Progress 01/01/08 to 12/31/12
Outputs
OUTPUTS: In this research, we conducted both lab-scale and commercial scale experiments manufacturing thermoplastic composites that contain 40% plastic and 50% plant fiber, by varying the amount of two types of fiber, wood (oak), and cotton burr and stem (CBS). These samples were tested for physical, chemical and mechanical properties. The samples were also subjected to accelerated aging, UV degradation and microbial degradation, and again tested for their physical, chemical and mechanical properties to understand their long-term performance. After concluding the study, we recommend that wood fiber and CBS could be used at a 1:1 ratio without significant degradation in the composite properties. 1. The feasibility of using cotton burr and stem (CBS) fibers as a filler in thermoplastic composites was demonstrated at laboratory scale as well as at commercial scale. The differences in properties associated with the amount of CBS observed at laboratory scale significantly diminished at commercial scale. 2. Many of the properties of the composite varied with different rates of CBS used in composites where the total amount of fiber filler was held constant at 50%. If strength properties and water absorption were important, up to 50% of wood fiber in the composite could be replaced with CBS without a significant difference. However, microbial degradation of the composites containing 50% or more of the fiber filler as CBS was significantly more compared to wood. 3. Long-term performance of the composites containing up to 50% of the fiber fraction as CBS exhibited similar properties to that of wood, under accelerated aging. 4. Addition of Guayule fiber or use of a compatabalizer or coupling agent improved both strength properties and reduced water absorption in composites containing CBS. 5. CBS was used to replace 50% of the wood fiber used in a few batches of commercial products such as deck board, paving stones and garden boxes, that went our to major distributors. 6. We have provided tour of the facility to representatives from Cotton Inc, USDA-ARS, and Legget & Platt, and explained the manufacturing process and the results from our research. Research results were presented at multiple conferences and published in journals. 7. Chemical composition of fibers from several agricultural waste streams were characterized. 8. Thermoplastic composites with natural fiber filler were evaluated for making prosthetic sockets to interface between residual limb and an artificial leg. However, the plastic did not join well, creating a problem with strength and integrity of socket that has a joint. 9. Plant fibers were also evaluated for a different type of composite containing only plant fibers and mycelium. We collaborated with Ecovative Design LLC in this study. The new composites were characterized by evaluating their various physical, chemical and mechanical properties. 10. This research resulted in several journal publications and conference presentations. 11. This research has brought industry, university and government together to solve a problem and generate a commercially viable and environmentally friendly product. PARTICIPANTS: Dilpreet Bajwa, Greenland Composite Inc, Greenland, AR Greg Holt, USDA-ARS, Lubbocki, TX Tom Weidegaertner, Cotton Inc, NC several undergraduate students TARGET AUDIENCES: Scientists, engineers, composite and agricultural industries PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
This research has a major impact in reducing agricultural waste that goes to landfills. Our research has opened up avenues for a major niche application of the cotton burr and stem fraction of cotton gin waste in composites. Thermoplastic composite industry will be able to use a significant fraction of the cotton gin waste and lock the carbon in the waste into a recyclable product for a long time. Also, farmers and ginners will be able to generate additional income for a waste stream they usually pay to dispose off. The research has generated both environmental and economical benefit. Our research at commercial scale in collaboration with Greenland Composites Inc demonstrated to the industry that CBS is a viable alternative to the expensive wood flour used in their commercial products. The company is willing to replace up to half of the wood flour used in their composites by CBS if a viable and quality supply of CBS can be identified. Currently, Cotton Inc, our funding agencies is exploring opportunities for setting up a cotton gin waste processing facility at a gin to meet this new opportunity. The price of wood fiber has increased tremendously in the past 5 years negatively impacting the composite industry. This research has identified a low cost input that the composite industry can use to improve their economics. The chemical composition of the agricultural fibers that were characterized in this research would be useful for many other studies and for analyzing the feasibility of these fiber in bioproducts applications. The bio-composite research has led to further collaborations and research with Ecovative Design LLC, evaluation of the material for a prosthetic socket, and also some community projects such as putting composite markers in trails and parks. Several undergraduate students gained research experience working in my lab, which led to their successful acceptance to graduate schools. One graduate project, and one undergraduate honors thesis resulted from bio-composite research. One student who worked in my lab as an undergraduate researcher received an NSF fellowship for graduate study.
