Wear Resistance of Polymers With Encapsulated Epoxy-Amine Self-Healing Chemistry

2015 ◽  
Vol 82 (5) ◽  
Author(s):  
Nay Win Khun ◽  
He Zhang ◽  
Jinglei Yang

In this study, epoxy resin was microencapsulated through in situ polymerization in an oil-in-water emulsion, and amine was loaded into etched glass bubbles (GBs) as a curing agent for the microencapsulated epoxy resin. The purpose was to develop a two-component-self-healing system. The two healing agent carriers were co-incorporated in the epoxy matrix to form novel epoxy composites for tribological applications. The tribological results clearly showed that an increase in healing agent carrier content significantly decreased the friction and wear of the epoxy composites tested against a 6 mm steel ball under different normal loads. This was due to the self-lubricating and self-healing of the composites with released core liquids via the rupture of healing agent carriers during the wear test. It could be concluded that the co-incorporation of two healing agent carriers was a potential way to achieve a significant improvement in the tribological properties of epoxy matrix composites.

2010 ◽  
Vol 148-149 ◽  
pp. 1031-1035
Author(s):  
Yang Zhao ◽  
Wei Zhang ◽  
Le Ping Liao ◽  
Wu Jun Li ◽  
Yi Xin

With the development of the embedded microcapsule concept for self-healing material, the preparation of microcapsule has been paid more attentions. A new series of microcapsules were prepared by in situ polymerization technology in an oil-in-water emulsion with polyoxymethylene urea (PMU) as shell material and a mixture of epoxy resins as core material. The PMU microcapsules were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electronic microscopy (SEM), particle size analyzer and thermo gravimetric analyzer (TGA) to investigate their chemical structure, surface morphology, size distribution and thermal stability, respectively. The results indicate that PMU microcapsules containing epoxy resins can be synthesized successfully. The optimized reaction parameters were obtained as follow: agitation rate 600 rpm, 60°C water bath, pH=3.5, core material 20ml and hot water dilution by in-situ polymerization. The size is around 116 μm. The rough outer surface of microcapsule is composed of agglomerated PMU nanoparticles. The microcapsules basically exhibit good storage stability at room temperature, and they are chemically stable before the heating temperature is up to approximately 200°C.


2014 ◽  
Vol 636 ◽  
pp. 73-77 ◽  
Author(s):  
Xin Hua Yuan ◽  
Qiu Su ◽  
Li Yin Han ◽  
Qian Zhang ◽  
Yan Qiu Chen ◽  
...  

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.


Author(s):  
Patryk A. Bolimowski ◽  
Ian P. Bond ◽  
Duncan F. Wass

Mechanically and thermally robust microcapsules containing diglycidyl ether bisphenol A-based epoxy resin and a high-boiling-point organic solvent were synthesized in high yield using in situ polymerization of urea and formaldehyde in an oil-in-water emulsion. Microcapsules were characterized in terms of their size and size distribution, shell surface morphology and thermal resistance to the curing cycles of commercially used epoxy polymers. The size distribution of the capsules and characteristics such as shell thickness can be controlled by the specific parameters of microencapsulation, including concentrations of reagents, stirrer speed and sonication. Selected microcapsules, and separated core and shell materials, were analysed using thermogravimetric analysis and differential scanning calorimetry. It is demonstrated that capsules lose minimal 2.5 wt% at temperatures no higher than 120°C. These microcapsules can be applied to self-healing carbon fibre composite structural materials, with preliminary results showing promising performance.


2013 ◽  
Vol 800 ◽  
pp. 471-475
Author(s):  
Wang Rui ◽  
Qian Jin Mao ◽  
Qi Dong Liu ◽  
Xiao Yu Ma ◽  
Su Ping Cui ◽  
...  

The self-healing polymer material which was embedded microcapsules possesses the ability to heal cracks automatically. The microcapsules were synthesized by in-situ polymerization in an oil-in-water emulsion with urea and formaldehyde as the raw shell material,and epoxy resin (E-51)/ xylene as the core material. The impact of stirring speed on the morphology and particle size of synthetic microcapsules were discussed by optical microscopy (OM), scanning electron microscopy (SEM), and Fourier-transform infrared spectrometer (FTIR).Microcapsules of 400~1500 um in diameter were produced by appropriate selection of agitation rate in the range of 300~600 r/min.


2007 ◽  
Vol 16 (5) ◽  
pp. 096369350701600 ◽  
Author(s):  
Min Zhi Rong ◽  
Ming Qiu Zhang ◽  
Wei Zhang

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.


2020 ◽  
Vol 32 (6) ◽  
pp. 669-680 ◽  
Author(s):  
Yong Sun ◽  
Shugang Wang ◽  
Xiaosu Dong ◽  
Yuntao Liang ◽  
Wei Lu ◽  
...  

Microcapsules containing isophorone diisocyanate were fabricated in oil-in-water emulsion. The emulsification effect of different emulsifiers during the capsule synthesis was systematically investigated by optical microscope. Three kinds of shell materials were discussed to obtain the high core content, smooth-surfaced, and robust capsule by scanning electronic microscope and Fourier transform infrared spectroscopy. Self-healing performance of corresponding self-healing epoxy composites was fully evaluated by accelerated corrosion test and mechanical test. The results demonstrated that high core content and smooth-surfaced capsules with dense composite shell could be synthesized in polyvinyl alcohol emulsion, and the core content of the optimized capsules was determined as 71.3–84.6 wt% at the capsule size from 35 µm to 154 µm. In addition, the optimized capsules had good processing properties and the corresponding self-healing epoxy composites exhibited excellent core release and self-healing performance.


2012 ◽  
Vol 430-432 ◽  
pp. 960-963 ◽  
Author(s):  
Wan Peng Ma ◽  
Wei Zhang ◽  
Yang Zhao ◽  
Le Ping Liao ◽  
Si Jie Wang

Urea-formaldehyde microcapsules containing epoxy resin is a promising material for self-healing design. The microcapsules were prepared by in-situ polymerization in an oil-in-water emulsion. The microcapsule formation process was monitored using optical microscopy. Surface morphology was observed using field emission scanning electron microscopy. The thermal property of microcapsules was characterized using thermogravimetric analysis. The results indicate that microcapsule wall has a rough outer surface and a smooth inner surface. The microcapsule size is controlled by different agitation rates. Microcapsules have a good thermal stability below 157°C.


2010 ◽  
Vol 20 (1) ◽  
pp. 015024 ◽  
Author(s):  
Yan Chao Yuan ◽  
Yueping Ye ◽  
Min Zhi Rong ◽  
Haibin Chen ◽  
Jingshen Wu ◽  
...  

2014 ◽  
Vol 775-776 ◽  
pp. 284-289 ◽  
Author(s):  
Sergio Neves Monteiro ◽  
Frederico Muylaert Margem ◽  
Wellington Pereira Inácio ◽  
Artur Camposo Pereira ◽  
Michel Picanço Oliveira

The tensile properties of DGEBA/TETA epoxy matrix composites reinforced with different amounts of sisal fibers were evaluated. Composites reinforce with up to 30% in volume of long, continuous and aligned sisal fibers were room temperature tested in an Instron machine. The fracture was analyzed by SEM. The results showed significant changes in the mechanical properties with the amount of sisal fibers. These mechanical properties were compared with other bend-tested composites results. The fracture analysis revealed a weak fiber/matrix interface, which could be responsible for the performance of some properties.


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