• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.4
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• pp.18-24
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• 2012

In this study, hybrid method using polyvinyl acetate (PVAc) which has a strong adhesion and flexibility in which acrylic copolymer chemical-reaction reacts with cement, and is eco-friendly, is to improve the watertightness. The hybrid method is applied applied primarily waterproof stuff comprising silicate system and secondary mortar mixed with PVAc on the concrete surface. And then, in order to evaluate the performance, the properties of bond strength and amount of water absorption were measured. Based on the above experiments, mock-up specimens for field application were fabricated, and then the properties were evaluated as laboratory experiments. As the results, specimens cast from hybrid method using PVAc showed the best results on watertightness and bond strength. And also, with respect to experiment of mock-up specimens, the properties were in agreement with laboratory results. Especially, it could know that PVAc has strengthening effect from the results of the compressive strength. Due to outstanding results of carbonation depth and resistance to chloride ion penetration, it may be applied in weak areas such as underground and marine structures.

• Journal of the Korean Ceramic Society
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• v.28 no.7
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• pp.509-516
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• 1991

The effect of various polymers on the freeze-thaw resistance of hardened cement mortar was investigated. For this study, styrene butadiene rubber (SBR), ethylene vinyl acetate (EVA), polyvinyl alcohol (PVA) were used to prepare cement mortar specimen, and then freeze-thaw experiment was carried out. By adding SBR adn EVA to the specimen, the freeze-thaw resistance of specimens was improved, but when PVA was added to the specimen, its freeze-thaw resistance was lowered. Particularly, the specimens which were added 5, 10% of SBR and 5% of EVA showed excellent freeze-thaw resistance in the salt environment.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.253-253
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• 2009

Electrospinning is one of the simple, cost- efficient methods to produce long continuous semiconducting oxide nanofibers. Polyvinyl Alcohol (PVA) and zinc acetate were used. PVA/Zinc acetate aqueous solutions were electrospun into nonwoven webs. CCD camera, with a lens of long working distance and digital video board were used in capturing the drop and web deposition. The diameter and morphology of nanofibers were analyzed with a Field-emission scanning electron microscopy (FE-SEM). In this study, the average diameter and morphology of nanofibers have been explorered.

• Journal of the Korea Furniture Society
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• v.16 no.1
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• pp.1-8
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• 2005

This experiment was carried out to investigate the gluing characteristics of poly vinyl acetate emulsion adhesive(PVAc) on the Cryptomeria japonica laminated boards. This sample trees are major planting species and have been planted in southern district for a long time. The optimum gluing conditions for laminated board were summarized as follows; the amount of spreading glue, assembly time, clamping pressure, and clamping time for PVAc resin were $200g/m^2$, 10min., $5kg/cm^2$, and 6hrs., respectively, and the relative formulae between extension ratio(x) and block shear strength(y) was $y=-9.6x+85.2(R^2=0.95)$.

• Journal of the Korea Furniture Society
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• v.17 no.2
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• pp.25-34
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• 2006

This experiment was carried out to investigate the high-frequency gluing characteristics of poly vinyl acetate emulsion adhesive(PVAc) on MDF edge-glued boards. The edge-glued boards were glued lengthwise with butt, scarf, or finger joint. The wastes of MDF boards were reused as board materials. The obtained results are summarized as follows; the bending strength of edge-glued MDF increased slightly with the HF heating time, but the economically desirable heating time was 6 minutes. The bending and tensile strength of edge-glued MDF were high with scarf, finger and butt joint, in order. The strength of finger jointed MDF showed 80% of scarf jointed MDF. The effects of location of finger joints on the bending strength of edge-glued MDF were larger than those of the numbers of finger joints. The bending strength of edge-glued MDF with one joint on the middle position showed 40% decrease in comparison with non-jointed MDF.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.5A
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• pp.299-305
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• 2012

The objective of this paper is to obtain the basic data in order to develop an eco-friendly concrete through evaluation on the properties of polymer cement mortar and concrete using PVAc (Polyvinyl Acetate), as a kind of water-soluble polymer. For this purpose, the physical properties of cement mortar and concrete which does not contain the PVAc as the control batch were compared and analyzed with those using the PVAc. And then, the replacement amount of the PVAc was 3%, 6%, 9% and 12% by binder, respectively. And also, the properties of concrete using the PVAc were evaluated, by adding an antifoaming agent in order to control the air contents increasing with an increase of amount of polymer usage. As a result, in the case of polymer cement mortar using the PVAc, it presented that the compressive strength reduced, while the performance of flexural strength and drying shrinkage increased. When the replacement of the PVAc was 6% within concrete, the compressive, tensile, flexural strength and elastic modulus were increased.

