• Proceedings of the Korean Society For Composite Materials Conference
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• 2002.05a
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• pp.65-68
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• 2002

This study dealt with autonomic microcapsules with the healing agent for damage repair of the composite structures. Autonomic microcapsules were made of a urea-formaldehyde resin for shell of microcapsule and a DCPD for the healing agent. Thermal analysis was conducted by using a DSC and a TGA for the healing agent, microcapsules without the healing agent, and microcapsules with the healing agent. According to the results, autonomic microcapsules were verified to be so thermally stable that the healing agent was kept inside the microcapsule until the shell of microcapsules were burned out.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.04a
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• pp.169-172
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• 2003

Manufacturing process for autonomic microcapsules was introduced and autonomic microcapsules were manufactured by varying with various manufacturing process variables. Urea-formaldehyde resin was used for the wall of microcapsules and DCPD (dicyclopentadiene) was used for the self-healing agent. The characteristics of these microcapsules was evaluated through a particle size analyaer, an optical microscope, and a TGA. The various manufacturing process variables, such as pH and agitation speed of the emulsified solution, were considered to focus in this study. According to the results, the particle size distributions were affected on the agitation speed of the emulsified solution, and the thermal stability was influenced by pH of the emulsified solution.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.508-511
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• 2004

This study focused on the effect of autonomic microcapsules on the mechanical properties of structural material. Several types of microcapsules with healing agents were manufactured by varying agitation speed of high speed stirrer. The size distribution of microcapsules was measured by a particle size analzer. The epoxy specimens embedded with microcapsules were manufactured and the degree of cure of such epoxy specimen was measured by a differential scanning calorimetry. The tensile modulus and tensile strength in epoxy specimens embedded with microcapsules were evaluated in order to investigate the effects of microcapsules on mechanical properties of structural materials. The configuration of microcapsules and morphology of fracture surfaces for the epoxy specimen were examined by an optical microcope and a scanning electron microscope. According to the results, tensile strength of the epoxy specimen embedded with microcapsules was indicated a little reduction, but tensile modulus was not much affected on microcapsules.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.3
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• pp.51-59
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• 2006

The physical characteristics of autonomic microcapsules manufactured with various agitation speeds in a stirred tank were observed experimentally by a particle size analyzer and an optical microscope. The flow characteristics in a stirred tank were also investigated through a 3-dimensional numerical simulation to understand the manufacturing process of autonomic microcapsules. According to the results, we found that the agitation speed was the important factor to determine the sizes of microcapsules. The impeller-induced flow allowed the jet and tip-vortex pair components in the mixed fluid of a stirred tank. The vorticity around the blades in the impeller was increased as increasing the agitation speed. In addition, the size of autonomic microcapsules was strongly affected on the small scale mixing pattern such as a tip-vortex pair.

• Composites Research
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• v.15 no.2
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• pp.32-39
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• 2002

This study focused on the introduction of processing procedure for microcapsules loaded with the healing agent and then microcapsules with the healing agent were manufactured by experiments. The DCPD (dicyclopentadiene) was used for the healing agent and the shell of microcapsules was consisted of urea-formaldehyde resin. The magnitude and the site distribution of microcapsules were measured by a particle size analyzer using laser diffraction technique. Thermal analysis was conducted by using a DSC fur the healing agent, microcapsules without the healing agent, and microcapsules with the healing agent. Also thermal stability was investigated by using a TGA under continuous and isothermal heating conditions far the healing agent, microcapsules without the healing agent, microcapsules with the healing agent. According to the results. microcapsules with the healing agent were verified to be so thermally stable that the healing agent could not evaporate until the shell of microcapsules were burned.

• Science of Emotion and Sensibility
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• v.18 no.2
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• pp.19-30
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• 2015

The healing effect of the aroma treated fabrics with lavender and lemon aromas was investigated by assessing the autonomic nervous responses of human body. For this cause Lemon and lavender microcapsules were coated on a cotton fabric using a water-based acrylic binder, respectively. And the study created a total of four aroma treated fabrics at a concentration of 2% and 5% respectively. Electrocardiogram(ECG), skin conductance, and Blood flow, of ten participants were measured for 30 sec at a stable condition, at a stress status (working memory task), and at a stimulation status (after rubbing aroma treated fabrics). Subjective sensibilities of the aromas were also evaluated. With regard to the responses of the autonomic nervous system, in order to understand how the values gained after the normalization process would cause different physiological signals between the stable state and the aroma-stimulated state as well as between the stress state and the aroma-stimulated state, the study conducted a non-parametric test, friedman test as well and analyzed tendencies. LF/HF turned out to be significantly different to the stress state, and according to the results of the post-hoc comparison, lemon 5% presented statistically significant differences among the lavender 2%, lavender5%, lemon2%. Lemon 5% stimuli increased stress but stimuli consisting of the lavender 2%, the lavender 5% and the lemon 2% decreased stress because of a psychological rest. And the stimuli of the lavender 2%, the lavender 5%, the lemon 2% presented a healing effect in this research.