• Title/Summary/Keyword: FT

Search Result 3,819, Processing Time 0.033 seconds

Silicon thin films and solar cells by HWCVD (열선 화학 기상 증착법에 의한 실리콘 박막 및 태양전지 특성)

  • Kim Sang-Kyun;Lee Jeong Chul;Jeon Sang Won;Lim Chung Hyun;Ahn Sae Jin;Yun Jae Ho;Kim Seok Ki;Song Jinsoo;Park S-J;Yoon Kyung Hoon
    • 한국신재생에너지학회:학술대회논문집
    • /
    • 2005.06a
    • /
    • pp.205-208
    • /
    • 2005
  • 최근 열선 화학 기상 증착법(HWCVD)은 낮은 온도에서 TFT용 Poly Si 중착을 할 수 있다는 점과 실리콘 박막을 빠른 속도로 증착할 수 있다는 점에서 각광을 받고 있다. 본 연구에서는 HWCVD를 이용하여 태양전지를 제조하고 그 특성을 평가하였다. 조건에 따른 실리콘 박막의 특성 변화를 알기 위해 corning glass 및 실리콘 wafer에 다양한 조건에서 단위 박막(intrinsic layer)을 증착하였고 이 결과를 바탕으로 p/i/n 구조의 태양전지를 제조하였다. Ta 열선 온도는 1700-2000도였고 가스 원료인 $SiH_4$와 수소의 비율을 조절하면서 그 영향을 관찰하였다. 태양전지의 경우 p충과 n충은 PECVD로 증착하였으며 단위박막 및 태양전지 i충 증착시 기판과 열선간의 거리는 7cm, 기판 온도는 $200^{\circ}C$$250^{\circ}C$로 고정하였고 작업압력은 30mTorr였다. 단위 박막 특성 평가를 위해 암/광 전도도, SEM, Raman Scattering, FT-IR등을 사용하였으며 태양전지 특성 평가를 위해 I-V 및 Spectral response를 측정하였다. 열선 온도가 증가함에 따라 증착속도 및 결정화 분율은 증가하였다. 특히 비정질에서 결정질로 전이되는 구간은 매우 좁았으며 여러 분석 방법에서 일치되는 결과를 보였다. $SiH_4$ 유량이 늘어날수록 비정질이 결정질로 바뀌는 열선 온도가 증가하였으며 기판 온도가 낮을 경우 또한 결정으로 바뀌는 열선 온도가 증가하였다. 태양전지의 경우 열선 온도가 증가함에 따라 $V_{oc}$ 및 W가 낮아졌으며 $J_{sc}$, 는 증가하는 경향을 보였으며 결정질 비율이 증가하는 것을 관찰할 수 있었다. 이러한 경향은 quantum efficiency 결과에서도 확인할 수 있었다.용을 반복하면서 석재 내부와 외부의 암석 및 결정에 균열과 미세열극 등이 생성되어 석재 자체의 구조적 안정성에 영향을 주고 있다. 따라서 감은사지 석탑은 지리적 환경 차이로 인해 일반적인 환경의 석조물들과는 다른 형태의 풍화양상을 보이고 있어서 풍화양상 및 풍화형태에 대한 정확한 연구와 이해를 바탕으로 보존대책이 마련되어야 한다.되었다. 이런 모든 시편들을 각 탈염방법에 따라 탈염처리한 후 XRD와 SEM-EDS으로 분석한 결과 인철광과 침철광은 어떠한 변화도 보이지 않았고, 다만 적금광으로 동정된 시편만이 잔존하지 않았다. 철기 제작별 $Cl^-$ 이온 추출량과 탈염효과에 대한 비교 실험은 이온 크로마토그래피 분석 결과와 마찬가지로 단조 철제유물이 주조 철제보다 $Cl^-$ 이온을 많이 가지고 있었으며, 탈염 처리 후에는 $Cl^-$ 이온은 전혀 발견되지 않았다. 이상의 결과 $K_2CO_3$와 Sodium 용액은 탈염처리에서 가장 적합한 탈염처리 용액으로 알수가 있었으며 특히 어떠한 탈염 용액으로 유물을 처리한다 해도 철제유물에 생성된 부식물은 제거되지 않는다는 것을 알게 되었다. 따라서 보존처리자는 유물 표면의 부식 상태만을 보고 처리하기 보다는 철기제작물로 고려하여 처리하는 것이 필요하다. 또한 금속에 부식을 야기시키는 $Cl^-$ 이온과 부식물을 완전하게 제거하여 탈염처리를 하는 것이 유물 부식을 최대한 지연시킬 수 있는 것이라 생각된다.TEX>$88\%$)였다.(P=0.063). 결론: 본 연구에서는 MTHFR C/T & T/T 유전자 다형성이 위암의 발생과 그 위치에 대해 관련이 있는 것으로 여겨지고, 흡연력, 음주력과는 관련이 없는 것으로 여겨진다.험이 커지는 경향을 보였으나, 나이 및 병기, 종양의 크기, MD-BED $Gy_{10}$ 등의 예후 인자를 보정한 다변

