• Journal of the Korean Wood Science and Technology
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• v.27 no.2
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• pp.23-30
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• 1999

This study was carried out to develop the Korean paper(Hanji) sludge-wood fiber composite boards utilizing the relinquished sludges occurring from the making process of Korean classic paper Hanji. The bark of paper mulberry(Broussonetia kazinoki Sieb.) has been used as a raw material since past hundreds and thousands years. Korean paper(Hanji) sludge was divided into two kinds, the one was the white sludge from the first stage and the other was the black sludge occurring from the final stage of Korean paper(Hanji) making. Four levels of the mixed ratio of each white or black sludge to wood fiber(10:90, 20:80, 30:70 and 40:60), three levels of the resin adhesives(PMDI, urea and phenol resin) and three levels of the density(0.60, 0.75 and 0.90) were designed to investigate the physical properties of Korean paper(Hanji) sludge-wood fiber composite boards. From the results and discussion, it could be concluded as follows : 1. In the white sludge-wood fiber composite board, the thickness swelling was not affected by the specific gravity and sludge additive of composite boards, but among the resin adhesives PMDI resin showed the best dimensional stability. Water absorption was superior in urea resin, secondly PMDI resin and very poor in phenol resin. 2. In the black sludge-wood fiber composite board, thickness swelling was superior in PMDI resin but very poor in phenol resin. In water absorption, PMDI and urea resin showed good results, regardless of specific gravity or sludge additive, but phenol resin showed poor results. 3. From the results and discussion of physical properties it is suggested that the white sludge-wood fiber composite boards bonded with PMDI or black sludge-wood fiber composite boards bonded with urea resin were made possibly with similar or better properties. compared with general fiberboard until the addition of 20% sludge into wood fiber.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.9
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• pp.1255-1259
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• 2004

The objective of this study was to evaluate the effects of halogenated compounds, organic acids, unsaturated fatty acids and their mixtures on in vitro methane production and fermentative characteristics of mixed rumen microorganisms. Agents used in two in vitro experiments were bromoethanesulfonic acid (BES) and pyromellitic diimide (PMDI) as halogenated compound, fumarate and malate as organic acid, and linoleic acid and linolenic acid as unsaturated fatty acid sources. Ruminal fluid collected from a Holstein steer fed tall fescue and concentrate mixtures was incubated at $39^{\circ}C$ for 48 h with addition of those materials. Single supplementation of halogenated compounds, organic acids or unsaturated fatty acids decreased in vitro methane production (p<0.05). The second experiment was designed to investigate effects of combination of one of halogenated compounds and either organic acids or fatty acids on methane production. Lower concentration of methane and lower A:P ratio were observed with PMDI compared with BES (p<0.01). In general medium pH, VFA, total gas and hydrogen production, and dry matter degradability were affected by addition of the same compounds. In addition, PMDI+malate treatment resulted in the highest molar proportion of propionate, and lowest A:P ratio and methane production (p<0.01). Hydrogen production was highest in PMDI+linolenic acid and lowest in BES+malate treatment (p<0.01). PMDI+malate combination was the most recommendable in reducing methane production without too much influence on digestibility under conditions of present studies.

• Journal of the Korean Wood Science and Technology
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• v.27 no.2
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• pp.31-37
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• 1999

This study was carried out to develop the Korean paper(Hanji) sludge-wood fiber composite boards utilizing the relinquished sludges occurring from the making process of Korean classic paper Hanji. The bark of paper mulberry(Broussonetia kazinoki Sieb.) has been used as a raw material since past hundreds and thousands years. Korean paper(Hanji) sludge was divided into two kinds, the one was the white sludge from the first stage and the other was the black sludge occurring from the final stage of Korean paper(Hanji) making. Four levels of the mixed ratio of each white or black sludge to wood fiber(10:90, 20:80, 30:70 and 40:60), three levels of the resin adhesives(PMDI, urea and phenol resin) and three levels of the density(0.60, 0.75 and 0.90) were designed to investigate the mechanical properties of Korean paper(Hanji) sludge-wood fiber composite boards. From the results and discussion, it could be concluded as follows : 1. In the white and black sludge-wood fiber composite boards, bending modulus of rupture showed the clear decreasing tendency according to the increase of sludge additive, but it was clearly increased with the increase of specific gravity. Modulus of elasticity showed the same tendency as in the modulus of rupture, and also tensile and internal bonding strength had the same tendencies as in these bending properties. 2. Among the resin adhesives, PMDI or urea resin showed great values in MOR of white sludge-wood fiber composite board, but urea resin was greater than PMDI in MOR and MOE of black sludge-wood fiber composite board. Tensile and internal bonding strength showed the same tendencies as in white sludge-wood fiber composite board. 3. It is suggested that the white sludge-wood fiber composite boards bonded with PMDI or black sludge-wood fiber composite boards bonded with urea resin were able to made similar boards to general fiberboard by the mixed ratio 20:80 of sludge to wood fiber.