Publications
- 1. Bajwa, D. S., S.G. Bajwa, G.H. Holt., R. Srinivasan, T. Coffelt, F. Nakayama, and R. Gesch. 2013. Recycling of ligno-cellulosic and polyethylene wastes from agricultural operations in thermoplastic composites. Waste and Biomass Valorization (Accepted) 2. Bajwa, S. G., D. S. Bajwa, and G. Holt. 2012. Commercial application of cotton burr/stem and module wrap in thermoplastic composites: Effect of scaling from laboratory to commercial. Journal of Thermoplastic Composites. DOI: 10.1177/0892705708091857 (online) 3. Bajwa, S.G., D. S. Bajwa, G. H. Holt, T. Coffelt, F. Nakayama. 2011. Properties of thermoplastic composites with Cotton and Guayule biomass residues as fiber filler. Industrial crops and products 33: 744-755. 4. Bajwa, S. G., D. S. Bajwa, G. H. Holt, and T. A. Coffelt. 2011. Performance of thermoplastic composites with cotton burr and stem (CBS) treated for water absorption. 2011 AAIC Annual Meeting: Challenges and Opportunities for Industrial Crops. 11-15 September 2011. Fargo, ND. 5. Bajwa, S. G., S. K. Kalidindi, D. S. Bajwa, and G. H. Holt. 2010. Long-term performance of thermoplastic composites with cotton burr and stem (CBS) as partial fillers . AAIC Annual Meeting- 2010 New Crops: Exploring Diversity, Preserving our Future. Fort Collins, CO.18-22 Sep. 2010. 6. Bajwa, S. G., D. S. Bajwa, and G. A. Holt. Application of Cotton Burr/Stem in Thermoplastic Composites. In. Arkansas Cotton Research Summaries - 2010, D. M. Oosterhuis (ed.), Research Series, Arkansas Agricultural Experiment Station, Fayetteville, AR. 7. Bajwa, D. S., S. G. Bajwa, and G. H. Holt. 2010. Laboratory to commercial scale - correlation in the physical properties of biofiber-polymer composites -. In. Proc. 11th International Conference on Biocomposites: Transition to Green Materials, 2-4 May 2010, Toronto, Canada. 8. Bajwa, S. G., D. S. Bajwa, and G. H. Holt. 2009. Evaluation of cotton gin byproducts as a lingo-cellulosic filler in polymer composites. International workshop on Cotton, 9-11Nov 2009, Central Institute for Research on Cotton Technology, Nagpur, India. 9. Bajwa, S. G., D. S. Bajwa, and G. Holt. 2009. Optimal substitution of cotton burr and linters in thermoplastic composites. Forest Product Journal 59(10): 40-46. 10. Bajwa, S. G., G. Holt, D. S. Bajwa, T. Coffelt, and F. Nakayama. 2008. Evaluation of two agricultural residues as ligno-cellulosic fillers in polymer composites. AAIC 20th Annual Meeting. 7-11 September 2008. College Station, Texas. 11. Bajwa, S. G., D. S. Bajwa, and G. Holt. 2008. A novel filler for natural fiber polymer composites from cotton gin waste. Tenth International Conference on Progress in Biofibre Plastic Composites. 12-13 May 2008. Toronto, Canada.
