• Journal of the Korean Applied Science and Technology
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• v.22 no.3
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• pp.257-269
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• 2005

This study was focused on the maximization of flame-retardancy of polyesters by a synergism of simultaneously introduced chlorine and phosphorus into polymer chains of modified polyesters. To prepare modified polyesters, reaction intermediates, TD-adduct (prepared from trimethylolpropane /2,4-dichlorobenzoic acid (2,4-DCBA)) and TMBO (prepared from tetramethlene bis (orthophosphate)), were prepared first, then condensation polymerization of the prepared intermediates, adipic acid, and 1,4-butanediol were carried out. In the condensation polymerization, the content of phosphorus was fixed to be 2wt%, and the content of 2,4-DCBA that provides chlorine component was varied to be 10, 20, and 30wt%, and we designated the prepared modified polyesters containing chlorine and phosphorus as ABTTs. The prepared intermediates and modified polyesters were characterized with FT-IR, NMR, GPC, and TGA analysis. Average molecular weight and polydipersity index of the preparation of ABTTs were decreased with increasing 2,4-DCBA content because of the incease in hydroxyl group that retards reaction. We found that the thermal stability of the prepared ABTTs increased with chlorine content at high temperatures.

• Journal of the Korean Applied Science and Technology
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• v.23 no.1
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• pp.26-36
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• 2006

The aim of this study is to synthesis basic resins for the preparation of PU flame-retardant coatings that contain phosphorus and chlorine. After synthesizing intermediates of tetramethylene bis(orthophophate) (TMBO) and neohexanediol trichlorobenzoate (TBA-adduct), the condensation polymerization was performed with the intermediates, 1,4-butanediol, and adipic acid to obtain four-component copolymers. In the condensation polymerization, the content of phosphorus was fixed to be 2%, and the content of trichlorobenzoic acid (TBA) that provides chlorine component was varied to be 10, 20, and 30wt%, and we designated the prepared modified polyesters containing chlorine and phosphorus as TTBA-10C, TTBA-20C and TTBA-30C. Average molecular weight and polydispersity index of the prepared TTBAs decreased with increasing TBA content because of the increase in the number of hydroxyl groups that retards reaction. We found that the thermal stability of the prepared TTBAs increased with chlorine content at high temperatures.

• Composites Research
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• v.35 no.6
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• pp.412-418
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• 2022

Flame-retardant vinyl ester (VE) resin films were developed from the mixtures of brominated and non-brominated epoxy resins via esterification with methacrylic acid without reactive diluents. The films were used to fabricate carbon fiber (CF) prepregs via a hot melt impregnation process. The viscosity of VE resins suitable for film production was optimized by mixing low-viscosity bisphenol-A and high-viscosity brominated bisphenol-A epoxy precursors. Increasing the bromine content of the cured VE resin further increased the limited oxygen index (LOI) (39%), storage modulus (2.4 GPa) at 25℃ and residual carbonization (16.1%) values compared to non-brominated VE. Manual layup of as-prepared VE prepregs with subsequent curing led to the successful fabrication of CF-reinforced composites with high tensile and flexural strength. The results from the study hold high promise for a styrene-free, environmentally friendly VE composite process in the future.

• 한국연소학회:학술대회논문집
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• 2014.11a
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• pp.249-251
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• 2014

Synthesis gas such as hydrogen and carbon monoxide was produced from $CH_4//oxygen$ mixture using two-section porous media combustor. Heat recirculation through the inner foam structure could extend the flow velocity of stable region over the laminar burning velocity. $H_2/CO$ ratio and module M from concentration of flue gas measured by Gas Chromatography was similar to those calculated by equilibrium. But it was made sure that the heat loss effect becomes more influential than heat recirculation effect as the mixture gets richer. To generate synthesis gas appropriate for methanol production, insulated pressurized porous media combustor will be designed and built in the future.

• Textile Coloration and Finishing
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• v.8 no.2
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• pp.25-34
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• 1996

Diphenyl ethanolamidophosphate(DPEAD) was synthesized for the purpose of developing a new flame retardant for cotton fabric. As the intermediate material was used diphenyl chlorophosphate(DPCP) and it was synthesized by using phosphorus oxychloride and phenol as the starting materials. The final product DPEAP was obtained by the reaction of DPCP and ethanolamine. The flame retardancy of cotton fabrics treated by DPEAP through pad-dry-cure(PDC) process was examined at various conditions. The physical property change of the DPEAP treated cotton fabrics were investigated by examining the drape stiffness, the wrinkle recovery, and the tensile strength. The results are summarized as follows: (1) DPEAP has shown excellent flame retardancy on cotton fabrics in comparison to other flame retardants for cotton fabrics available commercially. (2) The optimal condition for PDC process found was that the curing temperature was 16$0^{\circ}C$, the DPEAP concentration was 10%, the catalyst $({NH_{4})_{2}HPO_{4}$ concentration was 7.0%, and the fixing agent hexamethylol melamine (HMM)/DPEAP weight ratio was 1/8. (3) The wrinkle recovery of the processed fabrics increased with increasing DPEAP concentration. (4) The drape stiffness of the cotton fabrics treated by DPEAP have shown essentially no change until increasing DPEAP concentration to 15 %, however DPEAP concentration exceeds 20% the drape stiffness increased drastically with increasing DPEAP concentration. When DPEAP concentration is kept constant the drape stiffness increased with increasing $({NH_{4})_{2}HPO_{4}$ concentration and HMM/DPEAP weight ratio. (5) The tensile strength of the processed fabrics was lower than that of untreated fabrics, but the tensile strength retention increased with increasing DPEAP concentration.

