Calorimetry studies associated with the curing of DGEBA epoxy with hardener diethanolamine (DEA).  Curing involves a complex series of reactions (including zwitterion formation, anionic chain growth, and termination). The tertiary amine formed after initial reaction of the secondary amine to form an adduct acts to open the epoxide ring to form the zwitterion which then propagates in chain growth.  The hydroxyls accelerate the reaction.  Currently we are acting to separate contributions by studying DGEBA reaction with dibutylamine and octanol.

Recent Publications

The reaction of diglycidyl ether of bisphenol A (DGEBA) epoxy cured with diethanolamine: Dependency on temperature and extent of reaction, McCoy, Ancipink, Maestas, Draelos, Devries, Kropka, Thermochimica Acta (Submitted 2018)

The insulating effect of the low thermal conductivity of epoxy on the resolution of the heat of reaction during polymerization by differential scanning calorimetry, Arechederra, Draelos, Ancipink, McCoy, Kropka, Thermochimica Acta 656, 144 (2017)

Cure mechanisms of diglycidyl ether of bisphenol A (DGEBA) epoxy with Diethanolamine, McCoy, Ancipink, Clarkson, Kropka, Celina, Giron, Hailesilassie, Fredj, Polymer 105, 243 (2016)

Recent Presentations

Influence of hydroxyl concentration on the cure kinetics of diglycidyl ether of bisphenol A (DGEBA) epoxy in the presence of a tertiary amine, McCoy, M. House, E. House, S. Comeau, C. House, Kropka, Poster, American Physical Society, Los Angeles, CA (2018)

Effect of hydroxyl mobility on the cure kinetics of diglycidyl ether of bisphenol A (DGEBA) epoxy in the presence of a tertiary amine, D. Devries, M. House, E. House, S. Comeau, C. House, McCoy, Kropka, Poster, American Physical Society, Los Angeles, CA (2018)

Effect of Hydroxyl Groups on the Tertiary Amine Curing of Epoxy, M. House, E. House, S. Comeau, C. House, McCoy, Kropka, Poster, AiChe Annual Meeting, Minneapolis, MN (2017)

Complex Cure Kinetics of the Tertiary Amine activated Reaction in DGEBA Epoxy Hardened with Diethanolamine, Ancipink, McCoy, Clarkson, Kropka, Celina, Giron, Hailesilassie, Fredj, Poster, American Physical Society, New Orleans, LA (2017)

Complex Cure Kinetics of the Hydroxyl-Epoxide Reaction in DGEBA Epoxy Hardened with Diethanolamine, Ancipink, McCoy, Kropka, Celina, Poster, American Physical Society, Baltimore, MD (2016)

Thesis

Cure Kinetics of the Tertiary Amine Activated Reaction in DGEBA Epoxy Hardened with Diethanolamine – Ancipink (2017)

Thermal and mechanical properties of glasses vary with time as they “age” at temperatures below their glass transition.  Two epoxies have been studied.  DGEBA cured with diethanolamine (DEA) and DGEBA cured with a polyamine Jeffamine T-403.  Use is made of simple theories of aging (e.g., KAHR and Eyring Models) to understand the aging process.  Particularly interesting is the effect of compressive stress on the effects of aging, both small, sub-yield stresses and large, post-yield stresses are studied.

Recent Publications

Evolution of Thermomechanical Properties of the Diethanolamine Cured Diglycidyl Ether of Bisphenol-A (DGEBA) Epoxy, Arechederra, McCoy, Kropka, Polymer (To be Submitted - Draft)

Enthalpy recovery and its relation to shear response in an amine cured DGEBA epoxy, Clarkson, McCoy, Kropka, Polymer 94, 19 (2016)

Recent Presentations

The calorimetric signature of aging in an epoxy glass following mechanical rejuvenation, Comeau, M. House, E. House, Hoo, McCoy, Kropka, Poster, American Physical Society, Los Angeles, CA (2018)

Evolution of Yield Stress during Structural Relaxation for the Epoxy 828DEA, Arechederra, McCoy, Kropka, Poster, American Physical Society, Baltimore, MD (2016)

Relaxation Characteristics of 828 DGEBA Epoxy Over Long Time Periods, Hoo, Reprogle, Wisler, Arechederra, McCoy, Kropka, Long, Poster, American Physical Society, Baltimore, MD (2016)

Thesis

Evolution of Mechanical Properties during Structural Relaxation of the 828/DEA Epoxy Thermoset, Arechederra (2017)

The Effects of Physical Aging in a Polyetheramine-Cured DGEBA Epoxy, Wilson (2018)

A problem of long standing interest is how the thickness of a film affects the glass properties (e.g., glass transition temperature and relaxation behavior). Two of us (Curro and McCoy) proposed a Density Functional Theory based theory of how and Tg varies with film thickness.  In collaboration with former student, Stevenson, we are exploring this connection with Molecular Dynamics Simulations. Current work is focusing on relaxation times.

