• Korean Journal of Environmental Biology
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• v.26 no.3
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• pp.247-251
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• 2008

Degradation behavior in the seawater of Tongyeong, Incheon, Kunsan and Hongsung was explored for Mater-Bi$^{(R)}$, poly(3-hydroxybutyrate-co-3-hydroxy valerate) (PHBV), poly(butylene succinate-co-butylene adipate) (PBSA) and polycaprolactone (PCL) which can eventually be used for various fishery tools. Acinetobacter lwoffu/junii and Shewanella algae/putrefaciens inhabited all the seawater samples. Eikenella corrodens was also detected in all the seawater samples, although identified with poor confidence by VITEK system. Mater-Bi$^{(R)}$ was degraded faster than PHBV, PBSA and PCL in the seawater in contradiction to the degradation behavior in soil environment. The seawater retrieved from Incheon exhibited the most elevated activity for the plastic degradation, which may be partly ascribed to the largest number of total viable counts.

• Journal of Microbiology and Biotechnology
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• v.9 no.6
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• pp.784-788
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• 1999

The effects of pH, moisture content, and the relative amount of a polymer sample on the biodegradation of degradable polymers in soil were studied using various polymer materials such as cellulose, poly-(butylene succinate-co-adipate) (SG) polycaprolactone (PCL), a blend of PCL and starch (PCL-starch), and a poly-lactic acid (PLA). As with other materials, the polymers degraded faster at a neutral pH than at either acidic or basic conditions. Moisture contents of 60 and 100% water holding capacity exhibited a similar biodegradability for various polymers, although the effects differed depending on the polymer. For synthetic polymers, biodegradation was faster at 60%, while the natural polymer (cellulose) degraded faster at 100%. Fungal hypae was observed at a 60% water holding capacity which may have affected the biodegradation of the polymers. A polymer amount of 0.25% to soil revealed the highest biodegradability among the ratios of 0.25, 0.5, and 1%. With a higher sample amount, the residual polymer could be recovered after the biodegradation test. It was confirmed that a test for general biodegradation condition can be applied to plastic biodegradation in soil.

• Membrane Journal
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• v.30 no.5
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• pp.333-341
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• 2020

In this study, the optimum design conditions of a polymer electrolyte membrane for application to a flexible electrochromic device (ECD) were tried to be derived. Polyvinyl butyral (PVB) with excellent adhesive property and transparency was selected as the base polymer for the preparation of the electrolyte membrane, and adipate-based polymer was used as the plasticizer. As a result, it was confirmed that the most influential factors on the ECD performance were the ionic conductivity and permeability of the electrolyte membrane. In addition, it was found that the factor has a close relationship with the dissociation property of the lithium salt. Overall, the optimal ECD performance was achieved when LiTFSI salt having a large anion size among various lithium salts was dissolved in a content of about 25 wt.%.

• Journal of the Korean Electrochemical Society
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• v.11 no.1
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• pp.59-63
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• 2008

Poly (vinylchloride) (PVC) membrane electrodes based on neutral carrier, tetracycline was prepared as an active sensor for Hg(II) ion, and tested in different contents of the potassium tetrakis (4-chlorophenyl) borate (KTpClPB) as lipophilic salt. Bis (2-ethylhexyl) sebacate (DOS), bis(l-butylpentyl) adipate (BBPA), 2-nitrophenyl octyl ether (NPOE) and dibutyl phthalate (DBP) were used as diverse plasticizing solvent mediators. This electrode shows excellent potentiometric response characteristics and display good linearity with log $[Hg^{+2}]$ versus EMF response, over a range of concentrations between $10^{-7}$ and $10^{-3}M$. With 30.8mV/decade Nernstian slope, the detection limit was $6.9{\times}10^{-9}M$ and the response time was less than 20s. The proposed electrode yields very good selectivity for mercury (II) ion over many cations such as alkali, alkaline earth, transition and heavy metal ions. And it shows a very stable potential values in a wide pH range. This reliable electrode prepared was kept at least a month without considerable alteration in their response to Hg (II) ion.

• Applied Chemistry for Engineering
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• v.3 no.4
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• pp.614-619
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• 1992

Two types of polyurethane(PU) ionomer dispersion having different type of soft segment, viz. Poly (tetramethylene adipate) glycol(PTAd), and polypropylene glycol(PPG) were emulsion blended. Viscosity of emulsion blend, mechanical, and surface properties of the emulsion cast films were determined as a function of blend composition. Mechanical properties showed a large scatter of data or negative deviation from the additivity rule, and this was attributed to the incompatibility of soft segments. Contact angle measurement indicated that air facing surface of emulsion cast film contained more of PPG PU, due probably to its smaller particle diameter compared to PTAd PU.

