발포제에 따른 PIR 폼의 물성에 관한 연구

윤완희(Wan Hee Yun),김상범(Sang-Bum Kim) 한국고분자학회 2021 폴리머 Vol.45 No.4

본 연구에서는 오존층파괴지수와 지구온난화지수가 낮은 1-chloro-3,3,3-trifluoropropene(HFO-1233zd)와 탄화수소계 발포제인 cyclopentane 및 1,1-dichloro-fluoroethane(HCFC-141b)의 대체 발포제로 사용중인 1,1,1,3,3-pentafluoropropane(HFC-245fa)를 사용하여 polyisocyanurate(PIR) 폼을 합성한 후 발포제에 따른 폼의 열전도도와 기계적 강도 및 열적 성질을 비교하였다. HFO-1233zd를 사용하여 합성한 PIR 폼은 다른 발포제를 사용한 폼에 비해 낮은 열전도도를 나타내어 단열 성능이 가장 뛰어남을 확인하였으며, 압축강도 결과에서도 cyclopentane보다는 우수하고, HFC-245fa와 유사한 강도를 나타내었다. 한계산소지수(LOI) test결과 cyclopentane을 사용한 폼이 가장 낮은 LOI 값(23.7%)을 나타내었으며, HFO-1233zd를 사용하여 만든 폼이 가장 높은 값(26.3%)을 나타내어 난연성이 우수함을 확인하였다. In this study, 1-chloro-3,3,3-trifluoropropene (HFO-1233zd), which has low ozone depletion potential and global warming potential, was used to synthesize the polyisocyanurate (PIR) foam and its mechanical strength and thermal properties were compared with foam synthesized using cyclopentane, a hydrocarbon-based blowing agent, and 1,1,1,3,3-pentafluoropropane (HFC-245fa), an alternative blowing agent to 1,1-dichloro-fluoroethane (HCFC-141b). PIR foam synthesized using HFO-1233zd showed the lowest thermal conductivity among foam synthesized using other blowing agents, confirming its superior insulation performance. Furthermore, its compressive strength was higher than that of the foam using cyclopentane, having strength similar to foam using HFC-245fa. According to the limited oxygen index (LOI) test, foam synthesized using cyclopentane showed the lowest LOI value (23.7%) while HFO-1233zd based foams scored the highest (26.3%) proving their excellence in flame retardancy.

발포제에 따른 폴리우레탄 폼의 발포 특성 및 물성 분석

윤완희(Wan Hee Yun),김상범(Sang Bum Kim) 한국고분자학회 2021 폴리머 Vol.45 No.3

본 연구에서는 물, HCFC-141b, HFC-245fa, HFO-1233zd, HFO-1336mzz를 사용하여 경질 폴리우레탄 폼을 합성하였고 각각의 발포제가 폼의 합성 및 물성에 미치는 영향을 고찰하였다. 폼 합성 과정에서의 발포제 손실률은 발포제의 가스 생성 속도와 폼의 온도 상승 속도 및 최대 온도의 영향을 받는 것을 확인하였다. 폼의 압축강도는 셀 크기가 작을수록 높게 나타났으며 HFO-1233zd를 사용한 폼은 셀 크기가 작고 가스열전도도가 낮아 높은 단열성능을 나타내었다. 하지만, HFO-1233zd의 가소화 작용으로 인해 시간이 경과할수록 폼의 유리전이온도가 감소하는 것을 확인하였다. 다양한 분석을 통해 HFO-1233zd와 HFO-1336mzz가 HFC 계열의 발포제를 대체할 수 있는 발포제로서 적절한 것을 확인하였다. In this study, we synthesized rigid polyurethane foam using water, HCFC-141b, HFC-245fa, HFO-1233zd, and HFO-1336mzz and analyzed the effect of each blowing agent on the foam’s thermal and physical properties. It was confirmed that the loss rate of a blowing agent during blowing process is affected by gas generation rate of the blowing agent, the foam’s maximum temperature, and the rate of its temperature rise. Foam with smaller cells showed greater compressive strength, and foam produced using HFO-1233zd showed high insulation performance due to small cells and low gas thermal conductivity. However, the foam’s glass transition temperature decreased as time passed due to the plasticizing effect of HFO-1233zd. Through various analysis, it was confirmed that HFO-1233zd and HFO-1336mzz are suitable for replacing HFC-based blowing agents.

