• Title, Summary, Keyword: fast curing polyurethane

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Pot Life Assessment and Mechanical Property of Fast Curing Polyurethane Developed with Eco-friendly Pre-polymer

  • Joseph, Jessy;Moon, Junho;Kong, Tae Woong;Kim, Dong Ho;Oh, Jeong Seok
    • Elastomers and Composites
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    • v.55 no.1
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    • pp.13-19
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    • 2020
  • 4,4'-Methylenebis(2-chlorobenzenamine) (MOCA)-free fast curing polyurethanes were prepared. In this study, the processibility of a fast curing polyurethane system was characterized by assessing the pot life. The obtained pot life of the polyurethane was 6-8 s, indicating that this prepolymer-curative system is appropriate for ribbon flow casting. The influence of the NCO index on the viscosity and mechanical properties was evaluated. The viscosity, tensile strength, tear strength, and hardness of the as-prepared polyurethanes showed an increasing trend, with an increase in the NCO index, whereas the elongation at break increased initially and then decreased with an increase in the NCO index. The gel fraction and crosslink density showed a direct correlation with the NCO index, which substantiated the improved mechanical properties at the higher NCO index. The coefficients of friction and abrasion deteriorated with an increase in the NCO index.

Preparation and Properties of the Fast-Curing γ-Ray-Shielding Materials Based on Polyurethane

  • Ni, Minxuan;Tang, Xiaobin;Chai, Hao;Zhang, Yun;Chen, Tuo;Chen, Da
    • Nuclear Engineering and Technology
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    • v.48 no.6
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    • pp.1396-1403
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    • 2016
  • In this study, fast-curing shielding materials were prepared with a two-component polyurethane matrix and a filler material of PbO through a one-step, laboratory-scale method. With an increase in the filler content, viscosity increased. However, the two components showed a small difference. Curing time decreased as the filler content increased. The minimum tack-free time of 27 s was obtained at a filler content of 70 wt%. Tensile strength and compressive strength initially increased and then decreased as the filler content increased. Even when the filler content reached 60 wt%, mechanical properties were still greater than those of the matrix. Cohesional strength decreased as the filler content increased. However, cohesional strength was still greater than 100 kPa at a filler content of 60 wt%. The ${\gamma}$-ray-shielding properties increased with the increase in the filler content, and composite thickness could be increased to improve the shielding performance when the energy of ${\gamma}$-rays was high. When the filler content was 60 wt%, the composite showed excellent comprehensive properties.

Syntheses and Characterization of UV-curable Polyurethane Acrylates with Eco-friendly Polyols (친환경 폴리올을 이용한 광경화형 폴리우레탄 아크릴레이트의 합성)

  • Lee, Bong;Kim, Yeong Woo;Lee, Won-Ki
    • Journal of Adhesion and Interface
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    • v.20 no.4
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    • pp.140-145
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    • 2019
  • In view of environmental considerations, the control of carbon dioxide (CO2) and volatile organic compounds (VOCs) is one of important issues in the film and coating industries. Therefore, UV-curable system has been developed due to minimize emissions of VOCs and reduce CO2 emission due to low energy consumption from fast curing. Also, biodegradable polymers economically are attractive because of environmental and economic concerns associated with huge waste plastics. In this study, UV-curable polyurethane acrylates with different compositions of biodegradable polylactide (PLA) diol and poly(ethylene glycol) as diols were synthesized and curing reaction of their end-capped acrylates was performed by UV exposure. Tensile strength, elongation, and Tg of the UV-cured polyurethane acrylates increased with PLA diol content in the diol while their hydrophilicity and thermal stability increased with the PEG content. These results indicated a property of UV-cured polyurethane acrylates could be controlled by environment-friendly diols.

Modification of Water-borne Polyurethane Using Benzophenone Crosslinker (Benzophenone 가교제를 이용한 수분산 폴리우레탄 개질)

  • Kim, HyeokJin;Kim, Jin Chul;Chang, SangMok;Seo, BongKuk
    • Applied Chemistry for Engineering
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    • v.27 no.2
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    • pp.221-226
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    • 2016
  • Production of eco-friendly and biologically harmless materials is strongly required in all industries. In particular, reducing volatile organic compounds in coating processes is extremely important to secure worker's safety. During recent two decades, extensive research works on water-borne polyurethane dispersion (PUD) have been continuously developed as an alternative to solvent-borne polyurethane. However, PUD was shown inferior mechanical properties to the organic solvent-borne polyurethane due to a limit to the molecular weight increase, which resulted in the limit of applications. To overcome this drawback, several approaches have been examined such as polymer blends and thermal/radiation induced crosslinking. Among these methods, the radiation curing system was suitable for industrialization because of the high crosslinking density and fast curing speed. In this study, we overcame the drawback for PUD via introducing benzophenone radiation curable units to PUD. We synthesized PUD films which possessed good dispersion in water for 30 days, increased Tg and Td more than $5^{\circ}C$ after UV curing film as well as improved young's modulus more than double.

Synthesis and Curing Behavior of UV-curable Polycarbonate-based Polyurethane Methacrylate : Effect of Polyol Molecular Weight, Contents of Photoinitiator and Monomers on the Flexibility and Properties (자외선 경화형 폴리카보네이트계 폴리우레탄 메타아크릴레이트의 합성과 경화거동 : 폴리올 분자량, 광개시제 및 모노머 함량이 유연성과 물성에 미치는 영향)

  • Park, Eun-Suk;Hwang, Hyeon-Deuk;Park, Cho-Hee;Lee, Yong-Hee;Moon, Je-Ik;Kim, Hyun-Joong
    • Journal of Adhesion and Interface
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    • v.12 no.2
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    • pp.47-55
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    • 2011
  • UV-curable coatings have been used in various industries due to their advantages such as high mechanical property, good solvent resistance, fast curing process and low volatile organic compounds. However, a lack of flexibility of UV-cured films is a weak point for the pre-coated system of roll-to-roll process. In this study, UV-curable polycarbonate-based methacrylates were synthesized with polycarbonate diol, isophorone diisocyanate and 2-hydroxyethylmethacrylate to improve flexibility of the UC-cured films. The effects of polyol molecular weight, content of photoinitiator and monomers on the UV-curing behavior, flexibility and properties were investigated. The UV-curing behavior was measured by a photo-DSC, the pendulum hardness, tensile strength, viscoelastic properties were also evaluated.

Toughness Improvement of Unsaturated Polyester Mortars Blended with Polyurethane Liquid Rubber (폴리우레탄 액상고무를 혼합한 불포화 폴리에스테르 모르타르의 인성 증진효과)

  • 최영준;박준철;박정민;김화중
    • Journal of the Korea Concrete Institute
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    • v.14 no.3
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    • pp.283-290
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    • 2002
  • Generally polymer mortar and concrete using unsaturated polyester resin has high strengths and good chemical resistance. However it also has high brittleness and because of this reason, it is not used for the purpose that demands high resistance to impact. The purpose of this study is to improve the brittleness of unsaturated polyester mortar(UPE mortar) which could be used for the flooring material with recycled aggregates and UPE. Polyurethane liquid rubber(PU) and recycled aggregates were used to complement the brittleness and to recycle the resources respectively. The characteristics of mortar were investigated according to the molecular weight and substitution rate of PU. As the molecular weight and PU substitution rate were increased, the viscosity was increased, working life became fast and curing shrinkage was reduced. Compressive and flexural strengths were also reduced but tile brittleness was improved. Therefore, it is seemed that the improved WE mortar could be obtained by using polyurethane liquid rubber with the polyol of molecular weight 2000, 3000.