• Applied Chemistry for Engineering
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• v.8 no.2
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• pp.230-236
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• 1997

Polyurethane dispersions(PUD) were prepared from IPDI, PBEAG and PTMG as respectively ester type and ether type polyols and DMPA as anionic site. The effect of composition and type of polyols on the particle size of PUD and mechanical, thermal properties of PUD cast film were investigated. As the PTMG contents in mixed polyols increased, the particle size asymptotically increased and tensile strength showed a mild drop followed by a mild increase. This results from the incompatibility of two polyols, which was possibly identified by DSC analysis.

• Textile Coloration and Finishing
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• v.5 no.4
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• pp.60-66
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• 1993

Aqueous polyurethane(PU) anionomer dispersions were prepared from isophorone diisocyanate (IPDI), polytetramethylene adipate glycol(PTAd) and dimethylol propionic acid(DMPA) as potential anionic centers. The effects of polyol molecular weight(Mn) on the state of dispersion, thermal, mechanical, and viscoelastic properties and swelling of emulsion cast film were determined. With increasing Mn of PTAd, particle size of emulsion and soft segment T$_{g}$ decreased, and solvent swell, emulsion viscosity, and hard segment $T_{g}$ increased. Tensile strength showed minimum with PTAd 1000, and elongation at break generally increased with the Mn of PTAd. These results were possibly nterpreted in terms of soft segment-hard segment phase separation and crystallization of high molecular weight PTAd.

• Elastomers and Composites
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• v.50 no.4
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• pp.297-303
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• 2015

Ammonium polyphosphate-polyurethane foam composite (APP-PUF) was prepared from poly(adipate)diol/ammonium polyphosphate composite (f = 2), polyether polyol (f = 4.6), and PMDI (f = 2.5). As a blowing agent, $H_2O$ was used at various concentrations. The thermal decomposition behavior, morphology, closed-cell content, and density of APP-PUF were characterized. At the $H_2O$ concentrations lower than 3.5 php, the cell size of pure polyurethane foams (PUF) and APP-PUFs were close each other. As the $H_2O$ concentration became greater than 5.0 php, the cell size of the PUFs greatly increased compared to that of APP-PUFs. Addition of 1.5~1.9 wt% ammonium polyphosphate to the PUFs greatly enhanced the thermal stability of the PUFs, so 50 wt% residual temperature of APP-PUFs increased to $380{\sim}488^{\circ}C$, which were $30{\sim}70^{\circ}C$ higher than those of the PUFs. Thermal stability of the PUFs and APP-PUFs increased with $H_2O$ content and then decreased once $H_2O$ content exceeded 5 php.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.27 no.2
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• pp.85-90
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• 2021

The gamma irradiation was on to Poly(butylene sebacate-co-terephthalate) (PBSeT), Poly(butylene adipate-co-terephthalate) (PBAT), Poly(lactic acid) (PLA) and casting polypropylene (CPP) at dose levels from 0 to 50 kGy. The properties of gamma irradiated samples were analyzed using DSC, TGA, UTM and FT-IR spectra. The mechanical and thermal properties of PBSeT and PBAT after gamma irradiation were less affected than CPP. The tensile strength and elongation of PBSeT was not affected by gamma irradiation, while these of PBAT, PLA and CPP were significantly decreased at 50 kGy gamma-ray dose. The thermal stability of PBSeT, PBAT, PLA and CPP showed a similar tendency to tensile strength. The glass transition temperature(T_g) and melting temperature(T_m) of PBSeT and PBAT were not altered by increasing gamma-ray dose, while these of PLA and CPP decreased. The chemical composition of all samples was not modified by gamma irradiation, and it was confirmed by FT-IR spectra. Based on mechanical and thermal stability studies of gamma irradiation on bioplastics, tested biodegradable packaging materials showed a potential to be used in sterilization process up to 35 kGy.

• Elastomers and Composites
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• v.55 no.4
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• pp.347-353
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• 2020

Stearic acid (SA), polyethylene glycol (PEG), and malic acid (MA) have been used to modify the surface of waste gypsum to develop corresponding poly (butylene adipate-co-terephthalate) (PBAT) composites. According to the mechanical properties, MA-treated gypsum (MA-gypsum) showed the best performance, whereas SA-gypsum showed the worst performance. In contrast to SA and PEG (having -COOH and -OH as polar functional groups, respectively), the presence of both -OH and -COOH in MA is responsible for the superior surface treatment of gypsum and its better dispersion in the polymer matrix (as revealed by FE-SEM analyses). The presence of long aliphatic chain in SA is supposed to inhibit the dispersion of SA-gypsum. Further, the performance of MA-gypsum/PBAT was enhanced by adding polylactic acid (PLA). The maximum optimized contents of MA-gypsum and PLA are 20 and 7.5 wt% for developing a high-performance PBAT composite.