Self-Healing Epoxy Composites – Part I: Curing Kinetics and Heat-Resistant Performance

2013 ◽  
Vol 716 ◽  
pp. 383-386 ◽  
Author(s):  
Tao Yin ◽  
Min Zhi Rong ◽  
Ming Qiu Zhang
Keyword(s):  
Deformation Temperature ◽  
Urea Formaldehyde ◽  
Curing Kinetics ◽  
Epoxy Composites ◽  
Self Healing ◽  
Curing Process ◽  
Heat Resistant ◽  
Two Component ◽  
Healing Agent ◽  
Heat Deformation

This paper reports a study of self-healing epoxy composites. The healing agent was a two-component one synthesized in the authors laboratory, which consisted of epoxy-loaded urea-formaldehyde microcapsules as the polymerizable binder and CuBr2(2-MeIm)4 (the complex of CuBr2 and 2-methylimidazole) as the latent hardener. Both the microcapsules and the matching catalyst were pre-embedded and pre-dissolved in the composites matrix cured by 2-ethyl-4-methylimidazole (2E4MIm), respectively. The data of curing kinetics show that the latent hardener CuBr2(2-MeIm)4 is not affected during the curing process of 2 h at 80°C, 2 h at 120°C and 2 h at 140°C, and heat deformation temperature of composites consisting of 2 wt% CuBr2(2-MeIm)4 and 5 wt% mcirocapsules cured at the same curing process is 180.2°C.

Self-Healing of Cracks in Epoxy Composites

2008 ◽  
Vol 47-50 ◽  
pp. 282-285 ◽  
Author(s):  
Tao Yin ◽  
Min Zhi Rong ◽  
Ming Qiu Zhang
Keyword(s):  
Urea Formaldehyde ◽  
Epoxy Composites ◽  
Glass Fabric ◽  
Self Healing ◽  
Plain Weave ◽  
Composites Manufacturing ◽  
Healing System ◽  
Two Component ◽  
The Matrix

To provide epoxy based composites with self-healing ability, two-component healing system consisting of urea-formaldehyde walled microcapsules containing epoxy (30~70µm in diameter) and CuBr2(2-MeIm)4 (the complex of CuBr2 and 2-methylimidazole) latent hardener was synthesized. When cracks were initiated or propagated in the composites, the neighbor micro-encapsulated epoxy would be damaged and released. As the latent hardener is soluble in epoxy, it can be well dispersed in epoxy composites during composites manufacturing, and hence activate the released epoxy wherever it is. As a result, repair of the cracked sites is completed through curing of the released epoxy. The present work indicated that the plain weave glass fabric laminates using the above self-healing epoxy as the matrix have been provided with self-healing capability.

Self-Healing Epoxy Composites – Part II: Healing Performance

2013 ◽  
Vol 716 ◽  
pp. 387-390
Author(s):  
Tao Yin ◽  
Min Zhi Rong ◽  
Ming Qiu Zhang
Keyword(s):  
Fracture Toughness ◽  
Epoxy Composites ◽  
Repair System ◽  
Self Healing ◽  
Single Edge ◽  
Healing Efficiency ◽  
Two Component ◽  
Before And After ◽  
Healing Agent

Epoxy composites were provided with healing capability by pre-dispersing a novel repair system in the composites matrix cured by 2-ethyl-4-methylimidazole (2E4MIm). The healing agent consisted of ureaformaldehyde microcapsules containing epoxy and latent hardener CuBr2(2-MeIm)4 (the complex of CuBr2 and 2-methylimidazole). Single-edge notched bending (SENB) test were conducted to evaluate fracture toughness of the composites before and after healing. Moreover, healing efficiency was studied as a function of the content of the two-component healing agents. It was found that a healing efficiency of 173% relative to the fracture toughness of virgin composites was obtained in the case of 15 wt% epoxy-loaded microcapsules and 3 wt% CuBr2(2-MeIm)4.

Study on the Curing Kinetics of Epoxy Resin in Self-Healing Microcapsules with Different Shell Material

2011 ◽  
Vol 306-307 ◽  
pp. 658-662 ◽  
Author(s):  
Xiao Mei Tong ◽  
Min Zhang ◽  
Ming Zheng Yang
Keyword(s):  
Epoxy Resin ◽  
Urea Formaldehyde ◽  
Curing Kinetics ◽  
Core Material ◽  
Self Healing ◽  
Curing Process ◽  
Shell Material ◽  
Decomposition Products ◽  
The Stability ◽  
Kinetics Of

The curing process of self-healing microcapsules containing epoxy resin was studied with different shell material such as Poly (urea-formaldehyde), poly (melamine-urea-formaldehyde), Poly (urea-formaldehyde) modified by polyvinyl alcohol, and Poly (urea-formaldehyde) modified by phenol, respectively. The activation energy (ΔE) and the reaction order (n) have been obtained based on Kissinger method, Crane theory and Arrhenius equation. The results showed that: the curing process of epoxy resin as core material in self-healing microcapsules becomes more difficult compared with non-microencapsulated. The stability of shell material impacts on the cure process of core material. The resulting decomposition products of shell materials may participate in the curing reaction. So choosing suitable shell material is particularly important to self-healing microcapsules.