  • PDF

Clinical Analysis of Arterial Occlusive Disease in the Lower Extremity (하지 혈행장애의 임상적 고찰)

  • 서정욱;조은희
    • Journal of Chest Surgery
    • /
    • v.29 no.8
    • /
    • pp.889-896
    • /
    • 1996
  • Aggressive revascularization of the ischemic lower extremities in atherosclerotic occlusive diseases or acute embolic arterial occusion due to cardiac valvular disease by thromboembolectomy or an arterial by- pass operation has been advocated by some authors. To evaluate clinical pattern and operative outcome of the ischemic lower extremity, surgical experience in 101 patients who were admitted to Dong-A Univer- sity Hospital between March 1990 and August 1995 was analyzed. The patients were 92 males and 9 females ranging fro 25 to 87 years of age. The underlying causes of arterial occlusive disease were atherosclerotic obliterances in 54 case, Buerger's disease in 20 cases, thromboembolism in 24 cases, vascular trauma in 3 cases and pseudoaneurysm in 3 cases. - The major arterial occlusive sites of atherosclerotic obliterance were femoral artery in 30 cases, iliac artery in 23 cases, popliteal artery in 10 cases, distal aorta in 6 cases and the major arterial occlusive sites of Buerger's disease were posterior tibial artery in 14 cases, anterior tibial artery in 8 cases, popliteal artery in 5 cases. The operative procedures of arterial occlusive disease were bypass graft operation in 61 cases, thromboembolectomy in 21 cases, sympathectomy in 20 cases. Arterial bypass operations with autogenous or artificial vascular prosthesis were done in 61 cases which Included femoro-popliteal bypass in 21 cases, femoro-femoral bypass in 15 cases, axillo-bifemoral bypass in 7 cases, aorto-bifemoral with inverted Y-gr ft In 3 cases, femoro-profundafemoral bypass in 3 cases, popliteo-tibial bypass in 2 cases, aorto-iliad bypass in 1 case Over all postoperative patency rates were 83.6 oyo at 1 year, 75.5% at 3 years and limb salvage rate was 86.8 oyo . Six patients died in the hospital following vascular surgery for ischemic lower extremities, although the causes of death were not directly related to the vascular reconstructive operative proccedures. The leading causes of death were in the order of multiple organ failure, acute renal failure, and sepsis.

