Submitted to: Biomacromolecules
Publication Type: Peer reviewed journal
Publication Acceptance Date: 6/1/2003
Publication Date: 1/1/2005
Citation: Imam, S.H., Cinelli, P., Gordon, S.H., Chiellini, E. 2005. Characterization of biodegradable composite films prepared from blends of polyvinyl alcohol, cornstarch and lignocellulosicc fiber. Biomacromolecules. Journal of Polymers and the Environment, vol.13:1. Interpretive Summary: Corn is a renewable commodity produced in surplus in the United States. The ligno-cellulosic fiber produced as a waste from processed fruits by the citrus industry represents an inexpensive and vast resource of structural polymers. Utilization of such materials is in our national interest such as in plastics blends. We found that cast films prepared from starch, fiber and polyvinyl alcohol for use as mulch film had good physical properties and allowed water to permeate without destroying the film's integrity. Films degraded naturally in soil/compost in few months.This approach is expected to reduce the amount of petrochemicals conventionally used in plastic manufacturing of mulch films, but also add value to agricultural waste materials. Furthermore, use of natural polymers into plastic is perceived as environmentally beneficial since these materials are harmless and naturally biodegradable.
Technical Abstract: Several composite blends of poly(vinyl alcohol) (PVA) and lignocellulosic fibers were prepared and characterized. Cohesive and flexible cast films were obtained by blending lignocellulosic fibers derived from orange waste and PVA with or without cornstarch. Films were evaluated for their thermal stability, water permeability and biodegradation properties. The thermogravimetric analysis (TGA) indicated the suitability of formulations for melt processing, and for application as mulch films in fields at much higher temperatures. Composite films were permeable to water but, at the same time, able to maintain consistency and composition upon drying. Chemical crosslinking of starch, fiber and PVA, all hydroxyl functionalized polymers, by hexamethoxymethylmalamine (HMMM) improved water resistance in films. Films generally biodegraded within 30 days in soil, achieving between 50-80% mineralization. Both starch and lignocellulosic fiber degraded much more rapidly than PVA. Interestingly, addition of fiber to formulations enhanced the PVA degradation.