**5.2. Synthesis of PUD based on glycolyzed products with molar ratio PET/glycol, 1:2**

Anionic PUD based on glycolyzed products with molar ratio PET/glycol, 1:2, were prepared by modified acetone process. Acetone was added to the prepolymer and the dispersion is formed by the addition of water to this solution. Procedure for synthesis of anionic PUD has been developed adjusting the molar ratio of DMPA as a hydrophilic monomer to IPDI as 1:3.3. Mass of oligoester polyol, obtained by PET glycolysis, according to example 1, with a hydroxyl number which is equivalent to the hydroxyl number of 0.06 mol of poly(propylene glycol) PPG1000 (110 mg KOH/g), was for PG 15 g, TEG 20 g, poly (ethylene glycol) (PEG 400) 25 g.

The oligoester polyol and hydrophilic monomer (8 g, equ. 0.06 mol) was mixed in the cosolvent DMF (50:50 w/w), in a 250-ml round four-neck glass reactor connected to a stirrer, a thermometer, a reflux condenser and a nitrogen gas inlet. The reaction was carried out at 70 oC for 30 min to obtain a homogeneous mixture and the uniform distribution of hydrophilic monomer to PU backbone. IPDI (44.4 g, equ.0.2 mol) and catalyst DBTDL (0.03% of the total solid) were added to the homogenized mixture at 80 oC for about 4h until the amount of residual NCO groups reached a theoretical value, as determined by the dibutyl amine backtitration method. To reduce the viscosity and obtain a homogenous mixture of NCO prepolymers, acetone was added 50 wt% to the solid reaction mass. The theoretical value of NCO groups for PUD based on oligoester polyol obtained from the glycolysis with molar ratio of PET repeating unit to glycol, 1:2, was 19.2% for PG, 17.7%, for TEG and 16.1% for PEG.

After obtaining completely NCO terminated prepolymer, the mixture was cooled to 60 oC and the carboxylic groups in hydrophilic monomer were neutralized with TEA (DMPA equ). TEA was dissolved in NMP by stirring the solution for 60 min.

PU anionomer was cooled to 30 oC then dispersed in water (50% of total mass) under high speed stirring for 30 min. The rate of water addition to the mixture was carefully controlled, to obtain a stable inversion. Upon completing the phase inversion, EDA (0.03 mol) was added for 60 min. at 35 oC. PUD of about 30 wt% solids was obtained upon removal of acetone by rotary vacuum evaporation at 35 oC.

Thermal Analysis of Polyurethane Dispersions Based on Different Polyols 93

**Figure 4.** TG curves (a) and DTG curves (b) of PUD synthesized from glycolized oligoester PET/PG with molar ratio 1:2 (1) and 1:10 (2). TG curves (c) and DTG curves (d) of PUD synthesized from glycolized oligoester PET/TEG with molar ratio 1:2 (1) and 1:10 (2). TG curves (e) and DTG curves (f) of PUD synthesized from glycolized oligoester PET/poly(ethylene) glycol 400 with molar ratio 1:2 (1) and 1:10 (2).
