Publications

Kropka, Jamie M.; McCoy, John D.; White, Noah W.; Comeau, Stephan J.; Arechederra, Gabriel A.

Abstract not provided.

Kropka, Jamie M.; McCoy, John D.; House, Catherine T.

Abstract not provided.

Kropka, Jamie M.; McCoy, John D.; Comeau, Stephan J.

Abstract not provided.

Groves, Catherine G.; Kropka, Jamie M.; McCoy, John D.

Abstract not provided.

Kropka, Jamie M.; Arechederra, Gabriel A.; Wilson, Kelsey W.; McCoy, John D.; Tenney, Craig M.; Long, Kevin N.

Abstract not provided.

Kropka, Jamie M.; Arechederra, Gabriel A.; Wilson, Kelsey W.; McCoy, John D.; Tenney, Craig M.; Long, Kevin N.

Abstract not provided.

Kropka, Jamie M.; Arechederra, Gabriel A.; Wilson, Kelsey W.; McCoy, John D.; Long, Kevin N.; Tenney, Craig M.

Abstract not provided.

House, Margaret H.; Kropka, Jamie M.; McCoy, John D.

Abstract not provided.

Kropka, Jamie M.; Groves, Catherine G.; Nieto, Adrianna N.; House, Catherine T.; Comeau, Stephan J.; McCoy, John D.

Abstract not provided.

Kropka, Jamie M.; Arechederra, Gabriel A.; McCoy, John D.

Abstract not provided.

Wilson, Kelsey W.; Kropka, Jamie M.; McCoy, John D.

Abstract not provided.

Kropka, Jamie M.; Arechederra, Gabriel A.; McCoy, John D.

Abstract not provided.

Kropka, Jamie M.; McCoy, John D.; House, M.L.; House, E.E.; Comeau, S.J.; House, C.T.

Abstract not provided.

Kropka, Jamie M.; Devries, D.B.D.; House, M.L.; House, E.E.H.; Comeau, S.J.C.; House, C.T.H.; McCoy, John D.

Abstract not provided.

Kropka, Jamie M.; Comeau, S.J.C.; House, M.L.; House, E.E.H.; Nieto, A.N.; Groves, C.R.G.; McCoy, John D.; Kropka, Jamie M.

Abstract not provided.

Kropka, Jamie M.; Arechederra, Gabriel A.; McCoy, John D.

Abstract not provided.

Kropka, Jamie M.; McCoy, John D.

The Henkel technical data sheet (TDS) for Stycast 2651/Catalyst 11 lists three alternate cure schedules for the material, each of which would result in a different state of reaction and different material properties. Here, a cure schedule that attains full reaction of the material is defined. The use of this cure schedule will eliminate variance in material properties due to changes in the cure state of the material, and the cure schedule will serve as the method to make material prior to characterizing properties. The following recommendation was motivated by (1) a desire to cure at a single temperature for ease of manufacture and (2) a desire to keep the cure temperature low (to minimize residual stress build-up associated with the cooldown from the cure temperature to room temperature) without excessively limiting the cure reaction due to vitrification (i.e., material glass transition temperature, T_g, exceeding cure temperature).

Kropka, Jamie M.; McCoy, John D.

The Emerson & Cuming technical data sheet (TDS) for Stycast 2651/Catalyst 9 lists three alternate cure schedules for the material, each of which would result in a different state of reaction and different material properties. Here, a cure schedule that attains full reaction of the material is defined. The use of this cure schedule will eliminate variance in material properties due to changes in the cure state of the material, and the cure schedule will serve as the method to make material prior to characterizing properties. The following recommendation uses one of the schedules within the TDS and adds a “post cure” to obtain full reaction.

Kropka, Jamie M.; McCoy, John D.; House, M.L.H.; House, E.E.H.; Comeau, S.J.C.

Abstract not provided.

Kropka, Jamie M.; Stavig, Mark E.; Arechederra, Gabriel A.; McCoy, John D.

Develop an understanding of the evolution of glassy polymer mechanical response during aging and the mechanisms associated with that evolution. That understanding will be used to develop constitutive models to assess the impact of stress evolution in encapsulants on NW designs.

Kropka, Jamie M.; Arechederra, Gabriel A.; McCoy, John D.

Abstract not provided.

Kropka, Jamie M.; Ancipink, Windy A.; Draelos, Lara R.; McCoy, John D.

Abstract not provided.

Polymer

McCoy, John D.; Ancipink, Windy B.; Clarkson, Caitlyn M.; Kropka, Jamie M.; Celina, Mathias C.; Giron, Nicholas H.; Hailesilassie, Lebelo; Fredj, Narjes

When diethanolamine (DEA) is used as a curative for a DGEBA epoxy, a rapid “adduct-forming” reaction of epoxide with the secondary amine of DEA is followed by a slow “gelation” reaction of epoxide with hydroxyl and with other epoxide. Through an extensive review of previous investigations of simpler, but chemically similar, reactions, it is deduced that at low temperature the DGEBA/DEA gelation reaction is “activated” (shows a pronounced induction time, similar to autocatalytic behavior) by the tertiary amine in the adduct. At high temperature, the activated nature of the reaction disappears. The impact of this mechanism change on the kinetics of the gelation reaction, as resolved with differential scanning calorimetry, infrared spectroscopy, and isothermal microcalorimetry, is presented. It is shown that the kinetic characteristics of the gelation-reaction of the DGEBA/DEA system are similar to other tertiary-amine activated epoxy reactions and consistent with the anionic polymerization model previously proposed for this class of materials. Principle results are the time-temperature-transformation diagram, the effective activation energy, and the upper stability temperature of the zwitterion initiator of the activated gelation reaction. It is established that the rate of epoxide consumption cannot be generically represented as a function only of temperature and degree of epoxy conversion. The complex chemistry active in the material requires specific consideration of the dilute intermediates in the reaction sequence in order to define a model of the reaction kinetics applicable to all time-temperature cure histories.

Celina, Mathias C.; Giron, Nicholas H.; Quintana, Adam Q.; Kropka, Jamie M.; McCoy, John D.

Abstract not provided.

Kropka, Jamie M.; Arechederra, Gabriel A.; McCoy, John D.; Long, Kevin N.

Abstract not provided.