Correlations Between Micromechanical Failure Processes and the Delamination Toughness of Graphite/Epoxy Systems

2008 ◽  
pp. 68-68-30 ◽  
Author(s):  
MF Hibbs ◽  
WL Bradley
Keyword(s):  
Delamination Toughness ◽  
Epoxy Systems

Shape memory epoxy systems with a wide range of switching temperature

2017 ◽  
Vol 39 (1) ◽  
pp. 7-13
Author(s):  
Ye.P. Mamunya ◽  
◽  
O.K. Matkovska ◽  
O.V. Zinchenko ◽  
E.V. Lebedev ◽  
...  
Keyword(s):  
Shape Memory ◽  
Wide Range ◽  
Switching Temperature ◽  
Epoxy Systems

scholarly journals Studies on the Modification of Commercial Bisphenol-A-Based Epoxy Resin Using Different Multifunctional Epoxy Systems

2021 ◽  
Vol 2 (2) ◽  
pp. 419-430
Author(s):  
Ankur Bajpai ◽  
James R. Davidson ◽  
Colin Robert
Keyword(s):  
Mechanical Properties ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Bisphenol A ◽  
Epoxy Resin ◽  
Tensile Fracture ◽  
Chemical Structures ◽  
Amino Phenol ◽  
Epoxy Systems

The tensile fracture mechanics and thermo-mechanical properties of mixtures composed of two kinds of epoxy resins of different chemical structures and functional groups were studied. The base resin was a bi-functional epoxy resin based on diglycidyl ether of bisphenol-A (DGEBA) and the other resins were (a) distilled triglycidylether of meta-amino phenol (b) 1, 6–naphthalene di epoxy and (c) fluorene di epoxy. This research shows that a small number of multifunctional epoxy systems, both di- and tri-functional, can significantly increase tensile strength (14%) over neat DGEBA while having no negative impact on other mechanical properties including glass transition temperature and elastic modulus. In fact, when compared to unmodified DGEBA, the tri-functional epoxy shows a slight increase (5%) in glass transition temperature at 10 wt.% concentration. The enhanced crosslinking of DGEBA (90 wt.%)/distilled triglycidylether of meta-amino phenol (10 wt.%) blends may be the possible reason for the improved glass transition. Finally, the influence of strain rate, temperature and moisture were investigated for both the neat DGEBA and the best performing modified system. The neat DGEBA was steadily outperformed by its modified counterpart in every condition.

scholarly journals Highly ductile glassy epoxy systems obtained by network topology modification using partially reacted substructures

Polymer ◽  
2021 ◽  
Vol 212 ◽  
pp. 123260 ◽  
Author(s):  
J. Gao ◽  
X. Chu ◽  
C.K. Henry ◽  
S.C. Santos ◽  
G.R. Palmese
Keyword(s):  
Network Topology ◽  
Epoxy Systems ◽  
Topology Modification

scholarly journals Test methods for measuring pure mode III delamination toughness of composite

2016 ◽  
Vol 55 ◽  
pp. 261-268 ◽  
Author(s):  
Yangyang Ge ◽  
Xiaojing Gong ◽  
Anita Hurez ◽  
Emmanuel De Luycker
Keyword(s):  
Test Methods ◽  
Pure Mode ◽  
Mode Iii ◽  
Delamination Toughness

Migration and Settling of Particulates in Filled Epoxies

2003 ◽  
Author(s):  
Lisa Mondy ◽  
Rekha Rao ◽  
Eric Lindgren ◽  
Amy Sun ◽  
Robert Lagasse ◽  
...  
Keyword(s):  
Particle Concentration ◽  
Particle Migration ◽  
Polymerization Reaction ◽  
Temperature Dependent ◽  
Filled Polymers ◽  
Post Test ◽  
Manufacturing Applications ◽  
Microscopy Data ◽  
Suspension Model ◽  
Epoxy Systems

Manufacturing applications for filled polymers include encapsulation of microelectronics and injection molding of composite parts. Predictive tools for simulating these manufacturing processes require knowledge of time- and temperature-dependent rheology of the polymer as well as information about local particle concentration. The overall system rheology is highly dependent on the particle concentration. The local particle concentration can change due to gravity, convection and shear-induced migration. For the epoxy systems of interest, an extent of reaction can be used to track the degree of cure. We couple the curing model with a diffusive flux suspension model [Zhang and Acrivos 1994] to determine the particle migration. This results in a generalized Newtonian model that has viscosity as a function of temperature, cure and concentration. Using this model, we examine settling of the particulate phase in both flowing and quiescent curing systems. We focus on settling in molds and flow in wide-gap counter-rotating cylinders. The heat transfer, including the exothermic polymerization reaction, must be modeled to achieve accurate results. The model is validated with temperature measurements and post-test microscopy data. Particle concentration is determined with x-ray microfocus visualization or confocal microscopy. Agreement between the simulations and experimental results is fair.

Delamination toughness of electron beam physical vapor deposition (EB-PVD) Y2O3–ZrO2 thermal barrier coatings by the pushout method: Effect of thermal cycling temperature

2008 ◽  
Vol 23 (9) ◽  
pp. 2382-2392 ◽  
Author(s):  
M. Tanaka ◽  
Y.F. Liu ◽  
S.S. Kim ◽  
Y. Kagawa
Keyword(s):  
Electron Beam ◽  
Thermal Cycling ◽  
Bond Coat ◽  
Physical Vapor Deposition ◽  
Thermally Grown Oxide ◽  
Test Method ◽  
Thermal Barrier ◽  
Barrier Coating ◽  
Delamination Toughness ◽  
Cycling Temperature

A pushout test method was used to quantify effect of thermal cycling temperatures on the delamination toughness of an electron beam physical vapor deposited thermal barrier coating (EB-PVD TBC). The delamination toughness, Γi, was related to the maximum thermal cycling temperature, Th, equal to 1000, 1025, 1050, and 1100 °C. The measured delamination toughness varied from 9 to 95 J/m2. At Th = 1000 °C, Γi attained a maximum value, larger than that of the as-deposited sample and decreasing with increased Th. During the thermal cycling tests, the thermally grown oxide (TGO) was formed between the TBC and the bond coat deposited onto the superalloy substrate. Inside the TGO layer, mixture of Al2O3 and ZrO2 oxides was observed close to the TBC side with nearly pure Al2O3 phases close to the bond-coat side. During the pushout test, delamination occurred at the interface of the mixture and pure Al2O3 layer with an exception for Th = 1100 °C specimens where delamination also occurred at the interface between the TGO and bond-coat layers. The effect of thermal cycling temperatures on the delamination toughness is discussed in terms of the microstructural change and delamination behavior.

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