• Title, Summary, Keyword: Thermoplastic

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Physical properties of thermoplastic material for clear aligners (투명 장치의 열가소성 재료의 올바른 이해)

  • Cha, Jung-Yul
    • The journal of the Korean dental association
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    • v.54 no.7
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    • pp.542-550
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    • 2016
  • Recent technological advance have greatly expanded the application of invisible orthodontic treatment using clear thermoplastic materials. However, the final outcomes using clear aligner system do not achieve the level of final goal frequently, which results in case refinement, midcourse correction, or fixed orthodontic treatment. Therefore, mechanical properties of thermoplastic materials should be considered to improve the quality of outcomes. The purposes of this special article were to evaluate the force and stress depending on the materials, deflection and thickness of thermoplastic materials and to evaluate the mechanical properties of thermoplastic materials after repeated loading. Thickness and amount of deflection rather than products and materials showed the largest effect on force and stress. In all products, at least 159 gf of force was required for more than 1.0 mm deflection or when materials with 1.0 mm thickness were deflected. Orthodontic forces delivered by thermoplastic materials depend on the materials, thickness, amount of activation, and intra-oral condition. Proper thickness of thermoplastic materials and deflection level of tooth movement should be decided for the efficient and physiologic tooth movement.

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Tensile Properties of Thermoplastic Composites with Braid Structures of Commingled yarn (Braid구조를 갖는 Commingled Yarn을 사용한 열가소성 복합재료의 인장특성 연구)

  • 이덕래;최경은
    • Textile Science and Engineering
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    • v.32 no.9
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    • pp.844-852
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    • 1995
  • The thermoplastic resin is difficult to be impregnated into the reinforced fiber because the resin is a polymer and its melt viscosity is high. Commingled yarn has been developed in order to overcome the difficulties that are experienced when thermoplastic materials are impregnated to reinforce composite materials. Tensile and bending properties of thermoplastic braid composites were discussed. The middle-end-yarn and axial yarn were used to raise strength of thermoplastic braid composites. Tensile properties of thermoplastic braid composites were almost saturated from the molding pressure of 2.0MPa, however, the bending properties were increased along with the molding pressure. The tensile strength of the slow cooling type in double wrapped spun yarn(DSY) thermoplastic braid composites was higher than that of the rapid cooling type.

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Modeling Techniques for a Thermoplastic Bumper Analysis (플라스틱 범퍼 해석에서 모델의 단순화가 결과에 주는 영향에 대하여)

  • 이경돈
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • pp.115-130
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    • 1992
  • The analysis of thermoplastic automotive bumpers needs not only characterizations of the thermomechanical properties of thermoplastic materials but also the finite element method which can solve the problems with a large deflection, an elastic-inelastic deformation, and a change of a contact state. This paper describes the modeling techniques in the finite element analysis in order to get a good prediction of thermoplastic bumper behaviors. Simplification effects of a complex geometry of thermoplastic bumpers are studied by comparing the results from static loading tests and the finite element analysis.

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Effect of Textile Pattern on Mechanical and Impregnation Properties of Glass Fiber/Thermoplastic Composite (유리 섬유/열가소성 복합 재료의 기계적 및 함침 특성에 대한 직물 패턴의 영향)

  • Kim, Neul-Sae-Rom;Lee, Eun-Soo;Jang, Yeong-Jin;Kwon, Dong-Jun;Yang, Seong Baek;Yeom, Jung-Hyun
    • Composites Research
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    • v.31 no.6
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    • pp.317-322
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    • 2018
  • In various industry, the composite is tried to be applied to products and thermoplastic based composite is in the spotlight because this composite can be recycled. The use of continuous fiber thermoplastic (CFT) method increased gradually than long fiber thermoplastic (LFT). In this study, tensile, flexural, and impact test of different array types of glass fiber (GF)/thermoplastic composites were performed to compare with GF array. Impregnation property between GF mat and thermoplastic was determined using computed tomography (CT). At CFT method, thermoplastic film is not wet into GF roving and many voids are appeared into composite. This phenomenon affects to decrease mechanical properties. Plain pattern GF mat was the best mechanical and impregnation properties that distance between two roving was set closely to $100{\mu}m$.

