“GREEN” COMPOSITES BASED ON RECYCLED PAPER PRODUCTS AND BIODEGRADABLE RESINS

“GREEN” COMPOSITES BASED ON RECYCLED PAPER PRODUCTS AND BIODEGRADABLE RESINS A Thesis Presented to the Faculty of the College of Human Ecology of Cornell University in Partial Fulfillment of the Requirements of the Undergraduate Honors Program By Alexandra J Sonis May 2009 i © 2009 Alexandra J Sonis ii ABSTRACT “Green” composites were produced using recycled paper products first with Soy Protein Isolate (SPI)-based resin followed by starch-based resin SPI, starch and paper are all sustainable, plant-based and yearly renewable materials In addition, these composites offer the use of recycled paper to produce high value-added products These composites can be engineered with desired properties to replace currently available petroleum-based composites for a variety of applications, including packaging, furniture, car parts, etc The benefits of using these ‘green’ composites, as opposed to petroleum-based composites, include a) elimination of pollution during production of composites, b) capability of composting without harming the environment at the end of their life, c) the elimination of harsh chemicals that can be dangerous for workers as well as the users of the product and d) the sequestration of carbon dioxide In this thesis, fully biodegradable composites based on a variety of papers and biodegradable resins were prepared and characterized The resin also contained plasticizers to control their mechanical properties First, fully biodegradable SPI-based resin was prepared using glycerol as a plasticizer as well as Phytagel ® to enhance the mechanical properties Additionally, fully biodegradable starch-based resins were prepared using modified starch with sorbitol as a plasticizer additive in various forms to enhance the mechanical properties A total of six different starch-based resins were prepared, along with a total of three additives These resins showed excellent mechanical properties, with the greatest strength being provided by the pre-gelatinized maize starch with glycol stearate (MGS) with the addition of 30% by weight Carboxyl Methyl Gum (CMG) additive and 5% by weight sorbitol plasticizer These resins were then iii impregnated into recycled paper products and hot pressed into composite sheets The recycled paper composites with the best mechanical properties were various paper towels (Georgia-Pacific Acclaim® and en-Motion® paper towels) and Cornell Daily Sun newspaper This thesis discusses the mechanical properties of the resins and the composites iv BIOGRAPHICAL SKETCH Alexandra Judith Sonis was born in Albany, New York on January th, 1987 She was raised in Bala Cynwyd, Pennsylvania and graduated from Lower Merion High School in June of 2005 In August of 2005, she began her Bachelor of Science degree at Cornell University as a Fiber Science major in the Textiles and Apparel department (now referred to as Fiber Science and Apparel Design) in the College of Human Ecology She began working on “Green” Composites with Professor Anil N Netravali in January of 2007 In May of 2009, she received her Bachelor of Science degree from the Fiber Science program v For my parents, William Sonis and Jo Ann Sonis, for all of their love and support and for always encouraging me to reach my potential vi ACKNOWLEDGEMENTS First and foremost, I am extremely grateful to Professor Anil N Netravali for his support and guidance, not only on this thesis but also throughout my academic experience This thesis would not have been possible without his lessons and advice I am also grateful to the Fiber Science and Apparel Design faculty for all of their help and making my academic experience at Cornell so memorable I would like to thank the Human Ecology Alumni Association and the Human Ecology Research Association for their financial assistance towards my research projects I am also thankful to the members of Professor Netravali’s research group for their advice, generosity and their company when working in the lab I am