Preparation and characterization of poly(urea-formaldehyde) microcapsules filled with epoxy resins

Yuan, Li; Liang, Guozheng; Xie, Jiangjian; Li, Lan; Guo, Jing

doi:10.1016/j.polymer.2006.05.051

Cited by 341 publications

(209 citation statements)

References 38 publications

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“…These microcapsules can be used in the development of polymer self-healing composites for various applications such as aerospace, automotive, marine and building components etc. Currently, urea and melamineformaldehyde are the predominant shell wall materials in the preparation of such microcapsules [1][2][3][4][5][6][7][8][9][10][11][12]. However, the use of both shell wall materials has their own limitations and challenges.…”

Section: Introductionmentioning

confidence: 99%

Parametric study for epoxy loaded PMMA microcapsules using Taguchi and ANOVA methods

Sharma¹,

Choudhary²

2017

Express Polym. Lett.

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Abstract. In this study, we systematically investigated the effect of various process parameters, such as surfactant concentration, core-to-shell ratio taken in the initial feed, temperature and agitation speed on the core content of microcapsules. For this study epoxy loaded poly(methyl methacrylate) microcapsules were prepared by solvent evaporation method. Taguchi orthogonal array with L 25 matrix was implemented to optimize the experimental parameters for such microcapsules. The signal-to-noise ratio (SNR) and analysis of variance (ANOVA) were also performed to determine the optimum parameters and significance of various parameters. Morphological characterization (optical microscopy, scanning electron microscopy and transmission electron microscopy) and particle size analysis (mean particle size and particle size distribution) was done to investigate the effect of various parameters on the prepared microcapsules. SNR analysis identified the optimum levels of various parameters as: surfactant concentration-10 wt%, core-to-shell ratio-3:1, temperature-40°C and agitation speed-300 rpm. ANOVA analysis showed that surfactant concentration was the most significant parameter in improving the core content of such microcapsules. The findings of Taguchi method were also verified with contour plots. Maximum core content obtained under optimum conditions was 63.53 wt% and such microcapsules can find applications for the development of self-healing polymer composites.

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Section: Introductionmentioning

confidence: 99%

Parametric study for epoxy loaded PMMA microcapsules using Taguchi and ANOVA methods

Sharma¹,

Choudhary²

2017

Express Polym. Lett.

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“…The SEM image of Figure 2b was taken from the surface of a microcapsule-loaded epoxy. The surface of microcapsules is rough, and it may be composed of PMF nanoparticles protruding from the surface [15]. The protuberant nanoparticles can increase the surface area of microcapsules and enhance surface adhesion.…”

Section: Ftirmentioning

confidence: 99%

Fracture behaviour of a self-healing microcapsule-loaded epoxy system

Lee¹,

Bhattacharyya²,

Zhang³

et al. 2011

Express Polym. Lett.

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Polymer materials often experience micro-cracks during their service. Self-healing polymeric materials have the built-in capability to substantially recover their load transferring ability after damage. This field of self-healing materials is a relatively new one, beginning in the early 1990s, with the majority of the research occurring in the past decade [1,2]. The ring-opening metathesis polymerization of dicyclopentadiene (DCPD) [3,4], addition and ionic polymerization of epoxy [5], condensation polymerization of polysiloxane [6], organic solvents [7] and isocyanates [8], have been reported for automatically repairing cracks in polymers at room temperature.Several researchers [5,[9][10][11] have successfully measured fatigue-crack propagation in epoxy resins. Brown and coworkers [5,9] investigated the effect of embedded urea-formaldehyde (UF) microcapsules on the monotonic fracture properties of a selfhealing epoxy. In addition to providing an efficient mechanism for self-healing, the presence of liquidfilled microcapsules increased the virgin monotonic-fracture toughness of epoxy by up to 127%. The increased toughening was correlated with a change in the fracture plane morphology from mirror-like to hackle markings with subsurface microcracking. The addition of microcapsules to an epoxy matrix significantly increased the resistance to crack growth under dynamic loading conditions. Abstract. The effect of temperature on the fracture behaviour of a microcapsule-loaded epoxy matrix was investigated. Microencapsulated epoxy and mercaptan-derivative healing agents were incorporated into an epoxy matrix to produce a polymer composite capable of self-healing. Maximum fracture loads were measured using the double-torsion method. Thermal aging at 55 and 110°C for 17 hours [hrs] was applied to heal the pre-cracked samples. The addition of microcapsules appeared to increase significantly the load carrying capacity of the epoxy after healing. Once healed, the composites achieved as much as 93-171% of its virgin maximum fracture load at 18, 55 and 110°C. The fracture behavior of the microcapsule-loaded epoxy matrix was influenced by the healing temperature. The high self-healing efficiency may be attributed to the result of the subsurface micro-crack pinning or deviation, and to a stronger microencapsulated epoxy and mercaptanderivative binder than that of the bulk epoxy. The results show that the healing temperature has a significant effect on recovery of load transferring capability after fracture.

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“…Special polymeric chains that are separated by cracking or scratching can reconnect, building up a physical network by intrinsic (chemical/physical interactions) or extrinsic (healer-loaded tubes, fibres, capsules) repairing effects [1]. Hollow carriers, microcapsules containing polymerizable materials like epoxy resin [2], dicyclopentadiene [3,4], air-drying oil [5] when damaged, break together with the coating, releasing the fluid material. This liquid fills up discontinuities and soon fixes the polymer by initiator, catalyst, latent hardener [3,6] or other reagent, e.g.…”

Section: Introductionmentioning

confidence: 99%

SECM study of steel corrosion under scratched microencapsulated epoxy resin

Pilbáth

Szabó

Telegdi

et al. 2012

Progress in Organic Coatings

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Scratch tests were performed on epoxy coated steel samples with and without microcapsulated linseed oil, known to develop a polymerized protective layer after having been released from the capsules at the damaged sites. The scanning electrochemical microscope has been applied to monitor the protection efficiency of this self-healing coating in aqueous acidic solution. In the proximity of the local damage, both the anodic metal dissolution and the cathodic oxygen reduction showed that the coating with microcapsules substantially and spontaneously decreased the rate of corrosion proving the self-repair concept of the coating. Electrochemical impedance measurements underline the protective effect of the coating as well.

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Preparation and characterization of poly(urea-formaldehyde) microcapsules filled with epoxy resins

Cited by 341 publications

References 38 publications

Parametric study for epoxy loaded PMMA microcapsules using Taguchi and ANOVA methods

Parametric study for epoxy loaded PMMA microcapsules using Taguchi and ANOVA methods

Fracture behaviour of a self-healing microcapsule-loaded epoxy system

SECM study of steel corrosion under scratched microencapsulated epoxy resin

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