Interfacial Phenomena of Lignocellulose Fiber/Thermoplastic Polymer Composites (리그노셀룰로오스 섬유/열가소성 고분자 복합재의 계면 현상)

  • Son, Jungil;Yang, Han-Seung;Kim, Hyun-Joong
    • Journal of Adhesion and Interface
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    • v.3 no.4
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    • pp.44-52
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    • 2002
  • Composite materials are created by combining two or more component to achieve desired properties which could not be obtained with the separate components. The use of reinforcing fillers, which can reduce material costs and improve certain properties, is increasing in thermoplastic polymer composites. Currently, various inorganic fillers such as talc, mica, clay, glass fiber and calcium carbonate are being incorporated into thermoplastic composites. Nevertheless, lignocellulose fibers have drawn attention due to their abundant availability, low cost and renewable nature. In recent, interest has grown in composites made from lignocellulose fiber in thermoplastic polymer matrices, particularly for low cost/high volume applications. In addition to high specific properties, lignocellulose fibers offer a number of benefits for lignocellulose fiber/thermoplastic polymer composites. These include low hardness, which minimize abrasion of the equipment during processing, relatively low density, biodegradability, and low cost on a unit-volume basis. In spite of the advantage mentioned above, the use of lignocellulose fibers in thermoplastic polymer composites has been plagued by difficulties in obtaining good dispersion and strong interfacial adhesion because lignocellulose fiber is hydrophilic and thermoplastic polymer is hydrophobic. The application of lignocellulose fibers as reinforcements in composite materials requires, just as for glass-fiber reinforced composites, a strong adhesion between the fiber and the matrix regardless of whether a traditional polymer matrix, a biodegradable polymer matrix or cement is used. Further this article gives a survey about physical and chemical treatment methods which improve the fiber matrix adhesion, their results and effects on the physical properties of composites. Coupling agents in lignocellulose fiber and polymer composites play a very important role in improving the compatibility and adhesion between polar lignocellulose fiber and non-polar polymeric matrices. In this article, we also review various kinds of coupling agent and interfacial mechanism or phenomena between lignocellulose fiber and thermoplastic polymer.

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Color stability, water sorption and cytotoxicity of thermoplastic acrylic resin for non metal clasp denture

  • Jang, Dae-Eun;Lee, Ji-Young;Jang, Hyun-Seon;Lee, Jang-Jae;Son, Mee-Kyoung
    • The Journal of Advanced Prosthodontics
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    • v.7 no.4
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    • pp.278-287
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    • 2015
  • PURPOSE. The aim of this study was to compare the color stability, water sorption and cytotoxicity of thermoplastic acrylic resin for the non-metal clasp dentures to those of thermoplastic polyamide and conventional heat-polymerized denture base resins. MATERIALS AND METHODS. Three types of denture base resin, which are conventional heat-polymerized acrylic resin (Paladent 20), thermoplastic polyamide resin (Bio Tone), thermoplastic acrylic resin (Acrytone) were used as materials for this study. One hundred five specimens were fabricated. For the color stability test, specimens were immersed in the coffee and green tee for 1 and 8 weeks. Color change was measured by spectrometer. Water sorption was tested after 1 and 8 weeks immersion in the water. For the test of cytotoxicity, cell viability assay was measured and cell attachment was analyzed by FE-SEM. RESULTS. All types of denture base resin showed color changes after 1 and 8 weeks immersion. However, there was no significant difference between denture base resins. All specimens showed significant color changes in the coffee than green tee. In water sorption test, thermoplastic acrylic resin showed lower values than conventional heat-polymerized acrylic resin and thermoplastic polyamide resin. Three types of denture base showed low cytotoxicity in cell viability assay. Thermoplastic acrylic resin showed the similar cell attachment but more stable attachment than conventional heat-polymerized acrylic resin. CONCLUSION. Thermoplastic acrylic resin for the non-metal clasp denture showed acceptable color stability, water sorption and cytotoxicity. To verify the long stability in the mouth, additional in vitro studies are needed.

