• Journal of the Korean Wood Science and Technology
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• v.24 no.2
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• pp.15-19
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• 1996

To utilize the waste materials and develope wood adhesive from isolated bloods of slaughtered cow and pig and also to prevent water pollution, simple and rapid method of isolation and purification of plasma proteins from pig bloods with trichloroacetic acid(TCA) treatment was developed. Adding of TCA-precipitated blood powder to the phenol formaldehyde resin(PF) improved dry and wet strength of plywood and resulted in fast hot pressing times.

• Journal of the Korean Wood Science and Technology
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• v.47 no.4
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• pp.519-532
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• 2019

The objectives of this study were to evaluate the effects of shelling ratio and resin content on the properties of bamboo oriented strand board (BOSB) from betung (Dendrocalamus asper) and to determine the correlation between the results of dynamic and static bending tests. Strands were steam-treated at $126^{\circ}C$ for 1 h under 0.14 MPa pressure and followed by washing with 1% NaOH solution. Three-layer BOSB with the core layer perpendicular to the surface was formed with shelling ratios (face:core ratio) of 30:70; 40:60; 50:50; 60:40 and binded with 7% and 8% of phenol formaldehyde (PF) resin with the addition of 1% of wax. The evaluation of physical and mechanical properties of BOSB was conducted in accordance with the JIS A 5908:2003 standard and the results were compared with CSA 0437.0 standard for commercial OSB (Grade O-1). Non-destructive testing was conducted using Metriguard Model 239A Stress Wave Timer which has a wave propagation time from 1 to $9,999{\mu}s$ and a resolution of $1{\mu}s$. BOSB with 8% resin content showed better physical and mechanical properties than those with 7% resin content. The increase of the face layer ratio improved the strength of BOSB in parallel direction to the grain. The results suggested that shelling ratio of 50:50 could be used as a simple way to reduce PF resin requirements from 8% to 7% and to meet the requirements of CSA 0437.0 standard. The results of non-destructive and destructive tests showed a strong correlation, suggesting that non-destructive test can be used to estimate the bending properties of BOSB.

• Restorative Dentistry and Endodontics
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• v.31 no.1
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• pp.1-10
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• 2006

The purpose of this study was to compare the shaping ability of three Ni-Ti file systems used by dental students or the experts and consequently to aid in choosing a proper systems for educational courses of dental students and beginners. Fifty students and ten dentists who have clinical experience over two years prepared 180 simulated root canals in resin blocks with three Ni-Ti systems; $ProFile^{(R)}\;(PF),\;HeroShaper^{(R)}\;(HS),\;K3^{TM}\;(K3)$. After preparation, the Ni-Ti files were evaluated for distortion and canal preparation time was recorded. The images of pre- and post-instrumented canals were scanned and superimposed. Amounts of increased canal widths, deviation, and centering ratio were calculated at apical 1, 3 and 5 mm levels and statistical analysis was performed The results were as follows : 1. HS showed the shortest preparation time and instrumented canal width in K3 was significantly larger than other groups (P<0.05). 2. At 1 and 3mm levels, all groups had outward deviation. In student group, at the 1mm level, PF had the least deviation (P<0.05). 3. In the centering ratio, the PF had the best centering ability compared to the others at 5mm level. At 1 and 3mm levels, HS and PF had better abilities than K3. Student group had better ratio than the expert at 3mm level with PF (P<0.05). Based on the results, it is surmised that the $ProFile^{(R)}$ is the safest and most ideal instrument for students and beginners.

• Journal of the Korean Wood Science and Technology
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• v.44 no.1
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• pp.106-112
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• 2016

This study investigated electrical properties and far-infrared ray emission according to the carbonizing temperature and phenol-formaldehyde (PF) resin impregnation ratio of ceramics manufactured using sawdust and rice husk. The far-infrared ray emission values and emission energy values decreased as the carbonizing temperature increased. The far-infrared ray emission values of the ceramics manufactured using a carbonizing process at $600^{\circ}C$ and a board with a PF resin impregnation ratio of 60 percent was 0.930; the emission energy presented the highest value of $4.32{\times}10w/m^2$. The electric resistance decreased as the carbonizing temperature increased. For the increase in the carbonizing temperature above $1200^{\circ}C$, ceramics was very close to a conductor due to the small resistance. The power consumption increased by the decrease of electric resistance and increase of the electric current in the case of a higher resin impregnation ratio.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.110-111
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• 2013

