• Clean Technology
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• v.13 no.2
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• pp.127-133
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• 2007

Celite with enormous pore space inside can hold small molecules and can be well blended with polyethylene (PE) to make a Celite-PE film. Two types of Celite-PE film were prepared, one with Celite surface-treated with surfactant to reduce the hydrophilicity and another with plain Celite. The anti-rust chemical such as dicyclohexylamine, dicyclohexylamine nitrite, or diisopropylamine was allowed to permeate into celite pore in the film, and slowly evaporated to protect the packaged steel material from the rust for a long period of time. The chemical concentration in the different packaging film bags was analyzed by a gas chromatography for a month, and the anti-rust effect on iron labware was compared for a six month period. The Celite film was superior to PE film in anti-rust effect and the long-term anti-rust chemical evaporation.

• Food Science and Preservation
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• v.10 no.4
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• pp.498-505
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• 2003

This was studied to evaluate the rheology properties of the Dumpling shell added chitosans(commercial and prepared from fungal), polyphosphate, guargum and tapioca. The physicochemical properties of fungal chitosans (FCs95 and FCs 40) were as follows respectively. The nitrogen was 6.71% and 6.9％, the solubility 99.05% and 99.13％, the viscosity 2.23cps and 2.21cps, the acetylation 12.0% and 12.7% and the molecular weight 3.12${\times}$10$\^$5/Dalton and 3.01${\times}$10$\^$5/Dalton. From the above facts, the components and physicochemical properties of two kinds of fungal chitosan had little difference. The addition of polyphosphate, guargum and tapioca showed effect on the texture parameters(hardness, cohesiveness, springiness and gumminess) of Dumpling shell dough and the optimum addition concentration wag 0.074%, 6.59% and 0.062%(w/w), respectively. In case of chiotsans addition, texture of the dough by added SCs, FCs95 and FCs40 showed effect.

• Polymer(Korea)
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• v.26 no.5
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• pp.634-643
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• 2002

Ultrathin film of polyamic acid having benzene and sulfonyloxyimide moieties was prepared using the Langmuir-Blodgett (LB) technique, and then photosensitive polyimide LB film was obtained by the thermal treatment of precursor polyamic acid multilayers at 200$\^{C}$ for 1 hr. The polyamic acid was synthesized by condensation polymerization under THF and pyridine cosolvent. All monomers and polymers were identified through elemental analysis, FT-IR and $^1$H-NMR spectroscopic measurements. The microarray patterning of photosensitive polyimide LB film on a gold substrate was generated with a deep UV lithography technique. The well-characterized monolayer of cytochrome c was immobilized on the microarray patterns using two different self-assembly processes. Physical and electrochemical properties of the self-assembled cytochrome c monolayer were investigated based on cyclic voltammetry and atomic force microscopy (AFM). Also, its application in bioelectronic device was examined.

• Applied Chemistry for Engineering
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• v.19 no.3
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• pp.287-294
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• 2008

Molecularly imprinted polymer (MIPs) membranes were prepared by UV polymerization to separate racemates with opposite physiological activity, and then its separation selectivity of racemates was carried out. Likewise, their properties were examined. Polycarbonate (PC) membrane was polymerized as small spot form in pore inner wall, but anodisc (AD) membrane was polymerized as film form with thickness 500~700 nm onto the membrane surface. Also the study on the separation selectivity of prepared MIPs membranes was carried out in L-Tryptophane (Trp) racemate solution. The results showed that AD MIPs membrane polymerized as a film form, which was achieved by solution polymerizaion consisting of over 90% cross-linking agent (ethylene glycol dimethacrylate; EGDMA) and under 30% dispersing agent (methanol; MeOH), had predominant 3.5 selectivity.

• Journal of Adhesion and Interface
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• v.19 no.4
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• pp.154-162
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• 2018

Plasma treatment and corona treatment have been used for surface modification of polydimethylsiloxane (PDMS) film by activating its surface with the -OH group. Adhesion promoter or coupling agent was also used to improve adhesion of PDMS film with various materials. However, obtained hydrophilicity onto the surface of PDMS films with those processes was transient and vulnerable. In this study, a new alkoxysilane-functionalized acrylic polymer precursor was first synthesized by copolymerization process, and then was reacted with HO-terminated PDMS through condensation reaction to prepare a new surface modifier for PDMS film. The structure and molecular weight of the prepared surface modifier were confirmed by 1H-NMR and GPC measurement. Surface properties of surface modifier-coated PDMS films were also investigated by using XPS, ATR and WCA analysis. The adhesion between the PDMS film and the surface modifier was tested using cross-cut test.

