Synthesis of a Self-Healing Polymer Based on Reversible Diels–Alder Reaction: An Advanced Undergraduate Laboratory at the Interface of Organic Chemistry and Materials Science

Thermally reversible cross-links in a healable polymer: Estimating the quantity, rate of formation, and effect on viscosity The conversion behavior of 2MEP4FS, a polymer with thermally reversible Diels-Alder crosslinks, is modeled. A processing method is developed to create small, homogeneous prepolymer samples. The glass transition temperature of the prepolymer is estimated using temperature modulated differential scanning calorimetry and equated with the conversion of the polymer.Comparing the measured energy with the literature and computational estimates, the fully cured polymer appears to have a large portion of its moieties unreacted. An autocatalytic model is considered to approximate the reaction rate of 2MEP4FS as a function of conversion and temperature. Outside of the fitted temperature range, the model underpredicts the reaction rates at room temperature and 100 °C. Manual mixing of the monomers is determined to be inadequate to obtain a maximum level of cross-linking. Viscosity measurements made at room temperature and elevated temperatures are correlated with the conversion of the prepolymer.

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“…1) were synthesized according to established procedures [7,16]. At room temperature, 2MEP is a solid powder, while 4FS is a viscous liquid.…”

Section: Materials Synthesismentioning

confidence: 99%

Thermally reversible cross-links in a healable polymer: Estimating the quantity, rate of formation, and effect on viscosity

Nielsen

Weizman

Nemat‐Nasser

2014

Polymer

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“…During the development of self-healing material much attention is often given to the understanding the mechanistic perspective of a given reaction as much as possible. Such studies are frequently accompanied by kinetic investigations of the reaction [11][12][13][14][15][16]. Benzoxazines, because of their unique characteristics, are recently gaining much attention in polymer synthesis and design.…”

Section: Introductionmentioning

confidence: 99%

Characterization and kinetic study of Diels-Alder reaction: Detailed study on N-phenylmaleimide and furan based benzoxazine with potential self-healing application

Štirn¹,

Ručigaj²,

Krajnc³

2016

Express Polym. Lett.

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Abstract. The Diels-Alder reaction between N-phenylmaleimide and benzoxazine bearing furan group was investigated for the purpose of successful appliance of self-healing in benzoxazine polymer networks. The reaction as a function of temperature/time was performed in molten state and in a solution, where also the kinetic study was performed. The Diels-Alder reaction leads to a mixture of two diastereomers: endo presented at lower cyclo-reversion temperature and exo at higher. Therefore, the conversion rates and exo/endo ratio were studied in detail for both systems. For instance, in molten state the Diels-Alder reaction was triggered by the temperature of the melting point at 60°C with exo/endo ratio preferable to the endo adduct. The study of the kinetics in a solution revealed that the Diels-Alder reaction followed typical bimolecular reversible second-order reaction. The activation energies were close to the previous literature data; 48.4 and 51.9 kJ·mol -1 for Diels-Alder reaction, and 91.0 and 102.3 kJ·mol -1 for retro-Diels-Alder reaction, in acetonitrile and chloroform, respectively. The reaction equilibrium in a solution is much more affected by the retro-Diels-Alder reaction than in a molten state. This study shows detailed investigation of DA reaction and provides beneficial knowledge for further use in self-healing polymer networks.

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“…This method allows small quantities of polymer to be produced with precise monomer ratios and minimal wasted material. The bismaleimide and tetrafuran monomers had been previously synthesized according to standard procedures (Chen et al, 2002;Weizman et al, 2011). For each composite sample, two prepolymer batches were prepared in parallel to increase the quantity of prepolymer.…”

Section: Sample Preparationmentioning

confidence: 99%

Crack healing in cross-ply composites observed by dynamic mechanical analysis

Nielsen

Nemat‐Nasser

2015

Journal of the Mechanics and Physics of Solids

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Cross-ply composites with healable polymer matrices are characterized using dynamic mechanical analysis (DMA). The [90,0] s samples are prepared by embedding layers of unidirectional glass or carbon fibers in 2MEP4FS, a polymer with thermally reversible covalent cross-links previously shown to be capable of healing internal cracks and fully recovering fracture toughness under ideal conditions. After fabrication, cracks in the composites' transverse plies are observed and attributed to residual thermal stresses introduced during processing.Single cantilever bending DMA measurements show the samples exhibit periods of increasing storage moduli with increasing temperature. These results are accurately modeling using simple one-dimensional composite and beam analyses. The effect of cracks on the measured stiffness is considered using a shear lag model, and the predicted crack density of the glass fiber composite falls within a range estimated by microscopy observations. Crack healing is assumed to occur as a function of temperature, and rationales for the onset and conclusion of healing are given.

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Synthesis of a Self-Healing Polymer Based on Reversible Diels–Alder Reaction: An Advanced Undergraduate Laboratory at the Interface of Organic Chemistry and Materials Science

Cited by 41 publications

References 5 publications

Thermally reversible cross-links in a healable polymer: Estimating the quantity, rate of formation, and effect on viscosity

Thermally reversible cross-links in a healable polymer: Estimating the quantity, rate of formation, and effect on viscosity

Characterization and kinetic study of Diels-Alder reaction: Detailed study on N-phenylmaleimide and furan based benzoxazine with potential self-healing application

Crack healing in cross-ply composites observed by dynamic mechanical analysis

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