{
    "protocol": "The UV-PUA oligomer was prepared with isophorone diisocyanate (IPDI), polyether polyol (NJ-210), dimethylol propionic acid (DMPA), hydroxyethyl methyl acrylate (HEMA) via in situ and anionic self-emulsifying method; and the UV-PUA system was composed of the oligomer, photoinitiator Darocur 1173 and monomers (BA-TPGDA). The effects of the ratio of the BA/TPGDA, Darocur 1173 and the curing time on the performance of the UV-PUA films were investigated.Polyether polyols (NJ-210) were mixed with dimethylpropionic acid (DMPA) and isophorone diisocyanate (IPDI) under controlled conditions. Additionally, hydroxyethyl methyl acrylate (HEMA) and butyl acrylate (BA) were incorporated into the mixture. The reaction was catalyzed with triethylamine (TEA) and monitored with the use of acetone and dibutylbis (lauroyloxy) tin (DBLT). The resulting blend was then further processed by adding N-methyl -2-pyrrolidone (NMP) and tripropyleneglycol diacrylate (TPGDA). The polymerization was initiated using Darocur 1173, allowing the formation of hydrophilic polymers with desired functional groups.A certain amounts of NJ-210 (10.802 g) and IPDI (8.325 g) were added into a four-necked flask equipped with a mechanical stirrer, thermometer and reflux condenser. Then, DBLT was added as catalyst and the mixture was heated to 60°C and kept at this temperature for 2 hours to prepare the –NCO terminated prepolymer. Next, the prepolymer was reacted with 1.221 g of DMPA dissolved in a small amount of NMP at 80-85°C for another 2 hours, resulting in the –NCO terminated prepolymer containing a carboxyl group. The reactant was cooled down to 60°C, then 4.875 g of HEMA was added and the mixture was reacted at 60°C for 5 hours. When the temperature cooled down to 40°C, TEA was added into the flask and reacted at 40°C for 30 minutes. The mixture was then dispersed into deionized water under vigorous stirring for 30 minutes.UV-PUA films were prepared by casting the newly synthesized oligomer, BA and TPGDA onto a poly (tetrafluoroethylene) drying at 65°C for 3 h. Water was used as a diluent in this system, requiring a flash-off step to evaporate the water before UV curing. Physical entanglement occurred due to the large molecular weight of the prepolymer during water removal. The samples were then irradiated with UV light from a lamp with a main wavelength of 365 nm, power of 1000 W, UV energy per second of 1000 J/s, and at a distance of 20 cm from the UV lamp. This activated Darocur 1173, producing radicals that broke the acrylate double bond of the monomers and oligomers, resulting in crosslinking and the formation of the UV-PUA film.The PU or PUA films were cut into the size of 30mm x 30mm and put into water, 5% NaOH and ethanol at 25°C after being weighted. 24 hours later, the film was taken out, rubbed dry by wiping off the surface water with a piece of filter paper, and then weighted again. The water absorption (or swelling degree) was calculated using the formula: omega = (W2 - W1) / W1 x 100%, where W1 is the mass of the film before being put into the solution and W2 is the mass of the film after.The UV-PUA films were cut into the size of 2 cm x 2 cm, then the sample was put into a solvent (acetone) for 48 hours, and dried for 72 hours at 30°C to give a constant weight. The gel content was calculated using the formula G = (W/W0) x 100%, where W0 is the mass of the film before being put into the toluene, and W is the mass of the film after being put into the toluene.Put the UV-curable emulsion (the water had been evaporated) under the UV lamp irradiating for a certain amount of time, then gently pressed the UV-curable film with finger. If there is no trace on the film, the time of the UV lamp irradiating was the surface drying time of UV-PUA films.FT-IR spectrum of the UV-PUA film was obtained between 4000 and 400 cm-1 with an FTIR spectrometer (AVATAR 360, Madison, Nicolet). A minimum of 32 scans was signal-averaged with a resolution of 2 cm-1 in the 4000-400 cm-1 ranges.The synthesis of hydrophilic polymers with functional groups involves using a UV-PUA oligomer. The specific steps are not detailed in the provided text excerpt.Prepare a series of UV-PUA films by fixing the content of Darocur 1173 at 3%, maintaining an NCO:OH ratio of 2.0, and using a constant weight of the PUA oligomer at 10.8 g while varying the ratio of BA/TPGDA (R).Prepare UV-PUA films by fixing the ratio of BA/TPGDA to 5/5, adding 4% of Darocur 1173, and using 10.8 g of PUA oligomer. Change the curing time to prepare a series of films."
}