• Composites Research
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• v.35 no.1
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• pp.23-30
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• 2022

Polycarbosilane(PCS) is an important precursor for melt-spinning the silicon carbide(SiC) fibers and manufacturing ceramics. The PCS is a metal-organic polymer precursor capable of producing continuous SiC fibers having excellent performance such as high-temperature resistance and oxidation resistance. The SiC fibers are manufactured through melt-spinning, stabilization, and heat treatment processes using the PCS manufactured by synthesis, purification, and control of the molecular structure. In this paper, we analyzed the effect of purification of unreacted substances and low molecular weight through solvent treatment of PCS and the effect of heat treatment at various temperatures change the polymerization and network rearrangement of PCS. Especially, we investigated the complex viscosity and structural arrangement of PCS precursors according to solvent treatment and heat treatment through the rheological properties.

• Korean Chemical Engineering Research
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• v.54 no.5
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• pp.693-697
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• 2016

In this study, we fabricated the catalysts for enzymatic biofuel cell anode with carbon nanotube (CNT), glucose oxidase (GOx) and various molecular weights branched poly(ethyleneimine)(bPEI) and terephthalaldehyde (TPA) as cross-linker. In case of GOx/bPEI/CNT using only physical entrapments for immobilization, the molecular weights of bPEI didn't affect to electrochemical performances and long term stability. but that of the catalysts cross linked via TPA (TPA[GOx/bPEI/CNT]) improved and the mass transfer of glucose to FAD was interrupted as increasing of the bPEI's molecular weights. Furthermore, it was confirmed that the optimum molecular weight of PEI for TPA [GOx/bPEI/CNT]) structure is 750k that showed marvelous high performance (maximum power density of $0.995mW{\cdot}cm^{-2}$).

• Applied Chemistry for Engineering
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• v.8 no.5
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• pp.837-843
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• 1997

In oxidized polyethylene wax preparation, the effects of main parameters such as the property of used wax, oxidation time, oxidation temperature, air feed rates on the change of acid-numbers were investigated. The change in polymer property was also investigated. The results showed under given reaction conditions, the acid numbers with oxidation temperature increased upto $160^{\circ}C$, but at higher temperature, it decreased. The base resin which was lower molecular weight had higher acid number. The result showed molecular weight as a experimental parameter was more effective than density in oxidation experiment. In milder condition, free radical initiator was used for catalyst to get higher acid-numbers, which was successful in comparison to the non-catalyst system. Also the catalyst with longer half-life was efficient, in order of DCPO, HOPO and BPO.

• Applied Chemistry for Engineering
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• v.10 no.1
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• pp.19-23
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• 1999

Chitosan was partially degraded by using nitrous acid. The deacetylation degree of chitosan decreased with its degree of hydrolysis. Deacetylation degree of each fraction was less than 50%. The degraded product was fractionated by means of precipitation using aqueous methanol solution or aqueous methanol-acetone solution. The molecular weight of each fraction was distributed between 6000 and 4000, and below 2000 for being precipitated using aqueous methanol solution and aqueous methanol-acetone solution respectively. They had narrow molecular weight distributions, and their polydispersities were less than 1.7. The antibacterial activities for each fraction were evaluated against Bacillus subtilis HB 101 and E. coli PP 2, gram-positive bacteria and gram-negative bacteria, respectively. Fraction B (Mw=5100) showed high antibacteiral activity. All fractions were more active against Bacillus subtilis than E. coli.

• Polymer(Korea)
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• v.31 no.6
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• pp.461-468
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• 2007

In order to understand the structure of the existing aggregate in the nanocomposite, which has been prepared with polyester and trisilanolisobutyl polyhedral oligomeric silsesquioxane(TBPOSS), laser light scattering(LLS) and SEM-EDS were applied to its 1,1,1,3,3,3-hexafluoro-2-propanol solution and original sample, respectively. Although aggregate particles appeared as spherical shape of the average diameter of 120 nm in SEM image, they were not microgels but almost linear copolymer chains ($M_w=2.3{\times}10^6\;g/mol$) alternating 320 molecules of TBPOSS with polyester subchains. It has been microphase-separated from the matrix polyester due to the difference of chemical composition. As the matrix, polyester chain of $M_w=4.0{\times}10^4\;g/mol$ had averagely 2.5 molecules of TBPOSS per chain. It is also found that about 93% of total TBPOSS molecules existed in matrix phase and the residual 7% in spherically aggregated phase.