• Journal of the Korean Wood Science and Technology
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• v.35 no.1
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• pp.27-35
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• 2007

This experiment was carried out to investigate the appearance and surface gluing characteristics of laminated boards overlaied with teak sliced veneer, printing paper, wall paper, cotton cloth, and wool cloth, The overlaying sheets were glued on the laminated boards with polyvinyl acetate emulsion adhesives and the species for laminated boards was red pine. The obtained results are summarized as follows; in case of the teak sliced veneer overlaied boards, the appearance quality was very good and showed the first grade of KS standard. but the delamination rate was 44.0% and 895% for cold water or warm water dipping treatments, respectively, so the wet gluing properties were very bed. In the case of the paper or cloth overlaied boards, the appearance quality was same good and showed the first grade of KS standard, but their delamination rate was 10~20% and 39.3~49.0 for cold water or warm water dipping treatments, respectively, so the wet gluing properties were bed, relatively better than sliced veneer overlaied boards. The present work showed that appearance of laminated boards overlaid with several sheets appeared quite positive in terms of secondary gluing qualities of laminated boards, suggesting that sliced veneer, paper, and cloth would be appropriate for the overlaying materials of laminated boards.

• Membrane Journal
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• v.31 no.5
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• pp.333-342
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• 2021

A flexible electrochromic device (ECD) is a promising technology that is expected to be applied in various fields such as smart windows. Polymer electrolyte is an important component that determines the bleaching-coloration performance and physical stability of flexible ECDs. In this study, a pore-filled polymer electrolyte membrane (PFPEM) with excellent dimensional stability was developed to effectively fabricate flexible ECDs and improve durability. Polyvinyl acetate, which has excellent adhesion, and polyethylene glycol, which can improve ionic conductivity, were filled in the pores of a porous substrate made of polyethylene, which is inexpensive and has excellent physical and chemical stability. The optimal lithium salt (LiTFSI) content of the prepared PFPEM was determined at about 27 wt%, and it was confirmed to possess excellent dimensional stability, adhesive strength, and ion conductivity close to that of conventional polymer electrolytes. Although the visible light transmittance was lowered by the use of the porous substrate, it was expected to act as an advantage in the colored state.

• Journal of Conservation Science
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• v.37 no.6
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• pp.801-806
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• 2021

In order to improve the usability of glue, a traditional adhesive material, and the gelation process of seaweed extract carrageenan, a liquid adhesive for wood preservation was prepared by mixing the two materials. The prepared wood adhesive was mixed with a 15 wt% aqueous solution of glue, λ-carrageenan, an antibacterial agent, an antifoaming agent, and the maximum adhesive strength of 1.80 Mpa was confirmed. As a result of comparison, the adhesive strength was superior to that of 5 different types of traditional natural adhesive ingredients (aqueous solution) and 1 type of polyvinyl acetate-based adhesive.

• Composites Research
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• v.21 no.1
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• pp.40-45
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• 2008

Rubber hose assembly for automotive hydraulic brake during operation is subject to combined stresses of cyclic pressure, cyclic bending and torsion as well as thermal load. The rubber hose is composed of ethylene-propylene diene monomer(EPDM) rubber layers reinforced by polyvinyl acetate(PVA) braided fabrics. A durability tester with loading rigs for inducing the above cyclic stresses was used to investigate failure mechanisms in the rubber hose assembly. Failure examination was performed at every 100 thousands cycles of bending and torsion. Hose samples were sectioned with a diamond-wheel cutter and then polished. The polished surface was observed by optical microscope and scanning electron microscope (SEM). Some interfacial delamination with a length of about 1mm along the interface between EPDM rubber and PVA fabrics was shown at the test cycles of 400,000. The delamination induced some cracking into the outer rubber skin layer to leading the final rupture of the hose.