• Composites Research
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• v.30 no.3
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• pp.175-180
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• 2017

Currently, since carbon fiber reinforced plastics (CFRPs) are lightweight and have excellent physical properties, their demand has increased dramatically. Many works have studied the CFRPs based on recycled thermoplastics. In this study, the applicability of recycled composite was evaluated using recycled polyethylene terephthalate (PET). PET was collected from waste materials used in beverage bottles and processed to produce PET films. Optimal thermoforming temperature and time were analyzed by comparing the mechanical properties with forming temperature and time difference for producing PET films. CF mat and PET film were used to determine the suitable parameters for the optimum thermoforming of CF/PET composites. The mechanical properties of each thermoforming condition were verified by bending test. The degree of impregnation of the PET film into the CF mat was evaluated by cross-sectional photographs, whereas the interfacial properties were evaluated by interlaminar shear strength (ILSS). Ultimately, it was confirmed that the thermoforming condition for forming the CF/recycled PET composites yielding the optimal mechanical and interfacial properties was at $270^{\circ}C$ for 5 minutes.

• Journal of the Korea Concrete Institute
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• v.21 no.3
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• pp.265-273
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• 2009

There have been numerous studies to develop eco-friendly concrete. The attempt to reduce the amount of cement used is suggested as one of the solutions for eco-friendly concrete. To decrease the usage of cement, the pozzolan reaction materials are used as a mineral admixture. Hwang-toh, which is broadly deposited in Korea is a well known environment friendly material and the activated hwang-toh, which has the property of pozzolan reaction, is alternatively used as a mineral admixture of concrete. The purpose of this study is to investigate the drying shrinkage of hwang-toh concrete mixed with recycled PET fiber. Therefore, drying shrinkage experiments are performed to analyze mechanical property of hwang-toh concrete mixed with recycled PET fiber. Test results showed that the drying shrinkage is controlled by hwang-toh admixture and PET fiber.

• Science of Emotion and Sensibility
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• v.26 no.1
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• pp.79-86
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• 2023

This study aims to create a highly conductive E-textile made by recycling PET with a Dip-coating process. PET fiber with hydrophobic properties is characterized by the difficulty in imparting great conductivity when both Virgin and Recycled are made of electronic fibers through a Dip-coating process. To advance the effectiveness of the Dip-coating process, a sample made of recycled PET was surface modified for 50 w 5 minutes and 10 minutes employing a Covance-2mprfq model from FEMTO SCIENCE. After that, the sample was immersed in an SWCNT dispersion (.1 wt%, Carbon Co., Ltd.) for 5 minutes, and then dip coating was conducted to allow the solution to permeate well into the sample through a padder (DAELIM lab). After the procedure was completed, the resistance measurement was measured with a multimeter at both ends and then accurately remeasured with a wider electrode. As a result of this contemplation, it was affirmed that great conductivity might be given through an impregnation process through the plasma surface modification. When the surface modification was performed for 10 minutes, the resistance was reduced by up to 2.880 times. Dependent on the results of this research, E-fibers employed in the smart wearable sector can also be made of recycled materials, improving smart wearable products that can save oil resources and reduce carbon emissions.

• Journal of the Korea Concrete Institute
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• v.16 no.2 s.80
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• pp.205-212
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• 2004

Recently, as concerns over environmental issues are raised more and more trend to use recycled waste for producing construction materials is also raised. Especially, a case of waste resin is considerably destroying the environment due to disposal way that most waste resin produced is disposed of landfill. This study is performed by polymer concrete with recycled PET resin in terms of obtaining safely clean construction resources and protection of environment. High setting shrinkage and sensitivity to heat are main disadvantages of Polymer Concrete (PC) despites of a lot merits. The aim of this study is to investigate basic properties such as setting shrinkage, length change and sensitivity to heat about PET recycled polymer concrete. The other is to check the possibility of use of Montmorillonite as one of a lot of additive without special coupling agent. As results of experiments, various properties of polymer concrete with recycled PET resin are similar with conventional PC except that polymerization time is longer. Montmorillonite was efficiently used to reduce setting shrinkage, length change and coenicient of thermal expansion related to heat with enhanced strength

