• 한국가구학회지
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• 제10권1호
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• pp.65-71
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• 1999

The bending performance of sloped finger-jointed Rhus verniciflua were tested in order to improve the strength properties of finger-joint. Sloped finger-cut pieces were jointed with three kinds of adhesives (polyvinyl acetate, polyvinyl-acryl acetate and oilic resin). The slope ratios of finger joints were 0, 1.0, 1.5, and 2.0. The MOE, MOR and deflection to maximum load in bending of sloped finger-joints and solid wood specimen were measured. The results were : 1) The efficiencies of MOE to finger and sloped finger-joints to the solid wood were almost same in the three kinds of adhesives(polyvinyl acetate, polyvinyl-acryl acetate and oilic urethane resin) and there were some effect of slope on the MOE in a sloped finger-joint for three kinds of resin adhesives. 2) There was the effect of slope on the MOR in sloped finger-joints in every kind of adhesive. The efficiencies of MOR in slope ratios of 0 and 2.0 ranged 65-79%, respectively. There was also a slight effect of the kinds of adhesives on the MOR. However, the efficiencies of deflection to the urethane resin adhesive were much less than those of polyvinyl acetate, polyvinyl-acryl acetate resin adhesives except the slope ratio of 0. 3) It might be impossible to estimate the bending stregth of sloped finger-jointed Rhus verniciflua by using MOE. The correlation coefficient(0.192) between MOE was very low and not significant at 5% level.

• 한국가구학회지
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• 제10권2호
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• pp.73-78
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• 1999

This paper describes the relationship between the bending strength properties of sloped finger-jointed woods and the acoustic emissions(AEs) generated during the test. Rhus verniciflua pieces were cut in sloped-finger types and glued with three kinds of adhesives(polyvinyl acetate, polyvinyl-acryl acetate and oilic urethane resin). The slope ratios of finger joints were 0, 1.0, 1.5, and 2.0. The AE cumulative event count and cumulative count were measured during the bending test. The results were as follows: The lower the bending strength(load) was, the generation time of AE event count got and the higher the increasing rate of AE event count became in the sloped finger-jointed specimens bonded with polyvinyl acetate, polyvinyl-acryl acetate oilic urethane resin adhesives. Therefore, the slope from load-AE cumulative event count was very steep. The patterns of AE event count and count were very similar. The relationship between the MOR and the AE parameter from load and AE cumulatve event count in the early stage of the sloped finger-jointed specimens bonded with polyvinyl acetate, polyvinyl-acryl and oilic urethane resin adhesives was much greater than that between the MOE and the MOR. Therefore, the AE signals obtained during bending test are useful for estimating the strength of sloped finger-jointed Rhus verniciflua specimens.

• 펄프종이기술
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• 제30권4호
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• pp.28-34
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• 1998

Polyvinyl acetate emulsion has been widely used as adhesives for wood and paper, paint additives and binders for fiber, leather, and other materials because it is an excellent adhesive with many advantages including low in toxicity risks and manufacturing cost. It is expected the consumption of polyvinyl acetate emulsion as adhesives will increase in cigarette industry as well as in paperboard coating industry. Recently the operation speed of the cigarette tip wrapper increased so substantially that improvement of the emulsion properties is required including good wet tack development, narrow and controlled particle size distribution, low viscosity, etc. In this study the effects of such polymerization conditions as the type and amount of emulsifier, internal or external plasticizing, and emulsification methods on the viscosity and particle size of polyvinyl acetate emulsions were examined. Results showed that polyvinyl alcohol with a high degree of hydrolysis and low molecular weight and nonionic surfactants are superior to anionic surfactant in improving adhesion and emulsion stability. They also tend to produce emulsions with smaller particle size. External plasticization with dipropylene glycol dibenzoate was more effective in improving flexibility than internal plasticization with butyl acrylate. Monomer emulsification under high shear was more effective in decreasing the particle size.

• Elastomers and Composites
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• 제33권3호
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• pp.149-158
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• 1998

폴리초산비닐 에멀젼 수지에 SBR 라텍스, 폴리우레탄 라텍스, 에폭시 라텍스를 각각 혼합하여 물리적 특성 및 기계적 특성을 조사하였다. 에폭시 수지의 상용성은 양호하였으며 건조도막은 투명하였다. 폴리우레탄과 SBR은 높은 점도를 나타내었으며 건조도막은 불투명하였다. SBR과 폴리우레탄 수지에서 경도의 증가는 물의 증발속도에 의존하였지만 에폭시 수지에서는 가교밀도의 증가에 의존하였다. 에폭시 수지는 매우 뛰어난 내수성을 나타내었다. SBR은 높은 굴곡강도와 충격강도를 나타내었다. 폴리초산비닐에 라텍스를 10% 이내로 혼합하였을 때에는 연성파괴를 나타내었고 20% 이상 혼합하였을 때에는 취성파괴를 나타내었다.

• Journal of the Korean Wood Science and Technology
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• 제25권4호
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• pp.61-67
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• 1997

The bending performances of sloped finger-joints in Pinus densiflora S. et Z. were tested in order to improve the strength properties of finger-joint Sloped finger-cut pieces were jointed with four kinds of adhesives(resorcinol-phenol, oilic urethane, polyvinyl acetate, and polyvinyl-acryl acetate resin). The slope ratios of finger joints were 0, 0.5, 1.0, 2.0. The MOE, MOR and defletion to maximum load in bending of sloped finger-joints and solid wood specimen were measured. The results were: 1. The efficiencies of MOE to finger and sloped finger-joints were 82% or greater in every kind of adhesives except polyvinyl-acryl acetate resin adhesive and there were some effect of slope on the MOE in a sloped finger-joint for polyvinyl-acryl acetate and oilic urethane resin adhesives. 2. The effects of slope on the MOR to sloped finger-joints were showed in every kind of adhesive, because the efficiencies of MOR increased with increasing slope ratio in sloped finger-joints. The efficiencies of MOR to slope ratios of 0 and 2.0 ranged 43~65% and 76~82%, respectively. There was almost no effect of the kinds of adhesives on the MOR to the slope ratio of 2.0. 3. It was found impossible to estimate the bending strength of sloped finger-jointed Pinus densiflora S. et Z. by using MOE. The correlation coefficient(0.124) between MOE and MOR was very low and not significant at 5% level.

