This study compares and analyzes inorganic components of four different Pu-erh tea species consumed in Korea. The criteria for the inorganic components was based on the Royal Institute of Technology (KTH) recommendations. Out of the 19 general items: potassium, manganese, silicon and fluorine were detected in amounts exceeding the maximum allowable concentration by 5~23, 57~91, 1.6~1.8 and 9~18 times respectively. Out of the 15 potentially harmful elements: aluminum and nickel were exceeded the Maximum allowable concentration by 9~14 times and 0.8~1.2 times respectively. To reduce the concentration of inorganic elements in excess of the maximum allowable concentration, the extraction time of tea should be less than 1 minute in addition to limiting the amount. The amount of Pu-erh tea for extraction was about 0.1 g manganese, about 0.3 g potassium, about 0.5 g fluoride and about 2 g silicon. Therefore, the maximum amount of tea for extraction should be 0.1 g in regards to the safety of Pu-erh tea. Based on the recommended maximum daily intake of inorganic ingredients by the Ministry of Food and Drug Safety, it is desirable that the number of extractions be less than three.

Recently, Oil spill incidents from maritime activities and port operation have been causing the serious ocean environment pollution, these problems are said to be the negative effects on the natural environment, social economy, marine species, and human health. Due to the high costs of treating oil spills and oil slick in comparison with a low-income country like Vietnam, many incidents related to the oil spill and oil slick have not been thoroughly processed. Cellulose components from Vietnamese agricultural residues used to produce the absorbent materials are one of the most urgent issues and this is the research object of this work. In this study, two types of structural lengths of cellulose added into PU matrix foam are used to measure how much crude oil, fuel oil, diesel oil and kerosene can be absorbed. The absorbent materials are designed after adding cellulose with 5%, 15%, 25% of mass, respectively. The achieved results show that the oil absorption capacity of PU-cellulose implemented 5% cellulose with 500μm of cellulose structure length and 25% cellulose with 3000μm of cellulose structure length are highest for crude oil. These study results from this work provide a reasonable price for the protection of the marine environment in the strategies of recovery and treatment of oil spill and oil slick on the seawater surface.

This study describes the effects of polyurethane/loess powder (PU/LP) nanofiber thin films composite produced from electrospun for absorption volatile organic compounds (VOCs) from air. Environmental issue has become a focus with improving people's living quality. The VOCs are one of the factors that affect the environmental safety. So, in order to improve the environment and safety for people, many air cleaning techniques have been investigated. One of the methods is nanofiber filtration technology. In this study, the PU nanofiber thin film has been studied that it has the adsorption of VOCs capacity, and LP nanoparticles (NPs) can be used as an additive to load into PU nanofiber thin film by electrospinning. For studying PU/LP nanofiber thin films's absorption of VOCs capacity, 4 samples (0, 10, 30, and 50 wt% LP with respect to PU) were manufactured, respectively. The results show that PU composite mats containing 30 wt% LP NPs has the highest VOCs absorption capacity, and the adsorption capacity for toluene was the highest compared to benzene and chloroform.

The uniform nanofibers of polyurethane with different contents of Juniperus Chinensis extracts were successfully prepared by electrospinning method. Polyurethane is widely used as functional polymers in the industrials, medical field as their properties can be tailor-made by adjusting their compositions. Juniperus Chinensis has been reported for anti-tumor, anti-bacterial, anti-fungal, and anti-viral activities. PU/Juniperus Chinensis extracts composite nanofibers were produced at different Juniperus Chinensis extracts concentrations (0.25, 0.5, 1, 1.5wt.%). The effects of the major parameters in electrospinning process such as tip to collector distance (TCD), voltage, polymer concentration on the average diameter of electrospun nanoweb were investigated. As results, 12wt% PU solution concentration, 8kV applied voltage and 15cm tip to collector distance were identified as optimum conditions for electrospinning the composite nanofibers. The diameter and morphology of the nanocomposite nanofibers were confirmed by a scanning electron microscopy (SEM). The resulting fibers exhibited a uniform diameter ranging from 435nm∼547nm. It has been found that the average diameters of fibers decreased by the adding of Juniperus Chinensis extracts. These nanowebs can be used for medical materials, protective clothing, and antimicrobial filters.

