3가 양이온 산화물이 첨가된 2Y-TZP의 저온 상안정성

장주웅,김학관,이득용,김대준,박선민,Jang, Ju-Woong,Kim, Hak-Kwan,Lee, Deuk-Yong,Kim, Dae-Joon,Park, Sun-Min 한국세라믹학회 2002 한국세라믹학회지 Vol.39 No.11

정방정 지르코니아의 상안정성 및 저온열화기구를 고찰하기 위해 Y2O3 안정화 지르코니아에 3가 양이온 산화물을 첨가한 후 그 소결체의 기계적 물성, 라만 스펙트럼 및 격자상수 변화 등을 관찰하였다. 2Y-TZP에 $Zr^{4+}$ 보다 이온크기가 큰 3가 양이온($Sc^{3+},\;Yb^{3+},\;Y^{3+},\;Sm^{3+},\;Nd^{3+},\;La^{3+}$)들을 2 mol%까지 첨가하여 $1500{\circ}C$에서 1시간 소결후, X-ray 상분석 결과 $La^{3+}$의 경우에는 0.5 mol% 이상 첨가시 pyrochlore 상$(La_2Zr_2O_7)$의 형성으로 정방정상의 상안정성이 저하되었다. 첨가량이 증가할수록 $Zr6{4+}$과 이온크기가 거의 비슷한 $Sc^{3+}$를 첨가한 경우에는 정방정상만 관찰되었으나 $Yb^{3+},\;Y^{3+},\;Sm^{3+},\;Nd^{3+}$를 첨가한 경우에는 입방정상이 형성되었다. 양이온 크기가 커질수록 c/a비는 증가하였으나 $220{\circ}C$에서 500시간까지 열처리후 상분석 결과 단사정량은 감소하였다. The phase stability and the Low Temperature Degradation(LTD) mechanism of Tetragonal Zirconia Polycrystals(TZP), sintered specimens of $Y_2O_3$-Stabilized Zirconia(2Y-TZP), doped with trivalent cations, were evaluated by investigating meachnical properties, Raman spectra, lattice parameter variation and the oxygen vacancy behavior under applied electric field. XRD observation was put forward on 2Y-TZP doped with trivalent cation whose ionic radii were larger than $Zr^{4+}(Sc^{3+},\;Yb^{3+},\;Y^{3+},\;Sm^{3+},\;Nd^{3+},\;La^{3+})$ up to 2 mol% and sintered at 1500 h for 1h. For $La^{3+}$ doping, the stability of tetragonal phase was degraded due to the formation of the pyrochlore phase $(La_2Zr_2O_7)$ as the dopant content increased above exceeded 0.5 mol%. As the dosage increased, tetragonal phase maintained for the case of $Sc^{3+}$, whose radius was similar to $Zr^{4+}$, on the other hand, the cubic phase was formed for the cases of $Yb^{3+},\;Y^{3+},\;Sm^{3+},\;Nd^{3+}$. As the radii of dopant cation increased, c/a ratio increased and it was experimentally observed that the amount of monoclinic phase decreased when the specimens were annealed at $220{\circ}C$ for 500 h.

용융침투법으로 제조한 유리-알루미나 복합체: Ⅰ. 알루미나 입도 효과

이득용,장주웅,김대준,박일석,이준강,이명현,김배연,Lee, Deuk-Yong,Jang, Ju-Woong,Kim, Dae-Joon,Park, Il-Seok,Lee, Jun-Kwang,Lee, Myung-Hyun,Kim, Bae-Yeon 한국세라믹학회 2001 한국세라믹학회지 Vol.38 No.9

Two commercial alumina powders having different particle size of $0.5{\mu}m$ and 3${\mu}$m were presintered at 1120$^{\circ}$C for 2h and then lanthanum aluminosilicate glass was infiltrated at 1100$^{\circ}$C for up to 4h to obtain the densified glass-alumina composites. The effect of alumina particle size on packing factor, microstructure, wetting, porosity and pore size, and mechanical properties of the composite was investigated. The optimum mechanical properties and compaction behavior were observed for the 3${\mu}$m alumina particle dispersed composite. The 3${\mu}$m alumina particle size and distribution for he preform were within 0.1 to 48${\mu}$m and bimodal and random orientation. The strength and the fracture toughness of the composite having 3${\mu}$m alumina particles were 519MPa and $4.5MPa{\cdot}m^{1/2}$, respectively. 상용 알루미나 분말(0.5${\mu}$m, 3${\mu}$m)을 die-press법을 이용하여 1120$^{\circ}$C에서 2시간 1차 소결하여 다공성 전성형체를 제조하고 1100$^{\circ}$C에서 4시간 $La_2O_3-Al_2O_3-SiO_2$계 유리를 용융 침투시켜 치밀한 유리-알루미나 복합체를 제조하였다. 알루미나 입도가 유리-알루미나 복합체의 충진율, 미세조직, 젖음성, 기공률 및 크기, 기계적 특성에 미치는 영향을 조사하였다. 입도 범위가 0.1∼48${\mu}$m로 넓고 bimodal size 입도 분포를 가지면서 random orientation을 가진 3${\mu}$m 알루미나가 분산된 복합체가 최적의 기계적 특성 및 충진률이 관찰되었으며 강도와 인성값은 각각 519MPa, $4.5MPa{\cdot}m^{1/2}$이었다.

