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  • 1
    Electronic Resource
    Electronic Resource
    An analysis for the potential of floating guard rings
    Amsterdam : Elsevier
    Solid State Electronics 33 (1990), S. 1125-1129 
    Details
    ISSN: 0038-1101
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0038-1101(90)90089-W
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  • 2
    Electronic Resource
    Electronic Resource
    A self-consistent analytic threshold voltage model for thin SOI n-channel MOSFETs
    Amsterdam : Elsevier
    Solid State Electronics 34 (1991), S. 1421-1425 
    Details
    ISSN: 0038-1101
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0038-1101(91)90039-2
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  • 3
    Electronic Resource
    Electronic Resource
    Preparation of PEG-modified urethane acrylate emulsion and its emulsion polymerization (1996)
    Springer
    Colloid & polymer science 274 (1996), S. 920-927 
    Details
    ISSN: 1435-1536
    Keywords: PEG-modified urethane acrylate ; emulsion ; droplet size ; emulsion polymerization ; interfacial tension ; microsuspension polymerization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract In order to improve stability and reduce droplet size, the PEG-modified urethane acrylates were synthesized by the reaction of polyethylene glycol (PEG) with residual isocyanate groups of urethane acrylate to incorporate hydrophilic groups into the molecular ends. The droplet sizes of the PEG-modified urethane acrylate emulsions were much smaller than those of unmodified urethane acrylate emulsions at the same surfactant composition, and the droplet sizes of these emulsions were significantly effected not by surfactant compositions and types, but by the reaction molar ratio of PEG, because the urethane acrylate containing polyoxyethylene groups as terminal groups aided the interfacial activity of surfactant molecules and acted as a polymeric surfactant. The actions of PEG-modified urethane acrylate were confirmed by the investigation of adsorption of urethane acrylate in a water/benzene interface. For polymerization of emulsions, the stability of emulsion in the process of emulsion polymerization was changed by the type of surfactant or initiator. In the case of emulsion polymerization with a water soluble initiator (K2S2O8), the emulsions prepared using TWEEN 60 were broken in the process of polymerization. However, polymerization of these emulsions could be carried out using an oil soluble initiator (AIBN). The conversion of emulsion polymerization changed with the type of urethane acrylates, that is, the reaction molar ratio of PEG to 2-HEMA.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00656621
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  • 4
    Electronic Resource
    Electronic Resource
    Microphase separation of PEG-modified urethane acrylate and the swelling behavior of its gels (1996)
    Springer
    Colloid & polymer science 274 (1996), S. 1025-1032 
    Details
    ISSN: 1435-1536
    Keywords: PEG-modified urethane acrylate ; microphase separation ; viscosity ; interfacial tension ; gel-swelling ratio ; contact angle measurement
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The viscosity of PEG-modified urethane acrylate (PMUA) showed peculiar behavior in the course of soap-free emulsification. Moreover, the viscosity change with added amounts of water was influenced by the reaction molar ratio of polyethylene glycol (PEG). The rate of increase in viscosity slowed and the ratio of increase in viscosity increased as the reaction molar ratio of PEG increased. This peculiar viscosity behavior was due to the microphase separation between hydrophilic and hydrophobic segments of PMUA, and the orientation of polyoxyethylene groups at O/W interface which influenced droplet size of the soap-free PMUA emulsion. The location of polyoxyethylene groups of this resin at O/W interface was confirmed using the adsorption isotherm measurement of PMUA molecules containing polyoxyethylene groups at water/benzene interface. The microphase separation behavior of PMUA between hydrophilic and hydrophobic segments could apply to the preparation of the PMUA gels containing peculiar structure. PMUA gels were prepared using dioxane (UAG) and the swelling behavior of these gels were compared to that of gels prepared using water (UAHG) in the same medium. In the same medium, the swelling behavior of UAHG gels differed from that of UAG gels because of the difference in the microstructure of gel due to the microphase separation between hydrophilic and hydrophobic segments. This phase separation in the course of gelation in water could be confirmed using contact angle measurement.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00658367
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  • 5
    Electronic Resource
    Electronic Resource
    Amphiphilic urethane acrylate hydrogels having heterophasic gel structure: swelling behaviors and mechanical properties (1998)
    Springer
    Colloid & polymer science 276 (1998), S. 342-348 