국내 유통 중인 총 321건의 폴리아미드, 폴리우레탄, ABS, 아크릴 수지 재질 식품용 기구 중 이행우려가 있는 모노머인 4,4``-메틸렌디아닐린, 2,4-톨루엔디아민, 아닐린, 아크릴로니트릴 및 메틸메타크릴레이트에 대하여 이행량 을 조사하고 안전성 평가를 실시하였다. 83건의 폴리아미드, ABS 및 아크릴 수지 재질 식품용 기구 검체에서 현행 식품용 기구 및 용기·포장 공전상의 용출규격 이하인 4,4``-메틸렌디아닐린, 2,4-톨루엔디아민, 아크릴로니트릴 및 메틸메타크릴레이트가 이행되었다. 이행량 결과를 토대로 안전성 평가 시나리오에 적용하여 4,4``-메틸렌디아닐린, 2,4-톨루엔디아민, 아크릴로니트릴 및 메틸메타크릴레이트의 EDI를 산출한 후 TDI와 비교하여 위해도를 평가하였다. EDI는 폴리아미드 재질 기구의 4,4``-메틸렌디아닐린과 2,4-톨루엔디아민의 경우 각각 2.39 × 10-9, 및 1.20 × 10-9mg/kg bw/day, ABS 재질 기구의 아크 릴로니트릴의 경우 4.32 × 10-9mg/kg bw/day, 아크릴 수지 재질 기구 메틸메타크릴레이트의 경우 2.27 × 10-7mg/kg bw/day이었다. ABS 재질 기구 이행 아크릴로니트릴의 위해도는 RfD 대비 4.32 × 10-4% 수준이었고, 아크릴 수지 재질 기구 이행 메틸메타크릴레이트의 위해도는 TDI 대비 1.89 × 10-5% 수준이었다. 결론적으로 검토된 평가 항목들의 위해도는 TDI 대비 4.32 × 10-4%와 1.89 × 10-5%에 불과한 것으로 조사되어 안전한 수준인 것으로 사료되었다. 이러한 결과들은 앞으로 기구 및 용기·포장의 안전 관리를 위한 과학적인 근거자료로 이용될 수 있을 것으로 판단된다.

Two component polyurethane (PU) flame retardant coatings were prepared by blending trichloro modified polyesters (TCMPs) and isophorone diisocyanate isocyanurate. TCMPs were synthesized by polycondensation of trichlorobenzoic acid (TCBA), a flame retardant component, with adipic acid, 1,4 butanediol, and trimethylolpropane. The content of TCBA was varied in 10, 20, and 30 wt% for the reaction. Theses new flame retardant coatings showed various properties comparable to other non flame retardant coatings. Moreover, we carried out the combustion test and the flammability test for our flame retardant coatings. The results of vertical burning test for the coatings containing more than 20 wt% of TCBA were determined as no burn. The results of flammability test for the coatings with 20 wt% and 30 wt% of TCBA contents indicated the limiting oxygen index (LOI) values of 26% and 29% respectively, which implied relatively good flame retardancy.

The flame-retardant coatings were prepared by blending the synthesized triphosphorus modified polyester in the previous paper and hexamethylene diisocyanate-trimer and curing it at room temperature. The characterization of the films of the prepared coatings was performed. It was confirmed that no deterioration of physical properties of PU coatings was observed with the increasing phenylphosphonic acid (PPA) contents. Flame retardancy was tested by a 45˚ Meckel burner method and LOI method. With the 45˚ Meckel burner method, CATBTP-20C and CATBTP-30C that contain 20 wt% and 30 wt% of PPA, flame retarding component, respectively, showed the first grade flame retardancy with 2.8~3.9 cm of char length ; and, with LOI method, they exhibited a good flame retardancy as a range of 30~32% of combustion values.