  • PDF

Chitosan and Acetylchitosan from Squid Pen and Their Characteristics (오징어 연골을 이용한 Chitosan 및 Acetylchitosan의 제조와 특성)

  • CHOI Hyeon-Mee;HWANG Sun-Young;PARK Seong-Min;LEE Keun-Tai
    • Korean Journal of Fisheries and Aquatic Sciences
    • /
    • v.34 no.5
    • /
    • pp.563-569
    • /
    • 2001
  • In order to utilize the processing wastes of squid, chitosan was prepared by intermittent deacetylation treaoent of $\beta-chitin$ contained richly in the pen of squid. Acetylchitosan also was synthesized from squid pen chitosan with anhydrous acetic acid and their characteristics were investigated. The amounts of nitrogen and ash of squid pen chitosan were $5.80.2\% and 0.2\pm0.03\%$ respectively, the yield of squid pen chitosan was $25\pm3\%$, the degree of deacetylation was $92\%$, and the molecular weight was $1.15\times10^6$, Acetyl contents of N-acetylchitosan powder, acetylchitosan bead, N-ACF-1 (N-acetylchitosan film-1) and N-ACF-2 (N-acetylchitosan film-2) were $55.9\%, 63.2\%, 56\% and 58.7\%$ respectively. Two major peaks, amide I ($1,653 cm^{-1}$) and II ($1,558 cm^{-1}$) bent, on FT-IR spectra of the N-acetylchitosan from squid pen were almost similar to these of $\beta-chitin$, While there was a broad single peak at $1,601 cm^{-1}$assigned to be an amide I bend in squid pen chitosan. The CP/MAS NMR spectra of $\beta-chitin$, squid pen chitosan and N-acetylchitosan from squid pen showed a relative broad and single peak at 74 ppm assigned to fifth carbon (C-5) and third carbon (C-3). In case of $\beta-chitin$ and N-acetylchitosan from squid pen, single peak at 74 ppm was showed as the same of $\beta-chitin$ type.

  • PDF

Chemo-Mechanical Analysis of Bifunctional Linear DGEBA/Linear Amine (DDM, DDS) Resin Casting Systems (DGEBA/방향족 아민(DDM, DDS) 경화제의 벤젠링 사이의 관능기 변화가 물성 변화에 미치는 영향에 대한 연구)

  • 명인호;정인재;이재락
    • Composites Research
    • /
    • v.12 no.4
    • /
    • pp.71-78
    • /
    • 1999
  • To determine the effect of chemical structure of linear amine curing agents on thermal and mechanical properties, standard epoxy resin DGEBA was cured with diaminodiphenyl methane (DDM), diaminodiphenyl sulphone (DDS) in a stoichiometrically equivalent ratio. From this work, the effect of aromatic amine curing agents. In contrast, the results show that the DGEBA/DDS cure system having the sulfone structure between the benzene rings had higher values in the conversion of epoxide, density, shrinkage (%), glass transition temperature, tensile modulus and strength, flexural modulus and strength than the DGEBA/DDM cure system having methylene structure between the benzene rings, whereas the DGEBA/DDM cure system presented higher values in the maximum exothermic temperature, thermal expansion coefficient, and thermal stability. These results are caused by the relative effects of sulfone group having strong electronegativity and methylene group having (+) repulsive property and stem from the effect of the conversion ratio of epoxide group. The result of fractography shows that the each grain size of the DDM/DGEBA system with feather-like structure is larger than that of the DDS/DGEBA system.

  • PDF

The Effect of School Dental Service on Dental Health Knowledge, Beheaviors and Dental Health Status Among Elementary School Students (학교 구장보건실 운영이 초등학생들의 구강보건지식, 행태 및 건강상태에 미치는 영향)

