This grant provides funding for the development of experimental and theoretical approaches to determine the extent to which monomer eluting from the inside of hollow nano-tubes reduces stresses generated during polymerization. During polymerization (curing of polymer), a process during which a liquid monomer becomes a solid, the individual monomer units become more densely packed, and the material takes up less volume. When this decrease in volume is prevented because of constraints at the boundaries of the part, it causes the polymer chains to exert stresses. These stresses can cause the polymerized material to debond or induce failure of the part. Experiments and modeling will be performed to evaluate the extent to which this curing stress is reduced with the addition of nano-tubes. Nano-tubes of varying dimensions will be manufactured, blended with two different monomers in different volume fractions, and tests will be performed to determine the extent of reduction in polymerization stress. Experiments will also be performed to determine the extent to which mechanical properties are affected by the use of monomer filled nano-tubes. Modeling will be conducted to understand the underlying physics in order to optimize nano-tube dimensions and volume fractions to generate a maximum reduction in polymerization stress.
If successful, the results of this research will lead to improvements in the integrity of polymer-matrix and other composites while enabling their high speed manufacture. The primary goal of this work is to determine how nano-tubes of different dimensions added in varying volumes to neat resin contributes towards a reduction in polymerization stress. A reduction in polymerization stress can lead to improved dental fillings, and rapid manufacture of glass-fiber epoxy layups, among other applications. Computational tools will also be developed to enable modeling the development of polymerization stress and the extent to which it can be reduced by the addition of nano-tubes.
