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.

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.

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).

Glass-Transition Temperatures of Polyamide Textile Fibers

1977 ◽  
Vol 47 (6) ◽  
pp. 398-406 ◽  
Author(s):  
D. R. Buchanan ◽  
J. P. Walters
Keyword(s):  
Molecular Structure ◽  
Glass Transition ◽  
Monomeric Unit ◽  
Sudden Increase ◽  
Transition Temperatures ◽  
Scanning Calorimetry ◽  
Glass Transition Temperatures ◽  
Color Yield ◽  
Polyamide Fiber ◽  
Water Saturated

The glass-transition temperatures (Tg) of thirty-one polyamide homopolymers and copolymers of widely differing molecular structure have been determined by differential scanning calorimetry or, as fibers, by dynamic tensile property measurements, and the results have been related to molecular structure. The effect of water on Tg has been determined, and it is shown that the extent to which saturation with water lowers Tg of a dry polyamide fiber depends only on the average spacing of amide groups in the monomeric unit. From the value of Tg for the water-saturated fiber, the dyebath temperature at which a sudden increase in color yield occurs can be predicted for one disperse-dye system. Finally a procedure is outlined that allows the calculation of each of the above quantities with a precision that averages about 7°C, from a knowledge of the structure of the polyamide monomeric unit.

Thermal Characterization of a Microlayered Polycarbonate/Polymethyl Methacrylate Composite

1996 ◽  
Vol 461 ◽  
Author(s):  
Alex J. Hsieh ◽  
Alex W. Gutierrez
Keyword(s):  
Glass Transition ◽  
Polymethyl Methacrylate ◽  
High Speed ◽  
Thermal Characterization ◽  
Mechanical Analysis ◽  
Transition Temperatures ◽  
Scanning Calorimetry ◽  
Glass Transition Temperatures ◽  
High Speed Impact ◽  
The Individual

ABSTRACTThermal behavior of a coextruded microlayer composite with 388 alternating layers of polycarbonate and polymethyl methacrylate (PMMA) was investigated using differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). Two distinct glass transition temperatures were observed with DSC for the coextruded composite, however both were shifted very slightly towards each other, compared to the glass transition temperatures of the pure components, indicating limited miscibility. Adhesion between the alternating microlayers appeared to be very good; delamination did not occur after the microlayer composite was subjected to a high speed impact test. Adhesion is attributed to limited miscibility since little mixing resulted from the laminar flow which was required in the coextrusion process. DMA results revealed an additional damping peak, which was not observed with DSC, at a temperature between the glass transitions of the two components. This intermediate transition peak is more sensitive to change in frequency compared to the response for the individual pure components.

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