|
Progress 01/01/11 to 12/31/11
Outputs
OUTPUTS: Thermoplastic composite samples containing cotton burr & stem (CBS)manufactured with different treatments for reducing water absorption were tested for their long term performance. The long-term performance was tested with ASTM D 1037 6-cycle modified accelerated aging test as well as the microbial degradation test. Cotton burr and stem fibers were also tested as fillers in paving stones, a landscaping product made of thermoplastic composite. The samples were tested for physical and mechanical properties including specific gravity, water absorption and coefficient of linear thermal expansion. A third value added product that was manufactures and tested as a potential application for cotton ginning byproduct is manufactured fire logs. Fire logs were manufactured with 50% wax and 50% fiber. There were 3 combination of fibers, wood fiber, wood and CBS at 1:1 and CBS alone. Sample logs were manufactured and subjected to a preliminary burn test. PARTICIPANTS: Dr. Dilpreet Bajwa, Greenland Composites, Greenland, ARkansas Dr. Greg Hold, USDA-ARS, Lubbock, TX Funded by Cotton Inc TARGET AUDIENCES: Cotton Stakeholders Building industry Scientists and researchers PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Accelerated aging test showed similar performance for all treatments. All treatments showed an increase in hardness and nail holding capacity after 5 cycles of accelerated aging. Similarly, a 9-month biodegradation test showed that samples with up to 12.5% by weight of CBS showed biodegradation similar to that of control. As the amount of CBS increased to 25% or above, the weight loss or microbial degradation was significantly higher. In general the study showed that composite containing CBS will have perfomrance trend as those made with wood as the filler. The paving stone samples with 35.5% of CBS had significantly higher water absorption than those samples with 0 or 17.7% CBS. However, there was no difference in the CLTE. A commercial batch of raised garden boxes were manufactured and shipped for commercial trial of CBS in landscaping products. A burn test of the manufactured firelogs showed no difference in burn time or burn temperature when tested in the lab. However, a limiated commercial trial indicated that the wood-based samples burned for slightly longer time (~20 min) compared to the CBS containing logs of same weight.
Publications
- Bajwa, S.G., D. S. Bajwa, G. H. Holt, T. Coffelt, F. Nakayama. 2011. Properties of thermoplastic composites with Cotton and Guayule biomass residues as fiber filler. Industrial crops and products 33: 744-755.
- Bajwa, S. G., D. S. Bajwa, G. H. Holt, and T. A. Coffelt. 2011. Performance of thermoplastic composites with cotton burr and stem (CBS) treated for water absorption. 2011 AAIC Annual Meeting: Challenges and Opportunities for Industrial Crops. 11-15 September 2011. Fargo, ND.
|
Progress 01/01/10 to 12/31/10
Outputs
OUTPUTS: Previous research has shown that thermoplastic composites made with different combinations of cotton burr and stem (CBS) and wood fiber showed comparable performance with up to 50% of oak substituted with CBS, except for water absorption. As the next step in evaluating these composites, their long-term performance was evaluated using the modified 6-cycle accelerated aging test as well as a soil burial test for microbial degradation. The accelerated aging test showed that composites with up to 50% of fiber filler as CBS showed similar properties under 6 cycles of accelerated aging, except for thickness swelling. Thickness swelling of 50% CBS samples were significantly higher than that of wood-based composites. The microbial degradation test showed that composites with 50 and 75% of fiber filler as CBS had significantly higher microbial degradation than that of wood-based or 25% CBS samples. Two experiments were also conducted to evaluate (1) guayule as an additive to reduce water absorption and microbial degradation, and (2) chemical treatments such as compatabalizer and coupling agents for reducing water absorption. A commercial scale experiment was conducted with control, 50% CBS, 16.6% guayule& 33.4% CBS, and 33.4% guayule and 33.4% CBS as the fiber treatments. These samples were conditioned and will be tested in 2011. Also, a lab scale experiment was conducted to evaluate chemical treatments of compatabilizer and coupling agent, both as additives at 0.5% and 1% by weight. These samples will be tested in 2011. PARTICIPANTS: Dilpreet S. Bajwa, Research Manager, Greenland Composites, Greenland, Arkansas Greg H. Holt, USDA-ARS, Lubbock, Texas TARGET AUDIENCES: Thermoplastic composite industries, agricultural processing plants, farmers, commodity boards, scientists, researchers and other stakeholders. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Thermoplastic composites containing CBS by up to 50% of the fiber fraction showed similar long-term performance as the control (with wood filler) in all properties tested except for thickness swelling. Therefore, an appropriately chosen fiber treatment to make the CBS more water-phobic will ensure that composite using CBS fillers will be comparable to that of the commercially available wood-based composites. Such a fiber treatment is expected to reduce water absorption, thickness swelling and hence, microbial degradation of the composite material.
Publications
- Bajwa, S. G., S. K. Kalidindi, D. S. Bajwa, and G. H. Holt. 2010. Long-term performance of thermoplastic composites with cotton burr and stem (CBS) as partial fillers . AAIC Annual Meeting- 2010 New Crops: Exploring Diversity, Preserving our Future. Fort Collins, CO.18-22 Sep. 2010.