• Journal of the Korean Wood Science and Technology
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• v.29 no.2
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• pp.109-117
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• 2001

This research was carried out to develop the Hanji(Korean paper) sludge wood particle composite utilizing the waste sludges occurring from the making process of Hanji(Korean paper). In the research, four mixing ratios of white or black sludge to wood particle(10:90, 20:80, 30:70, and 40:60), three types of the resin adhesives(PMDI, urea and phenol resin) and three levels of the densities(0.60, 0.75 and 0.90) were designed to investigate the physical properties of Hanji(Korean paper) sludge wood particle composite. The linear expansion of Hanji(Korean paper) sludge wood particle composite was not always increased, compared to control boards. For thickness swelling, PMDI-bonded composites had the lowest value, and thickness swelling of composite was generally decreased with the increase of Hanji sludge. The water absorption of white sludge wood particle composite had no tendency, hut that of black sludge wood particle composite was decreased with an increase of mixing ratio of Hanji sludge.

• Journal of the Korean Wood Science and Technology
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• v.27 no.4
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• pp.57-64
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• 1999

This research was carried out to investigate the effects of density, resin and particle types on the physical and mechanical properties of the composites made from various wood particles mixed with coating paper. The experiment was designed to apply with three particles (flake, chip, and fiber) and three resin types (urea, phenol and PMDI resin). The mixed ratio of coating paper to wood particle was fixed on 50 to 50% in each board making. And also it was designed to apply for four density levels (0.6, 0.7, 0.8 and 0.9 g/$cm^3$) and four mixed formulations of coating paper to wood particle (10:90, 20:80, 30:70, and 40:60 %) to analyze clearly the effects of PMDI resin. Coating paper-wood particle composites have acceptable bending strength (MOR, MOE) though the mixed ratio of coating paper was increased, but have low internal bond strength and poor dimensional stability (WA, TS, LE). Composites with high density had higher mechanical properties but showed lower physical properties than composites with low density. In conclusion, at least up to 20% mixed ratios, coating paper-wood particle composites have acceptable physical and mechanical properties, and PMDI resin has possibility for coating paper-wood particle composite manufacture.

• Journal of the Korean Wood Science and Technology
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• v.30 no.1
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• pp.1-10
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• 2002

The aim of this research was to investigate the manufacturing possibility of the paper sludge-synthetic fiber-wood fiber composite. Three levels of the formulation of paper sludge, synthetic fiber and wood fiber (5:5:90, 15:15:70, 25:25:50), two types of adhesive (PMDI, urea-formaldehyde resin) and three levels of density(0.7, 0.8, 0.9) were designed. From the test result, composites with similar or better properties, when compared with commercial fiberboard, appeared to be possible by the addition of up to 30~50% paper sludge and synthetic fiber into wood fiber.

• Journal of the Korea Furniture Society
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• v.10 no.1
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• pp.51-56
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• 1999

This research was carried out to investigate the Hanji sludge(black color)-wood fiber and wood particle composited applied by waste sludges arising from the making process of Hanji (Korea paper). In experimental design, four levels of the mixed ratio of Hanji sludge to wood fiber or wood particle(10:90, 20:80, 30:70 and 40:60), three kinds of the resin(PMDI, urea and phenol resin)and three kinds of the specific gravity(0.6, 0.75 and 0.9) were designed to determine the tensile strength of Hanji sludge-wood fiber and wood particle composites. From the results and discussion, it may be concluded as follows: In Hanji sludge-wood fiber and wood particle composites, tensile strengths showed decreasing tendency absolutely by increasing Hanji sludge additive, but clearly increase with the increase of specific gravity. In Hanji sludge-wood fiber composites, there were no differences between PMDI and urea resin-bonded composites, but phenol resin-boned composites were made possibly until the addition of 30% Hanji sludge. On the other hand, Hnji sludge-wood particle composites(SpGr=0.6) have very low tensile strength values. But they were made favorably until the addition of 20% Hanji sludge in Hanji sludge-wood particle composites(SpGr=0.9).

