V. Wyatt, G. Strahan, C-K. Liu, T. Jin
United States Department of Agriculture,
Keywords: glycerol, biodiesel, bioplastics, polymers, gels, films
Summary:Developing new outlets for glycerol would have a significant impact on the economics of biodiesel production if value-added products made from glycerol can be identified. Glycerol is the major co-product produced from the process used to make biodiesel. Before the introduction of biodiesel-derived glycerol, the glycerol market was already saturated with uses in the food industry and in many pharmaceutical, chemical, and personal care applications. Therefore, increased production of biodiesel created a need to find new uses for glycerol. For several years, our research team has studied the synthesis of gels and films made from glycerol and characterized their physical, thermal and mechanical properties using a variety of analytical tools. We have designed polymer gels with varying degrees of branching and we have shown that polymer films (bioplastics) made from glycerol can behave as “smart polymers” by absorbing various solvents in response to the size, shape and polarity of the solvent. The absorption properties of the films also respond to external stimuli such as changes to pH, temperature, and polarity. Alternatively, these polymer films can be used in a variety of applications. Preliminary studies have also shown that these polymer films can be used in antimicrobial food packaging technologies or as conductive polymers. These types of polymers are important to develop for use in areas such as soil conservation, water remediation, filters, and drug delivery. Production and marketing of such new high-value products would decrease cost of biodiesel production and provide new products to improve the environment and human health. However, challenges in their production and use still exist. Specifically, improving their mechanical properties (i.e. % elongation and tensile strength) and decreasing the underside tackiness to the side of the films that are not directly exposed to heat during production. This under-side tackiness is observed in a small percentage of film samples. Minimal assistance from industrial partners could overcome these small obstacles. Conversely, the adhesion properties of these polymers can also be optimized to form biobased tackifiers and adhesive tapes.