Lotus-leaf-like structured chitosan-polyvinyl pyrrolidone films as an anti-adhesion barrier

백운용,강민지,임진익,이우걸 한국공업화학회 2014 한국공업화학회 연구논문 초록집 Vol.2014 No.1

For postsurgical anti-adhesion barrier applications, lotus-leaf-like structured chitosan-PVP films were prepared using a solution casting method with dodecyltrichloro-immobilized SiO₂ nanoparticles. We evaluated whether the lotus-leaf-like structured chitosan-PVP films (L-chitosan-PVP) could be applied as postsurgical anti-adhesion barriers. A recovery test using a tensile strength testing machine and measurement of crystallinity using X-ray diffraction indicated that films with 75% PVP were the optimal composition of the chitosan-PVP films. Also, dodecyltrichloro-immobilized SiO₂ nanoparticles was synthesized and sprayed on the film after pretreatment with the instant bio-glue. Analysis of cell adhesion, proliferation, and anti-thrombus efficiency were performed via a WST assay, field emission scanning electron microscopy, and hemacytometry. The contact angle with the lotus-leaf-like surface was of approximately 150°. Furthermore, the L-chitosan-PVP film yielded a lower cell and platelet adhesion rate (around less than 4%) than that yielded by the untreated film. These results indicate that the lotus-leaf-like structure has a unique property and that this novel L-chitosan-PVP film can be applied as a blood/tissuecompatible, biodegradable material for implantable medical devices that need an anti-adhesion barrier.

Rheological and electrical properties of polystyrene nanocomposites via incorporation of polymer-wrapped carbon nanotubes

박재상,안지훈,장건수,이성재 한국유변학회 2019 Korea-Australia rheology journal Vol.31 No.2

Carbon nanotubes (CNTs) are used as nanofillers in polymer nanocomposites to improve the properties of a matrix polymer because of their excellent properties. However, CNTs tend to aggregate due to the strong van der Waals force between CNTs. To solve the problem, surface-modified CNTs with hydrophilic polymers, such as polyvinyl pyrrolidone (PVP) and polystyrene sulfonate (PSS), were employed. Polystyrene (PS)/CNT nanocomposites were fabricated by latex technology, which is a suitable method for dispersing nanofillers in aqueous particle suspension. The effect of the incorporation of the modified CNT was significant, thereby resulting in increased modulus at lower frequencies when compared to that of neat PS. Electrical percolation thresholds of PS/PSS-wrapped CNT and PS/PVP-wrapped CNT nanocomposites corresponded to 0.39 and 0.52 wt.%, respectively. The PS/PSS-CNT nanocomposites exhibited higher rheological and electrical properties than the PS/PVP-CNT counterparts due to the hydrophilic nature of PSS with strong negative charge groups.

Influence of poly(vinyl pyrrolidone) additives in polysulfide electrolyte on the photovoltaic performances of quantum dot-sensitized solar cells

하승범,김재엽 한국공업화학회 2021 한국공업화학회 연구논문 초록집 Vol.2021 No.-

Enhanced Photovoltaic Performance of Cu-In-Se Quantum Dot-Sensitized Solar Cells by Poly(vinyl pyrrolidone) Additive in Electrolyte

하승범,김재엽 한국공업화학회 2023 한국공업화학회 연구논문 초록집 Vol.2023 No.0

Microwave-assisted drying of Prasakanphlu herbal granules and formulation development of Prasakanphlu tablets: Design of Experiments approach

Jirapornchai Suksaeree,Chaowalit Monton,Laksana Charoenchai,Natawat Chankana 경희대학교 융합한의과학연구소 2023 Oriental Pharmacy and Experimental Medicine Vol.23 No.4

This work aimed to apply the Design of Experiments (DOE) approach in microwave-assisted drying of Prasakanphlu (PSKP) herbal granules. Furthermore, DOE was applied in the formulation development of PSKP tablets. The 32 full factorial design consisted of two factors (i.e., microwave power and microwave time) and two responses (i.e., moisture content and eugenol content) that were used for optimized microwave-assisted drying of PSKP granules. The optimal condition was microwave power of 300 W for 15 min. This condition was used to dry the wet granules of PSKP for optimization of tablet formulation. The Box–Behnken design was applied in the formulation development of PSKP tablets; three factors (i.e., compression force, amount of polyvinyl pyrrolidone K30, and amount of sodium starch glycolate) and four responses (i.e., tablet thickness, hardness, friability, and disintegration time) were included in the design. Results showed that the optimal parameters were compression force of 1500 psi, 4.5% polyvinyl pyrrolidone K30, and 2% sodium starch glycolate. Furthermore, rapid dissolution of the optimal tablets was found. In conclusion, the work succeeded in applying DOE for PSKP granule drying by microwave and formulation development of PSKP tablets with desired properties.