    Details
    ISSN: 1435-1536
    Keywords: Key words Amphiphilic urethane acrylate hydrogels ; ionic groups ; polyethers ; heterophasic gel structure ; hydrophobic interaction ; salt- and pH-dependent
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract  Amphiphilic urethane acrylate hydrogels containing ionic group (dimethylopropionic acid, DMPA) were prepared by varying the molecular weight of the soft segment (polyether type, PTMG) and type of diisocyanate, and their swelling behaviors and mechanical properties were examined. They showed amphiphilic property due to the hydrophilic ionic groups and hydrophobic polyethers comprising the urethane acrylate network. Heterophasic gel structure could be found for the hydrogels prepared in water, but not for the hydrogels in organic solvent (1,4-dioxane), through scanning electron microscopy. Because of this heterophasic gel structure, they were able to take in a large amount of water as well. The hydrophobic interaction generated by the polyether soft segments between urethane acrylate network chains decreased the degree of swelling, however, increased reversibly the tensile strengths at equilibrium swelling state. MDI-based hydrogel showed low swelling ratio and high tensile strength because of its ordered hard domain structure. These amphiphilic urethane acrylate hydrogels showed salt- and pH-dependent swelling behaviors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003960050249
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  • 6
    Electronic Resource
    Electronic Resource
    Ultraviolet-curable epoxy acrylate dispersions: effect of urethane acrylate anionomers on stabilizing and film properties (1998)
    Springer
    Colloid & polymer science 276 (1998), S. 976-983 
    Details
    ISSN: 1435-1536
    Keywords: Key words Epoxy acrylate dispersions ; urethane acrylate anionomers ; two hydrophilic ionic segments ; ionic interaction ; final film properties
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract  Epoxy acrylate dispersions stabilized using urethane acrylate anionomers were prepared for an application of ultraviolet (UV) curing. By observing the optical microscopy and colloidal stability for the epoxy acrylate dispersions, it was confirmed that the urethane acrylate anionomers incorporated have an interfacial activity in the interface between the epoxy acrylate oil and the water/ ethanol mixture (80/20, w/w). This was possible by the structurally designed urethane acrylate anionomers, containing a hydrophobic soft segment and two hydrophilic ionic sites in their molecules. In addition, when ultraviolet (UV)-cured, the urethane acrylate anionomers agglomerated to form the rubber domains in the epoxy acrylate film, which were induced by the ionic interaction. Consequently, this agglomerated rubber domains improved the final film properties.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003960050336
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  • 7
    Electronic Resource
    Electronic Resource
    Mechanical properties of amphiphilic urethane acrylate ionomer hydrogels having heterophasic gel structure (1999)
    Springer
    Colloid & polymer science 277 (1999), S. 265-269 
    Details
    ISSN: 1435-1536
    Keywords: Key words Heterophasic gel structure ; Ionic hard domains ; Polyether soft domains ; Crystallinity ; Elastomeric properties
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Amphiphilic urethane acryale hydrogels containing ionic groups (dimethylolpropionic acid) were prepared by varying the molecular weight of the soft segment (polyether type) and the type of diisocyanate, and their mechanical properties were examined. They showed heterophasic gel structure composed of ionic hard domains induced by aggregation of the ionic groups and polyether soft domains comprising the urethane acrylate network. This heterophasic structure could be confirmed by dynamic mechanical analysis (DMA) and by wide-angle X-ray scattering analysis (WAXS); the crystallinity detected by WAXS and the transition peak of the ionic hard domains detected by DMA strongly suggested that there were ionic aggregates. These ionic aggregates acted as reinforcing fillers in the network, which eventually enhanced the tensile strength of the hydrogels. Above all, the tensile properties of the hydrogels were of interest in that the trends of the stress-strain curves were consistent with the rubbery ones. It is believed that the higher purity of the polyether soft domains resulted from the heterophasic gel structure imparting further elastomeric properties on the network.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00013754
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  • 8
    Electronic Resource
    Electronic Resource
    Highly monodisperse crosslinked polymethylmethacrylate microparticles by dispersion polymerization (1999)
    Springer
    Colloid & polymer science 277 (1999), S. 66-72 
    Details
    ISSN: 1435-1536
