Natural Protein‐Based Biocomposites with Superior Paramagnetism and Microwave Absorbing Properties by Incorporating Nanosized Fe2O3.

Soy protein is one kind of environment‐friendly nonbioactive plant protein with excellent properties. Paramagnetic γ‐Fe2O3 nanoparticles with a mean particle size of 7 nm are prepared by submerged circulative impinging stream reactor (SCISR). And a series of soy protein isolate (SPI)/Fe2O3 nanocomposites with excellent magnetic performance have been successfully prepared with glycerol as plasticizer and γ‐Fe2O3 as fillers. The results show that the strong hydrogen bonds are formed between polar amino acids of SPI and the fillers. The Fe2O3 nanoparticles exhibit homogeneous dispersion in the protein matrix. The resulting SPI/Fe2O3 nanocomposites exhibit good paramagnetism and good microwave absorbing properties at 2–18 GHz. In addition, the mechanical properties and thermal stability of soy protein materials are improved with the addition of Fe2O3 nanocomposites. The interactions between the fillers and matrix as well as between the fillers would influence the reinforcing effect of Fe2O3. These natural resources based on green functional materials would exhibit wide potential applications in electromagnetic interference shielding and packaging areas. [ABSTRACT FROM AUTHOR]