Self-healing of low-velocity impact damage in glass fabric/epoxy composites using an epoxy–mercaptan healing agent

2010 ◽  
Vol 20 (1) ◽  
pp. 015024 ◽  
Author(s):  
Yan Chao Yuan ◽  
Yueping Ye ◽  
Min Zhi Rong ◽  
Haibin Chen ◽  
Jingshen Wu ◽  
...  
Keyword(s):  
Impact Damage ◽  
Epoxy Composites ◽  
Low Velocity Impact ◽  
Glass Fabric ◽  
Self Healing ◽  
Low Velocity ◽  
Velocity Impact ◽  
Healing Agent

Preparation and Performance of Self-Healing Epoxy Composites by Microcapsulated Approach

2014 ◽  
Vol 636 ◽  
pp. 73-77 ◽  
Author(s):  
Xin Hua Yuan ◽  
Qiu Su ◽  
Li Yin Han ◽  
Qian Zhang ◽  
Yan Qiu Chen ◽  
...  
Keyword(s):  
Impact Strength ◽  
Epoxy Matrix ◽  
The Self ◽  
Epoxy Composites ◽  
Fracture Plane ◽  
Crack Plane ◽  
Curing Agent ◽  
Self Healing ◽  
Healing Agent ◽  
The Impact

Microencapsulated E-51 epoxy resin healing agent and phthalic anhydride latent curing agent were incorporated into E-44 epoxy matrix to prepare self-healing epoxy composites. When cracks were initiated or propagated in the composites, the microcapsules would be damaged and the healing agent released. As a result, the crack plane was healed through curing reaction of the released epoxy latent curing agent. In the paper, PUF/E-51 microcapsules were prepared by in-situ polymerization. The mechanical properties of the epoxy composites filled with the self-healing system were evaluated. The impact strength and self-healing efficiency of the composites are measured using a Charpy Impact Tester. Both the virgin and healed impact strength depends strongly on the concentration of microcapsules added into the epoxy matrix. Fracture of the neat epoxy is brittle, exhibiting a mirror fracture surface. Addition of PUF/E-51 microcapsules decreases the impact strength and induces a change in the fracture plane morphology to hackle markings. In the case of 8.0 wt% microcapsules and 3.0 wt% latent hardener, the self-healing epoxy exhibited 81.5% recovery of its original fracture toughness.

scholarly journals Self-Healing Performance of Multifunctional Polymeric Smart Coatings

Polymers ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1519 ◽  
Author(s):  
Sehrish Habib ◽  
Adnan Khan ◽  
Muddasir Nawaz ◽  
Mostafa Sliem ◽  
Rana Shakoor ◽  
...  
Keyword(s):  
Electrochemical Impedance ◽  
Linseed Oil ◽  
Steel Substrate ◽  
Urea Formaldehyde ◽  
Nanocomposite Coatings ◽  
Self Healing ◽  
Ph Change ◽  
Polymeric Nanocomposite ◽  
Smart Coatings ◽  
Healing Agent

Multifunctional nanocomposite coatings were synthesized by reinforcing a polymeric matrix with halloysite nanotubes (HNTs) loaded with corrosion inhibitor (NaNO3) and urea formaldehyde microcapsules (UFMCs) encapsulated with a self-healing agent (linseed oil (LO)). The developed polymeric nanocomposite coatings were applied on the polished mild steel substrate using the doctor’s blade technique. The structural (FTIR, XPS) and thermogravimetric (TGA) analyses reveal the loading of HNTs with NaNO3 and encapsulation of UFMCs with linseed oil. It was observed that self-release of the inhibitor from HNTs in response to pH change was a time dependent process. Nanocomposite coatings demonstrate decent self-healing effects in response to the external controlled mechanical damage. Electrochemical impedance spectroscopic analysis (EIS) indicates promising anticorrosive performance of novel nanocomposite coatings. Observed corrosion resistance of the developed smart coatings may be attributed to the efficient release of inhibitor and self-healing agent in response to the external stimuli. Polymeric nanocomposite coatings modified with multifunctional species may offer suitable corrosion protection of steel in the oil and gas industry.