  • Lee, Tae-Yong;Yun, Go-Eun;Kim, Kwang-Hwan
    • The Journal of Korean Society for School & Community Health Education
    • /
    • v.10 no.1
    • /
    • pp.87-104
    • /
    • 2009
  • Objective: In this study, the dental health care knowledge, dental health behaviors and dental health status of elementary school students were compared and analyzed in the cases of their schools having dental health care center or not one. Methods: The target groups were 167 students of A school (experimental group) where pit-and-fissure sealants, fluoride mouthrinsing, and fluoride gel application were carried out with all grades of students by school dental health care center and 158 students of B school (control group) where fluoride mouthrinsing, for all grades students and pit-and-fissure sealants for the first grade students are carried out but have no the school dental health care center. Results: This study was carried out through the answer sheets and recordings of dental inspection. The findings of this study are as follows: 1. The dental health care knowledge was compared and the results showed that on average 14.2$\pm$2.1 in experimental group and 14.0$\pm$1.9 in the control group were no significantly different (p>0.05). 2. The dental health behaviors were compared and the results showed that the experimental group was significantly different(p<0.05) in terms of the number of times of dental brushing a day, the method of tooth brushing, the time of tooth brushing, the experience of tooth brushing with fluorine, the kinds of snacks and tooth brushing in school after lunch. But there was no significant difference(p>0.05) in the time of tooth brushing and the tooth brushing after eating snacks. 3. The DMF rate was compared and the results showed the significantly difference between the average experimental group and 53.8$\pm$5.0 in the control group(p<0.05). 4. The DMFT index was compared and the results showed the significantly difference between the average 0.6$\pm$2 in the experimental group and 1.4$\pm$1.6 in the control group(p<0.05). 5. The DMFI rate was compared and the results showed the significantly difference between the average 4.2$\pm$8.3 in the experimental group and 9.5$\pm$11.0 in the control group. (p<0.05). 6. The DT rate were compared and the results showed the significantly difference between the average 10.2$\pm$29.5 in the experimental group and 32.4$\pm$44.0 in the control group(p<0.05). 7. The FT rate were compared and the results showed the significantly difference between the average 88.5$\pm$31.0 in the experimental group and 67.5$\pm$44.0 in the control group(p<0.05). Conclusions: Based on the results, above there was no significant difference in dental health care knowledge between both the experimental and the control group. But we discovered that the experimental group is better than the other one in dental health care behaviors and dental health status. Therefore, we could conclude that the school dental health care center efficiently carried out the dental care and treatment. As school dental health care centers did not work out efficiently in terms of their educating on the dental health acre knowledge, the related programs to be developed and supported.

  • PDF

A Study on the Identification of Animal Hair in Food (식품 중 동물 털 이물의 판별법 연구)

  • Lee, Jae-Hwang;Park, Young-Eun;Lim, Byung-Chul;Kim, Ju-Shin;Choi, Jong-Hyun;Kang, Tae Sun;Lee, Jin-Ha;Kwon, Kisung
    • Journal of Food Hygiene and Safety
    • /
    • v.32 no.1
    • /
    • pp.57-63
    • /
    • 2017
  • Foreign materials with a variety of types and sizes are found in food; thus, extraordinary efforts and various analytical methods are required to identify the types of foreign materials and to find out accurate causes of how they unintentionally enter food. In this study, human, cow, pig, mouse, duck, goose, dog, and cat were chosen as various types of animal hairs because they can be frequently incorporated into food during its production or consumption step. We morphologically analyzed them using stereoscopic, optical, SUMP method, and scanning electron microscopes, showing differences in each type. In addition, X-ray fluorescence spectrometer (XRF) was used to analysis chemical compositions ($^{11}Na{\sim}^{92}U$, Mass%) of samples. As a result, we observed that mammalian hairs were mainly composed of sulfur. Organic compounds of samples were further analyzed by fourier transform infrared spectroscopy (FT-IR) that can compare spectra of given materials; however, this method did not show significant differences in each sample. In this study, we suggest a rapid method for the identification of the causes and types of foreign materials in food.

Efficacy and Safety of Intraveous Iron Sucrose in the Perioperatively Anemic Patients of Gastrectomy (위 절제 수술 전후 빈혈 환자에 있어 철수크로오스의 유효성 및 안전성)

