PROPERTIES OF CONDUCTIVE ADHESIVES BASED ON ANHYDRIDE-CURED 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.

Download Full-text

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

Polymer ◽

10.1016/j.polymer.2020.123260 ◽

2021 ◽

Vol 212 ◽

pp. 123260 ◽

Cited By ~ 1

Author(s):

J. Gao ◽

X. Chu ◽

C.K. Henry ◽

S.C. Santos ◽

G.R. Palmese

Keyword(s):

Network Topology ◽

Epoxy Systems ◽

Topology Modification

Download Full-text

Sticky thermoelectric materials for flexible thermoelectric modules to capture low-temperature waste heat

MRS Advances ◽

10.1557/adv.2020.84 ◽

2020 ◽

Vol 5 (10) ◽

pp. 481-487 ◽

Cited By ~ 1

Author(s):

Norifusa Satoh ◽

Masaji Otsuka ◽

Yasuaki Sakurai ◽

Takeshi Asami ◽

Yoshitsugu Goto ◽

...

Keyword(s):

Thermal Conductivity ◽

Low Temperature ◽

Waste Heat ◽

Air Cooling ◽

Conductive Adhesives ◽

Hot Plate ◽

Low Thermal Conductivity ◽

Te Modules ◽

P Type ◽

Flexible Thermoelectric

ABSTRACTWe examined a working hypothesis of sticky thermoelectric (TE) materials, which is inversely designed to mass-produce flexible TE sheets with lamination or roll-to-roll processes without electric conductive adhesives. Herein, we prepared p-type and n-type sticky TE materials via mixing antimony and bismuth powders with low-volatilizable organic solvents to achieve a low thermal conductivity. Since the sticky TE materials are additionally injected into punched polymer sheets to contact with the upper and bottom electrodes in the fabrication process, the sticky TE modules of ca. 2.4 mm in thickness maintained temperature differences of ca. 10°C and 40°C on a hot plate of 40 °C and 120°C under a natural-air cooling condition with a fin. In the single-cell resistance analysis, we found that 75∼150-µm bismuth powder shows lower resistance than the smaller-sized one due to the fewer number of particle-particle interfaces in the electric pass between the upper and bottom electrodes. After adjusting the printed wiring pattern for the upper and bottom electrodes, we achieved 42 mV on a hot plate (120°C) with the 6 x 6 module having 212 Ω in the total resistance. In addition to the possibility of mass production at a reasonable cost, the sticky TE materials provide a low thermal conductivity for flexible TE modules to capture low-temperature waste heat under natural-air cooling conditions with fins for the purpose of energy harvesting.

Download Full-text