FcBP consisting of 13 amino acids specifically binds to Immunoglobulin G Fc domain. Initially, we utilized this peptide for preparation of antibody chip as a PEG composite for enhanced solubility. After then, the peptide conjugate was immobilized on agarose resin, resulting in highly efficient affinity column for antibody purification. The efficiency was comparable to commercial Protein A column. Recently, this peptide was conjugated with cell penetrating peptide (CPP) on a backbone of GFP, affording antibody transducer, which carries antibody into live cells by simple mixing of antibody and the transducer in cell culture media. Antibody transduction into cells was monitored by live cell imaging. More recently, the FcBP was fused to ferritin cage, which consists of 24 ferritin protein molecules. The FcBP-ferritin cage showed greatly increased binding affinity to human IgG. Its binding was analyzed by QCM and SPR analysis. Finally, it was selectively delivered by Herceptin to SKBR3, a breast cancer cell, over MCF10A, non-tumorigenic cells (Fig. 1). Fig. 1. Fluorescent microscopic images of SKBR3 breast cancer cells (A~C) and MCF10A breast cells (D~F) treated with Cy3-trastuzumab/fFcBP-Pf_Fn complexes. Trastuzumab and FcBP-Pf_Fn, which were labeled with Cy3 (Cy3-trastuzumab) and fluorescein (fFcBP-Pf_Fn), respectively, selectively targeted SKBR3 over MCF10A.

• Journal of the Korean Wood Science and Technology
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• v.45 no.5
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• pp.580-587
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• 2017

Woodfiber insulation board can be considered as a one of the key material for low energy consumption, comfortable and safety construction of residential space because of its eco-friendly and high thermal insulation performance. This study was carried out to investigate the formaldehyde (HCHO) total volatile organic compounds (TVOC) emission properties and combustion shapes by flame test of low density fiberboards (LDFs) prepared with different adhesives. HCHO TVOC emission and combustion properties of LDFs prepared by melamine urea formaldehyde (MUF), phenol formaldehyde (PF), emulsified methylene diphenyl diisocyanate (eMDI) and latex resin adhesives were measured by desiccator method, 20 L chamber method, and flame test, respectively. As results, LDFs manufactured by MUF, eMDI and latex resin adhesives satisfied the Super $E_0$ grade of HCHO emission performance except PF resin. Furthermore, TVOC emission of all LDFs were satisfied the Korean indoor air quality standard (below $400{\mu}g/m^2{\cdot}h$). Especially, LDF with eMDI resin adhesive showed the lowest HCHO and TVOC emissivity, that $0.14mg/{\ell}$, $12{\mu}g/m^2{\cdot}h$, respectively. However, eMDI emitted the small amount ($3{\mu}g/m^2{\cdot}h$) of toluene in VOC components. In the flame test, LDF with MUF resin adhesives showed the most favorable shape after flame test compare to LDFs prepared other adhesives. Based on HCHO and TVOC emission, and combustion shapes, MUF resin adhesive may be recommended to prepare LDF for insulation purpose.

• Korean Chemical Engineering Research
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• v.55 no.3
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• pp.385-394
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• 2017

