Semi-Interpenetrating Polymer Networks from Castor Oil-Based Polyurethane and Nitrokonjac Glucomannan

摘要

New semi-interpenetrating polymer networks (semi-IPNs) coded as PUNK were successfully synthesized from castor oil-based polyurethane (PU) prepolymer and 10-40 wt % nitrokonjac glucomannan (NKGM) containing a degree of substitution of 2.4 and a weight-average molecular weight of 4.75 X 10~4. The semi-IPN sheets that were 100 #mu#m thick were cured more speedily than PU, with curing times of 5 h for PUNK and 16 h for PU at 50-70°C. The structure and miscibility of the semi-IPN sheets were studied by Fourier transform infrared spectroscopy, ultraviolet spectros- copy, and scanning electron microscopy. The results showed that a strong intermolec- ular interaction caused by hydrogen bonding between NKGM and PU exists in PUNK, resulting in good miscibility. When the NKGM content of the semi-IPNs sheets was 20 wt %, the tensile strength and light transmittance were obviously higher than that of the PU sheets. The NKGM in the semi-IPN sheets plays an important role not only in accelerating the cure but also in improving the mechanical properties and biodegrad- ability. As a new material prepared from renewable resources, PUNK has potential applications because ofits biodegradability.