• Fire Science and Engineering
• /
• v.10 no.3
• /
• pp.29-40
• /
• 1996

The AFFF(Aqueous Film Forming Foam : 3M Company's Light Water) agent are synthetic compounds that foams which are similar to those produced by protein based materials. The foam extinguishing agent was used In the extinguisher was the AFFF agent. We sought, however, to make other foams by using halon 1301 (CF$_3$Br) and halon alternatives, such as HCFC Blend A($CHCIF_2$ 82%, $CF_3$CHCIF 9.5%m $C_{10}$$H_{16}$ 3.75%), HFC-227ea ($CF_3$ $CHFCF_3$) We selected these alternatives instead of air in order to raise the expansion ratio of the AFFF agent. By these means we discovered that it is possible to increase the expansion ratio of the AFFF agent up to 44:1 and up to 24:1 when HFC-227ea was used as a halon alternatives. Therefore our new foam extinguishing agents can be used in a portable extinguish agents can be used in a portable extinguishers.

• Elastomers and Composites
• /
• v.49 no.3
• /
• pp.225-231
• /
• 2014

In this study, we used polypropylene grafted with itaconic acid (PP-g-IA) as a compatibilizer to prevent phase separation phenomenon which occurs upon blending polypropylene (PP) and ethylene-vinyl alcohol copolymer (EVOH). A compatibilizer was prepared using graft copolymerization of itaconic acid (IA) onto PP where input ratio of IA was 1, 2, 5, and 10 wt.%. To confirm the structure of PP-g-IA and the graft ratio of IA onto PP, we used $^1H$ NMR and FT-IR. We tested the compatibilizer which has highest graft ratio of 1% in immiscible PP/EVOH blends. The morphologies of PP/PP-g-IA/EVOH blends were analyzed by SEM. Thermal and mechanical properties of the blends were analyzed by DSC and UTM. PP-g-IA enhanced the interfacial adhesion of PP and EVOH copolymer.

• Biomolecules & Therapeutics
• /
• v.32 no.1
• /
• pp.162-169
• /
• 2024

Particulate matter (PM) constitutes a hazardous blend of organic and inorganic particles that poses health risks. Inhalation of fine airborne PM with a diameter of ≤ 2.5 ㎛ (PM_2.5) can lead to significant lung impairments. (+)-afzelechin (AZC), a natural compound sourced from Bergenia ligulata, boasts a range of attributes, including antioxidant, antimicrobial, anticancer, and cardiovascular effects. However, knowledge about the therapeutic potential of AZC for patients with PM_2.5-induced lung injuries remains limited. Thus, in this study, we investigated the protective attributes of AZC against lung damage caused by PM_2.5 exposure. AZC was administered to the mice 30 min after intratracheal instillation of PM_2.5. Various parameters, such as changes in lung tissue wet/dry (W/D) weight ratio, total protein/total cell ratio, lymphocyte counts, levels of inflammatory cytokines in bronchoalveolar lavage fluid (BALF), vascular permeability, and histology, were evaluated in mice exposed to PM_2.5. Data demonstrated that AZC mitigated lung damage, reduced W/D weight ratio, and curbed hyperpermeability induced by PM_2.5 exposure. Furthermore, AZC effectively lowered plasma levels of inflammatory cytokines produced by PM_2.5 exposure. It reduced the total protein concentration in BALF and successfully alleviated PM_2.5-induced lymphocytosis. Additionally, AZC substantially diminished the expression levels of Toll-like receptors 4 (TLR4), MyD88, and autophagy-related proteins LC3 II and Beclin 1. In contrast, it elevated the protein phosphorylation of the mammalian target of rapamycin (mTOR). Consequently, the anti-inflammatory attribute of AZC positions it as a promising therapeutic agent for mitigating PM_2.5-induced lung injuries by modulating the TLR4-MyD88 and mTOR-autophagy pathways.

• Macromolecular Research
• /
• v.9 no.4
• /
• pp.238-246
• /
• 2001

Properties of ternary blends of nylon 6 (Ny6), a thermotropic liquid crystalline polymer (TLCP, poly(ester amide), 20 wt%) and a maleic anhydride grafted polypropylene (2 wt%) (MAPP) were studied under various processing conditions. TLCP was pre-blended with MAPP first and then the binary one blended again with Ny6. The processing temperature of the second mixing was varied. Thermal properties show the partial miscibility of the ternary blend. The morphology of the TLCP phase in the first blending shows mostly in the fibril bundle shape, but varies between droplets and oriented fibrils after the second processing. Some of TLCP phase lost the fibril morphology during the second processing stage. The morphology variation invokes the change in tensile properties. Low extrusion temperature (270$\^{C}$) provides more fibril shapes, which are associated with less deformation in the second stage. The processing temperature effect was more evident when the draw ratio was high. High drawing was applicable due to the stabilizing action of tile compatibilizer.

• Polymer(Korea)
• /
• v.28 no.1
• /
• pp.67-76
• /
• 2004

The effects of drawing temperature and draw down ratio on thermal properties, crystallinity and orientation of poly(trimethylene terephthalate)/poly(ethylene terephthalate) (PTT/PET) 100/0 ,90/10, and 80/20 blends have been investigated. The crystallinity and glass transition temperature increased while cold crystallization temperature and cold enthalpy decreased due to the development of orientation and stress induced crystallization by the cord drawing. Introducing PET to PTT decreased the crystallinity of PTT. However, it enhanced the orientation of PTT/PET blends drawn at below the glass transition temperature of PET. This lead to the increase of tensile modulus and tensile strength of PTT/PET blends. The shrinkage increased with increasing orientation, which might be minimized by the development of crystalline morphology of PTT in the course of cold drawing.

