• 접착 및 계면
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• 제16권3호
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• pp.108-115
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• 2015

본 연구는 poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV)/그래핀 복합체의 제조 및 특성에 관한 연구이다. 투입하는 그래핀의 함량에 따른 복합체의 전기적 물성, 소수성, 및 열적 성질에 미치는 영향에 대해 연구하였다. 표면주사전자현미경 연구결과 PHBV 고분자 matrix에 판상의 그래핀이 고르게 잘 분산되었음을 확인하였다. X-선 회절 연구와 시차열량주사계 분석을 통하여 그래핀을 첨가할수록 PHBV의 결정도를 증가시켰고, 투입하는 그래핀의 함량이 증가할수록 복합체의 열적 안정성, 소수성 및 전기전도도 등이 증가하는 것으로 나타났다.

• 한국환경과학회지
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• 제26권1호
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• pp.1-10
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• 2017

In this study, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV)/graphene oxide (GO) nanocomposite films containing various content of GO were prepared using solution casting method. The effect of GO content on Young's modulus and dispersion of GO in PHBV matrix was investigated. Also, the thermomechanical properties, oxygen transmission rates and hydrolytic degradation of PHBV/GO nanocomposite films were studied. The addition of GO into PHBV improves the Young's modulus and decreases thermal expansion coefficient. The improvement can be mainly attributed to good dispersion of GO and interfacial interactions between PHBV and GO. Furthermore, PHBV/GO nanocomposite films show good oxygen barrier properties. PHBV/GO nanocomposites show lower hydrolytic degradation rates with increasing content of GO.

• 폴리머
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• 제31권5호
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• pp.385-392
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• 2007

Poly (N-vinylpyrrolidone) (PVP) groups were grafted onto a poly(3-hydroxybutyrate-co-3-hydroryvalerate) (PHBV) backbone in order to modify its properties and synthesize a novel biocompatible copolymer. The crystallization behavior of PHBV and grafted PHBV was investigated by differential scanning calorimetry (DSC) and polarized optical microscopy (POM). During the cooling-induced crystallization process, the crystallization temperature and the crystallization rate of the grafted PHBV decreased with increasing PVP weight fraction. On the heating scans of all grafted PHBV samples, a new crystallization exothermic peak appeared at almost the same temperature, suggesting the operation of a recrystallization process, while the melting temperature ($T_m$) and the apparent enthalpy of fusion (${\Delta}H_f$) were not affected by graft modification. During the isothermal crystallization process at the same temperature, the presence of side PVP groups decreased the spherulitic growth rate and the spherulitic band spacing with increasing PVP weight fraction in samples.

• KSBB Journal
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• 제13권5호
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• pp.615-620
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• 1998

The readily fermentable carbon sources in swine were acetic acid, propionic acid and butyric acid at the average concentrations of 7.2 g/L, 2.2 g/L and 2.7 g/L, respectively. The swine waste also contained excess nitrogen and other mineral sources. In shake flask experiments, the optimal range of cell growth for Azotobacter vinelandii UWD were 1.0∼3.5 g/L of acetic acid, 0.7∼2.0 g/L of propionic acid and 0.5∼2.0 g/L of butyric acid. A mixture of these three acids simulating two times diluted swine waste supported the best cell growth but the amount of carbon sources was limited. In shake flask and fermentor experiments, an addition of 30 g/L of glucose increased the final cell dry weight 8 times while the final poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) concentration increased 86 times compared with using acid mixture only. A. vinelandii UWD preferred organic acids in the sequence of acetic acid, propionic acid, butyric acid, and valeric acid.

• 생명과학회지
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• 제32권7호
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• pp.510-522
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• 2022

Poly (3-hydroxyalkanoates) (PHA)는 탄소원과 에너지원으로서 미생물이 과립형태로 생합성하는 열가소성 플라스틱이다. PHA 중 가장 연구가 많이 된 polyhydroxyburyrate (PHB)는 높은 결정성과 부서지기 쉬운 성질로 인해 사용 및 응용범위가 제한적이다. 따라서 본 연구에서는 polypropylene과 좀 더 유사한 성질을 지닌 PHA를 생합성하고자, 3-hydroxybutyrate와 3-hydroxyvalerat의 공중합체인 poly (3-hydroxybutyrate-co-3-hydroxyvalerat) (PHBV)를 생합성하는 Bacillus sp. EMK-5020 균주를 토양에서 분리하였다. 플라스크로 배양한 결과, Bacillus sp. EMK-5020 균주는 효소를 이용한 막걸리 주박 가수분해산물(enzymatic makgeolli less hydrolysate, MLEH)에 포함된 환원당(환원당_MLEH)을 단일 탄소원으로 이용하여 1.3%의 3HV가 함유된 PHBV를 생합성하였으며, 보조탄소원으로 첨가한 propionic acid의 양이 증가할수록 3HV의 함량이 증가하여 최대 48.6%의 3HV가 포함된 PHBV를 합성하였다. 이 결과를 바탕으로 환원당_MLEH (20 g/l)와 propionic acid (1 g/l)를 각각 주 탄소원 및 보조탄소원으로 이용하여 3 l 발효기에서 균주를 72시간 배양한 결과 6.4 g/l DCW와 8.9% 3HV를 함유하는 PHBV (MLEH-PHBV)를 50 wt% 생합성함을 확인하였다. 겔 투과 크로마토그래피 분석을 통해 MLEH-PHBV의 평균 분자량은 152 kDa으로 standard PHBV의 평균 분자량(314 kDa)에 비해 절반으로 감소한 것을 확인하였으며, 열중량을 분석한 결과 MLEH-PHBV의 분해 온도가 standard PHBV보다 20℃ 높은 273℃임을 확인하였다. 결론적으로 본 연구에서는 Bacillus sp. EMK- 5020균주를 이용하여 MLEH 및 propionic acid를 탄소원으로 사용하여 다양한 3HV 분획을 함유하는 PHBV생합성할 수 있었으며, 대량배양을 통해 생합성된 8.9% 3HV를 함유한 PHBV-MLEH는 standard PHBV (8% 3HV)에 비해 높은 열 안전성을 지닌 것을 확인하였다.