In order to obtain the maximum flame retardancy with the minimal deterioration of physical properties of PU flame-retardant coatings, chlorine and phosphorous functional groups were introduced into the pre-polymer of modified polyesters. In the first step, the tetramethylene bis(orthophosphate) (TBOP) and neohexanediol dichloroacetate (DCA-adduct) intermediates were synthesized. In the second step, 1,4-butanediol and adipic acid monomers were polymerized with the two kind of intermediates to obtain copolymer. The modified polyesters containing chlorine and phosphorous (ATBA-10C, -20C, and -30C) were synthesized by adjusting the contents of chlorine compound (dichloroacetic acid, 10, 20, 30 wt%) with fixed the content of phosphorous compound (2 wt%). The PU flame-retardant coatings (TTBAH -10C, -20C, and -30C) were prepared using the synthesized ATBAs and HDI-trimer as curing agent at room temperature. The physical properties of PU flame-retardant coatings with chlorine and phosphorous were inferior to those with phosphorous only and the properties were getting worse with increasing chlorine content. Flame retardancy was tested with three methods. With the vertical method, Complete combustion time of ATBAHs were 259~347 seconds, which means that the prepared coatings are good flame-retardant. With the 45˚ Meckel burner method, char lengths of the three prepared coatings were less than 2.9 cm, which indicates that the prepared coatings are 1st grade flame retardancy. With the limiting oxygen index (LOI) method, the LOI values of the three prepared coatings were in the range of 30~35%, which proves good flame retardancy of the prepared coatings. From the results of flame retardancy tests of the specimens that contain the same amounts of flame retarding compounds, it was found that the coatings containing both phosphorous and chlorine show higher flame retardancy than the coatings containing phosphorous alone. This indicates that some synergy effect of flame retardancy exists between phosphorous and chlorine.

A high resolution spectrum of PU Vul obtained at Bohyunsan Astronomy Observatory on April 9, 2004 is presented. At this phase, PU Vul was an emission-line star and its continuum was very weak. Emission lines of He II, H I, [Ne IV], [N II], [O III], [Ar V ] and [Fe VII] dominated the spectrum of PU Vul. Many of them exhibited hat-top profiles with strong and multi-peaked emissions on flat-tops of their profiles. Radial velocities for these lines were measured. Origins of the spectral lines are discussed in terms of the wind and the photoionization models.

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 tetramethylene 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 2%, 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 ABTT-10C, -20C, -30C. Two-component PU flame-retardant coatings (ABTTC, ABTTC-10C, ABTTC-20C, ABTTC-30C) were prepared by the curing of synthesized ABTTs with a curing agent of allophanate/trimer at room temperature. To examine the film properties of the prepared PU flame-retardant coatings, film specimens were prepared with the prepared coatings. The film properties of ABTTC, ABTTC-10C and ABTTC-20C, which contain 0, 10 and 20wt% 2,4-DCBA, respectively, were proved to be good, whereas the film properties of ABTTC-30C, which contains 30wt% 2,4-DCBA, was proved to be a little bit poor. Two kinds of flame retardancy tests, ˚45Meckel burner method and LOI method were performed. With the ˚45Meckel burner method, three flame-retardant coatings except ABTTC showed less than 3.4cm of char length, and showed less than 2 seconds of afterflaming and afterglow. From this result, the prepared flame-retardant coatings were proved to have the 1st grade flame retardancy. With the LOI method, the LOI values of the coatings containing more than 10wt% 2,4-DCBA were higher than 30%, which means that the coatings possess good flame retardancy. From these results, it was found that synergistic effect in flame retardancy was taken place by the introduced phosphorus and chlorine.

