• Journal of Pharmaceutical Investigation
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• 제38권1호
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• pp.63-72
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• 2008

Meloxicam-loaded microspheres were prepared with poly(D,L-lactic acid)(PLA) by a solvent-emulsion evaporation method. The morphology, particle size, drug loading capacity, drug entrapment efficiency (EE) and release patterns of drug were investigated in vitro. Various batches of micro spheres with different size and drug content were obtained by changing the ratio of meloxicam to $PLA^{\circ}{\AE}s$ with different molecular weight, PLA concentration in the dispersed phase and stirring rate. Meloxicam crystals on microsphere surface, which were released rapidly and could act as a loading dose, were observed with increasing drug content. The release rate was increased with increase in drug contents and decrease in the molecular weight of PLA. Microspheres prepared with smaller molecular weight produced faster drug release rate. The release rate of meloxicam for long-acting injectable delivery system in vitro, which would aid in predicting in vivo release profile, could be controlled by properly optimizing various factors affecting characteristics of microspheres. Blood concentration-time profile of meloxicam after intramuscular injection of meloxicam-loaded microspheres in rabbits showed possibility of long term application of this system in clinical settings.

• 한국결정성장학회지
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• 제21권3호
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• pp.124-128
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• 2011

전기방사법을 이용하여 제조된 웹은 높은 비표면적 및 다공성으로 약물전달시스템에 적용하고자 널리 연구 되어지고 있다. 본 연구에서는 생체적합성을 가진 생분해성 고분자 Poly(lactic acid)(PLA)와 생체안정성을 가지는 재료인 $TiO_2$를 이용하여 복합소재를 제작하였다. 인체에 유해한 용매인 chloroform이 포함되어 있지 않은 복합화를 위하여 용융전기방사법을 이용하여 나노섬유를 제작하였다. 이렇게 제조된 PLA/$TiO_2$ web을 scanning electron microscope(SEM)와 field emission transmission electron microscope(FE-TEM)을 이용하여 섬유의 모양을 확인하였고, X-ray diffractometer(XRD)판 이용하여 PLA/$TiO_2$ web의 결정구조를 분석하였다.

• 한국포장학회지
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• 제28권2호
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• pp.89-95
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• 2022

The goal of this study was to evaluate the effect of spent coffee grounds (SCG) biofiller on the morphological, thermal, mechanical and hydrolytic degradation characteristics of poly(lactic acid) (PLA) based biocomposites. The PLA-based biocomposite films were fabricated by using a high-viscosity kneading and hot-pressing machine. The PLA/SCG biocomposites were analyzed with SEM, DSC, TGA, UTM and hydrolytic degradation test. Aggregation in the PLA matrix is a result of increasing SCG concentrations. In the thermal properties, it was described that the cold crystallization temperature (T_cc) decreased as SCG was added to PLA. When SCG was incorporated to PLA, the degradation onset temperature (T_onset) revealed a diminish. The elastic modulus increased while tensile strength of PLA diminished as SCG was applied. Through hydrolysis analysis, the decomposition of PLA was accelerated with the addition of SCG. This research confirmed the possibility of devloping an eco-friendly packaging material with high degradability as SCG hasten the breakdown of PLA.

• 한국염색가공학회지
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• 제25권1호
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• pp.75-81
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• 2013

Colorimetric and wash fastness data after repeated wash cycles of Poly Lactic Acid(PLA) fiber were examined with C. I. Vat Blue 1, also other comparing 2 dyes (C. I. Vat Blue 35, C. I. Vat Blue 5), in this study. The fastness of three vat dyes on PLA fiber to repeated washing according to KS K 0430 A-2 regulation increased with dyeing temperatures. The $L^*$ values of the dyed material gradually increased with increasing numbers of wash. Also the f(k) values were decreased reversely. During repeated washing, the vagrant dyes were deposited especially on nylon, polyester, cotton of the adjacent multifiber. C. I. Vat Blue 5 displayed lowest color change to repeated washing of the three dyes used.

• 폴리머
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• 제38권4호
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• pp.464-470
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• 2014

A chemo-mechanical method was used to prepare lignin-containing cellulose nanofibrils(L-CNF) from unbleached woodpulps dispersed uniformly in an organic solvent. L-CNF/PLA composites were obtained by solvent casting method. The effects of L-CNF concentration on the composite performances were characterized by tensile test machine, contact angle machine, scanning electron microscope (SEM), and Fourier transform infrared spectroscopy (FTIR). The tensile test results indicated that the tensile strength and elongation-at-break increased by 50.6% and 31.8% compared with pure PLA. The contact angle of PLA composites decreased from $79.3^{\circ}$ to $68.9^{\circ}$. The FTIR analysis successfully showed that L-CNF had formed intermolecular hydrogen bonding with PLA matrix.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 2003년도 가을 학술발표회 논문집
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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)

