• Polymer(Korea)
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• v.29 no.6
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• pp.557-564
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• 2005

Thermoplastic starch (TPS) was manufactured and blended with poly(butylene adipate-co-succinate) (PBAS), which is one of the most popular biodegradable aliphatic polyesters. The effects of the TPS contents on the mechanical properties, thermal characteristics, and biodegradability of PBAS/TPS blends were investigated. The foaming characteristics of those were also studied. With small amount of TPS, mechanical properties of the blends were largely deteriorated and the variations of them decreased with more addition of TPS. In addition, TPS decreased crystallinity and thermal decomposition temperature of PBAS. The PBAS/TPS foam having maximum blowing ratio was obtained with 20 Phr of TPS, and their blowing ratio decreased with the further increase of TPS.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.10a
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• pp.137-140
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• 2003

Impact of Automotive GMT(Glassfiber reinforced Mat Thermoplastic) Bumper for '5Mhp Barrier Test'was simulated using ls-dyna. The FE model consists of foam which is energy absorber, bumper beam and stay etc. Bumper intrusion and deflection was compared with the experimental results. Effects of uncertainty of material property and deviation of impact velocity were considered and results were compared with those of base design. Effects of number of integration points through th thickness was also investigated.

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.4
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• pp.618-624
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• 1989

Ultrasonically induced bubble formation in thermoplastic matrix was investigated experimentally and theoretically. polystyrene was saturated with nitrogen under the pressure of 0.2 to 3.45 MPa in a pressure chamber, followed by pressure release and ultrasonic bubble nucleation. Zinc stearate was added to polystyrene as the nucleating agent to induce heterogeneous nucleation. Various mixture of low density polyethylene and polyethylene wax was also saturated with the gas. The foamed specimens with or without ultrasonically induced bubble nucleation was modeled by modifying the classical nucleation theory. The rate of ultrasonic nucleation was predicted for homogeneous and heterogeneous nucleation at a conical cavity. This study showed that the heterogeneous and heterogeneous nucleation at a conical cavity. This study showed that the heterogeneous nucleation must be employed for ultrasonic production of bubbles in a viscous fluid and the homogeneous nucleation for ultrasonic production of bubbles in a low viscosity fluid.

• Fashion & Textile Research Journal
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• v.24 no.1
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• pp.127-137
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• 2022

Recently, various clothing items are being developed using 3D printing technology, but comfort has become an issue while wearing them for a long time. Therefore, this study researched on how the temperature and humidity of the devices developed by 3D printing change depending on the material combination. Five types of material combinations (EVA foam, TPU density 10%, TPU density 30%, EVA foam+TPU density 10%, and EVA foam+TPU density 30%) were selected as variables, and the experiment was conducted for two different cases with and without a cover. All the ten types of samples were placed on the hot plate set at 36℃, and the surface temperature and humidity were measured at three different points for 10 minutes. As a result, the case with only TPU showed the greatest temperature change while the case with 100% EVA foam showed the least temperature change. The humidity of the surface layer gradually decreased with time for 100% EVA foam. For the case with TPU materials, the moisture was transferred to the surface layer at first, thereby increasing the humidity but then dropped significantly. Meanwhile, the cases with the cover on showed similar tendencies of change in both temperature and humidity where the overall temperature and humidity delivery were slow.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2012.03a
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• pp.18-18
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• 2012

전 세계적으로 이산화탄소 배출량 저잠을 위해 모든 산업분야에서 연구개발의 중점을 두고 있다. 그의 일환으로 자동차 산업에서는 EU규제에 따라 리사이클이 가능한 소재 개발이 요구되고 있으며, 그중 많은 양이 사용되고 있는 PU Foam의 대체 재료 개발이 시급한 실정이다. 기존 자동차의 흡음재로 주로 사용되고 있는 PU Foam 소재는 통기성이 부족할 뿐만 아니라 연소 시 인체에 유해한 HCN Gas를 발생시키고, 한번 성형된 부품은 Recycle 및 Re-Use가 불가능하다는 단점이 있다. 또한 장시간 사용시 황변 발생과 악취가 발생하는 등으로 최근 대두되고 있는 자동차 내장재 감성품질 향상 측면에 한계를 나타내고 있다. 이러한 Low Melting 성능을 가지는 PET 부직포 소재의 한계를 극복하기 위하여 저융점 성능의 Elastic Fiber의 개발과 함께 고탄성 복합부직포 소재의 개발을 통해 높은 변형률과 우수한 복원력을 나타내는 환경친화형 열가소성 탄성체(Thermoplastic Elastomer) 개발을 추진하고 있다. 고탄성 복합부직포는 자동차 내장재 성형 시 열을 가하더라도 Elastomer 자체의 탄성 발현을 통해 초기의 Bulky성을 유지할 수 있으며, Recycle 및 Re-use가 가능하여 환경 친화적인 측면에서도 큰 장점을 갖고 있다. 자동차용 흡음 내장재뿐만 아니라 각종 수송용 차량의 경량화 및 쾌적성 향상을 위한 용도로써 자동차 내장용 PU Foam의 57% 이상을 차지하고 있는 Seat Cushion재 등의 대체가 가능하며, 다양한 산업분야에서 사용되고 있는 PU Foam의 대체로 다양한 용도 전개가 가능할 것으로 예상된다. 본 연구에서는 PU Foam의 대체 재료로 각광받고 있는 Elastic PET를 개발하여 자동차 내장재로의 적용 가능성을 검토하였다.