• Journal of the Korean Geosynthetics Society
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• v.13 no.4
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• pp.153-159
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• 2014

During the winter and spring seasons in Korea, structures such as buried water supply pipelines, roads, railways are frequently damaged due to frost heaving and thawing. Until now, the method of substituting the frost susceptible soil with the gravel or rubbles those are non-frost susceptible materials have been employed in Korea to prevent frost heaving. A series of laboratory soil tests and indoor frozen soil engineering experiments, as well as laboratory frost heaving tests were conducted for seeking the means of utilizing recycled PET bottles as substitute material.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.324-327
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• 2004

In this paper, fundamental properties of Polymer Concrete made from unsaturated polyester resin based on recycled PET and recycled aggregate(RPC) were investigated. Resins based on recycled PET and recycled aggregate offer the possibility of low source cost for forming useful products, and would also help alleviate an environmental problem and save energy. The results of test for resin contents and recycled aggregate ratio are showed that the strength of RPC increases with resin contents relatively, however beyond a certain resin content the strength does not change appreciably, and the relationship between the compressive strength and aggregate contents at resin $9\%$ has a close correlation linearly whereas there is no correlation between the compressive strength and the flexural strength of RPC with recycled concrete aggregate.

• Journal of the Korea Concrete Institute
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• v.16 no.4 s.82
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• pp.521-528
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• 2004

In general, polymer concrete has more excellent mechanical properties and durability than Portland cement concrete, but very sensitive to heat and has large deformations. In this study, the long-term creep behaviors was predicted by the short-term creep test, and then the characteristic of creep of recycled-PET polymer concrete was defined by material and experimental variables. The error in the predicted long-term creep values is less than 5 percent for all polymer concrete systems. The filler carry out an important role to restrict the creep strains of recycled PET Polymer concrete. The creep strain and specific on using the $CaCO_3$ were less than using fly-ash. The creep increases with an increase in the applied stress, but not proportional the rate of stress increase ratio. The creep behavior of polymer concrete using recycled polyester resin is not a linear viscoelastic behavior.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.816-821
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• 2003

This paper deals with a reduction in the setting shrikage of polymer concrete using bentonite as shrinkage reducing agent. This study with polymer concrete using unsaturated polyester(UP) based on recycled PET waste was performed to verify the effect of various shrinkage reducing agent contents and the types of filler which are fly ash and $CaCo_3$. Setting stress induced by setting shrinkage was investigated in temrs of mechanical and chemical combination.

• Resources Recycling
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• v.17 no.3
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• pp.21-28
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• 2008

Using the post-consumer waste and edge scrap mixed PET with small amount PP air filter elements of automobiles. It was studied that these mixed waste plastics of the various types of the PET were practicable for the material recycling. Various waste PET/PP plastics were collected, crushed, dried in vacuum, and extruded to recycled PET/PP chips. These chips were mixed with three kinds compatibilizers, EVA, MBS, and recycled PVB of the ratio of $3{\sim}10wt.%$ for the purpose of the compatibility for the post-consumer waste and edge scrap. We investigated mechanical and thermal properties of PET/PP mixtures which were compound with the weight ratio of compatibilizers. Compatibilizer, MBS application was showed the most excellent mechanical properties in the range of the $3{\sim}5wt.%$ EVA application was displayed good impact strength and thermal property in the range of $3{\sim}5wt.%$ Last, recycled PVB application was showed poor mechanical properties in the whole range ratio of the PVB.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.42 no.2
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• pp.95-101
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• 2010

For the development of higher-sizing performance of paper, a sizing agent using recycled PET was synthesised. Polyester resin was extracted from wasted PET by subcritical hydrolysis and finally modified to synthetic sizing agent by mixing water-disperse PET with triphenyl phosphite(TPP). The modified PET was considered as an internal sizing agent in different wet-end papermaking conditions. The optimum condition in sizing efficiency was obtained in initial pH of 6.5 in case of rosin+alum system, and 7.5 in case of rosin+alum+PET system, respectively, and in addition amount of PET 3%. The sizing efficiency was also closely related according to the fiber properties of wet-end slurry, such as virgin fibres from UKP and recycled fibres from KOCC. The application of modified PET was good in strength improvement of paper, specially in tensile strength.