  • Yoo, Moon-Won;Cho, Jae-Jin;Lee, In-Kyu;Ahn, Hye-Seong;Jeong, Sang-Ho;Lee, Hyuk-Joon;Kim, Hyung-Ho;Lee, Kuhn-Uk;Yang, Han-Kwang
    • Journal of Gastric Cancer
    • /
    • v.8 no.1
    • /
    • pp.35-39
    • /
    • 2008
  • Purpose: This study was aimed to evaluate the efficacy and safety of of intravenous iron sucrose ($Venoferrum^{(R)}$) for treating the perioperative anemic gastrectomy patients. Materials and Methods: From September 2006 to February 2007 at Seoul National University Hospital, the gastrectomy patients who displayed perioperative anemia (7.0 g/dl $\leq$ hemoglobin levels (Hb) < 11.0 g/dl) and who were admitted or visited the outpatient clinic of the Department of surgery, were divided into two groups. The preoperative (${\leq}\;2{\sim}3$ weeks before gastrectomy) or postoperative ($\geq$ 1 month after gastrectomy) patients without evidence of acute bleeding were included into Group 1. The immediate postoperative (< 1 month after gastrectomy) patients with stable vital signs were included into Group 2. The age, gender, diagnosis, Hb, hematocrit (Hct), mean corpuscular volume (MCV), serum ferritin (SF), total iron binding capacity (TIBC), serum iron and reticulocyte counts (RC) were evaluated before and after intravenous iron sucrose administration. The adverse effects of drugs were investigated. Results: The number of patients of group 1 and group 2 was 79 and 46, respectively. In group 1, there was a statistically significant difference in the Hb, Hct, MCV, SF, RC and TIBC with each mean change of 1.3 g/dl, 4.1%, 3.1ft, 195 ng/ml, 0.2% and -86.4 ug/dl, respectively. In group 2, there was a statistically significant difference in the Hb, Hct, MCV, SF and RC with each mean change of 1.8 g/dl, 6.1%, 3.4fl, 260 ng/ml and 0.3%, respectively. Two patients (1.6%) suffered local thrombophlebitis as an adverse effect. Conclusion: Intravenous iron sucrose for the perioperative anemia of gastrectomy patients was efficacious in the short period without significant adverse effects.

  • PDF

Eine kritische Betrachtung $\ddot{u}$ber das Kompensations-Zusicherungsgesch$\ddot{a}$ft und die Typenanalyse f$\ddot{u}$r die medizinische Geburtsbehandlungsfehler (분만 의료사고에 대한 보상사업 -의료사고 피해구제 및 분쟁조정 등에 관한 법률 제46조에 관하여-)