very thankful for having wonderful friends who supported me over the past four years and made my time at Cornell unforgettable Thank you especially to Jenny for accompanying me during late nights in the lab, to Jordana for always checking in on my progress, and to Elyse, Laura and Molly for welcoming me home after long hours of work Finally, I cannot express enough gratitude towards my family for everything they have done for me Thank you to my parents, to whom this thesis is dedicated, to my brother, Lee, for his valuable opinions, and to my fiancé, Andrew, for his willingness to help whenever he could and for always being there to support me vii TABLE OF CONTENTS CHAPTER 1: INTRODUCTION 1.1 Composites 1.2 The Limitations of Petroleum-based Composites 1.3 1.2.1 Petroleum Scarcity .3 1.2.2 Landfill Scarcity 1.2.3 Water Scarcity 1.2.4 Carbon Consequences The Solution: “Green” Composites CHAPTER 2: LITERATURE REVIEW 2.1 Truly “Green” Composites 2.2 Recycled Paper Products 2.3 2.4 2.5 2.2.1 Recycled Newspaper 2.2.2 Recycled Paper Towels 11 Soy Protein .12 2.3.1 Soy Protein Isolate (SPI) 12 2.3.2 Plasticization of SPI 13 2.3.3 Modification of SPI Using Phytagel® 14 Starch .15 2.4.1 Plasticization of Starch Using Glycol Stearate 16 2.4.2 Plasticization of Starch Using Sorbitol 16 2.4.3 Modification of Starch Using CMG, CMS and CMT 17 An Innovative Step in “Green” Composite Progress .17 viii CHAPTER 3: EXPERIMENTAL PROCEDURE 19 3.1 3.2 3.3 3.4 Materials 19 3.1.1 Materials for Resin Preparation .19 3.1.2 Paper Products 19 Processing and Modification of Resins 20 3.2.1 Resin Preparation of SPI Resin Sheet 20 3.2.2 Modification of SPI Resins 21 3.2.3 Resin Preparation of Starch Resin Sheet 21 3.2.4 Modification of Starch Resins 22 Composite Fabrication .23 3.3.1 Recycled Paper Products with SPI and Phytagel® Resin 24 3.3.2 Recycled Paper Products with Starch Resin 24 Characterization Techniques 25 3.4.1 Tensile Testing 25 3.4.2 Measurement of Moisture Content 27 CHAPTER 4: RESULTS AND DISCUSSION .28 4.1 Soy Protein Isolate Modified with Phytagel® 28 4.2 Recycled Paper Product Composites with SPI Resin 32 4.2.1 Dry Paper Products 32 4.2.2 Bounty® Paper Towel and SPI Composites 33 4.2.3 Georgia-Pacific Acclaim® Paper Towel and SPI Composite 33 ix 4.2.4 Georgia-Pacific enMotion® Paper Towel and SPI Composite 34 4.2.5 Kleenex® Scottfold Paper Towel and SPI Composite 34 4.2.6 Cornell Daily Sun Newspaper and SPI Composite 34 4.2.7 Comparison of Recycled Paper Product Composites with SPI Resin 35 4.3 Starch Resins 40 4.3.1 4.4 Starch Resins Modified with Thickeners 48 Recycled Paper Products with Starch-based Resins 58 4.4.1 Georgia-Pacific Acclaim® Paper Towel and Starch-based Composite 58 4.4.2 Georgia-Pacific enMotion® Paper Towel and Starch-based Composite 59 4.4.3 Cornell Daily Sun Newspaper and Starch-based Composite 60 4.4.4 Comparison of Recycled Paper Product and Starch-based Resin Composites .64 4.5 Comparison of Composites Produced with Modified SPI and Modified Starch .67 CHAPTER 5: CONCLUSIONS 69 CHAPTER 6: FUTURE DIRECTIONS 73 REFERENCES 74 x Table 4.17 Mechanical Properties of GP enMotion® Paper Towels with Starch Resins Tensile Stress at Tensile Strain at Modulus (Young’s Max Load Max Load 0.4-2.1%) (MPa) (%) (MPa) MGS + 30% CMG 15.57 2.38 1111.33 + 5% Sorbitol (1.23) (0.37) (68.31) MGS + 30% CMG 9.63 5.81 529.65 + 10% Sorbitol (0.73) (1.18) (55.12) GP enMotion® Paper Towels (dry) 6.13 (0.90) 3.08 (0.45) 372.99 (66.20) GP enMotion® Paper Towels with MGS + 30% CMG + 5% Sorbitol – Sheet GP enMotion® Paper Towels with MGS + 30% CMG + 5% Sorbitol – Sheets 19.06 (2.77) 6.80 (1.10) 954.20 (231.44) 48.98 (6.70) 10.79 (1.01) 2100.06 (288.95) GP enMotion® Paper Towels with MGS + 30% CMG + 10% Sorbitol – Sheet GP enMotion® Paper Towels with MGS + 30% CMG + 10% Sorbitol – Sheets 12.29 (1.94) 6.85 (1.18) 628.35 (54.49) 28.67 (4.01) 10.86 (1.59) 1112.27 (94.12) 62 Table 4.18 Mechanical Properties of CDS Newspaper with Starch Resin Tensile Stress at Tensile Strain at Modulus (Young’s Max