PMDI Trimer를 이용한 PT-PUIR 폼의 열 안정성 향상 연구

배정민(Jeong Min Bae),윤완희(Wan Hee Yun),김상범(Sang Bum Kim) 한국고분자학회 2020 폴리머 Vol.44 No.1

본 연구는 폴리우레탄 폼(polyurethane foam)의 열 안정성을 향상시키기 위해 polymeric methylene diphenyl diisocyanate(PMDI)를 pre-trimerization 시켜 pre-trimerized isocyanurate prepolymer(PT, PMDI trimer)를 합성한 후 이를 이용하여 pre-trimerized polyurethane polyisocyanurate foam(PT-PUIRF)을 합성하였다. TGA와 LOI, UL94 V 및 만능시험기를 사용하여 합성된 PT-PUIRF와 polyurethane-polyisocyanurate foam(PUIRF)의 열 안정성과 기계적 물성을 비교하였다. FTIR을 통해 PT-PUIRF에 포함되어 있는 이소시아누레이트의 함량이 PUIRF보다 높은 것으로 밝혀졌으며, 이로 인해 PT-PUIRF가 PUIRF보다 높은 내열성과 난연성을 나타냄을 알 수 있었다. To improve the thermal stability of polyurethane foam, the pre-trimerized polyurethane-polyisocyanurate foam (PT-PUIRF) was prepared using pre-trimerized isocyanurate prepolymer (PT). Herein, PT was synthesized by “pre-trimerization” using polymeric methylene diphenyl diisocyanate (PMDI) and trimerization catalyst. Thermal stabilities and mechanical properties of PT-PUIRF and polyurethane-polyisocyanurate foam (PUIRF) were evaluated via TGA and UTM. Also, the flame retardancy of these foams was investigated by limiting oxygen index (LOI) and vertical burning test (UL94 V). FTIR results showed that PT-PUIRF contained more isocyanurate than PUIRF, indicating that PT-PUIRF had higher heat resistance and flame retardancy than PUIRF.

TALP-32의 인체자궁암 세포주 HeLa에 대한 세포독성

박지훈(Ji-Hoon Park),김종석(Jong-Seok Kim),윤은진(Eun-Jin Yun),송경섭(Kyoung-Sub Song),서강식(Kang-Sik Seo),김훈(Hoon Kim),정연주(Yeon-Joo Jung),윤완희(Wan-Hee Yun),임규(Kyu Lim),황병두(Byoung-Doo Hwang),박종일(Jong-Il Park) 한국독성학회 2006 Toxicological Research Vol.22 No.4

TALP-32 is highly basic protein with a molecular weight of 32 kDa purified from human term placenta. Some basic proteins such as defensins and cecropins are known to induce cell death by increasing membrane permeability and some of them are under development as an anticancer drug especially targeting multi-drug resistant cancers. Therefore, we investigated cytotoxic effect and mechanism of TALP-32. When HeLa cell was incubated with TALP-32, cytotoxicity was increased in time and dose dependent manner. As time goes by, HeLa cells became round and plasma membrane was ruptured. Increase of plasma membrane permeability was determined with LDH release assay. Also in transmission electron microscopy, typical morphology of necrotic cell death, such as cell swelling and intracellular organelle disruption was observed, but DNA fragmentation and caspase activation was not. And necrotic cell death was determined with Annexin V/PI staining. The cytotoxicity of TALP-32 was minimal and decreased on RBC and Hep3B respectively. These data suggests that TALP-32 induces necrosis on rapidly growing cells but not on slowly growing cells implicating the possibility of its development of anticancer peptide drug.

12-O-Tetradecanoylphorbol-13-Acetate에 의한 HL-60 세포 분화유도중 Vimentin 유전자 전사조절에 대한 AP-1의 역할

임규,김진희,권도원,김승민,이명선,윤경아,손미영,박종일,윤완희,황병두 충남대학교 생물공학연구소 1999 생물공학연구지 Vol.7 No.-

Purpose: To gain insight on the role of AP-1 in transcriptional regulation of vimentin gene during differentiation of HL-60 cells by 12-O-tetradecanoylphorbol-13-acetate (TPA), the levels of vimentin mRNA and AP-1 have been investigated with Northern blot hybridization and DNA mobility shift assay. Materials and Methods: HL-60 cells were grown in RPMI 1640 medium supplemented with 10% heat-inactivated fetal calf serum and antibiotics in a humidified 5% CO_2 at 37℃. Total RNA was prepared by a modification of the method of Karlinsey et al. Northern blot hybridization was performed by the method of Virca et al. EcoRI fragment of pVIM-GEM was used as probe for vimentin mRNA. DNA mobility shift assay was performed by the method of Lim et al. End labeled DNA probe(Upper strand, 5'-CGCTTGATGAGTCAGCCG- 3') for AP-1 binding activity was mixed with nuclear extracts in a 20 μl reaction volume containing 300 mM KCI, 60 mM HEPES, pH 7.9, 25 mM MgCI_2, 1 mM EDTA, 1 mM DTT, 60% glycerol, and 2 ㎍ of poly[dI-dC]. Results: TPA increased vimentin mRNA levels, with maximal stimulation reached at 24 hr. The level of vimentin mRNA was induced in proportion to the concentration of TPA. TPA-induced vimentin mRNA was almost reduced by actinomycin-D pretreatment. TPA-induced stimulation of vimentin gene was completely reduced by staurosporin pretreatment. In DNA mobility shift assay, AP-1 newly appeared at 24 hr during TPA-induced differentiation and was almost not detected after the pretreatment of staurosporin. Conclusions: These results suggest that the induction of vimentin mRNA during TPA-dependent differentiation in HL-60 cells may be mediated by protein kinases C signal transduction and AP-1 is important to transcriptional regulation.

