Effects of Cellulose Whiskers on Properties of Soy Protein Thermoplastics

Abstract

Environmentally-friendly SPI/cellulose whisker composites were successfully prepared using a colloidal suspension of cellulose whiskers, to reinforce soy protein isolate (SPI) plastics. The cellulose whiskers, having an average length of 1.2 microm and diameter of 90 nm, respectively, were prepared from cotton linter pulp by hydrolyzing with sulfuric acid aqueous solution. The effects of the whisker content on the morphology and properties of the glycerol-plasticized SPI composites were investigated by scanning electron microscopy, dynamic mechanical thermal analysis, differential scanning calorimetry, ultraviolet-visible spectroscopy, water-resistivity testing and tensile testing. The results indicated that, with the addition of 0 to 30 wt.-% of cellulose whiskers, strong interactions occurred both between the whiskers and between the filler and the SPI matrix, reinforcing the composites and preserving their biodegradability. Both the tensile strength and Young's modulus of the SPI/cellulose whisker composites increased from 5.8 to 8.1 MPa and from 44.7 to 133.2 MPa, respectively, at a relative humidity of 43%, following an increase of the whisker content from 0 to 30 wt.-%. Furthermore, the incorporation of the cellulose whiskers into the SPI matrix led to an improvement in the water resistance for the SPI-based composites.

Characterization of cassava starch films plasticized with glycerol and strengthened with nanocellulose from green coconut fibers

“…The concentration of coconut nanocellulose directly influenced the permeability to water vapor; as the concentration of these nanoparticles increased in nano-biocomposites, the permeability to water vapor decreased (R 2 = 0.98) ( Figure 2). Similar results to this study were found by Lu et al (2005), Wang et al (2006) and Cao et al (2008) for nano-biocomposites with starch, protein and starch matrixes, respectively, containing nanocellulose from cotton linter (Lu et al, 2006) and from hemp (Cao et al, 2008).…”

Desenvolvimento e avaliação da eficácia de filmes biodegradáveis de amido de mandioca com nanocelulose como reforço e com extrato de erva-mate como aditivo antioxidante

“…Portanto, as duas formulações resultam em filmes que podem ser empregados para diferentes aplicações, independente do aditivo incorporado, já que diferem em relação ao módulo, tensão e deformação. Ressalta-se ainda que as ótimas propriedades mecânicas apresentadas pelos filmes (A, B, CA e CB) estão relacionadas à presença dos nanocristais de celulose de coco, como relatado por outros autores que também incorporaram nanocristais de celulose de diferentes fontes em matrizes poliméricas biodegradáveis (WANG et al, 2006;CAO et al, 2008). SOUZA et al (2012) relatam valores bastante inferiores para a tensão (1,85 a 4,81MPa) de filmes de amido sem a presença de nanocristais de celulose.…”

Starch-based nanocomposites reinforced with flax cellulose nanocrystals

“…Both natural and synthetic polymers were explored as the matrixes. Natural polymers such as poly(β-hydroxyoctanoate) (PHO) [19], soy protein [20], silk fibroin [21] reinforced with cellulose whiskers were reported. Meanwhile, Poly-(styrene-co-butyl acrylate) (poly(S-co-BuA)) [22], poly(vinyl chloride) (PVC) [23], polypropylene [24], waterborne polyurethane [25], were also used as synthetic matrixes.…”