• Journal of Pharmaceutical Investigation
• /
• v.31 no.2
• /
• pp.101-106
• /
• 2001

Alginate-chitosan (anion-cationic polymeric complex) was prepared to control the release rate of silver sulfadiazine (AgSD). Na-alginate (2%) solution containing AgSD was gelled in $CaCl_2$ solution. The gel beads formed were immediately encapsulated with chitosan (CS). The gel matrix and membrane were then reinforced with chondroitin-6-sulfate (Ch6S). Release rate of AgSD from the gel matrix was investigated by placing alginate beads in the sac of cellulose membrane simmered in HEPES-buffer solution. The concentration of AgSD released was analyzed by UV at 264 nm. Incorporation capacity of AgSD in Ca-alginate gel was more than 90%. Alginate-Ch6S-CS could control the release rate of AgSD. The amount of AgSD release was dependent on the AgSD loading dose. Incorporation of tripolyphosphate (polyanionic crosslinker) onto the alginate-Ch6S-CS bead increased the release rate of AgSD. Collagen-coating had no influence on the AgSD release rate. Alginate-Ch6S-CS beads with a sufficiently high AgSD encapsulation were capable of controlling the release of the drug over 10 days. In summary, alginate-Ch6S-CS beads could be used as a sustained delivery for AgSD and provide local targeting with low silver toxicity and patient discomfort.

• Bulletin of the Korean Chemical Society
• /
• v.25 no.3
• /
• pp.357-360
• /
• 2004

We developed in the present study molecular imprinted polymers (MIPs), using single templates (pentoxifylline, caffeine and theophylline) and mixed-templates (pentoxifylline-caffeine, pentoxifylline-theophylline and caffeine-theophylline). The MIPs were prepared with methacrylic acid (MAA) as the monomer, ethylene glycol dimetharylate (EGDMA) as the crosslinker and 2,2'-azobis(isobutyronitrile) (AIBN) as the initiator. The obtained polymer particles (particle size after grinding was about 25-35 ${\mu}$m) were packed into a HPLC column (3.9 mm i.d. ${\times}$ 150 mm). The selectivity and chromatographic characteristics of the MIPs were studied using acetonitrile as the mobile phase at a flow rate of 0.8 mL/min. UV detector wavelength was set at 270 nm. Different single template MIPs showed different molecular recognitions to the templates and the structurally analogues, according to the rigidity and steric hindrance of the compounds. Recognition was improved on the mixed-template MIPs as a result of the cooperation or sum effect of the templates, whereas on the pentoxifylline-theophylline imprinted polymer, the highest selectivity and affinity were obtained. Separations of the test compounds on different polymers were also investigated.

• Textile Coloration and Finishing
• /
• v.33 no.4
• /
• pp.230-237
• /
• 2021

The flame-retardant (FR) treatments of wool fibers using Hexafluorozirconate/titanate salts and tetrabromophthalic anhydride can cause skin irritation and gas toxicity due to Zr and Br compounds respectively. A water-soluble polyfunctional cyclophosphazene derivative, synthesized through substitution reaction of Hexachloro cyclophosphazene and N-[3-(Dimethylamino)propyl] metacrylamide, was applied as a durable flame-retardant for wool fabrics. Also, a crosslinked structure was introduced to improve washing durability of the FR-wool, up to 10 laundering cycles, using Acrylamide(AAm) and Triacryloylhexahydrotriazine (TAHT) as a comonomer and a crosslinker respectively. The mole ratios of the TAHT and AAm concentrations compared to the Dichloro tetrakis{N-[3-(Dimethylamino)propyl]methacrylamido} cyclcophosphazene (DCTDCP) were optimized to 1.33 and 7.5 respectively. In addition, the pyrolysis and combustion properties of the FR wool were assessed using LOI, TGA and microcalorimetry suggesting a solid-phase FR mechanism.

