Model-free kinetic analysis of thermal behavior of urea-formaldehyde microcapsules

Katoueizadeh, Elham; Zebarjad, Seyed Mojtaba; Janghorban, K.; Ghafarinazari, A.

doi:10.1007/s10965-018-1619-y

Cited by 9 publications

(6 citation statements)

References 53 publications

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“…Over the last decades, substantial efforts have been dedicated to endowing synthetic materials with self-healing abilities. One of the approaches is to incorporate a healing agent in the form of capsules or vascular networks into the material matrix. − The damaged part can be healed via the polymerized monomers that are released from the ruptured containers. This approach has high mending efficiency and applies to many polymeric materials, such as elastomers, epoxy resins, and fiber-reinforced composites.…”

Section: Introductionmentioning

confidence: 99%

Eugenol-Derived Molecular Glass: A Promising Biobased Material in the Design of Self-Healing Polymeric Materials

Cai

Yang

et al. 2020

ACS Sustainable Chem. Eng.

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One kind of molecular glass material was prepared via the epoxidation of eugenol and a subsequent thermochemical conversion process. This biobased molecular glass (ET-eugenol) shows high potential in the design of self-healing materials while being incorporated into a polymeric matrix to form a multiphase system. Here, an ET-eugenol/polymerized soybean oil (p-ESO) system with a mass ratio of 1:2 was investigated. Results show that the scratch damage can be healed effectively at a temperature of 90 °C within 15 min or by ultraviolet radiation within seconds. Good dimension stability even at high temperatures can be kept in the whole healing process. A mechanical tensile test shows that compared to the neat p-ESO matrix the incorporation of ETeugenol (weight percent of 33%) led to a 2.7-fold increase in ultimate stress and a healing efficiency up to 88%. Gel permeation chromatography, nuclear magnetic resonance, and gas chromatography−mass spectrometer were carefully conducted to reveal the complex thermochemical reaction during the preparation process of ET-eugenol. Self-healing behaviors were characterized via atomic force microscope and optical images, and the corresponding healing mechanism was discussed from a multiphase structural viewpoint. The work reported here demonstrates the possibility of molecular glass as a promising candidate in the design of selfhealing materials.

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Section: Introductionmentioning

confidence: 99%

Eugenol-Derived Molecular Glass: A Promising Biobased Material in the Design of Self-Healing Polymeric Materials

Cai

Yang

et al. 2020

ACS Sustainable Chem. Eng.

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“…36−38 The characteristic peak at 1020 cm −1 is the vibrational peak of C−O in urea compounds. 39 These characteristic peaks indicate that polymerization has occurred between urea and formaldehyde to produce the UF polymer. In addition, the peaks at 1245 and 1205 cm −1 correspond to the C−F stretching vibration peaks, and the peaks at 1110 and 1080 cm −1 correspond to the Si− O−C stretching vibration peaks.…”

Section: Resultsmentioning

confidence: 99%

In Situ Polymerized Self-Healing Microcapsules as Multifunctional Fillers toward Phosphate Ceramic Coatings

Wang,

Wu,

Huang

et al. 2024

ACS Appl. Mater. Interfaces

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The protective efficacy of chemically bonded phosphate ceramic coatings (CBPC) is notably diminished owing to the presence of micropores and inadequate self-healing capacity in prolonged corrosive environments. Consequently, it is imperative to augment the corrosion and wear resistance of phosphate ceramic coatings while imbuing them with self-healing capabilities. In this work, a novel self-healing phosphate ceramic coating (MC-PT x @CBPC, x = 0.5, 1.0, 1.5) is designed by ureaformaldehyde (UF) in situ polymerization of nanoscale microcapsules encapsulated with 1H,1H,2H,2H-perfluorodecyltriethoxysilane (PFDTES) and evaluated in detail for corrosion and wear resistance. The corrosion inhibition efficiencies of all formulated MC-PT x @CBPC (x = 0.5, 1.0, 1.5) coatings exceed 90%, with the impedance modulus at the lowest frequency (| Z| f=0.01 ) showing enhancements of 1−2 orders of magnitude compared to pure CBPC. Moreover, the self-healing function becomes active during prolonged immersion. This can be primarily ascribed to the formation of a unique micronanostructure facilitated by nanoscale microcapsules and micrometer-sized alumina ceramics, bonded via the AlPO 4 phase. This structure enhances both the hydrophobicity and the bonding strength of the coating. Specifically, following prolonged immersion, the encapsulated PFDTES is liberated from the microcapsules, undergoing hydrolysis and subsequent polymerization upon contact with the electrolyte to form a protective thin film. This film efficiently obstructs the ingress of corrosive agents. Furthermore, the special micronanostructure enhances the hardness of the coating and the releasing PFDTES can form a lubricating film at the interface of abrasion, thus reducing the wear rate and friction coefficient of the MC-PT x @CBPC (x = 0.5, 1.0, 1.5). Therefore, MC-PT x @CBPC (x = 0.5, 1.0, 1.5) possesses excellent corrosion protection, tribological properties, and self-healing capabilities, which provide thought-provoking ideas for phosphate ceramic coatings to protect metals in harsh environments.

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“…The characteristic peak at 3337 cm −1 is assigned to the stretching vibrations of NH and OH, the peak at 1640 cm −1 is assigned to the CO stretching vibration of amide, the peak at 1550 cm −1 is assigned to the NH stretching vibration of the secondary amide, [ 32 ] the peak at 1430 cm −1 is assigned to the CH vibration mode in CH 2 and CH 3 , and the peak at 1020 cm −1 is assigned to the CO stretching of CH 2 OH in mono‐ and dimethylol ureas. [ 33 ] The characteristic peaks of UF shell and FAS can be detected in the FTIR spectrum of FAS microcapsules, which indicates that FAS is successfully encapsulated in the UF shell.…”

Section: Resultsmentioning

confidence: 99%

Self‐healing corrosion‐resistant coatings based on fluorinated alkyl silane microcapsules

Wang

et al. 2022

Polymer Engineering & Sci

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In this study, microcapsules are prepared by in situ polymerization using the repairing agent fluorinated alkyl silane (FAS) as the core material and urea‐formaldehyde as the covering shell. Self‐healing coatings (FEP coatings) with repairing ability in water are prepared by adding FAS microcapsules in an epoxy resin matrix. The morphology, composition, and thermal properties of the microcapsules are studied. In addition, electrochemical impedance spectroscopy is used to study the barrier properties and self‐healing properties of the coating. The results show that FEP coating has good self‐healing ability, with the semiquantitative index of 105 Ω·cm2, which is greater than that of pure epoxy coating (EP coating). This is because that FAS leaked from the microcapsules reacts with water molecules to form a dense water‐insoluble film, which blocks the contact of corrosive ions with the substrate and inhibits the progress of metal corrosion. Moreover, the scratch width and depth results of the FEP coating after self‐healing also confirm the formation of the new film by FAS.

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Model-free kinetic analysis of thermal behavior of urea-formaldehyde microcapsules

Cited by 9 publications

References 53 publications

Eugenol-Derived Molecular Glass: A Promising Biobased Material in the Design of Self-Healing Polymeric Materials

Eugenol-Derived Molecular Glass: A Promising Biobased Material in the Design of Self-Healing Polymeric Materials

In Situ Polymerized Self-Healing Microcapsules as Multifunctional Fillers toward Phosphate Ceramic Coatings

Self‐healing corrosion‐resistant coatings based on fluorinated alkyl silane microcapsules

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