An eco-friendly urea-formaldehyde resin: preparation structure and properties

The preparation, structures and properties of UF resin prepared with concentrated formaldehyde at a low molar ratio F/U=1.1 were studied in this paper. According to the results obtained from 13C-NMR, FT-IR and DMA, UF resin prepared with concentrated formaldehyde showed better mechanical properties and heat resistance and lower formaldehyde emission responsible for its high degree of polycondensation and crosslinking than that of UF prepared with common formaldehyde, but its stability was so bad due to its high content of ether bridges. However, it was stated that adding hydrolyzed soy protein to this UF resin at the first alkali preparation stage of “alkali-acid-alkali”, its stability got improved due to the increase of methylene bridges, which was the key contribution to polycondensation.