Polymer Characterization: Density and Thermal Expansion

Mass divided by volume.

It causes a decrease in density due to thermal expansion.

It causes an increase in density due to reduction in volume.

<p>Because density can be affected by temperature and pressure.</p> Signup and view all the answers

<p>Helium gas is used to displace the polymer, allowing for accurate volume measurement.</p> Signup and view all the answers

<p>Injection molding.</p> Signup and view all the answers

<p>To apply a gas, such as helium, that flows into the interparticle volume and pores of the powder to measure its density.</p> Signup and view all the answers

<p>Bulk density includes the interparticle volume, while true density is the density of the particles themselves, excluding the interparticle volume.</p> Signup and view all the answers

<p>Porosity increases the volume of the material, thereby reducing its density.</p> Signup and view all the answers

<p>To create a range of densities from low to high, allowing for the accurate measurement of the density of a sample.</p> Signup and view all the answers

<p>To ensure that the density of the liquids remains constant, maintaining the accuracy of the measurements.</p> Signup and view all the answers

<p>The regular structure of polypropylene, such as its isotactic and syndiotactic configurations, allows for closer packing of the chains, resulting in a higher density.</p> Signup and view all the answers

<p>The high cohesion of Teflon, resulting in chains that are closely packed together, leading to a higher density.</p> Signup and view all the answers

<p>Polytetrafluoroethylene (Teflon) has a higher density than polypropylene, primarily due to its molecular structure and physical properties.</p> Signup and view all the answers

<p>Minimizing interparticle volume allows for a more accurate measurement of the true density of the powder.</p> Signup and view all the answers

<p>Porosity affects the density and performance of the polymer material, which can impact its efficacy and reliability in pharmaceutical applications.</p> Signup and view all the answers