• Textile Coloration and Finishing
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• v.28 no.1
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• pp.40-47
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• 2016

As a coating material for loudspeaker dampers, resilient polyurethane/epoxy hybrid resins were synthesized to replace conventional phenol resin and examined the physical properties, which are not only environmentally friendly but also not harmful to human. Five types of polyurethane resins were synthesized in the step-shot method using methylene diisocyanate, three polyols such as poly tetramethylene ether glycol(PTMEG, MW:2000), poly(1,4-buthylene adipate(PBAP, MW:2000), and poly carbonatediol(PCD, MW:2000), and three chain extenders such as ethylene glycol(EG), neopentyl glycol(NPG), and 1,4-buthandiol(1,4-BD). The five types of synthesized polyurethane resins and commercially available bisphenol A type epoxy resin were blended in weight ratios of 90:10, 70:30, and 50:50 to synthesize 15 types of polyurethane/epoxy hybrid resins. Among the polyurethane resins, the one that was synthesized using PCD and 1,4-BD showed excellent tensile strength, 100% modulus, low extension, and relatively high viscosity. Polyurethane/epoxy hybrid resins with higher epoxy resin contents showed better thermal properties and water resistance while those with higher polyurethane contents showed higher flexibility. The polyurethane/epoxy hybrid resin made by blending the polyurethane based on PCD and 1,4-BD with a bisphenol A type epoxy resin in a weight ratio of 70:30 was identified to be the most suitable to be used in speaker dampers.

• Journal of the Korean Wood Science and Technology
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• v.33 no.5 s.133
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• pp.57-65
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• 2005

Following our previous reports for finger-jointed woods with various finger profiles studied for the efficient use of small diameter logs and woods containing various defects, twelve types of finger-jointed woods glued with three kinds of adhesives and with two sizes of finger pitches were made with sitka spruce and red pine. The effects of the adhesives and finger pitches on bending creep performances of finger-jointed woods were investigated. The shape of creep curves differed among the used adhesives and finger pitches of finger-jointed woods for both tested species. Their creep curves showed a linear behavior beyond about one hour, and the N values fitted to power law increased with increasing finger pitches. The initial deformation increased with increasing finger pitches, regardless of the tested species and kinds of adhesives, whereas the effect of finger pitches on the creep deformation was not clear. For finger-jointed woods glued with polyvinyl acetate (PVAc) resin, creep failure occurred in 106 hours after the load was applied. And the difference of the creep compliance between finger-jointed woods glued with resorcinol-phenol formaldehyde (RPF) resin and aqueous vinyl urethane (AVU) resin was small. The ratios for creep performances of finger-jointed woods glued with RPF resin and AVU resin versus solid wood were higher in creep deformation than initial deformation for both species, and the difference between both adhesives was not found. The relative creep decreased with increasing finger pitches, and the marked differences was not found between RPF resin and AVU resin.

• Korean Journal of Environmental Agriculture
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• v.16 no.2
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• pp.161-165
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• 1997

This experiment were carried out to clarify the effects of several factory wastes on the emergence and seedling growth of five crop species, rice, Chinese cabbage, melon, and tomato. Wastes of three factories treated by several concentrations on the soil in which crop were seeded. In rice seedling experiments, the rice seedlings were treated with factory wastes hydroponically. Factory wastes used in the experiment were obtained from leather, phenol resin, and dye factory. The growth of rice seedlings was inhibited by each factory wastes, but the dry weight of rice seedling was increased by the low concentration below 1/16 dilution of leather factory waste. During 15 days, dry matter accumulation of rice seedlings treated with undiluted factory wastes decreased to 46.0, 51.4, -5.4% of control by treating wastes of phenol resin, leather, and dye factory respectively. The injury of crops by leather factory waste was severe in tomato but slight in barley. Waste of phenol resin factory affects highly both on Chinese cabbage and on melon. When dye factory waste was treated on each crop, all plants died in the treatments of waste solution which diluted to 1/8 of original waste. Tomato and melon were most sensitive crop species to the waste of dye factory. Although the responses of crops to each factory waste were various, the degree of injuries were more higher in vegetables than cereal crops.

• Journal of Korean Society of Forest Science
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• v.57 no.1
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• pp.32-38
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• 1982

This study was carried out to examine the possibility to replace imported wheat flour with taro. Taro and wheat flour were used for the extenders after oven drying($100{\pm}3^{\circ}C$)and pulverized into 80-100mesh minute powder by laboratory willey mill. Urea- and phenol-formaldehyde resin adhesives were used for plywood manufacture, and the extending materials mixed with the extension at the ratio of 10, 20, 30, and 50% to each resin solution. The results obtained at this study were summarized as follows; 1) In dry and wet shear strength of urea-formaldehyde resin adhesive, taro showed very excellent bonding strength compared with wheat flour in all extending ratio. Therefore taro showed the possibility that be usable to taro in place of wheat flour. 2) In dry and wet shear strength of phenol-formaldehyde resin adhesive, in general, wheat flour showed higher bonding strength than taro. But in dry shear strength, taro showed higher shear strength than wheat flour in 30 and 50% extension.