Fused Deposition Modeling of Iron-alloy using Carrier Composition

Harshada R. Chothe,임진환,김정기,이태경,남태현,오정석 한국고무학회 2023 엘라스토머 및 콤포지트 Vol.58 No.1

Additive manufacturing (AM) or three-dimensional (3D) printing of metals has been drawing significant attention due to its reliability, usefulness, and low cost with rapid prototyping. Among the various AM technologies, fused deposition modeling (FDM) or fused filament fabrication is receiving much interest because of its simple manufacturing processing, low material waste, and cost-effective equipment. FDM technology uses metal-filled polymer filaments for 3D printing, followed by debinding and sintering to fabricate complex metal parts. An efficient binder is essential for producing polymer filaments and the thermal post-processing of printed objects. This study involved an in-depth investigation of and a fabrication route for a novel multi-component binder system with steel alloy powder (45 vol.%) ranging from filament fabrication and 3D printing to debinding and sintering. The binder system consisted of polyvinyl pyrrolidone (PVP) as a binder and thermoplastic polyurethane (TPU) and polylactic acid (PLA) as a carrier. The PVP binder held the metal components tightly by maintaining their stoichiometry, and the TPU and PLA in the ratio of 9:1 provided flexibility, stiffness, and strength to the filament for 3D printing. The efficacy of the binder system was examined by fabricating 3D-printed cubic structures. The results revealed that the thermal debinding and sintering processes effectively removed the binder/carrier from the cubic structures, resulting in isotropic shrinkage of approximately 15.8% in all directions. The scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) patterns displayed the microstructure behavior, phase transition, and elemental composition of the 3D cubic structure.

Impedance spectroscopic study of biodegradable PVA/PVP doped TBAI ionic liquid polymer electrolyte

S. Adarsh Rag,DURAISAMI DHAMODHAR-AN,M. Selvakumar,Somashekara Bhat,Shounak De,Hun-Soo Byun 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.111 No.-

This work aims to understand the ion conduction mechanism in polymer electrolyte membranes. Polyvinyl alcohol and polyvinyl pyrrolidone are chosen as polymer matrix and tetrabutylammoniumiodideas the ionic liquid among various synthetic polymers. Four samples named A-1, A-2, A-3, andA-4 have been synthesized by various concentrations and characterized the membranes through impedancespectroscopy analysis which uncovers the conductivity features of the electrolyte. Out of the foursamples, the one with 25 wt.% ionic liquid sample shows better performance than the rest of the samples. The prepared membrane was analysed and understood various parameters such as impedance analysis,dielectric constant, dielectric loss, and electric modulus. The activation energy was calculated for thesamples A-2, A-3, and A-4, as 0.27 eV, 0.96 eV and 2.97 eV, respectively. The Arrhenius models for carriertransport have been explained to interpret the conduction mechanism in polymer membranes. The presentwork has been focused on studying the effect of tetrabutylammonium-iodide ionic liquid on polyvinylalcohol and polyvinyl pyrrolidone polymer matrix as an electrolyte membrane and thepossibility of using this as an electrolyte membrane in devices such as fuel cells, supercapacitors, andbatteries.