The PU flame-retardant coatings (TTBAH, ATBAH-10C, -20C, and -30C) were prepared using the synthesized ATBAs and HDI-trimer as curing agent at room temperature. The physical properties of PU flame-retardant coatings with chlorine and phosphorus were inferior to those with phosphorus only and the properties were getting worse with increasing chlorine content. Flame retardancy was tested with three methods. With the vertical method, complete combustion time of ATBAHs were 259~347 seconds, which means that the prepared coatings are good flame-retardant. With the 45˚ Meckel burner method, char lengths of the three prepared coatings were less than 2.9 cm, which indicates that the prepared coatings are first grade. With the limiting oxygen index (LOI) method, the LOI values of the three prepared coatings were in the range of 30~35%, which proves good flame retardancy of the prepared coatings. from the result of flame retardancy tests of the specimens that contain the same amounts of flame retarding compounds. it was found that the coatings containing both phosphorus and chlorine show higher flame retardancy than the coatings containing only phosphorus. This indicates that there exists, some synergy effect between coexisting phosphorus and chlorine.

PU type flame-retardant coatings (TBAO/L-75, TBAOL ; TBAO/N-100, TBAON) were prepared by blending bromine-containing modified polyester (TBAO) which was synthesized in our earlier work. with two kinds of isocyanate curing agents, Desmodur L-75 and Desmodur N-100. Physical properties of the prepared flame-retardant coatings were tested. TBAOL shows better hardness than TBAON, while TBAON shows better viscosity, accelerated weathering resistance, yellowness index and lightness index difference than TBAOL. There were no remarkable differences in fineness of grind, 60˚ specular gloss, cross-hatch adhesion, and abrasion resistance of TBAOL and TBAON. There was no discernable difference in flame-retardancy between the two flame-retardant coatings, TBAOL and TBAON. When the content of tribromo acetic acid, which is flame-retarding component, was 30wt% the LOI value was in a range of 29~30%, which indicates that the two coatings are good flame-retardant coatings.

Modified polyesters (TTBA-10C, -20C, -30C) that contain phosphorus and chlorine were synthesized by the condensation polymerization of tetramethylene bis(orthophosphate), neohexanediol trichlorobenzoate, 1,4-butanediol and adipic acid, in which tetramethylene bis(orthophosphate) and neohexanediol trichlorobenzoate were prepared previously in our laboratory. In this study, two-component flame-retardant polyurethane coatings (TTBA-10C/HDI-trimer=TTHD-10C, TTBA-20C/ HDI-trimer= TTHD-20C, TTBA-30C/HDI-trimer= TTHD-30C) were obtained by curing at room temperature with the synthesized TTBAs and hexamethylene diisocyanate (HDI)-trimer as a curing agent. The obtained TTHDs were made into coating samples and used as test samples for various physical properties. The physical properties of the flame-retardant coatings containing chlorine and phosphorus groups were generally inferior to those containing only phosphorus group. Flame retardancy was tested by vertical and horizontal combustion method, and 45˚ Meckel burner method. Since the retardancy of flame-retardant coatings containing chlorine and phosphorus groups was better than that containing only phosphorus group, it could be concluded that the retardancy by the synergism effect of chlorine and phosphorus groups exhibited.

We present a high resolution spectrum of PU Vul observed at Bohyunsan Optical Astronomy Observatory (BOAO) on April 9, 2004. Permitted emission and nebular lines of PU Vul had been significantly changed compared to all spectra observed since its eruption in 1979. Therefore all new lines should be re-identified and were done so. We do-convoluted a Hβ line into several emission components with Gaussian functions. Then we carefully discussed the geometrical feature of PU Vul in April 2004.

