Study on the properties and interfacial structure between regenerated cellulose film and polyurethane/poly(methyl acrylate) IPN coating

Interpenetrating polymer networks (TPN) coating were synthesized from casto r oil-based polyurethane (PU), methyl acrylate (MA), and coated onto the su rface of regenerated cellulose (RC) film to obtain biodegradable water-resi stant films. The tensile strength (sigma(b)), water resistance (R), water v apor permeability (P) percent light transmittance (T) and biodegradation ra te of the coated films cured at 80 degrees C for 5 minutes changed with the content of methyl acrylate in the coating. The introduction of methyl acry late can enhance the water resistance, but reduce the biodegradation rate o f the films. The most excellent values such as sigma(b), 444 kg cm(-2) in w et state, R, 0.59, P, 3.2 x 10(-2) mg cm(-2) day(-1) were obtained at 30 wt % methyl acrylate in the coating. The interfacial bonding of the coated fil m was investigated with infrared spectroscopy (IR), ultraviolet spectroscop y (UV), transmission electron microscopy (TEM), electron probe microanalysi s (EPMA), and differential thermal analysis (DTA). The results showed that the coated films exist strong interfacial bonding caused by covalent and hy drogen bonds between the RC film and the coating. Furthermore, while there was formation of IPN in the coating, the PU prepolymer in the coating penet rated into the RC film and crosslinked with the cellulose formed another se mi-IPN.