Polymer Blends Used to Prepare Nifedipine Loaded Hollow Microspheres for a Floating-type Oral Drug Delivery System: In Vitro Evaluation

Ling Zhao,Yu Yu,Wen-wu Zheng,Yu-meng Wei 대한약학회 2010 Archives of Pharmacal Research Vol.33 No.3

The aim of this study was to investigate whether hollow microspheres prepared from polymer blends of polyvinyl pyrrolidone (PVP) and ethyl cellulose (EC) could improve the vitro release behavior of the poorly water-soluble drug nifedipine. Hollow microspheres containing nifedipine were prepared by a solvent diffusion-evaporation method using various ratios of PVP and EC codissolved with drug in ethanol/ether (5:1, v/v). The hollow microspheres could float in release medium for more than 24 h, and floating capacities were not be influenced by mixing PVP. In vitro release profiles of hollow microspheres prepared using EC along showed an initial burst release to some extent, and the cumulative release percentage was less than 55% after 24 h. But, not only the slope but also the shape of the release curves was affected by using mixture of PVP and EC. What’s more important, when the ratio (PVP/EC) increased to 1.5:8.5, the cumulative release percentage could be increased to 95.8%. Furthermore, the release rate of microspheres showed a zero order approximate dynamic model and could be expressed by the following equation: Q=3.78t+8.52 (r=0.990). Consequently, hollow microspheres prepared using polymer blends of PVP and EC (1.5:8.5, w/w) could be suitable for floating-type controlled-release delivery systems for the oral administration of nifedipine.

탄소 나노튜브를 이용한 나노유체의 특성 비교 연구

안응진(An, Eoung-Jin),박성식(Park, Sung-Seek),김남진(Kim, Nam-Jin) 한국신재생에너지학회 2011 한국신재생에너지학회 학술대회논문집 Vol.2011 No.05

탄소나노튜브는 높은 전기 전도성과 열 전도성을 가지며, 이러한 특성 때문에 21세기를 주도해 나갈 수 있는 차세대 첨단 소재로서 각광을 받고 있다. 또한 최근에는 나노공학기술의 발달로 인하여 획기적으로 높은 열전도도를 나타내는 다중벽 탄소나노튜브(Multi-walled Carbon Nanotubes, MWCNTs)의 대량 생산이 가능하게 되면서 다중벽 탄소나노튜브의 높은 열전도도 특성을 이용하여 탄소나노튜브를 기본 유체 및 기능성 유체에 안정하게 분산 시킨 후 이를 이용하고자 하는 연구가 활발히 진행되고 있으며, 탄소나노튜브를 유체에 안정하게 분산시키기 위한 방법으로는 기계적 분산법, 물리적 흡착에 의한 분산법, 화학적 개질에 의한 분산법이 있다. 따라서 본 연구에서는 이들 분산 방법과 탄소나노튜브 입자의 물성치에 따른 나노유체의 특성을 알아보기 위하여 나노유체의 열전도도와 점도 특성을 비교 분석하였다. 모든 물성치는 같지만 탄소나노튜브의 길이만 다른 두 종류의 다중벽 탄소나노튜브에 각각 계면 활성제(Sodium Dodecyl Sulfate, SDS) 100 wt%와 고분자 화합물(Polyvinyl Pyrrolidone, PVP) 300 wt%를 첨가하여 나노유체를 제조하였으며, 산화처리 된 다중벽 탄소나노튜브(Oxidized Multi-Walled Carbon Nanotubes, OMWCNTs)를 증류수에 초음파 분산하여 산화나노유체를 제조하였다. 나노유체의 열전도도는 전기 전도성 유체의 비정상 열선법(Transient Hot-wire Method)을 이용하여 측정하였고, 나노유체의 점도는 회전형 디지털 점도계를 이용하여 측정하였다. 실험 결과, 상온에서 동일 혼합비의 나노유체를 비교했을 때, 산화나노유체가 SDS 100 wt%, PVP 300 wt%를 혼합한 다른 나노유체보다 높은 열전도도 특성을 보였으며 점도 특성 또한 가장 낮은 것으로 측정되었다. 특히 상온에서 0.1vol%의 산화 CM-100 나노유체는 증류수보다 열전도도가 8.34%가 증가하였고, 10?C의 저온에서는 상온에서 증류수와 비교하여 측정된 열전도도 값보다 0.36%가 감소한 7.98%가 증가함을 보였다. 본 연구를 통하여 얻어진 결과는 높은 열전도도를 필요로 하는 열교환기의 작동유체나 기타 활용 분야에 대한 기초 자료로써 유용한 정보를 제공할 것이라 판단된다.

전기방사한 TiO2 나노섬유의 광촉매 특성 연구

태범석 ( Bom Seok Tae ),Nguyen Trung Hieu,박준서 ( Jun Seo Park ) 한국공업화학회 2009 응용화학 Vol.13 No.2