Investigation into ramie whisker reinforced arylated soy protein composites

Whiskers were prepared from ramie fibers and were characterized using atomic force microscopy to evaluate their dimensions. SPI/whiskers composites (SW) were prepared by incorporating different weight contents (wt.%) of the whiskers into soy protein isolate (SPI). Thiodiglycol was used as a plasticizer for the preparation of SW composites. The SW composites were arylated with 2,2-diphenyl-2-hydroxyethanoic acid through the process of “dip-coating” and coded as SW-B. In this paper, the characterization of SW and SW-B composites, such as their morphologies, mechanical properties, thermal stability, optical transmittance, and water uptake, are discussed. The results indicated substantial improvement in the water resistance, thermal stability, and the modulus of the SW-B composites after arylation due to the formation of hydrophobic diphenylhydroxymethane (DPHM) microparticles on the surface. This work provides a novel method to increase the water resistance of protein based composites.