Divinyl Sulfone으로 가교된 히알루론산 마이크로비드의 특성평가

김진태,이득용,장주웅,김태형,장용운,Kim, Jin-Tae,Lee, Deuk Yong,Jang, Ju-Woong,Kim, Tae-Hyung,Jang, Yong-Wun 대한의용생체공학회 2013 의공학회지 Vol.34 No.3

Hyaluronic acid(HA) microbeads were synthesized by dropping the sodium hyaluronate(Streptococcus) solutions in NaOH into a solution mixture of divinyl sulfone(DVS) in 2-methyl-1-propanol, followed by stirring, cleaning and drying process at room temperature. The initial experimental conditions are crosslinking time(CLTi) of 5 h, crosslinking temperature(CLTe) of room temperature, injection air pressure(IAPr) of 5 psi, and DVS concentration( DVSc) of 0.2 vol%, respectively. Then, parametric studies were performed by varying the parameters to investigate the morphology, the porosity, the swelling ratio and the size of the beads. The microbead size pattern was not regular to function of the degree of crosslink. It was observed that the swelling ratio, the degree of crosslink, and the pore size can be controlled by adjusting the CLTi, CLTe and DVSc. Among the parameters investigated, the smallest bead size can be achieved by varying the CLTi parameter. The lowest swelling ratio, as an indication of the highest degree of crosslink, can be obtained by varying CLTe.

키토산-트리폴리인산염 나노입자의 제조와 응용

이은선 ( Eun Sun Lee ),박상준 ( Sang Jun Park ),장주웅 ( Ju Woong Jang ),심영복 ( Young Bock Shim ),김천호 ( Chun Ho Kim ) 한국키틴키토산학회 2014 한국키틴키토산학회지 Vol.19 No.4

For the past few decades, several polymeric nanoparticles using natural polymers have been studied extensively for medical applications. Among the natural polymers, chitosan has been used in drug delivery system as nanoparticles because of biodegradable, biocompatible, and low toxicity. The positively charged amino groups in chitosan could perform the stable nanoparticles with anionic materials via electrostatic interaction. Here, we introduce various parameters for controlled size and zetapotential of chitosan-tripolyphosphate (TPP) nanoparticles such as concentration, molecular weight, pH of chitosan, concentration of TPP, reaction time and temperature in ionotropic gelation. The objectives of this review are to study the preparation methods and characteristics of chitosan-TPP nanoparticles, and finally to investigate their potential applications in drug delivery system.

이종 탈회골기질과 피브린젤혼합체가 신생골형성에 미치는 영향

이광일 ( Kwang Il Lee ),이근수 ( Keun Soo Lee ),김일환 ( Il Hwan Kim ),장주웅 ( Ju Woong Jang ),김대현 ( Dae Hyun Kim ),김휘율 ( Hwi Yool Kim ),문성환 ( Seong Hwan Moon ),전홍재 ( Heung Jae Chun ) 한국조직공학·재생의학회 2009 조직공학과 재생의학 Vol.6 No.1

Demineralized bone matrix(DBM) might be an alternative graft material functioning as a bone void filler with osteoconductive and osteoinductive properties. But not all clinical studies have reported uniformly favorable results, because most commercial tissue banks do not generally evaluate the degree of bone forming potential of their DBM prior to distribution. The effectiveness of DBM might differ depending on the age and gender of the donor, the residual mineral, the particle size, or the preparation method. What is worse, Allogeneic DBM has shortcomings related to procuring, processing and characterizing bone from a human donor pool. Xenografting is increasingly being developed as a response to the shortage of human tissues. However, antigenic components of bone material are blamed for the reduction of the osteoinductive properties. of bone and bone-derived implants. So, xenogeneic bone will be an unlimited supply of available material if it can be processed to render it safe for transplantation to the human host. Fibrin gels, mainly composed of fibrinogen and thrombin, mimic the final stage of blood clotting. Thanks to their hemostatic, mitogenic and angiogenic and angiogenic properties, fibrin gels are widely used in surgery. Fibrin gels are usually sprayed over the wound in order to prevent blood loss. They are well known for their wound healing and tissue regeneration properties, but their use as a bone graft material has been infrequent. The purpose of this study is to determine wherher a combination of fibrin gel and xenogeneic DBM would provide three-dimensional tem-plates for bone growth resulting in new bone formation at heterotopic sites in the rat with plasticity.

