Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: November 8, 2009
Publication Date: November 11, 2009
Citation: Bajwa, S., Holt, G.A., Bajwa, D., Coffelt, T.A., Nakayama, F.S. 2009. Evaluation of cotton gin byproducts as a ligno-cellulosic filler in polymer composites [abstract]. International Workshop on Utilisation of Cotton Plant By-produce for Value Added Products, November 9-11, 2009, Nagpur, India. 2009 CDROM. Technical Abstract: The byproduct produced as a result of ginning has created disposal problems across the cottonbelt of the United States for several decades. Research has evaluated numerous potential applications for utilizing cotton gin byproducts (CGB) more commonly referred to by ginners as "gin waste" or "gin trash". Recently, value-added processing of the CGB has resulted in successful applications where the CGB are used as ingredients in a livestock supplement and a hydromulch. The latest research has focused on using the processed CGB in bio-fiber polymer composites. Bio-fiber composites (BFC) have been the focus of the automotive and building products industries for several years. Significant research has been done to improve the processing and performance characteristics of the BFC. Most of the initial research is conducted on a small scale in a laboratory environment. Conducting full scale commercial trials can be limited by resources and equipment availability. Several studies were, and are, in the process of being conducted to compare the physical and mechanical properties of bio-fiber polymer composites extruded on a laboratory extruder and a commercial extruder using comparable formulations. This report discusses results from two of those studies. The first compared CGB and guayule bagasse as fiber fillers in BFC and the other is a progress report on a study evaluating various mixtures comprised of virgin/recycled polymer, wood flour, and CGB in different ratios. The first study was conducted by manufacturing BFC with five fiber fillers, including cotton burr or carpels (CB), cotton burr mixed with 2% of second cut linters (BL), cotton burr mixed with 30% of guayule whole plant (GW), cotton burr mixed with 30% of guayule bagasse (GB), and oak as control (CL). All materials were ground to a size of 20-40 mesh. The formulation of the BFC was 50% ligno-cellulosic fiber filler, 40% high density polyethylene (HDPE), 6% lubricant, and 4% mineral filler. The treatments were replicated 5 times. The second study, currently underway, is evaluating four different formulations with various substitutions of wood flour, cotton burr fiber, and HDPE. The physical and mechanical properties being tested are water sorption, modulus of elasticity, modulus of rupture, compression strength, fastener withdrawal capacity, coefficient of linear thermal expansion (CLTE), and hardness. The laboratory test samples were extruded by manually mixing small batch sizes (2 lbs.) of material, whereas commercial test samples were prepared using mechanical mixer and a large batch size (170 lbs). Preliminary data indicates that differences between the lab and commercial samples may be attributed to factors such as moisture content of the raw materials, poor blending, lack of shear mixing, compression, screw design, and configuration of the extruder.