Load Max Load 0.4-2.1%) (MPa) (%) (MPa) MGS + 30% CMG 15.57 2.38 1111.33 + 5% Sorbitol (1.23) (0.37) (68.31) MGS + 30% CMG 9.63 5.81 529.65 + 10% Sorbitol (0.73) (1.18) (55.12) CDS newspaper (dry) 6.25 (1.22) 2.44 (0.90) 455.68 (52.38) CDS newspaper with MGS + 30% CMG + 5% Sorbitol – Sheet CDS newspaper with MGS + 30% CMG + 5% Sorbitol – Sheets 14.67 (1.82) 2.81 (0.69) 1206.61 (109.67) 38.60 (1.38) 6.86 (0.58) 1612.66 (150.25) CDS newspaper with MGS + 30% CMG + 10% Sorbitol – Sheet CDS newspaper with MGS + 30% CMG + 10% Sorbitol – Sheets 45.61 (4.33) 5.08 (0.62) 2021.71 (79.27) 51.70 (4.33) 7.67 (1.51) 1589.86 (112.47) 63 4.4.4 Comparison of Recycled Paper Product and Starch-based Resin Composites Based on the composites produced using recycled paper products and MGS + 30% CMG with either 5% or 10% sorbitol, it was determined that the valid composites contained 5% sorbitol The composites containing 10% sorbitol did not have significant cohesion between the sheets, demonstrating that the use of 10% sorbitol in MGS + 30% CMG does not produce desirable composites when using recycled paper products The comparison between the composites made with GP Acclaim ® paper towels, GP enMotion® paper towels and CDS newspaper with MGS + 30% CMG + 5% sorbitol can be found in Table 4.19 and Figure 4.13 The stress vs strain curves for these composites can be found in Figure 4.14 All three of these composites produced excellent mechanical properties and would make outstanding composites However, the best mechanical properties were obtained from GP enMotion® paper towels, which had the highest tensile stress (48.98 MPa) and highest modulus (2100.06 MPa) Table 4.19 Comparison of Recycled Paper Products with MGS + 30% CMG + 5% Sorbitol Composites Thickness Tensile Stress Tensile Strain Modulus (Young’s (mm) at Max Load at Max Load 0.4-2.1%) (MPa) (%) (MPa) GP Acclaim® Paper 0.39 34.11 12.86 1627.37 Towels with MGS + (0.01) (2.79) (1.05) (107.15) 30% CMG + 5% Sorbitol – Sheets GP enMotion® 0.37 48.98 10.79 2100.06 Paper Towels with (0.01) (6.70) (1.01) (288.95) MGS + 30% CMG + 5% Sorbitol – Sheets CDS Newspaper 0.51 38.60 6.86 1612.66 with MGS + 30% (0.03) (1.38) (0.58) (150.25) CMG + 5% Sorbitol – Sheets 64 Figure 4.13 Comparison of Recycled Paper Product Composites with Starch-based Resin 65 (a) (b) (c) Figure 4.14 Stress vs Strain Curves of: (a) GP Acclaim® Paper Towels with MGS + 30% CMG + 5% Sorbitol, (b) GP enMotion® Paper Towels with MGS + 30% CMG + 5% Sorbitol and (c) Cornell Daily Sun Newspaper with MGS + 30% CMG + 5% Sorbitol 66 4.5 Comparison of Composites Produced with Modified SPI and Modified Starch It was established that the mechanical properties of the modified starch resins were favorable to those of modified SPI resins, as described in section 4.3 Both resins were used to fabricate recycled paper product composites, and the comparison can be found in Table 4.20 and Figure 4.15 As seen in these comparisons, when comparing the same paper product for the two different resins, the modulus is higher for the modified starch resin Additionally, the tensile strain is lower for the composite with the modified starch than with the modified SPI The tensile stress is relatively similar for the composites with the two different resins, but there is a slight trend towards a higher tensile stress with the modified starch resin Based on the comparison of the composites produced with the two different resins, it can be determined that the recycled paper product composites with the modified starch resin have the best mechanical properties Table 4.20 Comparisons of Recycled Paper Product Composites with Modified SPI Resin and Modified Starch Resin Tensile Stress Tensile Strain Modulus (Young’s at Max Load at Max Load 0.4-2.1%) (MPa) (%) (MPa) ® GP Acclaim Paper Towels/SPI 35.10 17.44 1183.50 Resin – 14 Sheets (2.53) (1.65) (113.04) GP Acclaim® Paper 34.11 12.86 1627.37 Towels/Starch Resin – Sheets (2.79) (1.05) (107.15) GP enMotion® Paper Towels/SPI 37.11 13.72 1188.36 Resin- 11 Sheets (1.99) (0.99) (93.12) ® GP enMotion Paper 48.98 10.79 2100.06 Towels/Starch Resin– Sheets (6.70) (1.01) (288.95) CDS Newspaper/ SPI Resin – 15 36.35 8.22 1363.28 Sheets (4.14) (2.09) (195.77) CDS Newspaper/ Starch Resin– 38.60 6.86 1612.66 Sheets (1.38) (0.58) (150.25) 67 Figure 4.15 Comparison of Recycled Paper Products with Modified SPI or Modified Starch Resins 68 CHAPTER CONCLUSIONS Environmentally-friendly, sustainable “green” composites based on recycled paper products and modified starch resins were fabricated using MGS resins with the addition of 30% CMG Additionally, “green” composites based on the recycled paper products and modified Soy Protein Isolate (SPI) resin were fabricated with the addition of 30% Phytagel® The mechanical properties of the resin films, paper products, and combination of these two, in the form of a composite, were investigated and these properties were characterized Based on the results obtained, the following conclusions are drawn in this research: The tensile stress and the modulus of SPI resin film both increased with the increasing amounts of Phytagel®, from 0% to 30% Additionally, the tensile strain significantly decreased with this addition This confirmed the results of earlier studies in that the addition of Phytagel® improves the mechanical properties of SPI resin The paper products that were able to be fabricated into composites were both porous and had acceptable strength The paper products that were too porous broke when impregnated with the resin solution and the paper products that had a higher strength did not absorb significant amounts of resin Based on the recycled paper products used in this study, the recycled paper products fabricated into composites with the best mechanical properties are Georgia-Pacific Acclaim® paper towels, Georgia-Pacific enMotion® paper towels 69 and the Cornell Daily Sun newspaper This was determined by the composites created using SPI + 30% Phytagel® resin Starch resin films were able to form without cracks with the addition of sorbitol as a plasticizer, but not with the addition of glycerol as a plasticizer This confirmed the results of earlier studies in that the use of sorbitol as a plasticizer in starches is preferred to the use of glycerol Based on the mechanical properties of the six different starch-based resins produced, it was determined that the maize starches (MG and MGS) produce the preferred resin films when compared to the tapioca starches (TG and TGS) and the potato starches (PG and PGS) Based on the mechanical properties of the maize starches, it was determined that the addition of glycol stearate, as seen in MGS, enhanced the properties of the maize starch CMS and CMT were unable to be used as thickeners to enhance the mechanical properties of the maize starches due to their inability to form resin films without cracks The tensile stress, tensile strain and modulus of the MGS resin all increased with the increasing amounts of CMG, from 10% to 30% When sorbitol is added to MGS + 30% CMG, the optimal results are obtained when using 5% resin due to having a higher tensile strain than lesser amounts of sorbitol and higher tensile stress and modulus than greater amounts of sorbitol 70 10 The preferred modified starch resins produced in this study had a higher modulus and lower tensile stress than the modified SPI resin, while the tensile stress of these resins were similar 11 The tensile stress, tensile strain and modulus of MGS + 30% CMG + 5% sorbitol resin were: 15.57 MPa, 2.38% and 1111.33 MPa, respectively 12 The increasing amount of plasticizer in a resin decreases the ability of a composite to cohesively form This is based on the ability of MGS + 30% CMG with 5% sorbitol to form cohesive composites and the inability of this resin with 10% sorbitol to form a cohesive composite 13 The Georgia-Pacific Acclaim® paper towels, Georgia-Pacific enMotion® paper towels and the Cornell Daily Sun Newspaper produce composites of desirable properties when fabricated with MGS + 30% CMG + 5% sorbitol 14 The