• 접착 및 계면
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• 제15권1호
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• pp.14-21
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• 2014

본 연구에서는 이축압출기와 사출기를 사용하여 폴리유산(PLA)와 폴리부틸렌숙시네이트(PBS) 수지의 함량비를 달리하여 PLA/PBS 블랜드를 제조하고, 그들의 기계적, 열적 특성 및 모폴로지를 조사하였다. PLA/PBS 블랜드의 굴곡강도, 굴곡탄성률, 인장강도 및 인장탄성률과 같은 기계적 특성, 그리고 용융거동, 동역학적 열특성 및 열안정성과 같은 열적 특성이 PLA와 PBS 함량비에 크게 의존하였다. 그러나 PLA/PBS 블랜드의 열변형온도는 PLA 또는 PBS 함량 변화에 크게 영향을 받지 않았다. 또한 PLA/PBS 블랜드의 파단면은 PBS 함량이 증가함에 따라 brittle 양상으로부터 ductile 양상으로 변화되었다.

• 한국포장학회지
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• 제26권2호
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• pp.93-98
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• 2020

PEO 첨가에 따른 PLA/PBAT 블렌드 필름의 물성개선 효과를 확인하였다. PEO 농도에 따른 영향을 확인하기 위하여 기계적특성, 열적특성 및 화학적 특성을 조사하였다. PEO 농도가 증가함에 따라 PLA/PBAT/PEO 블렌드 필름의 인장강도는 소폭 감소하지만 열안정성은 증가하였다. PEO 2% 첨가군은 다른 샘플들에 비해 인장강도 감소폭 대비 높은 파단연신율(46.8%) 개선 효과를 보였다. 반면, PEO 4% 수준에서 PEO 무첨가와 유사한 파단연신율과 인장강도의 저하가 발생하였다. 열특성 분석을 통해 PLA/PBAT 블렌드 내 낮은 혼화성으로 발생한 두개의 T_m 피크가 PEO 첨가로 상용성이 증가하여 피크가 하나로 합쳐지는 것을 확인하였다. 또한, ¹H-NMR 분석을 통해 블렌드 내의 PEO의 농도가 증가함을 확인하였다. 향후, PEO 농도가 증가함에 따라 감소된 인장강도 유지와 파단연신율을 확보하기 위한 PEO의 분산성 향상에 대한 추가적인 연구가 필요하다.

• 한국응용과학기술학회지
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• 제34권3호
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• pp.643-649
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• 2017

리파아제 및 프로테이나아제와 같은 생분해성 효소는 지방산 에스테르 및 트리글리 세라이드뿐만 아니라 지방족 폴리에스테르를 가수 분해가 가능하다. 본 연구에서는 생분해성 효소가 자연 환경에서 PLA, 옥수수 전분 및 폴리에틸렌글리콜 등의 천연 지방족 폴리 물질이 분해에 중요한 역할인 생분해성을 측정했다. 본 실험에서는 PLA, PLA와 폴리에틸렌아크릴레이트, PLA 그라프트 중합체인 폴리에틸렌글리콜아크릴레이트를 사용한 PLAcoPolyethylene의 생분해성에 대해 실험하였다. 생분해성 고분자를 합성할 때. 이들의 기계적 특성은 생분해성도, 열적특성, 실시간으로 폴리머 수지의 전기적 모니터링을 통해 실험측정 결과, BOD와 PLAcoPolyethylene의 생분해도는 PLA와 그라프트 공중합된 폴리에틸렌아크릴레이트는 다른 시료보다 낮은 속도로 측정되었다.

• Journal of the Korean Wood Science and Technology
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• 제37권5호
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• pp.434-439
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• 2009

This study investigates the thermal properties of nanocomposites prepared from poly(lactic acid) (PLA), wood flour (WF) and montmorillonite (MMT) by melt compounding with a twin screw extruder. In order to enhance the mechanical properties of PLA/WF composites, maleic anhydride grafted PLA (MAPLA) is synthesized as a compatibilizer. MAPLA prepared in the laboratory is characterized using FR-IR. From SEM microphotographs, the presence of MAPLA has a positive effect on the mechanical properties of WF-reinforced PLA composites. The addition of WF/MAPLA into neat PLA increased the glass transition temperature ($T_g$). The addition of 1 to 5 wt% MMT into PLA/WF/MAPLA composite decreases the $T_g$. The cold crystallization temperature ($T_{cc}$) was decreased by the addition of MMT. The MMT could act as effective nucleating sites of PLA crystallization. The thermal stability evaluated by thermogravimetric analysis (TGA) is improved with the contents of MMT up to 3 wt%.