12-O-Tetradecanoylphorbol-13-Acetate에 의한 HL-60 세포 분화유도중 Vimentin 유전자 전사조절에 대한 AP-1의 역할

임규,김진희,권도원,김승민,이명선,윤경아,손미영,박종일,윤완희,황병두 忠南大學校 癌共同硏究所 1998 癌共同硏究所 硏究誌 Vol.2 No.1

Purpose: To gain insight on the role of AP-1 in transcriptional regulation of vimentin gene during differentiation of HL-60 cells by 12-O-tetradecanoylphorbol-13-acetate (TPA), the levels of vimentin mRNA and AP-1 have been investigated with Northern blot hybridization and DNA mobility shift assay. Materials and Methods: HL-60 cells were grown in RPMI 1640 medium supplemented with 10% heat-inactivated fetal calf serum and antibiotics in a humidified 5% CO_(2) at 37°C. Total RNA was prepared by a modification of the method of Karlinsey et al. Northern blot hybridization was performed by the method of Virca et al. EcoRI fragment of pVIM-GEM was used as probe for vimentin mRNA. DNA mobility shift assay was performed by the method of Lim et al. End labeled DNA probe(Upper strand, 5'-CGCTTGATGAGTCAGCCG- 3') for AP-1 binding activity was mixed with nuclear extracts in a 20 μl reaction volume containing 300 mM KC1, 60 mM HEPES, pH 7.9, 25 mM MgCl_(2), 1 mM EDTA, 1 mM DTT, 60% glycerol, and 2μg of poly[dI-dC]. Results: TPA increased vimentin mRNA levels, with maximal stimulation reached at 24 hr. The level of vimentin mRNA was induced in proportion to the concentration of TPA. TPA-induced vimentin mRNA was almost reduced by actinomycin-D pretreatment. TPA-induced stimulation of vimentin gene was completely reduced by staurosporin pretreatment. In DNA mobility shift assay, AP-1 newly appeared at 24 hr during TPA-induced differentiation and was almost not detected after the pretreatment of staurosporin. Conclusions: These results suggest that the induction of vimentin mRNA during TPA-dependent differentiation in HL-60 cells may be mediated by protein kinases C signal transduction and AP-1 is important to transcriptional regulation.

RAW264.7 세포에서 interferon-r 및 LPS에 의해 유도되는 NO생성에 미치는 TALT-35의 영향

박종일,박경석,김종석,박지훈,윤은진,송경섭,서강식,김훈,윤완희,박승길,임규,황병두 충남대학교 생물공학연구소 2006 생물공학연구지 Vol.12 No.-

TALP-35 purified from human term placenta is known to increase microtubule polymerization and stabilize the polymerized microtubule. To examine the effect of TALP-35 on immune system this study was performed. MTT assay was performed to investigate the effect of TALP-35 on the proliferation of RAW264.7 cells. TALP-35 dose dependently suppress the proliferation of RAW264.7 cells at high concentration (above 1 μM) in unstimulated cells, in case of 10 μM TALP-35 treated cells the suppression was 25% but in stimulated cells it was only 15%. Cosedimentation assay was carried out to investigate whether TALP-35 can bind to tubulin of RAW264.7, monocyte/macrophage lineage of mouse, and polymerize it. TALP-35 polymerize the tubulin of RAW264.7 cells and sedimented in dose-dependent manner. To investigate the effect of TALP-35 on the expression of iNOS protein western blotting was performed. The expression level of iNOS was decreased dose dependently in high concentration of TALP-35 treatment. To examine the activity of iNOS, secreted NO was determined by method based on Griess reaction. Interferon-γ and LPS-stimulated production of NO from RAW264.7 cells was decreased dose dependently above 0.1 μM concentration of TALP-35 and 50% is decreased at 10μM of it. This study shows TALP-35 can control cytokine induced-iNOS expression therefore it might control inflammatory diseases.