• Polymer(Korea)
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• v.39 no.1
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• pp.64-70
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• 2015

Thermally expandable microcapsules (TEMs) can be expanded upon heating since the activation energy of liquid hydrocarbon at the core of the TEMs increased at high temperature. Due to this property, TEMs are widely used in the industry as blowing agents or light-weight fillers. In this article, chemical blowing agent and TEM were used for making polypropylene (PP) foams, and their mechanical properties were compared. Physical properties (tensile strength, impact strength etc.) of PP foams decreased with increasing the amount of blowing agents while weight of specimen decreased. However, PP foam produced with TEMs showed higher impact strength than the one with a chemical blowing agent. In order to figure out the difference of impact strength, the morphology of PP foamed was investigated. Expanding properties of TEM can be controlled by changing core back distance.

• Journal of the Korean Applied Science and Technology
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• v.20 no.1
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• pp.20-26
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• 2003

Acidic degreasing agent(AADA) was prepared by blending sorbitol, Newpol PE-68, Na-dioctyl sulfosuccinate, Tetronix T-70l, MJU-100A, n-octanoic acid, and phosphoric acid, The physical properties of AADA tested with aluminum specimen showed the following results ; when 3wt% AADA-5 was performed at 70$^{\circ}C$, the degreasing rate was 95% which is comparitively good, and the percentage of etching was 0.277% which was found to be less than that of commercialized product. when 20wt% of AADA-5 was added at 65$^{\circ}C$, the percentage of derusting was 91% and the good defoaming effect proved by following low foaming power tests respectively : Ross and Miles, and Ross and Clark methods.

• Journal of the Korean Applied Science and Technology
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• v.10 no.2
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• pp.35-40
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• 1993

Alkaline cleaning agent(ACA) was prepared by blending of POE(4)octadecylmine(S-204), $Na_2CO_3$, sodium orthosilicate(Na-OSi). Tetronix T-701(T-701), and MJU-100A. The physical properties of ACA tested with steel specimen showed the following results. The cleaning powers of ACA-6(S-204 80g/$Na_2CO_3$, 160g/Na-OSi, 80g/T-701, 60g/MJU-100A, 20g mixture) for press-rust preventing oil was 98% and 99% degreasing at 2wt%, $70^{\circ}C$ and $90^{\circ}C$, respectively : for quenching oil, the cleaning power of ACA-6 was 95% degreasing at 2wt% and $70^{\circ}C$. From these results, it was ascertained that ACA-6 exhibited a good cleaning power. Foam heights measured immediately after foaming by Ross & Miles method and Ross & Clark method at 3wt%. $60^{\circ}C$ were 17mm and 40mm, respectively. As the result, ACA-6 was proved a good low foaming cleaning agent.

• Elastomers and Composites
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• v.35 no.3
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• pp.227-235
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• 2000

This study focused on the recycling technology and application of waste polyurethane scrap($5{\sim}7mm$) and waste urethane form from the footware scrap. Firstly we suggest the waste polyurethane can be used as a component of medium for hydroponic rose culture. Secondly, recycled thermoplastic polyurethane(RTPU) was produced and blended it with high impact polystyrene(HIPS). And also, in order to extend application of recycling field, the former was produced with adding the amine foaming agent to RTPU/HIPS alloy. The main purpose of this study is to diverse of the recycling of the waste polyurethane.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.21 no.6
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• pp.266-273
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• 2011

Foamed glass was fabricated by using glass powder and foaming agents. For the glass powder, we used sodalime glass which's manufactured by using refused coal ore obtained as by-product from Dogye coal mine in Samcheok. And for the foaming agents, we used Calcium carbonate, Calcium phosphate and powder of shale type refused coal ore itself which has high content of carbon materials. We additionally used liquid binder for forming, and mixed together. And we formed rectangular shape and treated $800^{\circ}C$ for 20 min in an electrical furnace. The various kinds of foam glass samples were fabricated according to the kinds of foaming agents. The physical properties of samples, as specific gravity and compressive strength, were measured. Pore structure of each samples were investigated too. Foam glass with specific gravity of 0.4~0.7 and compressive strength of 30~72 kg/$cm^2$. Especially we get satisfying foam glass sample with low specific gravity of 0.47 and high compressive strength of 72 kg/$cm^2$ by the use of liquid calcium phosphate as foaming agent. It also had small and even shape of pore structure. Therefore, it is concluded that refused coal ore can be used for raw materials to manufacture secondary glass products such as a foamed glass panel for construction and industrial materials.

