Submitted to: Journal of Applied Polymer Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/17/2013
Publication Date: 3/8/2013
Citation: Wyatt, V.T., Yadav, M.P. 2013. A multivariant study of the absorption properties of poly(glutaric-acid-glycerol) films. Journal of Applied Polymer Science. 130(1):70-77.
Interpretive 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. In this study, we have shown that polymer films (bioplastics) made from glycerol can absorb various solvents and they can respond to external stimuli such as changes to pH, temperature, and polarity. 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.
Technical Abstract: The solvent absorption into the matrix of poly(glutaric acid-glycerol) films made with or without either iminodiacetic acid, sugarcane bagasse, pectin, corn fiber gum or microcrystalline cellulose have been evaluated. The films were incubated in various solvent systems for 24h. The amounts of solvent absorbed were monitored and recorded at predetermined time intervals. The polymer composite films that absorbed the largest amounts of water or dimethylsulfoxide (DMSO) were corn fiber gum and pectin, respectively. The corn fiber gum composite film absorbed 35.4(+/-8.8) percent water while the pectin composite film absorbed 264.5(+/-35.3) percent DMSO. Water absorption into the control film, made from 2:1 molar ratio of glutaric acid and glycerol, increased from 5.3(+/-0.3) to 33.4(+/-4.8) percent when incubated in pH 10 buffer solutions but decreased to 2.8(+/-2.6) percent in pH 4 buffer solutions and to 2.5(+/-1.3) percent in 20 percent sodium chloride solutions. Incubating the polymers in solvent at elevated temperatures did not increase the amount of solvent absorbed into the polymers but it did increase the rate of solvent absorption. It was determined that pKa and polarity and solvent can be used to predict solvent absorption into poly(glutaric acid-glycerol) films and that as much as 88.2 percent of DMSO can be extracted by these films from other solvents. Erosion of the polymer films in DMSO ranged from 1.9(+/-0.2) to 34.7(+/-3.4) percent. In water, erosion ranged from 6.3(+/-3.2) to 32.7(+/-3.2) percent. The polymeric materials were able to resorb 227.1(+/-9.3) to 740.6(+/-34.5) percent and 6.7(+/-1.0) to 51.3(+/-4.1) percent of DMSO and water, respectively, equating to up to 3.3- and 2.3- fold increases when compared to original amounts of absorbed solvent.