• Elastomers and Composites
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• v.55 no.1
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• pp.20-25
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• 2020

The effect of the isocyanate index (NCO index) on the particle size and particle size distribution of a waterborne polyurethane dispersion (WPUD) with polycarbonate-diol was determined. The WPUDs were prepared using a conventional acetone process with polycarbonate-polyol (M_n = 2028), 4,4'-methylenebis(cyclohexyl isocyanate) (H₁₂MDI), 2,2-bis(hydroxymethyl) propionic acid (DMPA), and dibutyltin dilaurate catalyst. At NCO index values below 1.5, the number average particle diameter of the WPUDs significantly increased with the NCO index, whereas the particle diameter slightly varied at higher NCO indexes. The dependency of the WPUD viscosity on the NCO index exhibited similar behavior to that of the particle size. The relative values of the full width at half maximum of the WPUD particle distribution curves at various NCO indexes were not influenced by the NCO index.

• Polymer(Korea)
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• v.34 no.6
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• pp.507-510
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• 2010

Poly(cyclohexane carbonate) diol was synthesized by the alternating copolymerization of cyclohexene oxide and $CO_2$ over Cr based transition metal catalysts. The prepared PCCD was applied as a precursor for the preparation of waterborne polyurethane (PUD) in order to investigate an application field of carbon dioxide-based polycarbonate. The scratch resistance and thermal properties of PUDs, which was prepared with two kinds of polymeric diols (PCD and PCCD) were investigated. The scratch resistance and thermal decomposition temperature of PUD film prepared with PCCD is worse than those prepared with PCD, poly(hexamethylene carbonate) glycol. While, glass transition temperature of PUD film prepared with PCCD was higher than that prepared with PCD. It might be due to the rigid cyclohexane structure in the PCCD.

• Clean Technology
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• v.28 no.4
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• pp.278-284
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• 2022

This study presents an excellent planar heater based on low-dimensional composites. By optimizing the ratio of 1D carbon nanotubes (CNT) and 2D MXene (Ti₃C₂T_X), it is possible to create a planar heater that has superior electrical conductivity and high heat generation characteristics. Low-dimensional composites were prepared by mixing CNT paste and MXene solution with eco-friendly waterborne polyurethane (WPU). In order to find the optimal mixing ratio for the MXene-CNT-WPU composites, samples with MXene to CNT weight ratios of 3:1, 1:1, 1:3, 1:7, and 1:14 were investigated. In addition to these different weight ratios, 5 wt% WPU was equally applied to each sample. It was confirmed that the higher the weight ratio of CNT, the lower the sheet resistance and the higher the heating temperature. In particular, when the MXene-CNT-WPU planar heater was fabricated by mixing MXene and CNT at a weight ratio of 1:7 and 1:14, the heating temperature was higher than the heating temperature of a CNT-WPU planar heater. These characteristics are due to the optimized mixture of the 1D materials (CNT) and the 2D materials (MXene) causing the formation of a flat surface and a dense network structure. The low-dimensional composites manufactured with the optimized mixing ratios found in this study are expected to be applied in flexible electronic devices.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2009.03a
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• pp.179-180
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• 2009

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2009.03a
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• pp.181-182
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• 2009

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2010.03a
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• pp.197-198
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• 2010

• Proceedings of the Korean Fiber Society Conference
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• 2003.04a
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• pp.36-39
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• 2003

Conducting polymers are finding increasing number of applications in various electronic devices such as chemical sensors, electrochromic display, light emitting diodes, etc. Polyaniline(PANI) ranks among highly prospective conduction polymers. PANI was first synthesis in 1862[1] and has been extensively studied as a conducting polymer since the 1980s[2]. The side range of electrical, electrochemical and optical properties coupled with good environmental stability makes PANI potentially attractive for application as an electronic material. (omitted)

• Polymer(Korea)
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• v.33 no.6
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• pp.569-574
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• 2009

Organic- inorganic hybrid waterborne polyurethane (PUD) is synthesized by using hybrid polyol consist of carbonate (PCD), ester (PCL), and siloxane (PDSBP) in order to enhance anti-scratch property of PUD film. The diameter of graft type PUD emulsion is bigger than that of linear type PUD due to the graft structure of hydrophobic siloxane chain. The glass transition temperature of linear type PUD increase and the decomposition temperature of linear type PUD decrease with the content of PCD polyol. While, the decomposition temperature of graft type PUD almost same with increasing PDSBP content. The anti-scratch property and pencil hardness of graft type PUD improves as adding PDSBP polyol in the hybrid polyol system. When 9 wt% of PDSBP polyol is mixed, PUD films shows excellent anti-scratch property (~3.3 N), and pencil hardness (> 9 H).

• Journal of Adhesion and Interface
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• v.23 no.4
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• pp.137-143
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• 2022

In this study, the polyurethane acrylates (PUA) resin with good adhesive and flexibility for adhesive for shoes and clothing were synthesized using that poly(tetramethylene adiphate glycol) (PTAd), poly(tetramethylene ether glycol) (PTMG) as polyester polyol and polyether polyol respectively, including 4,4'-methylene diphenyl diisocyanate (MDI), isophorone diisocyanate (IPDI), 1,4-butandiol (1,4-BD), 2-hydroxyethyl methacrylate (2-HEMA) and dibutyl amine (DBA). The effect of polyol blend in the polyurethane acrylate on thermal and mechanical properties, adhesion strength and flexural strength were studied. The glass transition temperature (T_g) of PUA was confirmed in range of -70~-40 ℃. In addition, the glass transition temperature (T_g), decomposition temperature (T_d), tensile strength adhesion strength and heat resistance were increased as increasing of PTAd amount while the elongation, water resistance and flexural properties were decreased. The synthesized polyurethane acrylate with 5:5 ratio of PTAd and PTMG indicated the highest adhesion strength and flexural properties.

• Clean Technology
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• v.20 no.3
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• pp.232-240
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• 2014

The significance of thermoplastic polyolefin polypropylene (PP) lies in its potential to replace polyvinyl chloride (PVC), the most widely used material for automobile interiors (door trim, dash board), which discharges harmful compounds in certain conditions. Another benefit of PP (0.855 amorphous - 0.946 crystalline $g/cm^3$) is its low density compared to that of PVC ($1.1-1.45g/cm^3$), which reduces vehicle weight. Market demand for eco-friendly water-based adhesive/coating material is rising significantly as a substitute for solvent-based adhesive/coating material which emits VOC and causes harmful working conditions. Under such context, in this study, a series of eco-friendly waterborne polyurethane-urea primer (a paint product that allows finishing paint to adhere much better than if it were used alone) for hydrophobic PP were prepared from different mix of DMPA content, NCO/OH molar ratio, various wt% of silicone diol and various soft segment content, among which DMPA of 21 mole %, NCO/OH molar ratio of 1.2, modified silicone diol of 5 wt% and soft segment content of 73 wt% led to good adhesion strength. Additionally, the incorporation of optimum content of additives (0.5 wt% dispersing agent, 0.5 wt% levelling agent, 1.5 wt% antifoaming agent, 3.0 wt% matting agent) into the optimum waterborne polyurethane-urea also enabled good stability, levelling, antifoaming and non-glossy.