficiency of the media by providing the better shear strength characteristics.

How does a higher storage modulus affect molded plastic?

A higher storage modulus can result in larger normal forces in the molded plastic. The normal forces are those that occur when plastic is injection molded, it pushes out in the direction normal to the flow direction and creates a normal force. Pressure is a normal force.