- Bajwa, S.G., D. S. Bajwa, G. H. Holt, T. Coffelt, F. Nakayama. 2011. Properties of thermoplastic composites with Cotton and Guayule biomass residues as fiber filler. Industrial crops and products - accepted.
- Bajwa, S. G., D. S. Bajwa, and G. A. Holt. Application of Cotton Burr/Stem in Thermoplastic Composites. In. Arkansas Cotton Research Summaries - 2010, D. M. Oosterhuis (ed.), Research Series, Arkansas Agricultural Experiment Station, Fayetteville, AR.
- Bajwa, D. S., S. G. Bajwa, and G. H. Holt. 2010. Laboratory to commercial scale - correlation in the physical properties of biofiber-polymer composites -. In. Proc. 11th International Conference on Biocomposites: Transition to Green Materials, 2-4 May 2010, Toronto, Canada.
|
Progress 01/01/09 to 12/31/09
Outputs
OUTPUTS: Chemical characterization of cotton burr and stems (CBS) and motes: The CBS and motes were analyzed using ASTM methods for characterizing the concentrations of ash, alcohol benzene extractives, lignin, holocellulose and alpha-cellulose. Results from the chemical analysis indicated that CBS contained 9.8% ash, 5.2% extractives(alcohol benzene extraction), 15.8% lignin, 57% holocellulose and 28.2% alpha-cellulose, all percentage of dry material weight. The motes contained 2.1% ash, 3.0% extractives, 10.5% lignin, 82.5% holo-cellulose and 67% alpha-cellulose, all percentage of dry material weight. Evaluation of suitability of CBS in LCC: Two experiments were conducted at commercial scale with CBS as a replacement for wood. Wood was replaced by CBS at 0, 25, 50 and 75% by weight of the total fiber filler. The two experiments used two different die profiles of 2"X6" and 1"X6". In the first trial, the two materials were dried under similar setting, the moisture content in CBS remained at 3.5% and wood at ≤ 1%. In the second trial, both materials were dried to <1% moisture content. Comparison of mean strength properties of samples with different CBS substitution indicated that the strength and modulus all CBS treatments were similar to control. The water absorption of all CBS formulations in experiment 2 were higher while the specific gravity was lower than the control treatment. A 10-day water absorption test showed that the 50% CBS had the highest water absorption rate while control exhibited the lowest. The CLTE of all treatments in trial 1 was comparable to control, while the CLTE of samples with up to 50% CBS substitution in trial 2 was similar to control. Objective 3. Evaluation of suitability of cotton module wrap (CMW) in thermoplastic composites: An experiment was conducted by replacing HDPE with module wrap at 3 different rates of 25%, 50% and 75%, and the properties of these samples were compared against standard deck boards manufactured by a local industry, which contained 72% recycles LLDPE and 28% HDPE. The samples containing 25 and 50% CMW exhibited high strength and stiffness under flexure compared to the 75% CMW and GC samples. The screw withdrawal capacity was similar for all treatments. Specific gravity of the three CMW treatments was comparable to each other, but significantly lower than the industry samples. Although the 24-hr water absorption and thickness swelling of all four treatments were similar, a 10-day water absorption showed that the 50% CMW samples had the lowest water absorption rate and the 25% CMW treatment had the highest water absorption rate. The CLTE of the 25 and 50% CMW samples were significantly lower than the 75% CMW treatment. However, all CMW treatments showed similar CLTE as the industry samples. Overall, the samples containing 50% of CMW performed very well regarding strength and specific gravity. The high melt flow index of the module wrap may have helped in an even and complete coating of the fiber particles with the polyethylene substrate, especially at 50% substitution. PARTICIPANTS: Tim Wedegaertner, Cotton Incorporated, NC Greg Holt, USDA-ARS, Lubbock, TX Dilpreet Bajwa, Greenland Composites, Greenland, AR TARGET AUDIENCES: Scientists working on alternatate uses of agricultural waste streams, engineers working in biofiber composite area, composite industries, ginners, and consultants. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
The chemical analysis of CBS and motes indicated that holocellulose and alphacellulose content was slightly lower in CBS compared to wood fibers (ex, white oak) while motes had very high concentration of these material. Therefore, motes should be highly suitable as a fiber filler. However, the difficulty to separate and mix it homogeneously in a composite matrix makes it difficult to use motes. On the other hand, CBS can be used in partial substituion for wood fiber in composites. Commercial scale experiments have showed that CBS can be used to substitute up to 50% of wood fiber in thermoplastic composites without any deterioration in mechanical properties. The CBS also decreased the specific gravity of composites below unity, which an advantage. The oly disadvantage of CBS was the slightly high water absorption, which may be caused by a combination of high lignin and hemicellulose content and smaller particles with high bulk density. The CBS would be a good alternative for wood to counter the shortage of wood fiber faced by the market at present. Many industries use a combination of HDPE and LLDE as a substrate in wood plastic composites (WPC). Our research showed that one can achieve the best combination of physical and mechanical properties for the composite if the HDPE and CMW, an LLDPE, are used at a 1:1 ratio. Also, CMW substitution at comparable levels resulted in mechanical and physical properties that are comparable to commercially available WPC.
