IR spectra studies of core-shell type waterborne polyacrylate-polyurethane microemulsions

✍ Scribed by Anjie Dong; Tong Wan; Shiyou Feng; Duoxian Sun

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 182 KB
• Volume: 37
• Category: Article
• ISSN: 0887-6266
• DOI: 10.1002/(sici)1099-0488(19990915)37:18<2642::aid-polb8>3.0.co;2-d

✦ Synopsis

The hydrogen bonds in films of the polyurethane and the core-shell type polyacrylate-polyurethane microemulsions have been studied by FTIR spectroscopy in the regions of ONH absorption and CAO absorption. The effects on hydrogen bonds of the composition, the core-shell ratio were revealed. At the same time, the relationship between the hydrogen bonds and the crosslinked structures (Type A and Type B) was discovered. The shifts of the ONH and CAO stretching bands to higher frequencies and the shift of ONH bending bands to lower frequencies, with the increase of acetone CAO number in the core, mean that the hydrogen bonds between the soft and hard segments, and those in the short-range order in the hard segment phase, are broken. The dipole/dipole interaction which is supposed to exist between the acetone CAO groups in the core and the urethane CAO in the shell can change the hydrogen bond distribution in the shell, and at the same time, lead to hydrogen bonds between acetone CAO in the core and the urethane ONH in the shell. Type A and B crosslinked structure between the core and the shell located at the interface of the core and the shell can confine the acetone CAO within the crosslinking network, and Type B crosslinked structure also decreases the acetone CAO numbers. These weaken the dipole/dipole interaction between the acetone CAO and the urethane CAO, and lead to the decrease of the effect of the acetone CAO groups on the hydrogen bond distribution in the shell.