In this study, reaction mechanism and curing characteristics of adhesives formulated with NaOH- and $H_2SO_4$-hydrolyzed chicken feather (CF) and formaldehyde-based crosslinkers were investigated by FT-IR and DSC. In addition, adhesive properties and formaldehyde emission of medium-density fiberboards (MDF) applied with the adhesives were measured. CF-based adhesives having a solid content of 40% and over were very viscous at $25^{\circ}C$, but the viscosity reduced to $300{\sim}660m{\cdot}Pa{\cdot}s$ at $50^{\circ}C$. Consequently, the adhesives could be used as a sprayable resin. Through the FT-IR spectra of liquid and cured CF-based adhesives, addition reaction of methylol group and condensation reaction between the functional groups with the use of formaldehyde-based crosslinkers were identified. From the analysis of DSC, it was elucidated for CF-based adhesives to require a higher pressing temperature or longer pressing time comparing to commercial urea-formaldehyde (C-UF) resin. MDF bonded with CF-based adhesives, which was formulated with 5% NaOH-hydrolyzed CF (CF-AK-5%) and PF of formaldehyde to phenol mole ratio of 2.5 (PF-2.5), and pressed for 8 min had higher MOR and IB than those with other CF-based adhesives. MOR and IB of MDF bonded with the CF-based adhesives regardless of formulation type and pressing time were higher than those with C-UF resin. When the values compared with the minimum requirements of KS standard, IB exceeded the KS standard in all formulations and pressing time, but MOR of only MDF bonded with CF-AK-5% and PF-2.5 and pressed for 8 min satisfied the KS standard. What was worse, 24-TS of MDF bonded with all CF-based adhesives did not satisfied the KS standard. However, MOR and 24-TS can be improved by increasing the target density of MDF or the amount of wax emulsion, which is added to improve the water resistance of MDF. Importantly, the use of CF-based adhesives decreased greatly the formaldehyde emission. Based on the results, we reached the conclusion that CF-based adhesives formulated under proper conditions had a potential as a sprayable resin for the production of wood panels.

• Journal of the Korean Wood Science and Technology
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• v.36 no.3
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• pp.30-38
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• 2008

Petroleum-based resin adhesives have extensively been used for the production of wood panels. However, with the increase of manufacturing cost and the environmental issue, such as the emission of volatile organic compounds, of the adhesive resins, it is necessary to be developed new adhesive systems. In this study, the potential of okara, which is a residue wasted from the production of tofu, for the development of bio-based adhesives was investigated. At first, the physical and chemical properties of okara were examined. After okara was hydrolyzed in acidic and/or alkaline solutions, okara-based adhesive resins were formulated with the mixtures of the okara hydrolyzates and phenol formaldehyde (PF) prepolymer. The adhesive resins were used for the fabrication of plywood panels, and then the adhesive strength and formaldehyde emission of the plywood panels were measured to examine the applicability of the resin adhesives for the production of plywood panels. The solids content and pH of the okara used in this study were around 20% and weak acidic state, respectively. In the analysis of its chemical composition, the content of carbohydrate was the highest, and followed by protein. The shear strengths of plywood fabricated with okara-based resin adhesives exceeded a minimum requirement of KS standard for ordinary plywood, but its wood failure did not reach the minimum requirement. In addition, the formaldehyde emissions of all plywood panels were higher than that of E1 specified in the KS standard. Based on these results, okara has the potential to be used as a raw material of environmentally friendly adhesive resin systems for the production of wood panels, but further researches - biological hydrolysis of okara and various formulations of PF prepolymer - are required to improve the adhesive strength and formaldehyde emission of okara-based resin adhesives.

• Journal of the Korean Wood Science and Technology
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• v.39 no.5
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• pp.381-389
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• 2011

The effect of organoclays on the mechanical properties of cured phenol formaldehyde resin and oriented strand lumber made from Mountain Pine Beetle killed pine strands was analyzed. Three organoclays were used: a natural montmorillonite, hydrophobic organically modified 10 A, and hydrophilic organically modified 30 B. The oriented strand lumber samples were less creep deformation as well as improved internal bonding strength by adding organoclays in the order of 10 A 2% > MMT 2% > 30 B 2% > control. Furthermore, time-temperature superposition (TTS) analysis was proved to be able to predict the long-term creep behavior of MPB-OSL samples.

• Journal of the Korean Applied Science and Technology
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• v.14 no.2
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• pp.27-34
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• 1997

Naphthoquinone-1,2-diazide-5-sulfonyl [NDS]derivatives members of Quinone diazide compound that are utilizable as photoresist for printing plate were synthesized, and photoresist were prepared by mixing these derivatives with a matrix resin(PF, CF) at various weight ratios. Photosensitive characteristics of photoresist were studied by Gray scale method, and SEM to analyze if they can be used as photosensitive material in a printing plate. Experimental results showed using IR, UV, NDS derivatives were photoconverted and developer-soluble photoresist were produced. Photoresist in the mixing ratio of 1:4 of NDS[II] and CF resin gave rise to the highest dissolution rate. In addition, photoresist obtained at this condition resulted in the most superior sensitivity.