• Journal of Korean Association for Spatial Structures
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• v.10 no.1
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• pp.51-58
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• 2010

ETFE is the abbreviation of Ethylen Tetra Fluoro Etylene, a sort of colorless and transparent granules. The advantage ETFE film has daylight transmission and chemical the resistance and The thickness of ETFE film is used to from $50{\mu}m$ to $300{\mu}m$ and tensile strength of ETFE film changes from 40MPa to 60MPa and the tensile strain at break can get to about 300-400%. In this paper, ETFE film carried out the tensile proprieties, such as the tensile strain at break, the tensile strength are examined.

• Journal of Korean Association for Spatial Structures
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• v.9 no.2
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• pp.77-82
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• 2009

ETFE is the abbreviation of Ethlene Tetra Fluoro Ethlene, a sort of colorless and transparent granules. The advantage of ETFE film has chemical resistance, anti-stick property, very lightly material. The thickness of ETFE film is used to from 50 ${\mu}m$ to 300 ${\mu}m$ and have superior ability of daylight transmission and elongation, while the strength is lower than of fabric membrane. The tensile strength of ETFE film changes from 40Mpa to 60Mpa and the tensile strain at break can get to about 300-400%. The mechanical characteristic test of ETFE film is described in this paper. The tensile strain at break, the tensile strength and the stress-strain curve are obtained from the test. And then it was analyzed stress-strain characteristic by temperature and mechanical characteristic by cycling load.

• Journal of Korean Association for Spatial Structures
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• v.10 no.3
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• pp.57-64
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• 2010

Uniaxial tensile tests of ETFE membrane are performed in this paper. Three kinds ETFE membrane with different thickness are used in the tests. The tensile strength, the tensile strain at break and the stress-strain curve are obtained from the tests. Futhermore, The cycle loading test of ETFE membrane is carried out through using different values of cycle stress. The residual strain, the relaxation of stress and the change of the elastic modulus of foil are investigated. In the creep test, three kinds of temperature (25, 40 and 60 $^{\circ}C$)and three kinds of stress(3,6and9 MPa) are set respectively and the creep time lasts 24 hours.

• Polymer(Korea)
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• v.36 no.6
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• pp.803-809
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• 2012

The non-isothermal crystallization behavior of ethylene-tetrafluoroethylene (ETFE) copolymer was investigated by DSC and imaging FTIR analysis. Modified non-isothermal Avrami analysis was applied to interpret the crystallization behavior of ETFE. It was found that the less linearity in ln[-ln(1-X(t))] vs. ln(t) plot was obtained in thermal analysis comparison with imaging FTIR due to relatively small crystallization enthalpy change in ETFE. It means that imaging FTIR measured by overall IR absorption intensity change due to the crystallization was found to be effective to understand the non-isothermal crystallization kinetics of ETFE. In addition, the optical transmittance of ETFE was studied. The crystallite developed by slow cooling caused the light scattering and resulted in the increase of haze and the lowering of transmittance up to 8%. From our results, it was confirmed that cooling rate is an important processing parameter for maintaining optical transmittance of ETFE as a replacement material for glass.

• Journal of Korean Association for Spatial Structures
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• v.17 no.4
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• pp.159-165
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• 2017

In this paper, uniaxial tensile tests of ETFE films with three kinds of thicknesses(100, 200, $250{\mu}m$) and two kinds of directions(machine direction & transverse direction) are performed and the tensile strength, the tensile strain at break and the Young's modulus of ETFE films are compared for two kinds of specimen types(2 & 5). It could be figured out that there are no significant difference between tensile strengths of two specimen types but the tensile strain at break and the Young's modulus of ETFE films are affected by the specimen types. And it is concluded that the uniaxial tensile test of specimen type 2 are more reliable than that of specimen type 5.

