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Waste biomass can be used as a raw material for food packaging. Different concentrations of gelatin (GEL) were introduced into the leftover rice (LR) system to form an interpenetrating polymer network (IPN) for improving the properties of the films. The structure and morphology of films were evaluated by Fourier transform infrared, scanning electron microscopy, and atomic force microscopy, which showed good compatibility between LR and GEL. The moisture content and oil absorption rate of IPN films were down by 105% and 182%, respectively, which showed better water and oil resistance than the LR film. In addition, increasing GEL concentration led to enhancement in the tensile strength of films from 2.42 to 11.40 MPa. The water contact angle value of the IPN films (117.53°) increased by 147% than the LR film (47.56°). The low haze of IPN films was obtained with the increment of the mutual entanglement of LR and GEL. The 30–50% GEL addition improved the water vapor barrier and thermal stability properties of the IPN films. This study highlights that LR as waste biomass can have a practical application in food packaging.

A novel hydrogel slow-release nitrogen fertilizer based on sawdust with water absorbency was prepared using grafting copolymerization. Urea was incorporated as nitrogen source in a hydrogel fertilizer. Potassium persulfate (KPS) and N,N᾽-methylenebis acrylamide (MBA) were used as the initiator and cross-linker, respectively. The structure and properties of the samples were characterized by XPS, EDS, SEM, XRD and FTIR. The effects of various salt solutions, ionic strength and pH on swelling behavior were discussed. The results showed that the largest water absorbency of the sample reached 210 g/g in distilled water. In addition, the sample had the good nitrogen release property. Thus, the novel environmentally friendly hydrogel fertilizer may be widely applied to agricultural and horticultural fields.

A novel controlled release fertilizer was developed using interpenetrating polymer network (IPN) as the coating material. The IPN was successfully sprayed on the surface of the urea particles to form IPN-coated fertilizers (IPNCU) for controlled nitrogen release. The IPN was synthesized by bio-based polyamide (PA) from D-glucaric acid and epoxy (EP) through network interpenetrating. The chemical structure and microscopic morphology characteristics of IPN were examined by Fourier transform infrared spectroscopy, 1Hnuclear magnetic resonance, and scanning electron microscopy. The property of IPN with the different PA/EP mass ratios were investigated and compared with that of EP-coated fertilizers (EPCU). The nutrient release behaviors of IPNCU in water and soil were detected. The results showed that the IPNCU with 5% PA content increased the nitrogen release longevity by 41 days, raised the water contact angle of surface by 23.9°, and then significantly slowed the nitrogen release rate of the IPNCU. The nutrient release mechanism of IPNCU was discussed in detail. This work indicated that the environment-friendly IPN with superior controlled release properties could be especially useful in horticultural and agricultural applications. [ABSTRACT FROM AUTHOR]