• Journal of Sensor Science and Technology
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• v.7 no.5
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• pp.306-312
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• 1998

To develop the multi-channel fiber-optic sensor array system, two-channel TDM(Time Division Multiplexing) fiber-optic sensor array was constructed and characterized. The sensor array topology was Mach-Zehender ladder type and PMDI(Phase-Matched Differential Interferometer) technique was used to exploit the efficiency of the array signal processing. By using a synthetic heterodyne demodulation technique, outputs of the two channels were monitored simultaneously. The sensitivities of channel #1 and #2 were measured ${\sim}60{\mu}rad/\sqrt{Hz}$ and ${\sim}80{\mu}rad/\sqrt{Hz}$, respectively. Crosstalk of sensors in the array was found to be approximately -36dB. Based on the results, we could conclude that TDM Mach-Zehnder ladder type sensor array can be used to detect the acoustic signal with stability and efficiency of the sensor array.

• Polymer(Korea)
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• v.26 no.2
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• pp.185-192
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• 2002

Rigid polyurethane foams (PUFs) were prepared from polymeric 4.4'-diphenyl-methane diisocyanate (PMDI), polyether polyol, 1,4-butane diol, silicone surfactant, and distilled water. The density of the PUF was decreased from 173.7 to 41.7 kg/㎥ with an increase in distilled water from 0.5 to 3.0 php (parts per hundred polyol by weight), respectively, at the 0 php butane diol. The cell size of the PUF increased from 115 to 258 $mu extrm{m}$ with an increase in the amount of distilled water from 0.5 to 3.0 php, respectively, at the 10 php butane diol. It was found that the compressive strength of the PUF increased with the content of distilled water, at the same density. Out of the study for the surfactant effect on the properties of the PUF, it was observed that the cell site of the PUF decreased from 360 to 146 $mu extrm{m}$ with an increase in the amount of the surfactant from 0 to 0.33 php, respectively, but the tell size did not change significantly when the amount of the surfactant exceeded 0.33 php.

• Macromolecular Research
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• v.15 no.7
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• pp.676-681
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• 2007

A process designed to synthesize rigid polyurethane foam (PUF) with insulative properties via the modulation of PUF cell size via the addition of clay and the application of ultrasound was assessed. The blowing agents utilized in this study include water, cyclopentane, and HFC-365mfc, all of which are known to be environmentally-friendly blowing agents. The rigid PUFs were prepared from polymeric 4,4'-diphenylmethane diisocyanate (PMDI) and polyether polyol with a density of $50kg/m^3$. In addition, rigid PUFs/clay nanocomposites were synthesized with clay modified by PMDI with and without the application of ultrasound. The PUF generated using water as a blowing agent evidenced the highest tensile strength. The tensile strength of the PUF/nanocomposites was higher than that of the neat PUF and the strength was even higher with the application of ultrasound. The cell size of the PUF/clay nanocomposites was less than that of the neat PUF, regardless of the type of blowing agent utilized. It appears that the higher tensile strength and lower cell size of the PUF/clay nanocomposites may be attributable to the uniform dispersion of the clay via ultrasonic agitation. The thermal conductivity of the PUF/clay nanocomposites generated with HCFC-141b evidenced the lowest value when PUF/clay nanocomposites were compared with other blowing agents, including HFC-365mfc, cyclopentane, and water. Ultrasound has also proven effective with regard to the reduction of the thermal conductivity of the PUF/clay nanocomposites with any of the blowing agents employed in this study. It has also been suggested that the uniformly dispersed clay particles in the PUF matrix function as diffusion barriers, which prevent the amelioration of the thermal insulation property.