Multifunctional Polymerization Kinetics and Network Structure Thereof

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Abstract - Peppas - 9311563 Highly crosslinked polymers have potential uses as materials for information storage systems, aspherical lenses and optical fiber coatings. The requirements for the manufacture of these materials include a rapid polymerization rate, low volume shrinkage on polymerization, high dimensional and thermal stability of the polymer, and minimal structural inhomogeneities within the polymer network. Polydimethacrylates are currently used in many applications; often produced from dimethacrylate monomers. These reactions are slow, they may take 30-40 minutes to reach liniting conversions. Acrylate monomers react seven to ten times faster and are therefore better polymerization systems to study. The mathematical modeling of multifunctional polymerization/crosslinking reactions will be investigated in this research project. A theoretical model for the prediction of initiator efficiency thoughout the course of the polymerization will be developed. Fundamental descriptions for the propagation and termination rate constants will also be developed. These expressions will be incorporated into the typical initiation-propagation-termination mechanism and model simulations will be carried out. Kinetic gellation simulations will be carried out to determine the final network structure at the specified reaction conditions. Polymerization/crosslinking of polyethylene glycol diacrylate networks will be studied by exposure to UV light. Volume shrinkage on polymerization, swelling characteristics, molecular weight between crosslinks, glass transition temperature and thermal stability of the resulting networks will be determined and used to analyze the crosslinked struture. By varying the length of the etylene glycol unit between the two C=C bonds, changes in the kinetics of these polymerizations will be studied. The conversion-time profiles will be obtained at different light intensities using a calorimetric and a spectroscopic technique. limitingthroughoutstructureethylene9 9 9 9 9 9 9 9 9Abstract - Peppas - 9311563 Highly crosslinked polymers have potential uses as materials for information storage systems, asp L T ^ g o Z \ L ! ! D ! ! o L ( Times New Roman Symbol & Arial | V ^ L T ' ^ 6 g J " h A %F % / Maria K. Burka Maria K. Burka