Influence of Molecular Weight on Swelling and Elastic Modulus of Hyaluronic Acid Dermal Fillers

Deuk Yong Lee(이득용),Cheolbyung Cheon(전철병),Siwon Son(손시원),Young-Zu Kim(김영주),Jin-Tae Kim(김진태),Ju-Woong Jang(장주웅),Seok-Soon Kim(김석순) 한국고분자학회 2015 폴리머 Vol.39 No.6

분자량이 다른 세종류 히알루론산(HA)에 1,4-butanediol diglycidyl ether(BDDE)가 가교된 hyaluronic acid(HA)를 첨가하여 하이드로겔을 제조하고 HA 분자량에 따른 팽윤도와 탄성계수의 효과를 조사하였다. 최종 투석 후 잔류 BDDE 양은 0.5 ppm 이하이었다. 비가교된 분자량이 큰 HA에서 최대 팽윤도가 관찰되었다. 팽윤도는 비가교 HA 양과 가교도에 각각 비례와 반비례하였다. 1.0 w/v% BDDE 가교 HA와 HA(1368 kDa)를 혼합한 monophasic 하이드로젤의 탄성계수는 152~325 ㎩이었다. 15% 가교 HA(687 kDa)과 85% HA(1368 kDa)로 구성된 biphasic 하이드로젤의 탄성계수는 178 Pa이었다. 1,4-Butanediol diglycidyl ether (BDDE) crosslinked hyaluronic acid (HA) suspended in three different HAs (697, 1058, 1368 kDa) were prepared to investigate the effect of HA molecular weight on swelling property and elastic modulus of the hydrogels. The amount of the residual BDDE after final dialysis was less than 0.5 ppm. The highest swelling ratio was observed for the uncrosslinked HA having the largest molecular weight. The expansion capacity of HA rose with increasing the amount of pure HA and was inversely proportional to the crosslinking degree due to an increased number of coiled HA chain interactions. Elastic modulus (G’) of monophasic fillers having different ratios of 1.0 w/v% BDDE crosslinked HAs to pure HA (1368 kDa) were within 152 and 325 ㎩. 178 Pa was observed for the biphasic fillers consisting of 15% crosslinked HA (697 kDa) nanoparticles suspended in 85% of uncrosslinked HA (1368 kDa).

다공성 폴리(ε-카프로락톤)/실리카 복합체의 제조 및 특성평가

손시원(Siwon Son),최지은(Ji-Eun Choi),조훈(Hun Cho),강대준(DaeJun Kang),이득용(Deuk Yong Lee),김진태(Jin-Tae Kim),장주웅(Ju-Woong Jang) 한국고분자학회 2015 폴리머 Vol.39 No.2

졸-젤법을 이용한 전기방사법과 캐스팅법으로 폴리(ε-카프로락톤)(PCL) 나노섬유와 PCL/실리카 막을 각각 제조하였다. 용매에 N,N-dimethylformamide(DMF)를 혼합한 경우 부드럽고 연속적인 PCL 나노섬유가 제조되었다. PCL 기지상에 tetraethyl orthosilicate(TEOS) 농도가 0에서 40 vol%로 증가함에 따라 PCL/silica의 강도는 12에서 8MPa로 감소하였지만, 7주까지 phosphate buffered saline solution(PBS) 침지에 따른 강도값의 변화는 없었다. 실리카 첨가에 따른 인장강도의 감소는 기공도의 증가에 기인하였다. PCL/실리카 막의 결정구조는 사방정계로 실리카 농도가 0에서 40 vol%로 증가함에 따라 crystallite 크기는 57에서 18 nm로 감소하였다. 세포독성 실험결과, PCL/실리카는 시편의 수축 및 변형이 없고, 검체 주위에서 변색이나 L-929 세포의 이상이 관찰되지 않는 무독성이었다. Poly(ε-caprolactone) (PCL) nanofibers and PCL/silica membranes were synthesized by sol-gel derived electrospinning and casting, respectively. Smooth PCL nanofibers were obtained from the precursor containing N,Ndimethylformamide (DMF). PCL/silica membranes were prepared by varying the tetraethyl orthosilicate (TEOS) contents from 0 to 40 vol% to investigate the effect of silica addition on mechanical properties and cytotoxicity of the membranes. Although the strength of the membranes decreased from 12 to 8 MPa with increasing the silica content, the strength remained almost constant 7 weeks after dipping in phosphate buffered saline solution (PBS). The strength reduction was attributed to the presence of a patterned surface pores and micro-pores present in the walls between pores. The crystal structure of the membranes was orthorhombic and the crystallite size decreased from 57 to 18 nm with increasing the silica content. From the agar overlay test, the PCL/silica membranes exhibited neither deformation and discoloration nor lysis of L-929 fibroblast cells.