Crossover of the Curing Mechanisms and Double Glass Transition Temperatures of Tetrabromo-Bisphenol-a Epoxy Resin with 4,4-Diaminodiphenylsulfone

2011 ◽  
Vol 233-235 ◽  
pp. 2029-2033 ◽  
Author(s):  
Xing Fang Yao ◽  
Shi Feng Zhang
Keyword(s):  
Glass Transition ◽  
Bisphenol A ◽  
Epoxy Resin ◽  
Transition Temperatures ◽  
Scanning Calorimetry ◽  
Glass Transition Temperatures ◽  
Autocatalytic Model ◽  
Maximum Reaction ◽  
Higher Temperature ◽  
Lower Temperature

The curing process of tetrabromo-bisphenol-A epoxy resin (TBBPAER) with 4,4´-diaminodiphenylsulfone (DDS) was investigated by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and torsional braid analysis (TBA) methods. FTIR results indicated that the maximum reaction velocity was observed at initial stages at higher temperature, but it was occurred at conversion =10 - 40 % at lower temperature. It showed that there is the crossover from the autocatalytic model to the nth-order mechanism when the temperature was increased. While the double glass transition temperatures occuring in the system, according to the microstructure of the reactant, a theoretical and reasonable explanation may arise from this article.

Novel allyl and propenyl monomers for modification of the bismaleimide resins, with excellent dielectric properties and high glass transition temperatures

2019 ◽  
Vol 32 (1) ◽  
pp. 116-126
Author(s):  
Chunyan Qu ◽  
Jiaying Chang ◽  
Changwei Liu ◽  
Dezhi Wang ◽  
Wanbao Xiao ◽  
...  
Keyword(s):  
Glass Transition ◽  
Bisphenol A ◽  
Dielectric Constants ◽  
Resonance Spectroscopy ◽  
Transition Temperatures ◽  
Melting Points ◽  
Scanning Calorimetry ◽  
Bismaleimide Resin ◽  
Glass Transition Temperatures ◽  
Bismaleimide Resins

Two new monomers were prepared by the reaction of 2-allylphenol and 4,4′-biphenyldicarbonyl chloride under different reaction conditions. The monomers were characterized by Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy. The curing processes of N, N-4,4′-bismaleimidodiphenylmethyene with 4,4′-bis(2-allylphenyl) biphenyldicarbonylate (BABC) and 4,4′-bis(2-propenylphenyl benzoate) ether (BPBE) were studied by rheological analysis and differential scanning calorimetry. Melting points of two monomers, BABC and BPBE, are 64°C and 121°C, respectively. The ABMI [4,4′-bis(2-allylphenyl)biphenyl bismaleimide] and PBMI [4,4′-bis(2-propenylphenyl)biphenyl bismaleimide] resins showed exothermic peaks at 233°C and 204°C, respectively. The measured melting points are significantly lower than that of the traditional bismaleimide resin which is modified by allyl bisphenol A. Dynamic mechanical analysis of the materials showed glass transition temperatures of ABMI and PBMI to be in the range of 213–258°C and 302–339°C, respectively. Thermogravimetric analysis of the cured resins showed 5% weight loss for ABMI and PMBI at 437°C and 428°C, along with char residues of 35.6–39.5%, respectively, at 800°C under nitrogen atmosphere. Furthermore, dielectric constants of propenyl-modified resins were lower (2.46–3.10) with dissipation factors of 0.0034–0.0036, compared with those of allyl bisphenol A resins.

Time-temperature dependence of fracture toughness for bisphenol a epoxy resin

2002 ◽  
Vol 216 (2) ◽  
pp. 79-84 ◽  
Author(s):  
W Araki ◽  
T Adachi ◽  
M Gamou ◽  
A Yamaji
Keyword(s):  
Fracture Toughness ◽  
Glass Transition ◽  
Transition Temperature ◽  
Bisphenol A ◽  
Temperature Dependence ◽  
Epoxy Resin ◽  
Transition Temperatures ◽  
Glass Transition Temperatures ◽  
Brittle Ductile Transition ◽  
Fragility Parameter

The relationship between the curing conditions and the time-temperature dependence of fracture toughness was investigated for bisphenol A epoxy resin. The glass transition temperature and Angell's fragility parameter, which are obtained from thermoviscoelasticity measurements, were used to characterize epoxy resins cured under various conditions. Examination of the fracture toughness at various temperatures and displacement rates showed that it depends on both temperature and time, and that it follows the time-temperature equivalence principle. The time-temperature dependence of the fracture toughness was greatly affected by the fragility parameter. The fracture toughness of the resin with a smaller fragility parameter increased from lower temperatures to the brittle-ductile transition temperature than that of the resin with a larger fragility parameter when their glass transition temperatures were approximately 400 K. It was also found that the brittle-ductile transition temperature did not depend on the fragility parameter. This means that epoxy resin with a smaller fragility parameter has better fracture characteristics than epoxy resin with a larger fragility parameter if their glass transition temperatures are approximately 400 K.

Synthesis and Properties of Poly (N-arylenebenzimidazole ketone)s

2014 ◽  
Vol 881-883 ◽  
pp. 165-168
Author(s):  
Xiang Wang Cui ◽  
Lin Zhang
Keyword(s):  
Differential Scanning Calorimetry ◽  
Glass Transition ◽  
Coupling Reaction ◽  
Transition Temperatures ◽  
Scanning Calorimetry ◽  
Glass Transition Temperatures

Two bis (benzimidazoyl) monomers were synthesized, and Poly (N-arylenebenzimidazole ketone) s were prepared by N-C coupling reaction that replaced the NH sites from the bis (benzimidazolyl) derivatives with activated difluorides monomers in sulfolane at 210 °C. All the resulting polymers showed easy solubility compared with traditional polybenzimidazoles. Differential scanning calorimetry and thermogravimetric measurements showed that the polymers had high glass transition temperatures (>240 °C), good thermostability and high decomposition temperatures (>460 °C).

scholarly journals Study on tri-imidazole derivatives modified with triazine-trione structure as latent curing agents for epoxy resin

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Xiaodong Wan ◽  
Jianben Liu ◽  
Xi Chen ◽  
Jun Wang
Keyword(s):  
Glass Transition ◽  
Epoxy Resin ◽  
Storage Stability ◽  
Crosslinking Density ◽  
Exothermic Peak ◽  
List Type ◽  
Transition Temperatures ◽  
Glass Transition Temperatures ◽  
Imidazole Derivatives ◽  
Long Storage

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.

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