• Membrane Journal
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• v.20 no.4
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• pp.312-319
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• 2010

Carbon membrane materials have received considerable attention for the gas separation including hydrocarbon mixture of ingredients of the volatile organic compounds(VOCs) because they possess their higher selectivity, permeability, and thermal stability than the polymeric membranes. The use of activated carbon membranes makes it possible to separate continuously the VOCs mixture by the selective adsorption-diffusion mechanism which the condensable components are preferentially adsorbed in to the micropores of the membrane. The activated carbon hollow fiber membranes with uniform adsorptive micropores on the wall of open pores and the surface of the membranes have been fabricated by the carbonization of a thin film of phenolic resin deposited on porous alumina hollow fiber membrane. Oxidation, carbonization, and activation processing variables were controlled under different conditions in order to improve the separation characteristics of the activated carbon membrane. Properties of activated carbon hollow fiber membranes and the characterization of a gas permeation by pyrolysis conditions were studied. As the result, the activated carbon hollow fiber membranes with good separation capabilities by the molecular size mechanism as well as selective adsorption on the pores surface followed by surface diffusion effective in the recovery hydrocarbons have been obtained. Therefore, these activated carbon membranes prepared in this study are shown as promising candidate membrane for separation of VOCs.

• Bulletin of the Korean Chemical Society
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• v.33 no.2
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• pp.473-482
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• 2012

A novel malemide epoxy containing Co(II), Ni(II) and Cu(II) ions have been synthesized by curing malemide epoxy resin (MIEB-13) and Co(II), Ni(II) and Cu(II) complexes of macrocyclic bis-hydrazone Schiff base. The Schiff base was synthesized by reacting 1,4-dicarbnyl phenyl dihydrazide with 2,6-diformyl-4-methyl phenol. The Schiff base and its Co(II), Ni(II) and Cu(II) complexes have been characterized by elemental analyses, spectral (IR, $^1H$ NMR, UV-vis., FAB mass, ESR), thermal and magnetic data. The curing reaction of maleimide epoxy compound with metal complexes was studied as curing agents. The stability of cured samples was studied by thermo-gravimetric analyses and which have excellent chemical (acid/alkali/solvent) and water absorption resistance. Further, the scanning electron microscopy (SEM) and definitional scanning colorimetric (DSC) techniques were confirmed the phase homogeneity of the cured systems.

• Carbon letters
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• v.14 no.2
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• pp.110-116
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• 2013

This study investigated a developed process for producing a composite bipolar plate having excellent conductivity by using coal tar pitch and phenol resin as binders. We used a pressing method to prepare a compact of graphite powder mixed with binders. Resistivity of the impregnated compact was observed as heat treatment temperature was increased. It was observed that pore sizes of the GCTP samples increased as the heat treatment temperature increased. There was not a great difference between the flexural strengths of GCTP-IM and CPR-IM as the heat treatment temperature was increased. The resistivity of GPR700-IM, heat treated at $700^{\circ}C$ using phenolic resin as a binder, was $4829{\mu}{\Omega}{\cdot}cm$ which was best value in this study. In addition, it is expected that with the appropriate selection of carbon powder and further optimization of process we can produce a composite bipolar plate which has excellent properties.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.04a
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• pp.257-260
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• 2005

Graphite reinforced conductive polymer composites were fabricated by the compression molding technique. Graphite powder was mixed with an phenol resin to impart electrical property in composites. The ratio and particle size of graphite powder were varied to investigate electrical conductivity of cured composites. In this study, graphite reinforced conductive polymer composites with high filler loadings(>66wt.%) were manufactured to accomplish high electrical conductivity. With increasing the loading ratio of graphite powder, the electrical conductivity and flexural strength increased. However. above 80wt.% filler loadings, flexural strength decreased due to lack of resin. Regardless of graphite particle size, electrical conductivity wasn’t varied. On the other hand, with decreasing particle size, flexural strength increased due to high specific surface area.

• Textile Coloration and Finishing
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• v.13 no.3
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• pp.188-196
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• 2001

1, 1-diamino-3, 3, 5, 5-tetrachlorocyclotriphosphazene, 1, 1-diami-no3, 3, 5, 5-tetra-(p-bromophenoxy)cyclotriphosphazene, and 1, 1-diamino-3, 3, 5, 5-tetra-(p-chlorophenoxy) cyclotri-phosphazene(ACPP) was prepared from hexachlorocyclotriphosphazene and used for the curing agent of bisphenol A type epoxy resin and phenol novolak. The resistance to chemicals and water of the cured epoxy resins were examined by DMTA and compared with those of the epoxy rosins cured with phosphazene derivatives and 4, 4'-diaminodiphenylmethane. The effect of the curing agent on resistance to chemicals and water of the cured epoxy resins were investigated. The epoxy resins cured with 1, 1-diamino-3, 3, 5, 5-tetrachlorocyclotriphosphazene and 1, 1- diamino-3, 3, 5, 5-tetra- (p-bromophenoxy)cyclotriphosphazene showed superior resistance to chemicals and water to those of 1, 1-diamino-3, 3, 5, 5-tetra- (p-chlorophenoxy)cyclotriphosphazene and 4, 4'-diaminodiphenylmethane. It is an effective curing agent for epoxy resins to enhance the resistance to chemicals, water and tome proofing.

• Journal of Institute of Convergence Technology
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• v.3 no.1
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• pp.45-49
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• 2013

Spherical active carbon materials have been used for the removal of pollutants in the area of food processing, water treatment, air purification, oral administration. Moreover, they are now expected to make an epoch in the areas of electronics, life science, environmental technology, and so on due to their superior physical properties. Carbon particles should be requested for the edgeless spherical shapes in order to minimize the loss due to the abrasion during the process and/or practical use, but the carbon particles manufactured from petroleum-based pitch do not meet these needs. Nowadays, thus, the spherical active carbon particles carbonized from various spherical polymer beads are studied with thermoplastic and/or thermosetting polymers. In this paper, the synthesis of spherical phenolic beads and furan beads, which are thermosetting polymers, and their carbonization techniques are examined.