PCL-PEG-PCL triblock ester-ether copolydiol-based waterborne polyurethane. II. Effect of NCO/OH mole ratio and DMPA content on the physical properties

Yen, Ming‐Shien; Kuo, Shu-Chin

doi:10.1002/(sici)1097-4628(19980214)67:7<1301::aid-app21>3.0.co;2-2

Cited by 41 publications

(28 citation statements)

References 5 publications

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“…The particle size is affected by several external and internal factors of which the proportion of ionic centres is the most important. Similar behaviour has been observed for other systems including those based on IPDI17–19 and results from the maintenance of a uniform density of charged groups on the surface. The dispersion particles are stabilised through the presence of the electrical double layer generated by the surface carboxylic groups and their counterions.…”

Section: Resultsmentioning

confidence: 99%

Temperature‐Dependent Morphology, Magnetic and Optical Properties of Li‐Doped MgO

et al. 2010

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Li-doped MgO is a potential catalyst for the oxidative coupling of methane, whereby surface Li+ O- centers are suggested to be the chemically active species. To elucidate the role of Li in the MgO matrix, two model systems are prepared and their morphological, optical and magnetic properties as a function of Li doping are investigated. The first is an MgO film deposited on Mo(001) and doped with various amounts of Li, whereas the second is a powder sample fabricated by calcination of Li and Mg precursors in an oxygen atmosphere. Scanning tunneling and transmission electron microscopy are performed to characterize the morphology of both samples. At temperatures above 700 K, Li starts segregating towards the surface and forms irregular Li-rich oxide patches. Above 1050 K, Li desorbs from the MgO surface, leaving behind a characteristic defect pattern. Traces of Li also dissolve into the MgO, as concluded from a distinct optical signature that is absent in the pristine oxide. No electron paramagnetic resonance signal that would be compatible with Li+O- centers is detected in the two Li/MgO samples. Density-functional theory calculations are used to determine the thermodynamic stability of various Li-induced defects in the MgO. The calculations clarify the driving forces for Li segregation towards the MgO surface, but also rationalize the absence of Li+O- centers. From the combination of experimental and theoretical results, a detailed picture arises on the role of Li for the MgO properties, which can be used as a starting point to analyze the chemical behavior of the doped oxide in future

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Section: Resultsmentioning

confidence: 99%

Temperature‐Dependent Morphology, Magnetic and Optical Properties of Li‐Doped MgO

et al. 2010

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“…The properties of TPUs depend on many variables, such as the chemical structure of each type of segment, the molecular weight of the soft segments, the hard/soft segment content ratio, etc 1–4. In addition, it is well known that the polymerization method and preparation conditions affect the microstructure and the mechanical properties of TPUs 5–12…”

Section: Introductionmentioning

confidence: 99%

Synthesis and characterization of novel urethane‐siloxane copolymers with a high content of PCL‐PDMS‐PCL segments

Pergal

Antić

Govedarica

et al. 2011

J of Applied Polymer Sci

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Novel polyurethane copolymers derived from 4,4 0 -methylenediphenyl diisocyanate (MDI), 1,4-butanediol (BD) and a,x-dihydroxy-[poly(caprolactone)-polywere synthesized by a two-step polyaddition reaction in solution. In the synthesis of the polyurethanes, the PCL blocks served as a compatibilizer between the nonpolar PDMS blocks and the polar comonomers, MDI and BD. The synthesis of thermoplastic polyurethanes (TPU) with high soft segment contents was optimized in terms of the concentrations of the reactants, the molar ratio of the NCO/OH groups, and the time and temperature of the polyaddition reaction. The structure, composition, and hard MDI/BD segment length of the synthesized polyurethane copolymers were determined by 1 H, 13 C-NMR, and two-dimensional correlation (COSY, HSQC, and HMBC) spectroscopy, while the hydrogen bonding interactions in the copolymers were analyzed by FT-IR spectroscopy. The influence of the reaction conditions on the structure, molecular weight, thermal, and some physical properties was studied at constant composition of the reaction mixture. A change in the molar ratio of the NCO/OH groups and the reaction conditions modified not only the molecular weight of the synthesized polyurethanes, but also the microstructure and therefore the thermal and physical properties of the copolymers. It was demonstrated that only PCL segments with high soft segment contents crystallize, thereby showing spherulitic morphology.