scholarly journals A Novel Self-Healing Epoxy System with Microencapsulated Epoxy and Imidazole Curing Agent

2007 ◽  
Vol 16 (5) ◽  
pp. 096369350701600 ◽  
Author(s):  
Min Zhi Rong ◽  
Ming Qiu Zhang ◽  
Wei Zhang
Keyword(s):  
Urea Formaldehyde ◽  
Weight Ratio ◽  
The Self ◽  
Wall Material ◽  
Self Healing ◽  
Epoxy System ◽  
Water Emulsion ◽  
Fracture Toughness Measurement ◽  
Healing Agent ◽  
Oil In Water Emulsion

This work reported a novel epoxy system that can perform a self-repairing operation against cracks at elevated temperature. For this purpose, a two-component healing agent consisting of microencapsulated epoxy and imidazole was pre-embedded into epoxy matrix. The microencapsulated epoxy was self-synthesized in advance using poly(urea-formaldehyde) as the wall material through a two-step polymerization approach in an oil-in-water emulsion. The performance of the self-healing epoxy composite was evaluated by fracture toughness measurement. It was found that the self-healing epoxy containing 20wt.% healing agent received a healing efficiency of 106% at the optimum capsulated imidazole-to-epoxy weight ratio of 0.2.

Characterisation of Dicyclopentadiene Filled Microcapsules for Self-Healing Composite Materials

2015 ◽  
Vol 766-767 ◽  
pp. 3-7 ◽  
Author(s):  
J. Lilly Mercy ◽  
S. Prakash ◽  
Katta Sai Sandeep ◽  
Dasari Sai Praveen
Keyword(s):  
Particle Size ◽  
Composite Materials ◽  
Surface Morphology ◽  
Chemical Constituents ◽  
Urea Formaldehyde ◽  
Agitation Rate ◽  
Self Healing ◽  
Healing Agent ◽  
Different Diameters ◽  
Monomer Form

Self-healing composite materials possess healing agent which fills up the crack when ruptured and heals the crack by becoming a tough polymer when stimulated by a catalyst. Dicyclopentadiene (DCPD) in its monomer form is microencapsulated in the shell of Urea Formaldehyde (UF) under different agitation rates to acquire microcapsules of different diameters. The distribution of particle size, surface morphology and the presence of various chemical constituents in the microcapsules were analysed using optical microscopy, SEM and EDAX respectively. An agitation rate of 300 rpm, yielded capsules of diameters ranging from 800μm to 1700μm and at 900rpm the diameters were less than 300μm. Spherical shaped free flowing microcapsules were obtained through insitu polymerisation of dicyclopentadiene in Urea Formaldehyde.

scholarly journals Dual Monitoring of Cracking and Healing in Self-healing Coatings using Microcapsules Loaded with Two Fluorescent Dyes

2019 ◽  
Author(s):  
Young Kyu Song ◽  
Tae Hee Lee ◽  
Jin Chul Kim ◽  
Kyu Cheol Lee ◽  
Sang Ho Lee ◽  
...  
Keyword(s):  
Solid State ◽  
Fluorescent Dyes ◽  
Urea Formaldehyde ◽  
Uv Curing ◽  
Coating System ◽  
Self Healing ◽  
Matrix Resin ◽  
Healing System ◽  
Fluorescence Color ◽  
Healing Agent

We report the development of an extrinsic self-healing coating system that shows no fluorescence from the intact coating, yellowish fluorescence in cracked regions, and greenish fluorescence in healed regions, thus allowing the separate monitoring of cracking and healing of coatings. This fluorescence monitoring self-healing system consisted of a top coating, an epoxy matrix resin containing mixed dye-loaded in single microcapsule. The dye-loaded microcapsules consisted of a poly(urea-formaldehyde) shell encapsulating a healing agent containing MAT-PDMS and styrene, a photo-initiator and a mixture of two dyes, one that fluoresces only in the solid state (DCM) and a second that fluoresces dramatically increased in the solid than solution state (4-TPAE). A mixture of the healing agent, photo-initiator and the two dyes was yellow due to fluorescence from DCM. On UV curing of this mixture, however, the color changed from yellow to green and the fluorescence intensity increased due to fluorescence from 4-TPAE in the solid state. When a self-healing coating embedded with microcapsules containing the DCM/4-TPAE dye mixture was scratched, the damaged region exhibited a yellowish color that changed to green after healing. Thus, the self-healing system reported here allows the separate monitoring of cracking and healing based on changes in fluorescence color.

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