Waterborne polyurethane dispersions obtained by the acetone process: A study of colloidal features

Abstract

Waterborne polyurethane (PU) dispersions were prepared from isophorone diisocyanate (IPDI), 2-bis(hydroxymethyl) propionic acid (DMPA), 1,4-butane diol (BD), poly(propylene glycol) (PPG), and triethylamine (TEA) by means of phase inversion through the acetone process. Changes in DMPA content, initial PU content in acetone, phase-inversion temperature, evaporation conditions, and solvent nature were found to have a great impact on dispersion properties. Using a DMPA concentration of 0.30 mmol/g pol , stable PU dispersions could only be obtained when the initial PU content in acetone was at least 60 wt %, and phase-inversion temperature was lower than 30 C. However, when increasing the PU content to 75 wt %, stable dispersions were obtained using DMPA concentrations three times lower. Finally, viscosity curves during the water addition step as well as a phase diagram were determined to understand the particle formation mechanism.

Autonomic healable waterborne organic-inorganic polyurethane hybrids based on aromatic disulfide moieties

“…Waterborne polyurethanes were synthesized according to the so called 'acetone process' [28][29][30]. This methodology consists of the synthesis of the polyurethane structure in a low boiling point solvent, usually acetone, incorporating hydrophilic groups into the polymer backbone in order to act as internal emulsifiers.…”

Monitoring of polyurethane dispersions after the synthesis

“…Nevertheless, the chemical changes can be monitored with FT-IR. [4][5][6][7][8][9][10][11][12][13][14]21,26,27 Table 3 consists of the formulation and properties of the PU prepolymer before being dispersed. There is no doubt that PUD colloidal features depend upon the PU prepolymer.…”

“…Using an acetone process, the PUDs for adhesives are synthesized. [8][9][10][11] The prepolymer process can be subdivided. Firstly, a polymerization of diols and diisocyanates is performed in an organic solvent.…”

“…Therefore, those data were obtained by means of FT-IR spectroscopy, which represents a powerful tool to monitor NCO groups in an aqueous environment. 4,5,9,10,20 A conversion of the NCO groups was obtained through integrated absorbance-peak areas: [21][22][23][24] A v dv bc a v dv bcA…”

Waterborne hybrid alkyd–acrylic dispersion: Optimization of the composition using mixture experimental designs

“…Varieties of approaches have been adopted in an effort to lower VOC levels. Among these approaches: alkyd emulsions [1], polyurethane [2] and acrylic dispersions [3] which are the most widely available and popular systems that fulfill the various end-user demands.…”