Structural aspects of high temperature thermosets – Bismaleimide/propargyl terminated resin system-polymerization and degradation studies

Vinayagamoorthi, S.; Vijayakumar, Chinnaswamy Thangavel; Alam, Sarfaraz; Nanjundan, S.

doi:10.1016/j.eurpolymj.2008.12.026

Cited by 39 publications

(41 citation statements)

References 34 publications

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“…In the thermopolymerization of propargyl ether and BMI, partial propargyl ether was initially subjected to chromene rearrangement and Claisen rearrangement (A); subsequently, copolymerization and autopolymerization occurred between the double bonds from the chromenes and/or maleimide rings of BMI (B), and then a simultaneous Diels-Alder reaction took place between the acetylenic bonds of propargyl ether and the double bonds of maleimide rings (C). 30,33,34 Figure 8 displays the infrared spectra of the cured modified BMI resins. After curing, the absorption peak at 1149 cm À1 assigned to C-N-C groups shifted to 1180 cm À1 and broadened, with the peak intensity increasing.…”

Section: Rheological Behavior Of Modified Bmi Resinsmentioning

confidence: 99%

Preparation and properties of bismaleimide resins modified with hydrogen silsesquioxane and dipropargyl ether and their composites

Huang

2010

Polym J

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A new type of modified bismaleimide (BMI) resins with good heat resistance and processing properties for advanced composites was developed. Modifiers hydrogen silsesquioxane (HSQ), dipropargyl ethers of bisphenol A, hexafluorobisphenol A, 4,4¢-dihydroxydiphenyl ether and resorcinol were used to modify 4,4¢-bismaleimidodiphenylmethane. The structure of the resins was verified by Fourier transform infrared spectrometry. The relationship between viscosity and temperature was used to characterize the processability of the resins. The curing behaviors of resins were investigated by a differential scanning calorimeter. The glass transition temperatures and thermal stabilities of cured resins were investigated by dynamic mechanical analysis and thermogravimetric analysis, respectively. The relationship between structures and properties of the resins was discussed, and the mechanical properties of the glass-fiber-fabric-reinforced composites were measured.

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Section: Rheological Behavior Of Modified Bmi Resinsmentioning

confidence: 99%

Preparation and properties of bismaleimide resins modified with hydrogen silsesquioxane and dipropargyl ether and their composites

Huang

2010

Polym J

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“…Equation (2) is the basis of the differential method proposed by Friedman [46]. This method requires differentiation of the curve a versus T. However, this procedure usually produces a great degree of scatter in the results for E a .…”

Section: Isoconversional Methodsmentioning

confidence: 99%

“…5, all these thermal events were shifted to higher temperatures when the heating rate was increased from 10 to 25 K min -1 . The integral methods developed by KAS [49] and OFW [47,48] and the differential method of Friedman [46] were used to determine the activation energies associated with each thermal event (A, B, C, and D) observed during ettringite dehydration. Figure 6 shows the profile of activation energy values found for each such event and indicates that the apparent activation energies vary considerably with the extent of conversion (between 45 and 65 kJ mol -1 for event A and between 55 and 65 kJ mol -1 for event B, Fig.…”

Section: (C)mentioning

confidence: 99%

“…This task was accomplished by applying the isoconversional equations of Friedman [46], OFW [47,48], and KAS [49]. The extent of conversion was determined through Eq.…”

Section: Thermal Analysismentioning

confidence: 99%

“…Therefore, the first aim of the present work is to characterize the ettringite decomposition products by applying the techniques of X-ray diffraction (XRD), infrared (IR) spectroscopy, thermogravimetry (TG/DTA), and scanning electron microscopy (SEM). The second and principal aim is to determine the activation energy for each step of the thermal decomposition of a synthetic ettringite sample using the isoconversional methods of Friedman [46], Ozawa-Flynn-Wall (OFW) [47,48], and Kissinger-Akahira-Sunose (KAS) [49]. Such a comprehensive approach has not been described so far.…”

Section: Introductionmentioning

confidence: 99%

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Kinetic and thermal decomposition of ettringite synthesized from aqueous solutions

Guimarães

Oliveira

Leão

2016

J Therm Anal Calorim

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The kinetics of the thermal decomposition of a synthetic ettringite sample was studied between 298 and 820 K in an inert atmosphere for the present work. The ettringite and its thermal decomposition products were characterized using X-ray diffraction, infrared spectroscopy, and scanning electron microscopy. Four endothermic events were observed with thermogravimetry curves, the maxima of which occurred at 366, 397, 537, and 641 K. All events were associated with the loss of water molecules with different degrees of interaction within the ettringite structure. Chemical equations for each decomposition step were proposed based on the percentages of mass loss observed. In addition, for the first time, the activation energies of each ettringite decomposition events were determined by the isoconversional methods of Ozawa-Flynn-Wall, Friedman, and Kissinger-AkahiraSunose. The modeling revealed that the activation energy varied from *50 kJ mol -1 , characteristic of mass transfer control steps, to *150 kJ mol -1 , which is typical of chemical control, as the temperature increased and the ettringite structure lost water. A total of 32 mol of water was released equivalent to 43.1 % of the initial sample mass.

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A Tailorable Family of Elastomeric‐to‐Rigid, 3D Printable, Interbonding Polymer Networks

Zhou

Gardea

Sang

et al. 2020

Adv Funct Materials

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Soft materials with widely tailorable mechanical properties throughout the material's volume can shape the future of soft robotics and wearable electronics, impacting both consumer and defense sectors. Herein, a platform of 3D printable soft polymer networks with unprecedented tunability of stiffness of nearly three orders of magnitude (MPa to GPa) and an inherent capability to interbond is reported. The materials are based on dynamic covalent polymer networks with variable density of crosslinkers attached to prepolymer backbones via a temperature‐reversible Diels–Alder (DA) reaction. Inherent flexibility of the prepolymer chains and controllable crosslinking density enable 3D printed networks with glass transition temperatures ranging from just a few degrees to several tens of degrees Celsius. Materials with an elastomeric network demonstrate a fast and spontaneous self‐healing behavior at room temperature both in air and under water—a behavior difficult to achieve with other crosslinked materials. Reversible dissociation of DA networks at temperatures exceeding ≈120 °C allows for reprintability, while control of the stereochemistry of DA attachments enables reprogrammable shape memory behavior. The introduced platform addresses current major challenges including control of polymer interbonding, enhanced mechanical performance of printed parts, and reprocessability of 3D‐printed crosslinked materials in the absence of solvent.

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Structural aspects of high temperature thermosets – Bismaleimide/propargyl terminated resin system-polymerization and degradation studies

Cited by 39 publications

References 34 publications

Preparation and properties of bismaleimide resins modified with hydrogen silsesquioxane and dipropargyl ether and their composites

Preparation and properties of bismaleimide resins modified with hydrogen silsesquioxane and dipropargyl ether and their composites

Kinetic and thermal decomposition of ettringite synthesized from aqueous solutions

A Tailorable Family of Elastomeric‐to‐Rigid, 3D Printable, Interbonding Polymer Networks

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