• Journal of Chest Surgery
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• 제28권6호
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• pp.557-564
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• 1995

Microvel knitted double velour vascular grafts coated with biodegradable algin were evaluated in the canine experimental model as a new biologically coated Dacron graft. Three series of implantations were conducted involving the insertion of 6 mm diameter grafts in the abdominal aortae of mongrel dogs. The first series used the regular Microvel vascular grafts coated with algin,whereas the second and third series used Hemashield [collagen-coated grafts and the regular Microvel grafts with preclotting,respectively as control groups. Each series involved the implantation of one prosthesis for each of 2 preselected periods,namely 3 months and 6 months. In addition,algin-impregnated grafts were implanted for 4 hours,72 hours,2 weeks,and 4 weeks. All grafts were patent when the animals were sacrificed at intervals ranging from 4 hours to 6 months. Histological examinations revealed no obvious or significant differences in the healing characteristics of the algin-coated grafts and the control grafts after 3 months and 6 months of implantation. Endothelial cell-like cells were present on the midsegments of all grafts explanted from animals sacrificed after 3 months and 6 months,except a suspicious finding in the 3 month-implantation animal of a preclotted graft. With special stains,the algin became invisible between the polyester filaments during the first 3 months of implantation. This study has demonstrated that the use of a biodegradable algin coating is a feasible approach as biological sealants for textile arterial prostheses.

• Advanced Composite Materials
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• 제16권4호
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• pp.335-347
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• 2007

Green composites composed of long maize fibers and poly $\varepsilon$-caprolactone (PCL) biodegradable polyester matrix were manufactured by the thermo-mechanical processing termed as 'Sequential Molding and Forming Process' that was developed previously by the authors' research group. A variety of processing parameters such as fiber area fraction, molding temperature and forming pressure were systematically controlled and their influence on the tensile properties was investigated. It was revealed that both tensile strength and elastic modulus of the composites increase steadily depending on the increase in fiber area fraction, suggesting a general conformity to the rule of mixtures (ROM), particularly up to 55% fiber area fraction. The improvement in tensile properties was found to be closely related to the good interfacial adhesion between the fiber and polymer matrix, and was observed to be more pronounced under the optimum processing condition of $130^{\circ}C$ molding temperature and 10 MPa forming pressure. However, processing out of the optimum condition results in a deterioration in properties, mostly fiber and/or matrix degradation together with their interfacial defect as a consequence of the thermal or mechanical damages. On the basis of microstructural observation, the cause of strength degradation and its countermeasure to provide a feasible composite design are discussed in relation to the optimized process conditions.

• 생명과학회지
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• 제8권5호
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• pp.526-531
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• 1998

In this study, the composition and characteristics of poly-$\beta$-hydroxybutyrate (PHB) biosynthesized by Actinobacillus sp. EL-9 are investigated. PHB produced by Actinobacillus sp. EL-9 was identified as the homopolymer of 3-hydroxy-butyric acid (PHB) by infrared spectroscopy and nuclear magnetic resonance spectroscopy analysis. The melting tem-perature (T$_{m}$), and crystallization temperature(T$_{c}$) of PHB was 169.7$^{\circ}C$ and 69.13$^{\circ}C$, respectively. The viscosity on he basis of Brookfield viscometer was 6.01 ㎗/g. The viscosity-average molecular weight estimated by Mark-Ho-wink-Sakurada equation was 1.08$\times$10$^{6}$ ($\pm$3,000).00).

• Macromolecular Research
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• 제12권4호
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• pp.374-378
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• 2004

The biodegradable and biocompatible poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), a copolymer of microbial polyester, was fabricated as nanofibrous mats by electrospinning. Image analysis of the electrospun nanofibers fabricated from a 2 wt% 2,2,2-trifluoroethanol solution revealed a unimodal distribution pattern of fiber diameters with an observed average diameter of ca. 185 nm. The fiber diameter of electrospun fabrics could be controlled by adjusting the electro spinning parameters, including the solvent composition, concentration, applied voltage, and tip-to-collector distance. Chondrocytes derived from rabbit ear were cultured on a PHBV cast film and an electrospun PHBV nano-fibrous mat. After incubation for 2 h, the percentages of attached chondrocytes on the surfaces of the flat PHBV film and the PHBV nanofibrous mat were 19.0 and 30.1 %, respectively. On the surface of the electrospun PHBV fabric, more chondrocytes were attached and appeared to have a much greater spreaded morphology than did that of the flat PHBV cast film in the early culture stage. The electro spun PHBV nanofabric provides an attractive structure for the attachment and growth of chondrocytes as cell culture surfaces for tissue engineering.

• 펄프종이기술
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• 제42권1호
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• pp.54-63
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• 2010

Recently, as the function of largest supplier of biomass for "low carbon green growth", the necessity for systematic management of afforestation areas is emphasizing. The forestation of seedling, besides the afforestation cost itself, is required some additional follow-up management costs, like mowing and fertilizing of forestation area, and removal of bindweed. The mulching mat for afforestation seedlings is available for rooting of little seedlings as well as initial forestation expenses. Mulching technique is also used to control soil temperature and moisture by covering the surface of ground. In this study, the paper based-mulching film coated with biodegradable polymer and functional additive was specially produced using laboratory bar coater, and analyzed for its degradable behavior. Coating colors were prepared by dissolving PE (polyester) 80 % and PLA(polylactic acid) 20 % in chloroform and finally applied to handsheet prepared by preceding study conditions. Base paper and polymer-coated paper were artificially aged by 2 kinds of degradation methods, which are soil degradation by microorganism and light degradation by 257 nm UV wavelengths. Strength property, oxidation index and morphological property were evaluated by reduction rates of tensile strength, FTIR spectra ratio of carboxyl and carbonyl group and SEM micrograph. As these results, polymer coated-paper was superior to base paper in degradation behaviors, having results with lower reduction rate of strength properties.