• Prospectives of Industrial Chemistry
• /
• v.23 no.6
• /
• pp.25-36
• /
• 2020

용액공정을 통해 유기 전자소자를 대면적으로 제조하는 것은 다양한 장치 구성 요소(반도체, 절연체, 도체)의 패터닝 및 적층이 필요하기 때문에 매우 어려운 과제이다. 본 연구에서는 4개의 광 가교 기능기를 가지는 3차원 사면체 가교제인 (2,2-bis(((4-azido-2,3,5,6-tetrafluorobenzoyl)oxy)methyl)propane-1,3-diyl bis(4-azido-2,3,5,6-tetrafluorobenzoate) (4Bx)를 활용하여 용액공정을 기반으로 형성된 전자재료 박막을 고해상도로 패터닝 및 적층하는 기술을 개발하고, 이를 사용하여 고분자 박막 트랜지스터(PTFTs) 및 논리회로 어레이 제작을 진행하였다. 4Bx는 다양한 용액공정이 가능한 전자재료와 용매에 쉽게 혼합될 수 있으며, 자외선(UV)에 의해 가교제가 광 활성화되어 전자재료와 가교 결합을 형성할 수 있다. 4Bx는 기존의 2개의 광 가교 기능기를 갖는 가교제에 비해 높은 가교 효율로 인해 적은 양을 첨가하여도 완전하게 가교된 전자재료 박막을 형성할 수 있어 전자재료의 고유한 특성을 보존할 수 있다. 더욱이, 가교된 전자재료 박막은 화학적 내구성이 향상되어 고해상도 미세 패터닝을 할 수 있을 뿐만 아니라 용액공정을 통해 전자소자를 구성하는 전자재료의 적층이 가능하다. 4Bx의 광 가교 방법은 전용액공정을 통한 전자소자의 제작에 대한 혁신적인 방안을 제시한다.

• Membrane Journal
• /
• v.31 no.3
• /
• pp.219-227
• /
• 2021

Molecularly imprinted membrane (MIM) is a porous polymer membrane incorporating with the molecular recognizing sites. In this study, the supporting P(AN-co-MA) asymmetric membrane was prepared by nonsolvent induced phase separation (NIPS) method. And then, MIM with lysozyme template sites was prepared using the surface imprinting method on the P(AN-co-MA) asymmetric membrane introducing a photoactive iniferter and then photo-grafting. The P(AN-co-MA) asymmetric membrane was modified with 3-chloropropyltrimethoxysilane and dithiocarbamate as a photoactive iniferter. To prepare a lysozyme imprinted membrane, the modified P(AN-co-MA) membrane was copolymerized with acrylamide as a functional momomer, N,N'-methylene bisacrylamide as a crosslinker and lysozyme as a template in the UV irradiation environment. The lysozyme imprinted MIM was analyzed by using SEM, FT-IR and EDS measurements. Its results confirm that all the P(AN-co-MA) membranes have an asymmetric structure and the iniferter group is successfully introduced on the membrane surface. The process parameters were adjusted to obtain MIM having the excellent lysozyme adsorption. The maximum lysozyme adsorption capacity reaches at 2.7 mg/g, which is 13 times higher than that of the non imprinted membrane (NIM). The permselective membrane filtration experiments of ovalbumin to lysozyme show that the P(AN-co-MA) MIM preferentially bounds a greater amount of lysozyme.

• Applied Chemistry for Engineering
• /
• v.27 no.2
• /
• pp.221-226
• /
• 2016

Production of eco-friendly and biologically harmless materials is strongly required in all industries. In particular, reducing volatile organic compounds in coating processes is extremely important to secure worker's safety. During recent two decades, extensive research works on water-borne polyurethane dispersion (PUD) have been continuously developed as an alternative to solvent-borne polyurethane. However, PUD was shown inferior mechanical properties to the organic solvent-borne polyurethane due to a limit to the molecular weight increase, which resulted in the limit of applications. To overcome this drawback, several approaches have been examined such as polymer blends and thermal/radiation induced crosslinking. Among these methods, the radiation curing system was suitable for industrialization because of the high crosslinking density and fast curing speed. In this study, we overcame the drawback for PUD via introducing benzophenone radiation curable units to PUD. We synthesized PUD films which possessed good dispersion in water for 30 days, increased Tg and Td more than $5^{\circ}C$ after UV curing film as well as improved young's modulus more than double.