Doctor of Philosophy (PhD)
Thermal frontal polymerization is a type of polymerization in which a localized reaction zone propagates through an unstirred system. It is incumbent upon the production and transport of heat produced as a result of the exothermic reaction associated with free-radical polymerization. First discovered in the 1970s, frontal polymerization has been since utilized to produce a variety of different materials, utilizing a variety of different chemistries. The temperature of the propagating front and the velocity at which it propagates can be influenced via chemical or physical means. We show that through careful selection of monomers and control of the concentration of double bonds in a system, that increasing the functionality of the monomer can increase the velocity of a propagating front. We have also shown that residual water in the monomer can effectively lower the front velocity and temperature via heat loss due to vaporization. It was also shown that secondary functional groups present in certain monomers can act as chain-transfer agents. This slows the propagation of the front.
We have also tested influencing the fronts’ velocity and temperature with fillers and conductive elements. The use of powdered fillers with high thermal diffusivity and thermal conductivity can lead to more efficient transport of heat through a system. As heat is transported more efficiently the front can propagate much faster with less heat. Using powdered fillers can become expensive in real world applications so composites were studied that had a continuous conductive element embedded through the length of the composite. In our study copper was used. Copper strips were shown to increase the velocity of the front without changing the front temperature by conducting heat ahead of the propagating front.
Bynum, Samuel Morris, "Influencing Factors on the Velocity and Temperature of Propagating Fronts in Acrylate Composites" (2019). LSU Doctoral Dissertations. 5124.