• Journal of Welding and Joining
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• v.32 no.4
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• pp.20-25
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• 2014

Laser heat source was applied on 3D poly urethane model built by 3D printer and cellulous acetate for joining. A diode laser with 808nm wavelength was transmitted through the 3D model and applied on the boundary of ABS/Acetate and 3D poly urethane model. Based on the experimental result, the ABS and 3D built poly-urethane polymers was successfully joined, but the mechanical strength was not enough at the joining boundaries in the range of 6watt to 8watt of laser heat source. However, biodegradable acetate was successfully joined without damaging the 3D built model and mechanical strength was properly achieved. The optimum laser power was found between 5watt and 8watt with scanning speed of 500mm/min, 700mm/min and 1,000mm/min. Based on the SEM analysis the filling mechanism was that the applied pressure on 3D built model squeezed the fluidic thermoplastics, ABS and acetate, into the structure of 3D model. Therefore soundness of joining was strongly depending on the viscosity of thermoplastics in polymers. The developed laser process is expected to increase productivity and minimize the cost for the final products.

• Polymer Science and Technology
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• v.18 no.5
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• pp.450-457
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• 2007

• Polymer Science and Technology
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• v.10 no.2
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• pp.207-214
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• 1999

• Polymer Science and Technology
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• v.2 no.5
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• pp.341-354
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• 1991

• Polymer Science and Technology
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• v.5 no.6
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• pp.551-557
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• 1994

• Proceedings of the Korean Fiber Society Conference
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• 2003.10b
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• pp.209-210
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• 2003

The durability and anti-microbial stability of plastics, which have been thought to be favorable characteristics, cause ecoloical problems due to non-degradation after disposal. For a possible solution of these ecological and environmental problems, the biodegradable polymers. especially aliphatic polyesters, have been widely investigated. Poly(tetramethylene succinate)(PTMS) is one of the most promising biodegradable polyesters. (omitted)

• Bulletin of the Korean Chemical Society
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• v.33 no.10
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• pp.3208-3212
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• 2012

Controlled drug delivery systems employing microparticles offer lots of advantages over conventional drug dosage formulations. Microencapsulation technique have been conducted with biodegradable polymers such as poly(lactic-co-glycolic acid) (PLGA) and poly(lactic acid) (PLA) for its adjustable biodegradability and biocompatibility. In this study, we evaluated two techniques, oil-in-water (o/w) emulsion solvent evaporation and spray drying, for preparation of polymeric microparticles encapsulating a newly synthesized drug, SS-AG20, for the long-term drug delivery of this low-molecular-weight drug with a very short half-life. Drug-loaded microparticles prepared by the solvent evaporation method showed a smoother morphology; however, relatively poor encapsulation efficiency and drastic initial burst were discovered as drawbacks. Spray-dried drug-loaded microparticles had an imperfect surface with pores and distorted portions so that its initial burst was critical (70.05-87.16%) when the preparation was carried out with a 5% polymeric solution. By increasing the concentration of the polymer, the morphology was refined and undesirable initial burst was circumvented (burst was reduced to 35.93-74.85%) while retaining high encapsulation efficiency. Moreover, by encapsulating the drug with various biodegradable polymers using the spray drying method, gradual and sustained drug release, for up to 2 weeks, was achieved.

• Proceedings of the Korean Fiber Society Conference
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• 2003.04a
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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)

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.48-49
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• 2006

The incorporation of heparin to biomaterials has been widely studied to improve the biocompatibility (blood and cell) of biomaterials surfaces. In our laboratory, various kinds of heparinized polymers including heparinized thermosensitive polymers ($Tetronic^{(R)}$-PLA(PCL)-heparin copolymers) and star-shaped PLA-heparin copolymers have been developed as a novel blood/cell compatible material. These heparinized polymers have demonstrated their unique properties due to bound heparin, resulting in improved biocompatibility. These heparinized bioactive polymers can be applied as blood and tissue compatible biodegradable materials in variable medical application such as tissue engineering and drug delivery system.

• Proceedings of the Korean Fiber Society Conference
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• 2003.10a
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• pp.97-97
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• 2003

Recently, attention has been paid to biodegradable polymers in relation to the global environment. Poly-lactide (PLA) is one of such polymers and has studied by some investigators. In this study, the changes of crystal structure, crystal orientation and supermolecular structure of Poly(L-lactide) (PLLA) during drawing or annealing have been investigated.