• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.548-548
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• 2012

Thermomechanical and surface chemical properties of composite films of poly(D, L-lactic-co-glycolic acid) (PLGA) were significantly improved by the addition of graphene oxide (GO) nanosheets as nanoscale fillers to the PLGA polymer matrix. Enhanced thermomechanical properties of the PLGA/GO (2 wt.%) composite film, including an increase in the crystallization temperature and reduction in the weight loss, were observed. The tensile modulus of a composite film with increased GO fraction was presumably enhanced due to strong chemical bonding between the GO nanosheets and PLGA matrix. Enhanced hydrophilicity of the composite film due to embedded GO nanosheets also improved the biocompatibility of the composite film. Improved thermomechanical properties and biocompatibility of the PLGA composite films embedded with GO nanosheets may be applicable to biomedical applications such as scaffolds.

• Proceedings of the Korean Fiber Society Conference
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• 2003.10b
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• pp.183-184
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• 2003

Poly(lactic acid) (PLA) is a highly versatile, biodegradable, aliphatic polyester derived from 100% renewable resources, such as corn and sugar beets. Because of the degradation mechanism, PLA is ideally suited for many applications in the environment where recovery of the product is not practical, such as agricultural mulch films and bags. Composting of post consumer PLA items is also a viable solution for many PLA products. (omitted)

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2009.03a
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• pp.86-87
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• 2009

• Proceedings of the Zoological Society Korea Conference
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• 1997.10b
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• pp.136.1-136
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• 1997

No Abstract, See Full Text

• Proceedings of the PSK Conference
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• 2000.04a
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• pp.213.1-213.1
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• 2000

• Applied Chemistry for Engineering
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• v.34 no.3
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• pp.285-290
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• 2023

Poly-lactic acid (PLA) is the most promising polymer in additive manufacturing as an alternative to acrylonitrile butadiene styrene (ABS). Since it is produced from renewable resources such as corn starch and sugar beets, it is also biocompatible and biodegradable. However, PLA has a couple of issues that limit its use. First, it has a comparatively low glass transition temperature of around 60 ℃, such that it exhibits low thermal resistance. Second, PLA has low impact strength because it is brittle. Due to these problems, scientists have found methods to improve the crystallinity and ductility of PLA. Polyethylene glycol (PEG) is one of the most studied plasticizers for PLA to give it chain mobility. However, the blend of PLA and PEG becomes unstable, and phase separation occurs even at room temperature as PEG is self-crystallized. Thus, it is necessary to investigate the optimal mixing ratio of PLA-PEG at the molecular scale. In this study, molecular dynamics will be conducted with various ratios of L-type PLA (PLLA) or DL-type PLA-PEG (PDLA-PEG) systems by using BIOVIA Materials Studio.

• Polymer(Korea)
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• v.32 no.2
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• pp.116-124
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• 2008

A commercialized biobased and biodegradable poly(lactic acid)(PLA) containing the functional monomer of glycidyl methacrylate (GMA) was chemically modified using reactive extrusion to enhance its melt strength. Modified PLAs were prepared with various contents of GMA and initiator, and were characterized by observing their gel fraction, thermal properties, melt viscoelasticity and biodegradability. The complex viscosity and storage modulus of chemically modified PLA with the initiator alone was increased by addition of initiator and were more increased in the presence of GMA. There was a optimum content of GMA showing the maximum complex viscosity with the amount of initiator. The biodegradebility of modified PLA was slightly decreased by addition of GMA.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.11
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• pp.5595-5600
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• 2012

This paper is to review and study about the crystallization nucleating agent to improve the heat-resistance properties of poly(lactic acid). Four sub-micron sized nucleating agents, metallic salts of 2,2'-methylene bis(4,6-di-tert-butylphenol), were prepared and used as a crystallization nucleating agent. Thermal and mechanical properties of polymer compounds were investigated by DSC, HDT and UTM. As the results, While the heat-resistance properties of the polymer compound samples were increased linearly with the contents of nucleating agent as well as their smaller size. Among them, the highest heat-resistance property of compound was observed with 2 wt% of MPZ2. HDT values of PL98Z2 compound was $116^{\circ}C$ at 0.455Mpa.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.21 no.3
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• pp.124-128
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• 2011

Electrospun webs have been widely investigated for applying to drug delivery system (DDS) because of their high specific surface area and high porosity. In this study, the composite webs of PLA (poly(lactic acid)) and $TiO_2$ were fabricated by melt-electro-spinning method for applying to drug delivery system. The morphologies of PLA/$TiO_2$, webs were observed using scanning electron microscope (SEM) and field emission transmission electron microscope (FE-TEM). The crystal structures of PLA/$TiO_2$ composite webs were confirmed by X-ray diffractometer (XRD).

• Journal of Pharmaceutical Investigation
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• v.24 no.1
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• pp.41-48
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• 1994

A new local drug delivery device to treat otitis media (OM) has been developed. This device consists of a biodegradable poly(L-lactic acid) (PLLA) film containing antibiotic (ampicillin, AMP), which can be placed into the middle ear cavity and release the therapeutic concentration of AMP for prolonged period. Biodegradable films containing AMP (10 w/w%) were prepared by solution casting method using a suspension of the drug in a $PLLA/CH_{2}Cl_{2}$ solution (molecular weight of PLLA, 100,000 (100 K) and 300,000 (300 K), respectively). PLLA-AMP films were characterized by FTIR, DSC, and SEM. In vitro release of AMP from AMP-PLLA films were examined. The release pattern of AMP from AMP-PLLA films remained consistent from 1 day to 14 days, and the release rates of AMP from AMP-100K-PLLA film and AMP-300K-PLLA film were $0.7384\;{\mu}g/ml/day$, $0.4107\;{\mu}g/ml/day$, respectively.