• Macromolecular Research
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• 제10권3호
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• pp.150-157
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• 2002

Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) is a microbial storage polymer with biodegradable properties. In order to improve the cell compatibility of PHBV surfaces, the physicochemical treatments have been demonstrated. In this study, physical method was corona discharge treatment and chemical method was chloric acid mixture solution treatment. The physicochemically treated PHBV film surfaces were characterized by the measurement of water contact angle, electron spectroscopy for chemical analysis, and scanning electron microscopy (SEM). The water contact angle of the physicochemically treated PHBV surfaces decreased from 75 to 30～40 degree, increased hydrophilicity. due to the introduction of oxygen-based functional group onto the PHBV backbone chain. The mouse NIH/3T3 fibroblasts cultured onto the physicochemically treated PHBV film surfaces with different wettability. The effect of the PHBV surface with different wettability was determined by SEM as counts of cell number and [$^3$H]thymidine incorporation as measures of cell proliferation. As the surface wettability increased, the number of the cell adhered and proliferated on the surface was increased. The result seems closely related with the serum protein adsorption on the physicochemically treated PHBV surface. In conclusion, this study demonstrated that the surface wettabilily of biodegradable polymer as the PHBV plays an important role for cell adhesion and proliferation behavior for biomedical application.

• 폴리머
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• 제25권3호
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• pp.334-342
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• 2001

항생제의 서방형 전달을 위해 황산겐타마이신 gentamicin sulfate (GS)을 함유한 poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) 제형을 제조하였다. 본 연구에서는 제형의 두께, hydroxyvalerate (HV) 농도, 초기 약물함유량 및 첨가제의 함유에 따른 약물 방출거동의 변화를 조사하였다. 전자주사현미경을 이용하여 제형의 표면형태와 매트릭스 내부 약물의 조성을 관찰한 결과 약물방출 전과 후 모두 거칠고 다공성인 형태를 가짐을 알 수 있었다. 또한, HV와 첨가제의 함량이 증가할수록 약물이 고분자 매트릭스에 더 조밀하게 배열함을 관찰하였고, 이러한 구조가 약물의 방출에 영향을 미침을 알았다. HPLC를 이용하여 약물의 방출량을 측정한 결과, 모든 제형이 복합적인 방출 방향을 나타내었고, 일부 매트릭스는 30일 동안 거의 영차에 가까운 방출거동을 보였다. 이상의 결과에서 우리는 제형의 두께, 고분자 매트릭스의 조성, 첨가제의 함유량 등을 조절함으로 약물 방출을 제어할 수 있음을 확인하였다.

• Macromolecular Research
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• 제8권6호
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• pp.253-260
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• 2000

Biodegradable wafers were prepared with poly (hydroxybutyrate-co-hydroxyvalerate) (PHBV;5, 10, and 15 mole% for 3-hydroxyvalerate) by simple heat pressing method for the sustained release of antibiotic agent, gentamicin sulfate (GS) to investigate the possibility of the treatment for osteomyelitis. The effects of hydroxyvalerate (HV) content, thickness of wafers, various types of additives such as sodium dodecyl sulfate (SDS), microcrystalline cellulose, polyvinylpyrrolidone, and hydroxypropylcellulose (HPC), and different initial drug loading ratio on the release profile have been investigated. In vitro release studies showed that different release patterns and rates could be achieved by simply modifying factors in the preparation conditions. PHBV wafers with 3 mm thickness, 10% of GS initial loading, 15% of HV content and addition of 5% of SDS and HPC were free from initial burst and a near-zero-order sustained release was observed for over 30 days. It might be suggested that the mechanisms of G5 release may be more predominant simple dissolution and diffusion of GS than erosion of PHBV in our system.

• KSBB Journal
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• 제13권5호
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• pp.626-630
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• 1998

Ammonium limitation did not promote ply(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) production of Azotobacter vinelandii UWD. In acid phase, ammonium limitation during utilization of propionic acid and butyric acid led to 35% decrease in product yield. In glucose phase, both biomass yield and polymer yield decreased about 22% under ammonium limitation. However, in nitrogen-fixing culture glucose was consumed 25% faster and the final PHBV wt% decreased slightly. Under nitrogen limitation a portion of the carbon sources was used fro nitrogen fixation rather than biomass and polymer formation, resulting in a decrease in biomass yield and polymer yield.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2009년도 추계학술발표대회
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• pp.39.2-39.2
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• 2009

In this work, Poly($\varepsilon$-Caprolactone)(PCL) andpoly(3-hydroxybutyrate-co-3-hydroxyvalerate)(PHBV) mats were fabricated usingelectrospinning process. The electrospinning process is a simple and efficient method to fabricate the nanofibrous mats. PCL and PHBV is a kind of biodegradable polymer but their mechanical properties aren't good. For improving mechanical properties, PHBV mats were coated by TCP. Using PCL mats and TCP-coated PHBV composite mats, a bio-resorbablebone plate were made by pressing. Detailed micro-structural characterization was done by SEM techniques. Tensile strength and bending strength were also evaluated for mechanical properties. The cytotoxicity evaluation ofPCL/TCP-coated PHBV composite multilayer was done by MTT assay. The evidence obtained in this work implies the potential for use as a biodegradable boneplate.