  • Baek, Kyoung-Hee;Ahn, Bup-Young
    • The Korean Society of Law and Medicine
    • /
    • v.12 no.2
    • /
    • pp.11-61
    • /
    • 2011
  • In dieser Arbeit ist zum ersten allgemeiner $\ddot{U}$berblick auf die Verschuldensprinzip, das grunds$\ddot{a}$tzlich f$\ddot{u}$r die Unfalls-Haftung im Bereich der medizinischen Behandlungsfehler noch immerhin gelten, in aller K$\ddot{u}$rze angef$\ddot{u}$hrt und zugleich in rechtsvergleichender Weise auf die sozialrechtliche Typenentwicklung in Bezug auf die haftungsrechtlich motivierte Entsch$\ddot{a}$digung. Gem$\ddot{a}{\ss}$ dem ${\S}$ 46 Gesetzes zur Abhilfe f$\ddot{u}$r medizinische Besch$\ddot{a}$digungenund auf die Mediation-Schlichtung f$\ddot{u}$r medizinische Streitigkeiten ist die rechtssystematische Bedeutung des Kompensations-Zusicherungsgeschafts als eine Art institutioneller Fremdversorgung zu erfassen. Demzufolge geht es h$\ddot{a}$uptsachlich um die Problematik von tatbest$\ddot{a}$ndlichen Merkmalen der Kompensation im ${\S}$ 46 obigen Gesetzes (unten 1) und im Bezug auf die im voraus von GF-Ministerium bekanntgegebene AO (provisorische Fassung) von 8. 11. 2011. um die Analyse einer Reihe von KHG-Entscheidungen $\ddot{u}$ber $\ddot{a}$rztliche Geburtsbehandlungsfehler (unten 2). Dabei ist noch die Geltungsbereich mit entsprechendem Kompensationssystem in Japan zu vergleichen (unten 3). 1. Der terminologische Sinn von "h$\ddot{o}$here Gewalt" ist sowohl semantisch wie auch juristisch-rechtstechnisch eine negative Vorausaussetzung f$\ddot{u}$r haftbar machende Gef$\ddot{a}$hrdungstatbestand. Nicht nur im Inhalt und Umfang vertr$\ddot{a}$gt dieser Rechtsbegriff sich nicht mit dem anderen tatbest$\ddot{a}$ndlich parallell zu erf$\ddot{u}$llenden Merkmal, also "die Besch$\ddot{a}$digung aus unverschuldeter $\ddot{a}$rztlicher Geburtsvorsorge", weil die jene enger als die diese auf dem Begriffsfeld ist, sondern auch im dogmengeschichtlichen, auch doch rechtstechnichen Sinne ist die Terminologie von "h$\ddot{o}$here Gewalt" ungeeignet, f$\ddot{u}$r den kompensatorischen Tatbetand als ein positives Merkmal, zu sein, statt derer, m. E. sollte der Begriff von "unkontrollierbarer Zuf$\ddot{a}$lligkeit" als L$\ddot{o}$sungsansatz verwendet werden. Dazu ist auch die ratio legis zur institutionellen Einf$\ddot{u}$hrung des obigen Kompensations-Zusicherungsgesch$\ddot{a}$fts, das sich auf die Entsch$\ddot{a}$digung des f$\ddot{u}$r Patienten unertr$\ddot{a}$glichen Verlustes gerichtet, d. h. gerade die Augabe des nachteilsausgleichenden Einstehens f$\ddot{u}$r Ungl$\ddot{u}$ck, nicht f$\ddot{u}$r Unrecht, zu ber$\ddot{u}$cksichtigen. 2. Die Typen der KHG-Entscheidungsf$\ddot{a}$llen im Bereich von Gyn$\ddot{u}$kologie k$\ddot{o}$nnten diagnostisch bzw. therapeutisch im folgenden differenziert sein werden; je nach der Kriterien von der Weise und dem Zeitpunkt zur Geburtshilfe, technischen Behandlungsfehlern beim Geburtsvorgang, und Besorgungsfehlern nach dem Geburt u. dgl. 3. Die japanische verschuldensunabh$\ddot{a}$ngige Kompensation ist eigentlich eine Art institutionelle Vorsorge, die anders als koreanische Versorgungssystem auf Grund privatsicherungsfinaler Vorleistung gew$\ddot{a}$rleistet wird. Der kompensatorische Bereich beschr$\ddot{a}$nkt sich auf die schwere infantile Zerebralparese (Cerebralparese) beim medizinischen Geburtsbehandlung. Schlie${\ss}$lich w$\ddot{u}$rde diese Arbeit erw$\ddot{u}$nscht sein, zur Konkretisierung des Voraussetzungen f$\ddot{u}$r die Kompensation nach ${\S}$ 46 Abs. 1 u. 4 des obigen Gesetzes beitragen zu k$\ddot{o}$nnen, welcher spatestens am 8. 4. 2013. zur Geltung gebracht sein sollte.

  • PDF

Radiation Therapy of Intracranial Germinoma (두개강내 배아종의 방사선 치료)

