Submitted to: Polymer Preprints
Publication Type: Proceedings
Publication Acceptance Date: June 16, 2009
Publication Date: August 16, 2009
Citation: Jong, L. 2009. Effect of Phthalic Anhydride Modified Soy Protein on Viscoelastic Properties of Polymer Composites. Polymer Preprints. 50(2):15-16. Technical Abstract: Phthalic anhydride (PA) modified soy protein isolates (SPI), both hydrolyzed and un-hydrolyzed, are investigated as reinforcement fillers in styrene-butadiene (SB) composites. The modification of SPI by PA increases the number of carboxylic acid functional groups on the protein surface and therefore the amount of its anionic charges. The PA-modified SPI was mixed with the SB latex homogeneously in water and pH of the mixture was adjusted to 9 or 5.2 to form composites, after freeze-drying and compression molding. The measurement of temperature-dependent shear elastic moduli indicates the reinforcement effect of PA-modified SPI in the composites is significant and the composite moduli are less sensitive to the pH of the composites, compared to our previous studies on the unmodified SPI. However, the magnitude of shear elastic moduli of modified SPI composites over the temperature range studied is similar to that of unmodified SPI composites. For the strain recovery properties, the composites of PA-modified SPI showed slightly better recovery behaviour in the composites prepared at pH 9, while showed similar recovery behaviour in the composites prepared at pH 5.2. Compared to the effect of SPI hydrolysis, the effect of PA modification on SPI is smaller in terms of changing the viscoelastic properties of the composites.