• Corrosion Science and Technology
• /
• v.4 no.3
• /
• pp.89-94
• /
• 2005

This paper presents the results of a study that was undertaken to optimize the ratio of the components of a new multi-component inhibitor blend composed of orthophosphate/ phosphonates/ acrylate copolymer/ isothiazolone. The effects of newly developed inhibitor on carbon steel dissolution in synthetic cooling water were studied through weight loss tests, electrochemical tests, scale tests, and micro-organism tests. The obtained results were compared to blank (uninhibited specimen) and showed that developed inhibitor revealed very good corrosion, scale, and micro-organism inhibition simultaneously. All measurements indicated that the efficiency of the blended mixture exceeded 90 %. The inhibitive effects arose from formation of protective films which might contain calcium phosphate, calcium phosphonate, and iron oxide. The nature of protective films formed on the carbon steel was studied by scanning electron microscopy (SEM) and auger electron spe ctroscopy (AES). Inhibitor used in this study appeared to have better performance for scale inhibition due to their superior crystal modification effect and excellent calcium carbonate scale inhibition properties. The effect of inhibitor on microorganisms was evaluated through minimum inhibitory concentration (MIC) test. All kinds of micro-organisms used in this study were inhibited under 78ppm concentration of inhibitor.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
• /
• 1996.11a
• /
• pp.57-61
• /
• 1996

Our goal was to make a cost-effective automatic fire extinguishing system for the engine compartment use of automobiles. We designed this system for the engine compartment. This system consists of 1)foam extinguisher, 2)four nozzles, 3)a pipe arrangement, and 4)an extinguishing device which is equipped with a glass bulb as detector. First and foremost, the extinguishing device was carefully designed to keep the system cost to a minimum. Second, a AFFF foam extinguisher was used because no other fire-fighting agents proved effective against fire in the engine compartment. The AFFF(Aqueous Film Forming Foam) agent which was used in the extinguisher is the 3M company's Light Water. We sought, however, to make other foams by using Halon 1301 and Halon alternatives such as HCFC Blend A, HFC-227ea. We selected these alternatives instead of air in order to raise the expansion ratio of the AFFF agent. By these means we discovered that it is possible to increase the expansion ration of the AFFF agent up to 44:1. We then demonstrated that our automatic fire extinguishing system is the most effective and lowest cost-system yet devised for passenger cars.

• Journal of Environmental Health Sciences
• /
• v.25 no.3
• /
• pp.58-63
• /
• 1999

Biodegradable films were prepared by solution blend method in the weight ratio of chitosan for the purpose of useful biomaterials. The possibility of biomaterials prepared from natural polymer as a skin substitute was evaluated by measuring biocompatibility. These films were inserts in the back of rat and their biodegradability was investigated by the film weight and hematology as a function of time for the biotransformation. The result of rat test showed that medium, high viscosity chitosan induced some suspects of inbiocompatibility in the tissue by goreign body reaction 48 and 72 hours after implantation. Also, we prepared the official burn ointment which is made by low viscosity chitosan. This burn ointment was covered on the skin wound of artificial burn and their effect of healing was investigated by the evaluation of the naked eye and hematological change as a function of time. The result of rats test showed that burn ointments made from chitosan was effective reductio of inflammation than negative group.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.42 no.5
• /
• pp.799-808
• /
• 2018

This study develops triacetate-containing functional fabrics with a cool-touch and cool-absorbent. For this purpose we used composite yarns made using triacetate filament and PET High absorbance quick dry filament as well as the composite fabric woven. The fineness of the yarn and structure of fabric varied the cover factor varied. The blend ratio of triacetate was differently set. When the triacetate content was the same, the cool touch of the fabric having a large cover factor and small SMD increased. The surface became smooth and the contact area became large; in addition, both the Qmax value and the cool-touch became large. In the case of similar density, the cool-touch of the fabric having a large content of triacetate increased. The cool-absorbent of the fabric containing triacetate showed a similar level of the PET High absorbance quick dry filament fabric treated with and endothermic cooling agent. It was possible to develop a functional coolness fabric with a cool-touch and a cool-absorbent when the content of triacetate and cover factor were well combined.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2009.11a
• /
• pp.14-14
• /
• 2009

High frequency electromagnetic(EM) waves are increasingly being applied in industries because of saturationat lower frequency bands as a result of huge demand. However, electromagneticinterference (EMI) has become a serious problem, and as a result, highfrequency EM absorbers are now being extensively studied. Also, recentdevelopments in absorber technology have focused on producing absorbers thatare thin, flexible, and strong. Hence, one-dimension ferrous nano-materials area potential research field, because of their interesting electronic andmagnetic properties. Commercially, EM wave absorbing products are made ofcomposites, which blend the insulating polymer with magnetic fillers. Inparticular, the shape of the magnetic fillers, such flaky, acicular, or fibrousmagnetic metal particles, rather than spherical, is essential for synthesizingthin and lightweight EM wave absorbers with higher permeability. High aspectratio materials exhibit a higher permeability value and therefore betterabsorption of the EM wave, because of electromagnetic anisotropy. Nanowires areusually fabricated by drawing, template synthesis, phase separation, selfassembly, and electrospinning with a thermal treatment and reduction process.Producing nanowires by the electrospinning method involves a conventionalsol-gel process that is simple, unique, and cost-effective. In thispresentation, Magnetic nanowire and dielectric materials coated magneticnanowire with a high aspect ratio were successfully synthesized by theelectrospinning process with heat treatment and reduction. In addition toestimating the EM wave absorption ability of the synthesized magnetic anddielectric materials coated magnetic nanowire with a network analyzer, weinvestigated the possibility of using these nanowires as high-frequency EM waveabsorbers. Furthermore, a wide variety of topics will be discussed such as thetransparent conducting nanowire and semiconducting nanowire/tube with theelectrospinning process.