transition temperatures
Recently Published Documents


TOTAL DOCUMENTS

1851
(FIVE YEARS 166)

H-INDEX

83
(FIVE YEARS 8)

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Xiaodong Wan ◽  
Jianben Liu ◽  
Xi Chen ◽  
Jun Wang

Abstract In this paper, four novel kinds of triazine-trione based tri-imidazole derivatives (IM-TT, 2MI-TT, 2EI-TT and EMI-TT) were synthesized through the addition reaction between triglycidyl isocyanurate (TGIC) and imidazole (IM), 2-methylimidazole (2MI), 2-ethylimidazole (2EI) and 2-ethyl-4-methylimidazole (EMI), respectively. The triazine-trione based tri-imidazole derivatives were blended with epoxy resin and the reactivity, thermal latency and thermal property were investigated. The results on curing behaviors indicated that the curing exothermic peaks of the blends with triazine-trione based tri-imidazole derivatives shifted to higher temperatures compared with those with commercial imidazoles. The curing exothermic peak temperatures (Tps) of the synthesized tri-imidazole derivatives were increased by 23–32 ℃ compared with the unmodified imidazoles. In addition, Rheological behavior results indicated that the EP blends with tri-imidazole derivatives also exhibited excellent storage stability which was as long as 38 days under room temperature. Last but not the least, the EP blends with triazine-trione based tri-imidazole derivatives also exhibited high glass transition temperatures due to introducing of triazine-trione structures with high crosslinking density. The glass transition temperatures (Tgs) of the prepared thermosets ranged from 128 to 152 ℃. The triazine-trione based tri-imidazole derivatives provide a way to prepare latency epoxy resin with high high glass transition temperature and long storage stability. Article Highlights Four novel kinds of triazine-trione based tri-imidazole derivatives were synthesized. The EP cured with the tri-imidazole derivatives displayed great thermostability. The EP cured with the tri-imidazole derivatives exhibited long storage stability.


2021 ◽  
pp. 2100666
Author(s):  
Ruizhe Liu ◽  
Chao Yang ◽  
Zixuan Huang ◽  
Rohan French ◽  
Zi Gu ◽  
...  

Metals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1936
Author(s):  
Toni Sprigode ◽  
Andreas Gester ◽  
Guntram Wagner ◽  
Thomas Mäder ◽  
Björn Senf ◽  
...  

The aim of this study was to investigate the mechanical behavior, and the microstructure of NiTiCu shape memory alloy wires joined with silver-coated copper ferrules via ultrasonic spot welding. Therefore, the electrical resistance was measured during tensile testing, and the joints were analyzed by scanning electron microscopy. Energy-dispersive X-ray spectroscopy has determined the compounds of the developed welding zones. Furthermore, the influence of the ultrasonic welding on the transition temperatures of the NiTiCu wires was examined via differential scanning calorimetry. Tensile tests have shown that the ultimate tensile strengths of the joints reached almost 100% of that of the base material. An additional heat treatment rebuilt the typical shape memory alloy behavior after the ultrasonic welding process detwinned the martensitic wires. In addition, the B19′ structure of the welding zone and the ultrasonic spot-welding process did not affect the transition temperatures of the shape memory alloy.


Molecules ◽  
2021 ◽  
Vol 26 (21) ◽  
pp. 6383
Author(s):  
Elena Gómez ◽  
Pedro Velho ◽  
Ángeles Domínguez ◽  
Eugénia A. Macedo

Ionic liquids (ILs) are being widely studied due to their unique properties, which make them potential candidates for conventional solvents. To study whether binary mixtures of pure ionic liquids provide a viable alternative to pure ionic liquids for different applications, in this work, the thermal analysis and molar heat capacities of five equimolar binary mixtures of ionic liquids based on imidazolium, pyridinium, pyrrolidinium, and piperidinium cations with dicyanamide, trifluoromethanesulfonate, and bis(trifluoromethylsulfonyl)imide anions have been performed. Furthermore, two pure ionic liquids based on piperidinium cation have been thermally characterized and the heat capacity of one of them has been measured. The determination and evaluation of both the transition temperatures and the molar heat capacities was carried out using differential scanning calorimetry (DSC). It was observed that the thermal behavior of the mixtures was completely different than the thermal behavior of the pure ionic liquids present, while the molar heat capacities of the binary mixtures were very similar to the value of the average of molar heat capacities of the two pure ionic liquids.


2021 ◽  
Vol 104 (14) ◽  
Author(s):  
Sijin Long ◽  
Shu Cai ◽  
Rico Schönemann ◽  
Priscila F. S. Rosa ◽  
Luis Balicas ◽  
...  

Author(s):  
Graham W. Tindall ◽  
Spencer C. Temples ◽  
Mikhala Cooper-Robinson ◽  
Villő Enikő Bécsy-Jakab ◽  
David B. Hodge ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document