• Polymer(Korea)
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• v.38 no.4
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• pp.441-448
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• 2014

Polyurethane/melamine phosphate composite foam (MP-PUF) was prepared from poly(adipate)diol/melamine phosphate composite (f=2), polyether-polyol (f=4.6), and PMDI (f=2.5). The thermal properties of MP-PUF such as morphology, closed-cell content, thermal conductivity, and thermal stabilities were characterized. Water was used as a blowing agent, and the composition of melamine phosphate (MP) was maintained at $1.43{\pm}0.3wt%$ of MP-PUF. As the content of water increased, the thermal conductivity of pure polyurethane foam (PUF) decreased, whereas the thermal conductivity of MP-PUF increased. The thermal stabilities of the PUF and the MP-PUF were maximized at 5 php $H_2O$, and then decreased at the higher $H_2O$ contents. The thermal stabilities of MP-PUF were greatly enhanced due to the synergetic effect of MP and urea, which was generated during the blowing process. The temperature of 50% residual mass of MP-PUF increased to $370{\sim}450^{\circ}C$ and the temperature of 30% residual mass exceeded over $700^{\circ}C$. Compared to the PUF, the temperature of 50% residual mass and 30% residual mass were higher than 25 and $70^{\circ}C$, respectively.

• Resources Recycling
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• v.29 no.1
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• pp.53-61
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• 2020

This study aimed to develop a foam concrete material for a ground repair system that has low strength and low fluidity by using an eco-friendly binder, which substitutes industrial by-products for more than 90% of cement. Basic properties were evaluated after substituting a small amount of calcium sulfo aluminate (CSA) for the binder to improve the sinking depth rate and volume change, commonly found when it had a large amount of industrial by-products. The substitution rates of CSA for the eco-friendly binder used for the foam concrete were 2.5, 5, and 10%. Fresh properties, hardened properties, pore structure, and hydrates were analyzed. Experimental results showed that using only 2.5% of CSA could improve the deep sinking depth which occurred when using an eco-friendly binder. As a result, the weight difference between the upper, middle, and lower parts of cast specimens was improved even after being hardened. The addition of CSA also contributed to the formation of small, uniformly sized closed pores and improved initial strength. However, when the proportion of CSA increased, the long-term strength decreased. However, it satisfied the target strength when 5% or less of CSA was used. The results of this study revealed that it was possible to manufacture foam concrete with low strength and high fluidity for repairing ground satisfying target qualities by adding 2.5% of CSA to the eco-friendly binder containing a large amount of industrial by-products.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.111-112
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• 2023

With the development of cities, the density of the population is continuously increasing as buildings become larger and more high-rise, but since the Haeundae residential complex fire in Busan in 2010, there has been a growing need to meet the fire protection performance of buildings as large-scale fires continue to occur every year. On the other hand, fire doors, which are one of the fire protection performance of buildings, have been judged unqualified in 82% of cases when fire doors constructed on the actual site were inspected after completion. The reason for this is that paper honeycomb and glasswool, which are used as core materials for fire doors, absorb moisture, reducing thermal insulation performance, and sagging due to increased weight, leading to performance degradation due to warping in empty spaces. To overcome these problems, research is underway to apply lightweight aerated concrete, an inorganic material, as a core material. Therefore, in order to select a blowing agent that produces stable bubbles prior to the production of lightweight bubble concrete for application as a fire door inner core, this study examined the physical performance according to the type of blowing agent and dilution concentration, and the following conclusions were drawn. Compared to vegetable bubbles and independent bubbles, synthetic bubbles have 3~8% higher thermal conductivity than independent bubbles, but 3~6% lower slurry density than vegetable bubbles, and 2~13% higher compressive strength, which is thought to be an improvement of synthetic bubbles.

• Journal of the Korean Ceramic Society
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• v.46 no.3
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• pp.275-281
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• 2009

Porous materials were manufactured by hydrothermal treatment of waste bottle glass without foam agent. Factorial design was applied to analyze data by statistical methods and deal with the important factors for a process. The largest effect for porosity was for temperature of hydrothermal treatment. Amount of water and temperature-water interaction appeared to have little effect. The particle size of raw material was also identified as a major factor by one-way ANOVA and the porosity decreased as the size increased. The sintering temperature was not statistically significant for the porosity but was significant for the pore size. The porous material had compressive strength and thermal conductivity comparing with those of ALC (autoclaved lightweight concrete), although it has higher porosity than for ALC.

• Journal of the Ergonomics Society of Korea
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• v.6 no.1
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• pp.41-44
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• 1987

Researches were made on foot-warming, anti-bacteria and deodorant treatment. Feet, the very important organ to human body, perspire much and their temperature is lower than those of other parts. Hence, keeping feet warm, sanitary and deodorant is the area of this study. Latex sponge of activated carbon, impregnated open cell foam, treated with Vikol DZ-anti-bacteria finishing agent, was developed and tested for warmth-keeping by KSK 0560 test method and for sanitization by AATCC 90 HALO test method and for deodorization by wearing tests. The results show that the new developed latex spongee has warmth-keeping ratio of 2.5 times higher than that of the conventional spong and it has an excellent anti-bacteria effect. Actual wearing function tests also show that it improves significantly the performance of deodorization, sanitization, warmth-keeping and bulkiness.