The use of ATR-FTIR to determine the effects of functional groups on interfacial crosslinking of reactive nanoparticles

The film formation and crosslinking of complementary reactive nanoparticle blends of acetoacetoxy (or acetoacctamido) functional particles with isocyanate functional particles were investigated using attenuated total reflectance-Fourier transform infared (ATR-FTIR) spectroscopy. A series of copolymers of 2-ethylhexyl methacrylate (EHMA) with acetoacetoxy ethyl methacrylate (AA), 2-methyl-acrylic acid 2-methyl-2-(3-oxo-butyrylamino)-propyl ester (AM), and dimethyl meta-isopropenyl benzyl isocyanate (TMI) were prepared by emulsion polymerization techniques at room temperature. These blends were air-dried on ATR-FTIR germanium (Ge) discs while the FTIR spectra were taken during the film formation process. The interfacial crosslinking reaction between functional moieties during the film formation process was determined using the FTIR data. The reactivity of acetoacetamido group is higher than that of acetoacetoxy group and the rate constant for the crosslinking reaction between two reaction moieties of terpolymer samples is higher as compared to the blended systems.