Recent Publication

The glass transition temperature of thin films: A molecular dynamics study for a bead-spring model, Stevenson, Curro, McCoy, Journal of Chemical Physics 146, 203322 (2017).

Stephan Comeau (Current)

Jonathan R. Brown
Linear and Nonlinear Dynamic Heat Capacity of a Simple Simulated Polymer (2012)

Joanne L. Budzien
Computer Simulation Study of the Glass Transition in Chain Molecules Using A Scalar Metric Approach (2004)

Shyamal K. Nath
Structure and Thermodynamics of Inhomogeneous Polymeric Systems: Surfaces, Blends and Diblocks (1996)

Giovanni Gabaldon (Current)

Brandon McReynolds (Current)

Noah White
Effect of aging on the syntactic foam DGEBA/DEA/GMB (2022)

Kelsey Wilson
Physical aging In a polyether-amine cured DGEBA epoxy (2018)

Gabriel Arechederra
Evolution of the thermal-mechanical properties of the 828/DEA epoxy thermoset (2017)

Windy Ancipink
Cure kinetics of the tertiary amine acivated reaction in DGEBA epoxy hardened with diethanolamine (2017)

Caitlyn Clarkson
Structural Relaxation of a DGEBA Epoxy 828/T403 (2015)

Sara Waters
Molecular Dynamics Simulation of Diffusivity and Mobility of Ionic Charge Carriers in Model Poly(ethylene-co-acrylic acid) Monomers (2014)

Jonathan Brown
Dynamic Heat Capacity of the East Ising Model (2009)

Taylor Dotson
Relaxation Behavior in Molecular Dynamics Simulations of Simple Polymers (2008)

Julieanne V. Heffernan
Molecular Flexibility Effects Upon Liquid Dynamics (2007)

Kristy Visconti
Three Dimensional Thermal and Mechanical Characterization of Glass-Fiber Reinforced Polymer-Matrix Composites (2007)

Yuan Ye
Structure of Tethered Polymer Chains in Varying Solvents: A Density Funtional Theory Study (2002)

Steven Deal
The Flow Behavior of an Uncured Epoxy/Filler Composite (2002)

Morgan T. Pileggi
On The Solvation Thermodynamics of Nonideal Fluids and Fluid Mixtures (2001)

Dana R. Rottach
Small molecule diffusion through polymers : a molecular dynamics study (1999)

Justin B. Hooper
Interactions of Tangent Hard Sphere Chains near a Hard Wall: A Density Functional Theory Approach (1999)

Joanne L. Budzien
Prediction of the Solubility of Simple Gases in Rubbery Polymers (1998)

Patrick A. Tillman
Effects of Attractive Interactions on the Structure of Model Polymer Liquids (1997)

Timothy (Dash) Weeks
Fracture Properties as a Function of the Extent of Reaction for an Epoxy Network (1997)

Sudeepto Sen
The Structure of a Rotational Isomeric State Alkane Melt Near a Hard Wall (1994)

Craig S. Stevenson
A Molecular Dynamics Simulation of a Binary Homopolymer Blend and a Comparison with the Polymer Reference Interaction Site Model (1994)

Meltem Zorlu
Thermal Characterization of Recycled High Density Polyethylene (1994)

Many undergraduates have been group members - This list is probably incomplete

Taylor Lee

Brandon McReynolds

Noah White

Adrianna Nieto

Catherine House

Catherine Groves

Margaret House

Lara Draelos

Kelsey Wilson

Sam Burleigh

Eleanor House

Katheryn Husmann

Brian Wisler

Riley Reprogle

Victoria J. Aston

Francisco Avila

Robert J. Baca

Gwendolyn Bahun

Ethan Buchner

Andrea Buckel

Partick Burton

K. Thomas Dotson

Shannon Ferrel

Annie Hohmann

Phillip Jenks

David Limmer

Ganlu "Lulu" Liu

Tyler Payton

Salomon Mateas

Daniel McCoy

Katheryn Mireles

Robin Montoya

Matthew Rush

Timothy Schutt

Jason Sharkey

Laura Stanley

Meredith Schuh

Melody A. Teixeira

Devon Turner

Jedediah (J.D.) Tratechaud