Preparation and characterization of aqueous polyurethane dispersions containing ionic centers

Abstract

Aqueous polyurethane dispersions were prepared from toluene di-isocyanate, polytetramethylene glycol, and 1,4-butanediol, with different weight percent of dimethylol propionic acid (DMPA) as anionic center. IR Spectroscopy was used to follow the polymerization reaction as well as the polymer characterization. The effect of DMPA content on the state of dispersion, particle size distribution, mechanical, and thermal properties of the emulsion-cast films were studied. Average particle size of the prepared emulsion polyurethanes decreased with increasing DMPA content. Tensile strength and hardness increase and elongation at break and contact angle decrease by increasing the ionic content. Glass transition temperature (T g ) shifted toward higher temperature and thermal stability decreased by increasing the DMPA content. The increased T g and tensile properties are interpreted in terms of the increased hard segments and coulombic forces between ionic centers. The decreased contact angle is ascribed to the increase in the hydrophilicity of the polyurethanes because of the incorporation of more hydrophilic moiety in polymer backbone.

Relationship between reagents molar ratio and dispersion stability and film properties of waterborne polyurethanes

“…It has been observed a decrease in contact angle value as the IPDI/(PCL + DMPA) molar ratio increases, due to increase of HS content and so, urethane polar groups, which induces to a more hydrophilic surface. Generally, the increase in DMPA content tends to decrease contact angle values [30] due to carboxylic groups polarity. At higher IPDI/(PCL + DMPA) molar ratio, the behavior is accomplished from 76.7 to 65.0 • , but at lower ratios similar contact angle values around 79 • are obtained.…”

Polyurethane modified with 3‐aminopropyltriethoxysilane as wool antifelting agent

“…To confirm the above reactions, the prepolymer and precursor were characterized with FTIR 19,20 The FTIR spectra of PPT (a) and prepolymer (b) were shown in Figure 1. Graph (a) shows a distinct absorption peak at 1100 cm 21 in the region of À ÀCÀ ÀOÀ ÀC stretching for ether groups and the peak at 3480 cm 21 , which confirms the existence of À ÀOH groups.…”

Investigation On The Possibility Of Using Water-Based Polyurethane Acrylates In The Production Process Of Fiberglass Reinforced Composite Materials

“…The stronger hard segment acts as physical crosslinks, leading to a difficult segmental motion of the polymer chain, which results in a more significant phase separation between the hard and soft segments. The phase separation improves mechanical properties of polyurethanes but reduces their flexibility and solubility [16]. Figure 5 presents the results for the mechanical properties of the prepared composite materials with WPUA matrices and different glass fiber contents.…”