• Journal of Korean Association for Spatial Structures
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• v.11 no.3
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• pp.115-123
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• 2011

It is needed to investigate the material properties of ETFE foil under various temperatures because ETFE membrane foils have very thin depth and relatively high flexibility. In this paper, the material properties of ETFE membrane foil obtained from 3 testes under various temperatures are presented. First, the uniaxial test under four temperatures as -20$^{\circ}C$, 0$^{\circ}C$, +20$^{\circ}C$ and +40$^{\circ}C$ was performed. Each 5 specimen was tested and the yield stress, tensile strength and the Young's modulus of the foils are obtained. Second, the creep testes under three temperatures as 25$^{\circ}C$, 40$^{\circ}C$ and 60$^{\circ}C$, 3MP, 6MP and 9MP tension load was subjected to the specimen and the creep characteristics was investigated. Finally, the tear test under $5^{\circ}C$, $^0{\circ}C$ and $20^{\circ}C$ was performed. It is concluded that the shape of stress-strain curve or general behaviors are similar with that of normal temperatures but the mechanical characteristics of ETFE membrane foils were affected by the temperatures, obviously.

• Polymer(Korea)
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• v.35 no.6
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• pp.610-614
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• 2011

In this study, the effect of solvent on the pre-irradiation grafting of VBC(vinylbenzyl chloride) onto a ETFE(polyethylene-co-tetrafluoroethylene) was evaluated. ETFE film was irradiated to generate radical species onto its backbone chain. Each irradiated film was immersed into VBC monomer mixtures diluted with various solvents such as toluene, heptane, and isopropanol etc. for grafting process and then the degree of grafting of each film was measured. FTIR analysis confirmed that the VBC-g-ETFE film was successful prepared. For the films prepared in the various solvents, the mechanical strength and the distribution pattern of the graft polymer over the cross-section of the films were measured and the effect of solvent was evaluated.

• Journal of Korean Association for Spatial Structures
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• v.16 no.1
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• pp.35-42
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• 2016

Until recently, almost all ETFE film structures that have been erected is the cushion type because there are problems at lower allowable strength under elastic range and viscosity behaviour such as creep and relaxation of ETFE films under long-term stresses. But the number of tension type structures is currently increasing. This paper proposes the stretch fabrication of ETFE film to verify the applicability of ETFE films to tensile membrane structures. First of all, to investigate the possibility of application on tensile membrane structures, the stretch fabrication test is carried out, and it is verified that it is possible to increase the yield strength of the film membrane structures. After simulating the experiment also carries out an analytical investigation, and the effectiveness of the elasto-plastic analysis considering the viscous behavior of the film is investigated. Finally, post-aging tension measurement is conducted at the experimental facilities, and the viscosity behavior resulting from relaxation is investigated with respect to tensile membrane structures.

• Journal of Korean Association for Spatial Structures
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• v.14 no.3
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• pp.93-100
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• 2014

Ethylene Tetrafluoroethylene (ETFE) has been widely used in long-span buildings because of its light weight and high transparency. This paper studies the short and long term creep behaviour of ETFE foil. A series of short-term creep and recovery tests were performed, in which the residual strain was observed. A long-term creep test of the ETFE foil was also performed over 110 days. A viscoelastic-plastic model was then established to describe the short-term creep and recovery behaviour. The model contains a traditional multi-Kelvin part and an added steady-flow component to represent the viscoelastic and viscoplastic behaviour, respectively. The model successfully fit the data for three stresses and six temperatures. Additionally, time-temperature equivalency was adopted to predict the long-term creep behaviour of ETFE foil. Horizontal shifting factors were determined from the process of shifting creep-curves at six temperatures. The long-term creep behaviours at three temperatures were predicted. Finally, the long-term creep test showed that the short-term creep test at identical temperatures insufficiently predicted additional creep behaviour, and the long-term test verified the horizontal shifting factors derived from the time-temperature equivalency.

• Polymer(Korea)
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• v.35 no.5
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• pp.478-482
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• 2011

In this study, several poly(styrene-co-(trimethoxysilyl)propyl methacrylate)-grafted ETFE films were prepared by a simultaneous irradiation grafting method. After mixing of styrene/(trimethoxysilyl)propyl methacrylate(TMSPM) monomers with various solvents, the effects of various irradiation conditions such as total dose, dose rate and monomer concentration on the degree of grafting of the prepared membranes were investigated. Results indicated that the higher degree of grafting was obtained when acetone was used as a solvent. The formation of poly(styrene-co-TMSPM) grafts on the ETFE films was verified using FTIR spectrometry and the distribution of the poly(PTMSPM) graft polymer over the cross-section of the grafted film was confirmed using SEM-EDX instrument.