• 한국재료학회지
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• 제33권12호
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• pp.550-557
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• 2023

In zinc-air batteries, the gel polymer electrolyte (GPE) is an important factor for improving performance. The rigid physical properties of polyvinyl alcohol reduce ionic conductivity, which degrades the performance of the batteries. Zinc acetate is an effective additive that can increase ionic conductivity by weakening the bonding structure of polyvinyl alcohol. In this study, polymer electrolytes were prepared by mixing polyvinyl alcohol and zinc acetate dihydride. The material properties of the prepared polymer electrolytes were analyzed by Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). Also, Electrochemical impedance spectroscopy was used to calculate ionic conductivity. The electrolyte resistances of GPE, 0.2 GPE, 0.4 GPE, and 0.6 GPE were 0.394, 0.338, 0.290, and 0.213 Ω, respectively. In addition, 0.6 GPE delivered 0.023 S/cm high ionic conductivity. Among all of the polymer electrolytes tested, 0.6 GPE showed enhanced cycle life performance and the highest specific discharge capacity of 11.73 mAh/cm² at 10 mA. These results verified that 0.6 GPE improves the performance of zinc-air batteries.

• Journal of Rhinology
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• 제25권2호
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• pp.86-90
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• 2018

Background and Objectives: Although polyvinyl acetate ($Merocel^{(R)}$) has been widely used as a packing material after septoplasty, removable nasal packing can increase patient discomfort, local pain, and pressure. Furthermore, the removal of nasal packing has been described as the most uncomfortable and distressing feature associated with septoplasty. The purpose of this study was to investigate the efficacy of polyvinyl acetate with carboxymethyl cellulose sheet ($Rhinocel^{(R)}$) nasal packing on patient subjective symptoms, degree of bleeding, hemostasis, and wound healing following septoplasty. Subjects and Method: Forty patients with nasal septum deviation requiring septoplasty were included. Following surgery, one nasal cavity was packed with $Rhinocel^{(R)}$ and the other one with $Merocel^{(R)}$. Patient subjective symptoms while the packing was in situ, hemostatic properties, pain on removal, degree of bleeding on removal, duration of hemostasis after removal, postoperative wound healing, and the cost of the pack were evaluated. Results: Although the two types of packing materials were equally effective in controlling postoperative bleeding after septoplasty, $Rhinocel^{(R)}$ was significantly more comfortable while in situ and less painful on removal than $Merocel^{(R)}$, which was associated with significantly more bleeding on removal and so more time was needed to control hemorrhage. There was no significant difference in postoperative wound healing or pack cost. Conclusion: The use of $Rhinocel^{(R)}$ after septoplasty has less discomfort, greater patient satisfaction, and less bleeding on removal with no adverse reactions compared to $Merocel^{(R)}$ packing. Therefore, $Rhinocel^{(R)}$ may be a useful packing material after septoplasty.

• Journal of Microbiology and Biotechnology
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• 제11권6호
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• pp.928-933
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• 2001

Approximately 0.1 mg/ml of polyvinyl alcohol (PVA) was degraded by the growing cell, Brevibacillus laterospours, for 30 h, and 0.2 mg/ml of PVA was degraded by the cell-free extract that was isolated from Brevibacillus laterosporus. Approximately $0.29{\mu}g$/ml of acetic acid was produced from PVA by using the cell-free extract as a catalyst for 40 min. $V_{max}\;and\;K_m$ value of purified PAV-degradation enzyme was 3.75g/l and 2.75 g/l/min in reaction with EDTA and 3.99 g/l and 2.98 g/l/min in reaction without EDTA, respectively. Molecular weight of the purified enzyme determined by SDS-PAGE was 63,000 Da. Alcohol dehydrogenase and aldehyde dehydrogenase activities were qualitatively detected on a native acrylamide gel by an active staining method, indicating the existence of the metabolic pathway to use PVA as a substrate.

• 대한화학회지
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• 제6권1호
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• pp.19-24
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• 1962

In the emulsion polymerization of vinyl acetate with Triton-X(Alkyl-aryl-polyether alcohol) and polyvinyl alcohol as emulsifier, some relations between the conditions of polymerization and the polymerization rate, polymerization degree and stability of the emulsion are studied and discussed.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제33권5호
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• pp.437-444
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• 2007

Vinyl acetate has been widely used for the manufacture of polyvinyl alcohol emulsion, which is primary ingredient of adhesive, paints, textile, paperboard coatings, etc. Since these products are plentiful and frequently used around us, workers and consumers are at health risk. International Agency for Research on Cancer(IARC) classified vinyl acetate as group 2B(possibly carcinogenic to humans). Among the organs targeted, the oral cavity is the most vulnerable organ affected by the carcinogenic effects of vinyl acetate. Since the origin of most of oral cancer is derived from the epithelial cells, it is important to understand the carcinogenic potential of vinyl acetate in human epithelial cells. Thus, the present study has attempted to utilize the immortalized human epithelial cell model to assess the carcinogenic potency of this chemical and to understand the underlying mechanisms.