• Resources Recycling
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• v.14 no.6 s.68
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• pp.37-43
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• 2005

[ $LiCoO_{2}$ ] nanoparticles were synthesized from leach liquor of lithium ion battery waste using flame spray pyrolysis. Electrode Materials containing lithium and cobalt could be concentrated with thermal and mechanical treatment. After dissolution of used cathode materials of the lithium battery with nitric acid, the molar ratio of Li/Co in the leach liquor was adjusted at 1.0 by adding a fresh $LiNO_{3}$ solution. The nanoparticles synthesized by the flame spray pyrolysis showed clear crystallinity and were nearly spherical, and their average primary particle diameters ranged from 11 to 35 nm. The average particle diameter increased with an increase in the molar concentration of the precursor. Raising the maximum flame temperature by controlling the gas flow rates also led to an increase in the average diameter of the particles. The $LiCoO_{2}$ powder was proved to have good characteristics as cathode active materials in charge/discharge capacity and cyclic performance.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.8
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• pp.626-631
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• 2012

$SnO_2$ nanoparticles were synthesized by flame spray pyrolysis, which were directly deposited on Pt interdigitated substrates. Gas sensing performance was evaluated for various gases such as $H_2$, CO, $H_2S$, and $NH_3$, and it was compared with that of commercial $SnO_2$ nanopowder. The synthesis of $SnO_2$ nanoparticles was also conducted in various solvents. As a result, the primary particle size was changed with the solvent of precursor solution, and their $H_2$ sensing properties were significantly affected.

• Journal of the Korean Applied Science and Technology
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• v.26 no.3
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• pp.317-327
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• 2009

In this study DMT(Dimethylterephthalate), NDC(Dimethyl-2, 6-Naphthalene Dicarboxylate) were used to synthesize polyester polyol which shows enhanced storage stability, improved flame retardancy, and good compressive strength. If DMT and NDC react respectively with DEG(Diethylene Glycol) which is kind of linear diol, the obtained polyester polyols tend to crystallize easily after the reaction. In case of DMT, PA(Phthalic Anhydride) which has asymmetric structure was introduced to retard the crystallization. In case of NDC, DPG(Dipropylene Glycol) which has an methyl side chain was introduced to prevent the crystallization. It was found that to introduce DPG was much more effective method to prevent the crystallization than PA. NDC and DMT were reacted together with DPG for various compositions of NDC:DMT(8:2, 6:4, 4:6 mol ratio). The obtained NDC-DMT-DPG based polyester polyol showed improved flame retardancy, and good compressive strength with increasing the content of NDC.

• Polymer(Korea)
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• v.35 no.5
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• pp.431-437
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• 2011

A polymeric coating solution based on poly(acryloyl diphosphoric acid)(poly(ADP)) was prepared via a radical polymerization of acryloyl diphosphoric acid using ammonium persulfate (APS) as an initiator in water at 70 $^{\circ}C$. The prepared polymeric coating solution exhibited significant antibacterial activity against salmonella typhimurium, pseudomonas aeruginosa, escherichia coli, and staphylococcus aureus. It also exhibited good antifungal activity against Asperigillus niger and good antiviral activity against the influenza (H1N1) virus. Additionally, it exhibited good flame retardant efficiency after applying it as a coating to a cotton fabric.

• Particle and aerosol research
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• v.9 no.4
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• pp.209-219
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• 2013

We have used the modified diffusion flame burner to synthesize silica coated iron oxide nanoparticles having enhanced superparamagnetic property. Silica-encapsulated iron oxide particles were directly observed using a high resolution transmission electron microscope. From the energy dispersive X-ray spectroscopy (EDS) and zeta potential measurements, the iron oxide particles were found to be completely covered by a silica coating layer. X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) measurements revealed that the iron oxide core consists of ${\gamma}-Fe_2O_3$ rather than ${\alpha}-Fe_2O_3$. Our magnetization measurements support this conclusion. Biocompatibility test of the silica-coated iron oxide nanoparticles is also conducted using the protein adsorption onto the coated particle.