IngentaConnect Preparation and characterization of soy protein plastics plastici...

Authors: Niangui Wang; Lina Zhang¹

Source: Polymer International, Volume 54, Number 1, January 2005 , pp. 233-239(7)

Abstract:

Utilizing anionic waterborne polyurethane (WPU) as a plasticizer, for the first time, we prepared new soy protein isolate (SPI) plastics. The WPU was prepared by using the emulsion-extending-chain method, and mixed with soy protein in aqueous dispersion. The mixture was cast, cured, pickled and hot-pressed to form SPI plastics plasticized with WPU. The plastics sheets were characterized by infrared spectroscopy, scanning electron microscopy, ultraviolet spectrophotometry and wide-angle X-ray diffraction, and their properties were measured by using dynamic mechanical analysis, differential scanning calorimetry and tensile testing. The results revealed that SPI plastics plasticized with WPU possess good mechanical properties, such as a tensile strength ( sigma

_b) of 7–19 MPa, water resistance ( sigma

_b(wet)/

_b(dry) = 0.4–0.5), optical transmittance and thermal stability, because of the good miscibility and strong interaction between WPU and SPI. With an increase of WPU content from 20 to 50 wt%, the elongation at break ( epsiv

_b) value of the sheets increased from 50 up to 150 %, and is much higher than that of the pure SPI sheet. WPU as a plasticizer can play an important role in improving the properties of SPI plastics. Copyright © 2004 Society of Chemical Industry

Keywords: waterborne polyurethane; soy protein plastics; miscibility; plasticization behavior

Document Type: Research article

DOI: 10.1002/pi.1696

Affiliations: 1: Department of Chemistry, Wuhan University, Wuhan 430072, China

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Preparation and characterization of soy protein plastics plasticized with waterborne polyurethane