Date of Award
Master of Science
This project encompasses three different methods to fabricate syntactic foams using a PDMS matrix i.e., hollow spheres inclusion, pore generator leaching by solvent, and emulsion. The foam formation by using polysiloxane hollow spheres is done in a 3-step process. The first step is to create a core of polystyrene following a dispersion polymerization process. The goal for the size of the pore is to monodisperse and have an average diameter of 5-10 ÃÂÃÂ¼m, so the polystyrene core must be as well within that range. After that, the cores are coated with a polysiloxane shell by following a polymerization by condensation process. The biggest issue with this process has been to avoid agglomerations from the microspheres. Lastly, the core-shell spheres were subjected to heat to degrade the polystyrene core thermally resulting in polysiloxane hollow microspheres.The second process uses the previously mentioned polystyrene core to act as a pore former and then leached with a compatible solvent. This resulted in the partial leach of the polystyrene leaving some pores open and some closed. The third method created a foam by emulsion where water and PDMS were used. PDMS is a hydrophilic polymer which makes it immiscible with water resulting in water droplets contained in the PDMS matrix. Afterward, the composite was subjected to vacuum and heat to evaporate the water and cure the polymer base. These syntactic foams were characterized to analyze their morphology, thermal conductivity, and mechanical properties.
Received from ProQuest
Irigoyen, Andrea, "Synthesis, Characterization, and Direct-Ink-Writing of Syntactic Foams" (2021). Open Access Theses & Dissertations. 3420.