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Polyurethane Dispersions (polyurethane + dispersion)

Distribution by Scientific Domains
Polymers and Materials Science100%

Selected Abstracts

Comparison of properties of acrylic,polyurethane hybrid emulsions prepared by batch and semibatch processes with monomer emulsion feed

POLYMER INTERNATIONAL, Issue 5 2003
ebenik
Abstract Aqueous acrylic,polyurethane hybrid emulsions were prepared by batch and semibatch polymerization of acrylic monomer mixtures (butyl acrylate, methyl methacrylate and acrylic acid) in the presence of polyurethane dispersion. The acrylic component was introduced in the monomer emulsion feed. The weight ratio between acrylic and polyurethane components was varied to obtain different emulsion properties, microphase structure and mechanical film properties. Scanning electron microscopy, average particle size and molecular weight measurements were performed to characterize the latex systems. Mechanical properties were examined by measuring Koenig hardnesses of dried films. The average particle size increased with the acrylic/polyurethane ratio. Particles of larger than average size and, to some extent, higher than average molecular weights by batch process were formed. Koenig hardnesses decreased with increasing acrylic/polyurethane ratio. Properties of emulsions synthesized by semibatch processes were compared with the results reported for a different polyurethane dispersion. Copyright © 2003 Society of Chemical Industry [source]

Aqueous polyurethane dispersions derived from polycarbonatediols and Di(4-isocyanatocyclohexyl)methane

POLYMER ENGINEERING & SCIENCE, Issue 5 2006
Da-Kong Lee
Aqueous polyurethane dispersions derived from various polycarbonatediols, di(4-isocyanatocyclohexyl)methane (HMDI), and various carboxylic diols, including dimethylol propionic acid (DMPA), dimethylol butyric acid (DMBA), and a carboxylic polycaprolactonediol, were prepared by a method in which the dispersing procedure was modified to enhance the molecular weight. The molecular weight, particle size, tensile properties, thermal properties, and dynamic mechanical properties of the polyurethane dispersions were investigated. The dynamic mechanical property data indicate that these polyurethane dispersions can exhibit higher temperature resistance when compared with those derived from isophorone diisocyanate (IPDI). POLYM. ENG. SCI. 46:588,593, 2006. © 2006 Society of Plastics Engineers [source]