• Composites Research
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• v.31 no.4
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• pp.122-127
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• 2018

Sandwich composites of carbon fiber reinforced plastic(CFRP) and polymer foam will be used to automobile and aerospace industry according to increasing importance of light weight. In this study, mechanical and heat resistance properties of sandwich composites were compared with type of polymer foam (polyethylene terephthalate(PET), polyvinylchloride(PVC), epoxy and polyurethane). All types of polymer foams were degraded to 30, 60, 120, 180 minutes in $180^{\circ}C$. After heat degradation, the polymer foams were observed using optical microscope and compressive test was performed using universal testing machine(UTM). Epoxy foam had the highest compressive property to 2.6 MPa and after thermal degradation, the mechanical property and structure of foam were less changed than others. Epoxy foam had better mechanical properties than other polymer foams under high temperature. Because the epoxy foam was post cured under high temperature. As the results, Epoxy foam was optimal materials to apply to structures that thermal energy was loaded constantly.

• Elastomers and Composites
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• v.35 no.3
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• pp.227-235
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• 2000

This study focused on the recycling technology and application of waste polyurethane scrap($5{\sim}7mm$) and waste urethane form from the footware scrap. Firstly we suggest the waste polyurethane can be used as a component of medium for hydroponic rose culture. Secondly, recycled thermoplastic polyurethane(RTPU) was produced and blended it with high impact polystyrene(HIPS). And also, in order to extend application of recycling field, the former was produced with adding the amine foaming agent to RTPU/HIPS alloy. The main purpose of this study is to diverse of the recycling of the waste polyurethane.

• Polymer(Korea)
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• v.27 no.5
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• pp.436-442
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• 2003

Thermosetting elastomer such as EPDM (Ethylene Propylene Dien Rubber) has been applied to the sponge weatherstrip of a vehicle as a main material. However, the thermosetting elastomers have limited recycling and have brought about the environmental problems. Furthermore, many steps of the manufacturing process such as formulation, mastication and vulcanization make difficult to control uniformity of the endproducts. These problems of current EPDM weatherstrip necessitated development of a new recyclable material, Thermoplastic Vulcanizates (TPV). In this study the influence of the water contents, and the processing conditions. On the foam density and structure in water blowing process was carried out. We found that TPV also can be foamed with water, maintaining the uniformity form this study. Therefore, many inevitable problems of EPDM weatherstrip can be solved, and this new technique is expected to take a roll of making a breakthrough in the rubber industry.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.8
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• pp.562-570
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• 2018

New physical properties of polymer materials were obtained by blending two or three different type of polymers. TPE is used widely in the display, automotive and electronics industries. Consumers have sought emotionally more sensitive and advanced interior automotive parts. A polymer with high foamibility (Ed note: Please check this.) and flowability would be more plausible. TPE composed of foam is a good polymer material to satisfy these trends. In this research, two different TPE were tested, focusing on foamibility and flowability. Two type of TPE were prepared. The first was blended Homo-PP, oil and SEBS. The second was Co-PP, oil and SEBS. The blending temperatures were $180^{\circ}C$, $190^{\circ}C$, and $260^{\circ}C$(second one). The blending speed was 50rpm and blending time was 5 min. The MI of the blended material was affected by the MI of PP and not affected by the blending temperature. The hardness and tensile elasticity were less affected by the MI of PP and blending temperature. The hardness and tensile elasticity were lower at a higher SEBS/Oil content ratio. The soft touch feel was higher with high SEBS/Oil contents. The IPN (Interpenentration polymer network) structure was observed by dissolving the SEBS/Oil layer in xylene. Strain-hardening phenomena also was observed. TPE behaves in a rubber and foamed closed-cell improved its stability.

• Fashion & Textile Research Journal
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• v.14 no.4
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• pp.635-640
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• 2012

In this study, thermoplastic urethane (TPU) coating yarns were prepared at various extruding temperatures. The fine structure and mechanical properties of resultant TPU coating yarns examined by the wide angle X-ray diffractometer (WAXD), differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA), and tensile test. TPU coating yarns (prepared at extruding temperatures at $175^{\circ}C$) were confirmed as a stable fine structure that obtained excellent tensile strength and flexibility. The C samples prepared by optimized conditions made by TPU woven floor mat. The structure of the woven mat is $4{\times}4$ basket weave and have laminated with the EVA foam to obtained final TPU woven floor mat products. The resultant TPU woven floor mat was obtained to 1.5MN of tensile strength, 22% of the elongation, and 0.2MN of tear strength. The weight loss abrasion and the resilience by the ball rebound of the TPU-woven floor mat was prior to those of the PVC subsequently, we were able to develop a woven floor mat with TPU coating yarn and produce an eco-friendly high valuable woven floor mat using an interior product.