To maximize a synergy effect in flame-retardancy of flame-retardant coatings, phosphorus and chlorine were introduced in polymer chains. Two-components PU flame-retardant modified polyesters (ABTTC-10C, -20C, -30C) were prepared by curing, at room temperature, of isocyanate (allophanate-trimer) and prepared modified polyesters which contain phosphorus and chlorine. To examine the film properties of the prepared flame-retardant coatings, film specimens were prepared with the prepared coatings. The film properties of ABTTC, ABTTC-10C and ABTTC-20C, which contain 0, 10 and 20wt%, 2,4-dichlorobenzoic acid (2,4-DCBA), respectively, were proved to be good, whereas the film properties of ABTTC-30C, which contains 30wt% 2,4-DCBA, were proved to be a little bit poor. Two kinds of flame retardancy tests, 45˚Meckel burner method and LOI method, were performed. With the 45˚Meckel burner method, three flame-retardant coatings except ABTTC showed less than 3.4 cm of char length, and showed less than 2 seconds of afterflaming and afterglow. From this result, the prepared flame-retardant coatings were proved to have the 1st grade flame retardancy. With the LOI method, the LOI values of the coatings containing more than 10wt% 2,4-DCBA were higher than 30wt%, which means that the coatings possess good flame-retardancy. From these results, it was found that synergistic effect in flame-retardancy was taken place by the introduced phosphorus and chlorine.

Reaction intermediates PCP/BZA (PBI) and tetramethylene bis(orthophosphate)(TBOP) were synthesized from polycaprolactone (PCP) and benzoic acid (BZA) and from pyrophosphoric acid and 1,4-butanediol, respectively. Benzoic acid modified polyesters containing phosphorus (APTB-S, -10, -15) were synthesized by polycondensation of the prepared PBI (containing 5, 10, 15wt% of benzoic acid), TBOP, adipic acid, and 1,4-butanediol. Network structured PU flame-retardant coatings (APHD) were prepared by curing the synthesized benzoic acid modified polyesters containing phosphorus (APT B - 5 , -10, -15) with hexamethylene diisocyanate (HDI)-timer. From the TGA analysis of APTBs, it was found that the afterglow decreased with the amount of BZA content at the high temperatures. With the introduction of BZA, the film viscosity and film hardness of APHD decreased. With the introduction of caprolactone group, the flexibility, impact resistance, accelerated weathering resistance of APTBs increased. Flame retardancy of the coatings was tested. In a vertical burning method, APHD shows 210~313 seconds, which indicates that the coatings are good flame-retardant coatings. Moreover, the amount of afterglow and flame retardancy of the coatings are decreased with increasing BZA content.

유기증기에 대한 PDMS의 단점을 보완하기 위해 4,4'-diphenylmethane diisocyanate (MDI)와 1,4-butanediol(BD)를 이용하여 poly(dimethylsiloxane)를 기초로 한 polyurethane-polysiloxanes (PU/PDMS)를 합성하였다. 그리고 poly(tetrafluoroethylene) (PTFE)를 다공성 지지체로 이용하여 복합막을 제조하여 SEM 분석으로 코팅층의 존재와 두께를 확인하였다. 증기투과실험에서 투과온도와 feed의 농도가 증가할수록 flux는 점차 증가하였고, separation factor는 이와 반대로 점차 감소하는 'trade-off'현상을 보였다. 본 연구에서의 PU/PDMS는 soft segment의 함량보다는 비교적 hard segment의 함량이 높기 때문에 투과온도의 증가에 따른 영향이 크지 않았던 것으로 사료된다. PU/PDMS막은 VOCs와 상대적으로 높은 친화도를 가지고 있기 때문에 PU/PDMS 균질막과 비교하여 복합막의 형태에서도 향상된 flux와 높은 separation factor를 나타내었다.

Chlorine-containing modified polyester polyols were synthesized by two-step condensation reactions. Intermediate was synthesized by the esterification of monochloroacetic acid with trimethylolpropane in the first step. Polycondensation of the intermediate (MCAOs), 1,4-butanediol, and trimethylolpropane with adipic acid was carried out. Two-component polyurethane (PU) coatings were prepared by blending MCAOs and IPDI-isocyanurate. There new flame-retardant coatings showed various properties comparable to other non-flame-retardant coatings. They were superior to flammable coatings from the experimental results showing rapid and 10 to 13 hours of pot-life. Coatings with 30wt% monochloroacetic acid was not flammable by the vertical flame retardancy test.