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“…Generally, mixed polyols or special type polyols were used to impart special properties to PU. Yen et al6 used polyol blends such as binary [poly(ethylene glycol)/polypropylene glycol (PEG/PPG), PPG/poly(tetramethylene oxide) glycol (PTMG), and PEG/PTMG] or ternary (PEG/PPG/PTMG) systems for waterborne polyurethane (WBPU). They found that the WBPU having different polyol components had significantly different particle sizes and dispersion behaviors.…”

Section: Introductionmentioning

confidence: 99%

“…PDMS/PTMG‐based materials had higher water absorption values than either the pure PTMG or pure PDMS‐based material. Yen et al12, 13 synthesized the polycaprolactone–poly(ethylene glycol)–polycaprolactone (PCL–PEG–PCL) triblock copolydiol from PEG and ϵ‐caprolactone under uncatalyzed reaction conditions according to Piero's synthesis method,14 and examined the effects of length ratios of PEG/PCL chains on the WVP of WBPU‐coated fabrics.…”

Section: Introductionmentioning

confidence: 99%

Preparation and properties of waterborne polyurethanes for water‐vapor‐permeable coating materials

Kwak

Park

Lee

et al. 2003

J of Applied Polymer Sci

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Waterborne polyurethanes were prepared by polyaddition reaction using isophorone diisocyanate, dimethylol propionic acid, various polyols with a fixed molecular weight (M n ϭ about 2000), ethylene diamine as a chain extender, and triethylamine as a neutralization agent. Three types of polyols such as (1) solo glycols [polypropylene glycol (PPG) (M n ϭ 2000), poly(tetramethylene oxide) glycol (PTMG) (M n ϭ 2000), poly(tetramethylene adipate glycol) (PTAd) (M n ϭ 2000), or polycaprolactone glycol (PCL) (M n ϭ 2000)], (2) the polyol blends (PPG/PCL, PTMG/PCL, PPG/PTAd, PTMG/PTAd), and (3) a triblock glycol (TBG) (M n ϭ 1990) were used in this study. The triblock glycol (TBG) [(CL) 4.5 -PTMG (M n ϭ 1000)-(CL) 4.5 (M n ϭ1990] was synthesized from PTMG and ⑀-caprolactone (CL) in this study. The triblock glycol was found to have two main melting peaks at about 13 and 40°C. This study was examined on the effect of the types of polyols on the particle size, viscosity, dynamic thermal properties, and water vapor permeability. The particle size of the aqueous polyurethaneurea dispersion increased in the order of polyol-blendsbased samples (183-350 nm) Ͼ TBG-based sample (167 nm) Ͼ solo-polyol-based sample (58 -96 nm). By dynamic thermal mechanical analysis, the ester-type polyol-(PTAd and PCL) based samples were found to have higher storage modulus and T g than those of ether-type polyol-(PPG and PTMG) based samples. The water vapor permeability (WVP) increased in the order of TGB-based sample Ͼ PCL/PTMGbased sample Ͼ PTAd/PTMG-based sample Ͼ PCL/PPGbased sample Ͼ PTAd/PPG-based sample Ͼ PTMG-based sample Ͼ PPG-based sample Ͼ PCL-based sample Ͼ PTAdbased sample. WVP was found to increase in the order of TBG-based sample Ͼ polyol-blend based samples Ͼ solopolyol-based samples. It was also found that the samples containing ether-type glycols (PTMG, PPG) had higher permeability than samples having ester-type glycols (PCL, PTAd). PTMG-based samples were found to have higher permeability than PPG-based samples if other compositions were constant.

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PCL-PEG-PCL triblock ester-ether copolydiol-based waterborne polyurethane. II. Effect of NCO/OH mole ratio and DMPA content on the physical properties

Cited by 41 publications

References 5 publications

Temperature‐Dependent Morphology, Magnetic and Optical Properties of Li‐Doped MgO

Temperature‐Dependent Morphology, Magnetic and Optical Properties of Li‐Doped MgO

Synthesis and characterization of novel urethane‐siloxane copolymers with a high content of PCL‐PDMS‐PCL segments

Preparation and properties of waterborne polyurethanes for water‐vapor‐permeable coating materials

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