Studies on Mechanical Properties of Thermoplastic Vulcanizate Containing Acid Group (Acid Group이 도입된 TPV (Thermoplastic Vulcanizate)계 열가소성 탄성체의 기계적 물성에 관한 연구)

  • Kim, Dong Ho;Kim, Gu Ni
    • Journal of Adhesion and Interface
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    • v.16 no.2
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    • pp.63-68
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    • 2015
  • We synthesized thermoplastic polyurethane elastomer containing carboxylic acid group and TPV (thermoplastic vulcanizate). We measured the mechanical, grip, debris, contact angle and adhesion properties according to introducing acid group in elastomer structure. Mechanical and wet slip properties were improved because of the hydrogen bonding by introduction of acid group. Also adhesion strength was increased as increasing of surface polarity by carboxylic acid group. The debris property of TPV made from TPU containing carboxylic acid group was improved.

Filling Imbalance in Injection Mold with Branch Type Runner System (나뭇가지형 러너시스템을 갖는 사출금형에서의 충전 불균형)

  • Han, Dong-Yeop;Jeong, Yeong-Deug
    • Journal of the Korea Society of Die & Mold Engineering
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    • v.1 no.1
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    • pp.45-50
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    • 2007
  • Recently, the study for filling imbalance in thermoplastic polymer has gradually been increased. However, it is hard to find the researches for filling imbalance of thermoplastic elastomer(TPE). The experiment of filling imbalance was conducted for thermoplastic vulcanize(TPV) and PP, ABS polymers in the mold with un-geometrically balanced runner system(Branch Type Runner System). In this experiment, the effects of the melt temperature, injection pressure and injection speed on the filling imbalance were investigated.

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Physical properties and color stability of injection-molded thermoplastic denture base resins

  • Song, So-Yeon;Kim, Kyoung-Soo;Lee, Jeong-Yol;Shin, Sang-Wan
    • The Journal of Advanced Prosthodontics
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    • v.11 no.1
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    • pp.32-40
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    • 2019
  • PURPOSE. The purpose of this study was to compare mechanical and physical properties of injection-molded thermoplastic denture base resins. MATERIALS AND METHODS. In this study, six commercially available products (VA; Valplast, LC; Lucitone, ST; Smiltone, ES; Estheshot-Bright, AC; Acrytone, WE; Weldenz) were selected from four types of thermoplastic denture base materials (Polyamide, Polyester, Acrylic resin and Polypropylene). The flexural properties and shore D hardness have been investigated and water sorption and solubility, and color stability have evaluated. RESULTS. For the flexural modulus value, ES showed the highest value and WE showed significantly lower value than all other groups (P<.05). Most of experimental groups showed weak color stability beyond the clinically acceptable range. CONCLUSION. Within the limits of this study, thermoplastic denture base resin did not show sufficient modulus to function as a denture base. In addition, all resins showed discoloration with clinical significance, and especially polyamides showed the lowest color stability.

Overview on Development for Thermoplastic Solid Propellants (열가소성 고체추진제 개발 현황)

  • Cho, Joonhyun;Heo, Jinwook;Kim, Dukhyun;Lee, Hyoungjin
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • pp.495-497
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    • 2017
  • Thermoplastic propellants using thermoplastic elastomer binders show moderate performance and mechanical properties compared to thermoset propellants, but these propellants are widely used in a variety of fields due to low cost of raw materials, simple manufacturing process and stable handling process. In order to utilize thermoplastic solid propellants in various fields, we will study properties depending on the content of oxidants, metal fuels and additives.

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