Georgia-Pacific enMotion® paper towels with MGS + 30% CMG + 5% sorbitol produced the composite with the best mechanical properties, as compared to the other paper product composites studied The tensile stress, tensile strain and modulus of this composite were: 48.98 MPa, 10.79% and 2100.06 MPa, respectively 15 When the resin used in recycled paper product composites was changed from modified SPI to modified starch, the tensile stress and modulus increased while the tensile strain decreased For the results obtained in this thesis, it can be concluded that the mechanical properties of “green” composites using recycled paper products and modified starch resin demonstrate that these composites could be used to replace petroleum-based composites 71 It is important to note that the mechanical properties of these composites can be manipulated to fit the requirements of a wide range of applications, rather than consisting of a set value of mechanical properties At the end of their life, the components of these composites can easily be separated and disposed of or composted into organic soil with no waste whatsoever However, further research could include the degradability study of these composites and the length of the composite lifecycle, as well as their reactions to changes in environmental conditions The composites studied in this thesis have shown significant innovation and improvement in the “green” composite field and demonstrate the ability to be used in composite applications 72 CHAPTER FUTURE DIRECTIONS This thesis focused on introducing the possibility of using recycled paper products with biodegradable resins to create composites that can replace petroleum-based composites While this thesis introduced this concept and presented the mechanical properties of these recycled paper product-based composites, there is a significant amount of opportunity for further study Improvements for further study include the selection and characterization of the paper products that are used to engineer the “green” composites In terms of selecting the paper products, there are two major areas that can be considered The first is the selection based on mechanical properties As the type of paper product changes, the mechanical properties will also change The second area to be considered would be to select the paper products based on how “green” they are Further steps should include finding recycled paper products that are 100% post consumer, chlorine-free and hand-crafted These selection criteria will lead to “greener” composites, which is the ultimate goal of this research area The characterization of the paper products used to fabricate the composites can also be improved The paper products can be characterized by factors such as the fiber length used in the products, the strength of the paper product, as well as the porosity of the paper product, which will determine the amount of resin that is absorbed The changes in fiber length, strength and porosity can all be characterized when comparing the final composite With these improvements to the paper products, future research could continue the study of recycled paper product-based “green” composites that were first introduced in this thesis 73 REFERENCES Flores, O., A Romo-Uribe, M E Robero-Guzman, A E Gonzalez, R Cruz-Silva and B Campillo “Mechanical Properties and Fracture Behavior of Polypropylene Reinforced with Polyaniline-Grafted Short Glass Fibers.” Journal of Applied Polymer Science 112 (2009) 934-941 Netravali, A N and S Chabba “Composites Get Greener.” Materials Today (2003) 22-29 Netravali, A N “‘Green’ Composites: From Skateboards to Ballistic Applications.” Board of Trustees and Cornell University Council: 58 th Annual Meeting 18 October 2008 Cornell University: Ithaca, NY Stevens, E S “Green Plastics.” Princeton University Press Princeton 2002 Bender, N “The Impact of Water Scarcity and Pollution on the Textile Industry.” Philadelphia University 2004 Thomas, S “Our Thirst for Water.” The World &I 18 (2003) 148 Marland, G., T A Boden