  • Nho Young Ju;Chang Hyesook;Choi Eun Kyung;Kim Jong Hoon
    • Radiation Oncology Journal
    • /
    • v.15 no.3
    • /
    • pp.207-213
    • /
    • 1997
  • Purpose : Intracranial germinoma is the most radiocurable tumor of theprimary intracranial neoplasm. But, the optimum radiation dose and target volume remain controversial In this retrospective study, we analysed the spreading pattern at presentation and the pattern of the failure and survival of intracranial germinoma, Materials and Methods : From 1989 to 1996, 23 Patients were treated for intracranial germinoma at Department of Radiation Oncology, Twenty-one Patients were treated at their initial Presentation and 2 Patients were treated for recurrent disease. Six patients had multiple tumor masses on MRI and 7patients had ventricular seeding on MRI. The examination of cerebrospinal fluid cytology was done in 15 patients and 3 out of 15 patients had positive cerebrospinal cytology. In tumor marker study of $\alpha-FP\;and\;\beta-hCG$, 6 patients had mildly elevated $\beta-hCG$ in serum or cerebrospinal fluid. Twentyone Patients were treated with whole craniospinal axis irradiation and 2 Patients were given whole ventricular radiation therapy. The total dose was ranged between 4500cGy and 5600cGy to primary tumor site (median 5580cGy) Dose to the entire ventricular system ranged from 1980cGy to 3960 cGy (median 2700cGy) and dose to the spinal axis ranged from 2160cGy to 3900cGy (median 2700cGy) Results : Of 23 patients, 21 Patients are alive without evidence of diseasefor median 4 years follow-up. One Patient who had markedly elevated $\alpha-FP\;and\;\beta-hCG$, suffered from Persistent disease after radiation therapy and received 2 cycles of chemotherapy. She died 9 months after chemotherapy One patient who developed ventricular seeding after gamma-knife was treated with whole craniospinal irradiation, he died after 1 year due to probably brain necrosis. The hematologic toxicity of 3 or 4 grade were seen in 7 patients and patient's endocrinologic dysfunction was not deteriorated after radiation therapy. One patient had been treated with growth hormone replacement due to short stature. Conclusions : This retrospective study has confirmed the excellent result of radiation therapy in intracranial germinoma. The complication rate during or after radiation therapy is considered within acceptable range. ft is necessary to further investigate the optimal dose and treatment volume of radiation therapy. The role of chemotherapy in the treatment of intracranial germinoma should be further investigated.

  • PDF

Effect of Acrylic Acid on the Physical Properties of UV-cured Coating Films for Metal Coating (금속코팅용 광경화 코팅필름의 물성에 대한 아크릴산(Acrylic acid)의 영향)

  • Seo, Jong-Chul;Choi, Jun-Suk;Jang, Eui-Sung;Seo, Kwang-Won;Han, Hak-Soo
    • Korean Chemical Engineering Research
    • /
    • v.49 no.1
    • /
    • pp.75-82
    • /
    • 2011
  • Five different composition UV-cured poly(urethane acrylate-co-acrylic acid) (PU-co-AA) films have been prepared by reacting isophorone diisocyanate(IPDI), polycaprolactone triol(PCLT), 2-hydroxyethyl acrylate(HEA), and different weight ratio trimethylolpropane triacrylate(TMPTA) and acrylic acid(AA) as diluents, and characterized using a Fourier transform infrared spectroscopy(FT-IR). The adhesion properties onto the stainless steel, morphology, mechanical hardness, and electrical property of UV-cured PU-co-AA films were investigated as a function of acrylic acid(AA) content. All the PU-co-AA films are structure-less and the molecular ordering and packing density decreased with increasing content of AA due to the flexible structure and -COOH side chains in AA. The crosscut test showed that PU-co-AA films without AA and with low content of AA showed 0% adhesion(0B) and the adhesion of PU-co-AA films in the range of 40-50% AA increased dramatically as the content of AA increases. The pull-off measurements showed that the adhesion force of PU-co-AA films to stainless steel substrate varied from 6 to 31 kgf /$cm^2$ and increased linearly with increasing AA content. The mechanical hardness also decreased as the content of AA increases. This may come from relatively linear and flexible structure in AA and low crystallinity in PU-co-AA films with higher content of AA. The higher AA-containing PU-co-AA films showed higher dielectric constant due to the increase of polarization by introducing AA monomer. In conclusion, the physical properties of UV-cured PU-co-AA films are strongly dependent upon the content of AA and the incorporation of AA in polyurethane acrylate is very useful way to increase the adhesion strength of UV-curable polymers on the stainless steel substrate.