Investigating Polymer Nanocomposites Using Positron Annihilation Lifetime Spectroscopy

By determining the characteristics of the porosity of a polymer, one can gain a greater understanding of its properties as a whole. We can alter the free volume and mobility of strands in a polymer without altering its chemistry through the incorporation of inorganic nanoparticles, forming a polymer nanocomposite (PNC). Positron Annihilation Lifetime Spectroscopy (PALS) provides an effective means of determining the characteristics of the porosity of a sample PNC. Positrons from a radioactive source (Na-22) are directed into a PNC, where they form positronium (Ps). There the Ps tends to localize in voids, where the size of the pore directly affects its lifetime. By measuring the mean Ps lifetime in a PNC, we gain insight into the sample\u27s porosity, and as a result, the sample\u27s properties as a whole. We have formed pristine samples of a DGEBA/DDS based polymer and have examined them using our constructed PALS system. These results and the basis of further studies will be discussed