    Keywords: Key words Highly monodisperse polymethylmethacrylate microparticles ; Carboxylic group-containing urethane acrylate ; Monomer-swellable surface ; Long tetramethylene oxide groups ; Lower polymerization rate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Highly monodisperse polymethylmethacrylate (PMMA) microparticles crosslinked with carboxylic group-containing urethane acrylates (CUA) were produced by simple dispersion polymerization in methanol solution. In contrast to conventional crosslinkers, the CUA employed as a crosslinker was excellent for maintaining the monodispersity of PMMA microparticles even at moderate crosslinker concentrations (to about 5 wt%). It was believed that the CUA helped form the monomer-swellable surface of primary particles, because of the structurally long tetramethylene oxide groups in the molecule. Carboxylic groups in the molecular backbone resulted in larger primary particles by increasing the solubility of the monomer mixture in the medium. Owing to these larger primary particles, the crosslinked PMMA particles showed lower polymerization rates than the linear ones during particle growth. However, at high CUA concentrations (about 10 wt%), bimodal distributions were observed. This was attributed to the high crosslinking density of the primary particle surfaces. Therefore, monomer diffusion toward the polymer phase was restricted, resulting in more favorable secondary nucleation in the medium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003960050368
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  • 9
    Electronic Resource
    Electronic Resource
    Monodisperse micron-sized crosslinked polystyrene particles. IV. Effect of network structure on polymerization procedure (1999)
    Springer
    Colloid & polymer science 277 (1999), S. 1205-1209 
    Details
    ISSN: 1435-1536
    Keywords: Key words Monodisperse micron-sized polystyrene particles ; Urethane acrylate ; Particle diameter ; Particle number density ; Polymerization rate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Monodisperse micron-sized polystyrene particles crosslinked using urethane acrylate were produced by dispersion polymerization in ethanol solution and the effect of the crosslinked network structure on the polymerization procedure was studied. The influences of the concentrations of the initiator and urethane acrylate on the particle diameter (D n), the particle number density (N p), and the polymerization rate (R p) were found to obey the approximate relationships D n ∝ [initiator]0.43 [urethane acrylate]0.05, N p ∝ [initiator]−1.30 [urethane acrylate]0.19, and R p ∝ [initiator]0.24 ± 0.02. The power-law dependence of D n and N p on the initiator concentration showed a similar trend to that of linear polystyrene reported in the literature. Especially, it was found that urethane acrylate does not have a serious effect on D n and N p of the particles produced. The dependence of R p on the initiator concentration was observed to be higher than that of linear polystyrene, suggesting that there is still competition between heterogeneous polymerization and solution polymerization because of the crosslinked network structure of the primary particle.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003960050511
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  • 10
    Electronic Resource
    Electronic Resource
    Poly(methyl methacrylate) hollow particles by water-in-oil-in-water emulsion polymerization (1999)
    Springer
    Colloid & polymer science 277 (1999), S. 252-256 
    Details
    ISSN: 1435-1536
    Keywords: Key words Hollow structure ; Reactive viscosity enhancer ; Stable water-in-oil-in-water ; emulsion droplets ; Multi-hollow-structured particles ; Lyophilicity increase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Poly(methyl methacrylate) particles having hollow structures were produced by water-in-oil-in-water (W/O/W) emulsion polymerization where sorbitan monooleate (Span80) was used as a primary surfactant and sodium laurylsulfate and Glucopen (APG, polypeptide derivative) were used as secondary surfactants. Urethane acrylate having a molecular structure with a hard segment in the molecular backbone, a long soft segment in the middle, and vinyl groups at both ends was employed as a reactive viscosity enhancer. At low concentration of urethane acrylate, only a few particles contained a void in the polymer phase. However, as the concentration of urethane acrylate increased, the number of the particles containing the void increased. This was because urethane acrylate increased the viscosity of the monomer mixture and helped to form the stable W/O/W emulsion droplets, which possibly restricted droplet coalescence during emulsion polymerization. Moreover, at high concentration of urethane acrylate (above 7 wt%), multi-hollow-structured particles were obtained. It is believed that the increase in the lyophilicity of the monomer mixture caused by urethane acrylate led to stronger interfacial activity of the primary surfactant (Span80) and finally resulted in many internal aqueous droplets.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00013751
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