• 공업화학
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• 제5권6호
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• pp.1068-1077
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• 1994

생분해성 고분자의 실용화 검토를 위하여 생분해성 Copolyesterethylene(CPEE)과 LDPE를 0~100%까지 10% 간격으로 전조성에 걸쳐 용융 블렌드하였다. 각 조성에서 블렌드한 시료의 녹는점 변화, 용융 엔탈피, 결정화 온도 및 결정화 엔탈피를 시차주사열량계고 측정하여 miscibility에 관하여 고찰하였으며 만능시험기를 이용하여 인장강도 및 신장률을 측정하였다. 열분석 결과로부터 CPEE의 조성이 30%일 때까지 약간의 miscibility를 보임을 알 수 있었으며, 인장 강도값으로부터는 CPEE조성이 30~80%를 제외한 조성에서 유용한 compatibility를 갖는 것을 알았다. SEM 관찰을 통한 각 조성에서의 형태학적 모습으로부터 이들 상용성의 결과를 확인하였으며, 또한 CPEE/LDPE 블렌드 각 조성에 대한 생분해성을 미생물 접종 4주 후의 중량감소율을 측정하여 확인하였다.

• 접착 및 계면
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• 제17권1호
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• pp.21-28
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• 2016

본 연구에서는 불법 조업 어선 제압 및 장비 불용화를 위한 접착형 퇴치제 개발의 일환으로 발포형 생분해성 폴리우레탄 연구를 수행하였다. 발포형 폴리우레탄 접착제는 폴리에스터계 및 폴리에테르 폴리올을 포함하는 주재와 고분자형의 이소시아네이트로 이루어진 경화제를 혼합하여 반응이 완결되는 2액형으로, 단기간의 생분해성을 위해 주재에 starch와 dextrin 및 amylase 등을 첨가하여 4주간 약 34%의 생분해도를 OECD 301C법에 의해 얻을 수 있었다. 주재와 경화제의 온도에 따른 점도를 $0{\sim}50^{\circ}C$의 온도범위에서 측정하여 혼합 시 참고할 수 있도록 하였으며, 또한 신속한 발포 및 접착성능을 위해서 $0{\sim}50^{\circ}C$의 온도 범위에서 발포형 폴리우레탄 접착제의 반응 완결 속도(rising time)를 조절하여 1 min 내외로 제어하였다. 또한 면 직물에 대한 T-peel 시험을 수행한 결과 최대 20.78 N/cm, 평균 11.95 N/cm의 접착력을 얻을 수 있었다.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 2003년도 봄 학술발표회 논문집
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• pp.301-302
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• 2003

Recently, synthetic polymers containing units of carbohydrate derivatives with pendatnt functional groups have been much studied. The polymers should be able to be used drug carriers and scaffold for tissue engineering, because of their nontoxicity, biocompatibility, and biodegradability.$\^$1-6/ During the last three decades, various polyfunctional polymers, e.g. polyhydroxypolyamides and polyesteramides, based on carbohydrates have been reported and synthesized by condensation polymerization between sugar derivative and diamines, although it could be done via complicated reaction routes going through protecting.$\^$1-6/ (omitted)

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.352-352
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• 2006

Corynebacterium glutamicum, which is well known as an amino acid fermentation bacterium, has been used as a producer of poly(3-hydroxybutyrate) [P(3HB)]. P(3HB) was synthesized in recombinant C. glutamicum harboring the expression plasmid vector with a strong promoter for cell surface protein gene derived from C. glutamicum and P(3HB) biosynthetic gene operon derived from Ralstonia eutropha. The expression of P(3HB) synthase gene was detected by enzyme activity assay. Intracellular P(3HB) was microscopically observed as inclusion granules and its content was calculated to be 22.5 % (w/w) with molecular weight of $2.1{\times}10^{5}$ and polydispersity of 1.63.

• 대한의용생체공학회:의공학회지
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• 제13권2호
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• pp.147-154
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• 1992

Poly (glycolic aclu-co-glycine-L-lactic aclu) has been prepared by rlng opening polymerlzation. The monomer 6-methyl morpholine-2, 5-dlone was synthe-slzed by bromoproplonylation of 2 bromopropionyl bromide with glycine. Glycolide and 6-methyl morpholine-2, 5-dione have been used as starling materials for polydepsipeptides. The synthesized copolymers have been Identlrled by NMR and FT-lR spectrophotometer. The Tg value of poly(glycollc aclu-co glycine-L-tactic acld ) Is In creased with increasing mole fraction of 6-methylmorpholine-2, 5-dlone(60-$84^{\circ}C$). The glass trasltion temperature of poly(glycolic acid-co-glycine-L-lactic-acid) (62-$86^{\circ}C$) is lower than that of poly (L-lactic acrid-co-glycine-L-lactic acid ). The thermal degradation of poly( L-lactic acid-co- glycine-L-lactic acid ) Is decreased with increasing mole fraction of L-lactide. The thermal degrada pion of poly(glycolic acrid-co-91ycine-L-lactic aclu ) is increased with increasing mole Fraction of glycolide.