Submitted to: Journal of Applied Polymer Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 17, 1996
Publication Date: N/A
Interpretive Summary: Polyurethane foams are used for a variety of industrial and commercial applications. Such foams are flexible to rigid, water repellent, and essentially non-biodegradable. The blending of polymers has been an effective method of enhancing product properties and performance. In this study a new composite containing starch (a natural polymer), vegetable oil, ,and water was explored as an additive in polyurethane foams in order to increase the foam's biodegradability and broaden the range of water permeability and rigidity. Microscopy and spectroscopy were used to evaluate the cell structure and homogeneity of formulations and to identify reaction products. This work has established that starch/vegetable oil composites can be incorporated into polyurethane foams to introduce desirable properties, and that microscopy and spectroscopy are useful analytical techniques for optimizing formulations.
Technical Abstract: A new jet-cooked starch-oil composite has been blended with a polyester polyol and then reacted with isocyanate to give a polyurethane foam. Infrared spectroscopy and microscopy have been used to examine the resultant products. Infrared spectra have shown the products contain the urethane structures and light and electron microscopy have shown the differences in the cell wall structures and networks of the foams when compared to the control foams. Inclusion of the starch-oil composite in the formulation resulted in increased viscosity of the reaction mixture as well as a more irregular cellular structure and a rougher texture of the cured foam. Larger cells were more abundant and there was more evidence of tearing during expansion. The scanning electron photomicrographs show the open-cell structure of both the control and blended foams and their reticular network, which is more uniform in the control. This examination provides insight into the foaming process and provides information to make the necessary adjustments for acquiring the desired polymeric product. Incorporation of the starch-oil composite in polyurethane foams provides a new dimension of possibilities for enhancing their physical, functional, and environmental properties.