Publications
- Bajwa, S. G., D. S. Bajwa, and G. H. Holt. 2009. Evaluation of cotton gin byproducts as a lingo-cellulosic filler in polymer composites. International workshop on Cotton, 9-11Nov 2009, Central Institute for Research on Cotton Technology, Nagpur, India.
|
Progress 01/01/08 to 12/31/08
Outputs
OUTPUTS: This project was conducted with the goal of developing alternate uses or value added products such as ligno-cellulosic fiber reinforced thermo lastic composites from agricultural residues. The specific objectives of the project were to characterize the agricultural fiber properties relevant for composite application, and to test the suitability of various agricultural fibers as reinformcement in composites. Two set of experiment were conducted to achieve the above objectives. The first experiement included 5 sources of fibers such as oak (control), cotton burr, cotton burr with 2% second cut linters, 70% cotton burr mixed with 30% guayule whole plant, and 70% cotton burr mixed with 30% guayule bagasse. The second experiment had 9 fiber treatments, which included control (100% oak), and 25, 50 and 75% of the oak fiber fraction replaced with cotton burr and cotton burr with 2% second linters. In both experiments, thermoplastic composite samples were manufactured and tested for physical and mechanical properties. These fibers were also tested for their holocellulose, alpha cellose, lignin, extractives, and ash contents. PARTICIPANTS: Greg Holt, USDA-ARS, Lubbock, TX TARGET AUDIENCES: Scientists, ginners, composite industries and other industries involved in the manufacture of cotton byproducts PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
The chemical composition of the fibers showed that all fibers except linters had relatively lower concentrations of holocellulose and alpha cellulose and higher amount of lignin. The ash content was very high in cotton burr. cotton burrs and linters indicate relatively high amount of lignin and lower quantities of alpha and holocellulose. The agricultural fibers generally had higher water absorption and lower bulk density than wood (oak) flour. Composite made from oak flour (control) was superior to the other 4 fibers tested. However, composite made from cotton burr and cotton burr mixed with guayule bagasse has strength properties very close to the control. In general, water absorption of all four fibers were inferior to control. The composite samples made from various amounts of CB and CBL indicated that the wood fibers can be substituted by up to 50% of CBL and 75% of CB without significant degradation in physical and mechanical properties. A grant from Cotton Inc., access to the fibers of specific quality from the USDA-ARS collaborator, and resource support (extruder access) from Greenland Composites were the critical component that made this project a success.
Publications
- Bajwa, S. G., G. Holt, D. S. Bajwa, T. Coffelt, and F. Nakayama. 2008. Evaluation of two agricultural residues as ligno-cellulosic fillers in polymer composites. AAIC 20th Annual Meeting. 7-11 September 2008. College Station, Texas.
- Bajwa, S. G., D. S. Bajwa, and G. Holt. 2008. A novel filler for natural fiber polymer composites from cotton gin waste. Tenth International Conference on Progress in Biofibre Plastic Composites. 12-13 May 2008. Toronto, Canada.
- Bajwa, S. G., D. S. Bajwa, and G. Holt. 2008. Optimal substitution of cotton burr and linters in thermoplastic composites. Forest Product Journal (In Review, submitted on 09/29/08).
|
|