Tuning the self-healing behavior of one-component intrinsic polymers

Kötteritzsch, Julia; Hager, Martin D.; Schubert, Ulrich S.

doi:10.1016/j.polymer.2015.03.027

Cited by 38 publications

(33 citation statements)

References 39 publications

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“…Temperature of the rDA reaction leading to the appearance of the endo adduct is typically lower than that of the exo adduct [5,6]. Due to the thermal reversibility of DA reactions, they are frequently applied in the production of remendable and recyclable materials [7][8][9][10]. 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.…”

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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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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“…[2] In extrinsic self-healing polymers, monomersa re stored in capsules or vascular networks embedded in ap olymer matrix. Molecular interactions and reactions utilized for the crosslinking process in intrinsic self-healing polymers [2,6] include but are not limited to hydrogen bonds, [7] metal-ligand interactions, [8] halogen bonds, [9] Diels-Alder reactions [10,11] as well as thiol-ener eactions. The monomers are polymerized by catalysts embedded in the polymer matrix and, thus, close scratches and cracks.…”

Section: Introductionmentioning

confidence: 99%

Do You Get What You See? Understanding Molecular Self‐Healing

Geitner

Legesse

Kuhl

et al. 2018

Chemistry A European J

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The self-healing ability of self-healing materials is often analyzed using morphologic microscopy images. Here it was possible to show that morphologic information alone is not sufficient to judge the status of a self-healing process and molecular information is required as well. When comparing molecular coherent anti-Stokes Raman scattering (CARS) and morphological laser reflection images during a standard scratch healing test of an intrinsic self-healing polymer network, it was found that the morphologic closing of the scratch and the molecular crosslinking of the material do not take place simultaneously. This important observation can be explained by the fact that the self-healing process of the thiol-ene based polymer network is limited by the mobility of alkene-containing compounds, which can only be monitored by molecular CARS microscopy and not by standard morphological imaging. Additionally, the recorded CARS images indicate a mechanochemical activation of the self-healing material by the scratching/damaging process, which leads to an enhanced self-healing behavior in the vicinity of the scratch.

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“…During the healing process, the flow and flexibility of the linear polymer necessary for a smooth and homogeneous damage repair of a surface coating is tremendously enhanced in case of polymers with low T g . Whereas short, side‐chained polymers such as poly(methyl methacrylate) with a high glass transition temperature preclude homogeneous film formation properties and thus the flow of the material, the introduction of dodecyl side chains in the polymer backbone such as in PLMA results in T g < −60 °C . On the contrary, the implementation of comonomers for introducing functionalities in the side chains increases the T g .…”

Section: Introductionmentioning

confidence: 99%

“…Whereas short, side‐chained polymers such as poly(methyl methacrylate) with a high glass transition temperature preclude homogeneous film formation properties and thus the flow of the material, the introduction of dodecyl side chains in the polymer backbone such as in PLMA results in T g < −60 °C . On the contrary, the implementation of comonomers for introducing functionalities in the side chains increases the T g . Hence, enhancing the flexibility of the linker units is one obvious possibility for lowering the T g and thus improving the flow of the material .…”

Section: Introductionmentioning

confidence: 99%

Lowering the Healing Temperature of Photoswitchable Dynamic Covalent Polymer Networks

Fuhrmann

Broi

Hecht

2017

Macromol. Rapid Commun.

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of the Diels-Alder reaction [17] of a tetra-furylsubstituted molecular crosslinker and the maleimide side chains of a linear poly(lauryl methacrylate) (PLMA) backbone. This combination allowed for formation of a robust yet highly reversible network. Thermally induced healing, however, requires heating above 120 °C-a main drawback of Diels-Alder type decrosslinking-and thus running the risk of degradation of the material at the expense of thermal integrity. To overcome this problem, decreasing the activation barrier for the retro Diels-Alder decrosslinking reaction and thus lowering the healing temperature are highly desirable.Advances reported in the literature have shown that the structure of the crosslinker, including the valency, i.e., number of crosslinking functionality per crosslinker, strongly influences the flexibility of polymer networks, and thus the mechanical properties and healing ability of a polymer film. [18][19][20][21] In our previous work, [13] we chose a tetrafunctional motif X 4 ( Figure 1a,b) inspired by Wudl and co-workers [10] to warrant sufficient crosslinking. Moreover, healing temperatures of polymer networks are remarkably connected to the glass transition temperature (T g ) of the decrosslinked, linear polymethacrylate. Thus, a low T g of the starting material is the most important precondition for the mechanical properties of the resulting polymer film. During the healing process, the flow and flexibility of the linear polymer necessary for a smooth and homogeneous damage repair of a surface coating is tremendously enhanced in case of polymers with low T g . Whereas short, side-chained polymers such as poly(methyl methacrylate) with a high glass transition temperature preclude homogeneous film formation properties and thus the flow of the material, the introduction of dodecyl side chains in the polymer backbone such as in PLMA results in T g < −60 °C. [22][23][24] On the contrary, the implementation of comonomers for introducing functionalities in the side chains increases the T g . [13,24,25] Hence, enhancing the flexibility of the linker units is one obvious possibility for lowering the T g and thus improving the flow of the material. [24,[26][27][28] Furthermore, it is well-known for small molecular systems that polar surroundings lower the barrier for the retro Diels-Alder reaction. [29][30][31] Therefore, the introduction of polar comonomers, for example methacrylates bearing (oligo)ethylene glycol side chains, could in principle also influence the healing temperature. [24,26,32,33] Herein, we describe a new set of bis-furyl-substituted diarylethene-type crosslinkers (X 2,2 and X 2,6 , Figure 1a,b) in combination with previously reported copolymer P(LMA-co-MIMA1) Smart MaterialsTo reduce the environmental footprint of the modern society, it is desirable to elongate the lifetime of consumer products, for example by implementing healable coatings and protective layers. However, since most healing processes carried out by heat or light suffer from material degradation, improving t...

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Tuning the self-healing behavior of one-component intrinsic polymers

Cited by 38 publications

References 39 publications

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

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

Do You Get What You See? Understanding Molecular Self‐Healing

Lowering the Healing Temperature of Photoswitchable Dynamic Covalent Polymer Networks

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