The use of waste plant protein obtained from underutilized and non-food-producing plants may be a promising strategy in the development of bioactive packaging. A series of blend films were prepared by casting from cottonseed protein (CP) and poly(vinyl alcohol) (PVA) and modified with different plasticizers. The morphology, structure, and crystallinity of each of the blend films were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction. CP and PVA were found to be compatible in the appropriate ratios, and the CP/PVA blend films were partially crystalline. We compared the effects that four plasticizers, i.e., glycerol, triethanolamine (TEA), ethylene glycol, and polyethylene glycol, had on the performance of the CP/PVA blend films. Plasticizers altered the degree of interaction between CP and PVA, which changed the secondary structure of the CP but had little effect on the crystallinity of CP/PVA blend films. Among the different plasticizers tested, TEA was the most efficient at improving the elongation at the break, tensile strength, and oxygen barrier properties of the CP/PVA blend films. Such CP/PVA blend films plasticized using TEA can, therefore, be considered emerging and promising plastics for potential applications in food packaging and flower planting applications.

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The efficient use of vegetable oil and animal oil resources has enormous economic and ecological value and has attracted tremendous interest in the field of bio-based synthetic polymers in the past years. Given that conventional oil and their derivative polymers are subject to unsatisfactory mechanical properties or short-term use, these materials are not suitable for practical applications. Herein, a series of novel C36 dimer fatty acid-based unsaturated polyester resins with covalent and noncovalent networks were prepared by C36 dimerized fatty acid-based unsaturated polyester and crosslinking agents (styrene, acrylic acid, methacrylic acid, etc.). Owing to crosslinking structure of the polymers, their stable covalent bonds and hydrogen bonds, the matrix exhibits outstanding mechanical properties, including increased stretch ability (52.6% of unsaturated polyester resin (UPR)-St/acrylic acid (AA), 57.3% of UPR-St/methylacrylic acid (MAA)), tensile strength (15.2 MPa of UPR-St/AA, 17.1 MPa of UPR-St/MAA), elasticity modulus (327.1 MPa of UPR-St/AA, 316.8 MPa of UPR-St/MAA), and flexural strength (14.8 MPa of UPR-St/AA, 33.4 MPa of UPR-St/MAA). Micromorphological investigations indicated that the fracture features of the resin changed from brittle to ductile. Additionally, the resin is shown to possess an impressive thermal stability, solvent resistance, and certain autonomous self-healing properties.

The surface of reactive nano-silica coated with a silage coupling agent containing the epoxy group (denoted as E-SiO 2 ) and dimer fatty acids (DFA) were allowed to participate in the in-situ polycondensation reaction of unsaturated polyester resin (UPR), thus obtaining E-SiO 2 /DFA/UPR hybrid material. Fourier transform infrared spectrometer, scanning electron microscope, and X-ray energy dispersive spectrometer were used to analyze the structure of the material, morphology of tensile section, and the element composition of the section. It was found that E-SiO 2 grafted onto the DFA/UPR backbone by chemical bonds, and the material exhibited ductile fracture with Si element on the fracture surface. Thermogravimetric analysis, differential scanning calorimetry, stress-strain test, tensile test, bending test, hardness test, and water resistance test, the influence of the content of E-SiO 2 on the thermal stability, mechanical properties, and water resistance of the materials was studied. The resultsshow that E-SiO 2 has a good reinforcing and toughening effect for the in-situ polymerized E-SiO 2 /DFA/UPR composite due to the chemical reaction between the epoxy group of E-SiO 2 and the hydroxyl group (carboxyl group) of DFA/UPR. A heterogeneous network structure was formed in the cured E-SiO 2 /DFA/UPR composites. The mechanical properties and thermal properties of E-SiO 2 nanocomposites were improved. When 0.8 wt% E-SiO 2 was added, the tensile strength, Young's modulus, flexural strength, flexural stress, elongation at break, and Shore A hardness