and R J Andres “Global, Regional and National FossilFuel CO2 Emissions.” Carbon Dioxide Information Analysis Center Pervaiz, M and M M Sain “Carbon Storage Potential in Natural Fiber Composites.” Resources, Conservation and Recycling 39 (2003) 325-340 John, M J., R D Anandjiwala, L A Pothen and S Thomas “Cellulosic FibreReinforced Green Composites.” Composite Interfaces 14 (2007) 733-751 10 Cheang, M “Debunking the Myths of Recycled Paper” Recycling Point Dot Com 1992 11 Pati, R K., P Vrat and P Kumar “Economic Analysis of Paper Recycling Vis-à-vis Wood as Raw Material.” International Journal of Production Economics 103 (2006) 489-508 12 “Newspaper Sector.” The Green Press Initiative 13 “Newspaper Furniture: Read it and Sit on it too!” Instablogs Network http://www.ecofriend.org/entry/newspaper-furniture-read-it-and-then-sit-on-it-too/ 14 “Recycled Newspaper Jewelry.” Clip Marks 798B2BFE-D500-48D5-B864-B51D1AE79CF4/ 74 http://clipmarks.com/clipmark/ 15 Fillho, C R., D S Monteiro, C de Silva Meireles, R N Nascimento de Assuncao, D A Cerqueria, H S Barud, S J L Ribeiro and Y Messadeq “Synthesis and Characterization of Cellulose Acetate Produced From Recycled Newspaper.” Carbohydrate Polymers 73 (2008) 74-82 16 Ashori, A “Characteristics of Wood-Fiber Plastic Composites Made of Recycled Materials.” Waste Management 29 (2009) 1291-1295 17 Srinivasan, A K and G C Blomquist “Ecolabaled Paper Towels: Consumer Valuation and Expenditure Analysis.” Journal of Environmental Management 90 (2009) 314-320 18 Yamamoto, Y “Engineered ‘Green’ Composites using Kenaf and Bamboo Fibers with Modified Soy Protein Resin.” Cornell University 2006 19 Ghorpade V M., H Li, A Gennadios and M A Hanna “Chemically Modified Soy Protein Films.” Transactions of the ASAE 38 (1995) 1805-1808 20 Singh, H “Modification of Food Proteins by Covalent Cross-linking.” Trends in Food Science and Technology (1991) 196-200 21 Mo X.Q., X Z Sun “Plasticization of Soy Protein Polymer by Polyol-Based Plasticizers.” Journal of the American Oil Chemists Society 79 (2002) 197-202 22 Wang, S., H J Sue and J Jane “Effects of Polyhydric Alcohols on the Mechanical Properties of Soy Protein Plastics.” Journal of Material Science- Pure and Applied Chemistry (1996) 557-569 23 Lodha, P and A N Netravali “Characterization of Phytagel® Modified Soy Protein Isolate and Unidirectional Flax Yarn Reinforced “Green” Composites Polymer Composites 26 (2006) 647-659 24 Speling, L H “Interpenetrating Polymer Networks: An Overview.” Interpenetrating Polymer Networks Washington D.C.: American Chemical Society, 1994 3-38 25 Tiefenbacher, K F “Starch-based Foam Materials: Use and Degradation Properties.” Pure Applied Chemistry 30 (1997) 727-731 26 Chen, C.R and H S Ramaswamy “Rheology of Tapioca Starch.” Food Research International 32 (1999) 319-325 27 Nagano, T., E Tamaki and T Funami “Influence of Guar Gum on Granule Morphologies and Rheological Properties of Maize Starch.” Carbohydrate Polymers 72 (2008) 95-101 75 28 “Starch.” The Macrogalleria University of Southern Mississippi; Department of Polymer Science http://pslc.ws/macrogcss/starch.html 29 Cobe, Patricia “Tapioca.” Restaurant Business 101 (2002) 83 30 Sailaja, R R N., R A Prasad and M Chanda “Effect of Epoxy Functionalized Compatibilizer on the Mechanical Properties of Low Density Polyethylene/Plasticized Tapioca Starch Blends.” Polymer International 50 (2001) 1352-1359 31 Kumar, V N G., M V Bhandari and A N Bhat “Modifications of Tapioca Starch Properties by Polyethylene Glycol (4000) and Polyethylene Glycol (4000) Stearate Additives.” Starch 43 (1991) 93-98 32 Krogars, K., J Heinamaki, M Karjalainen, A Niskanen, M Leskela and J Yliruusi “Enhanced Stability of Rubbery Amylose-rich Maize Starch Films Plasticized with a Combination of Sorbitol and Glycerol.” International Journal of Pharmaceutics 251 (2003) 205-208 33 McHugh, T H and J M Krochta “Sorbitol- vs Glycerol-Plasticized Whey Protein Edible Films: Integrated Oxygen Permeability and Tensile Property Evaluation.” Journal of Agricultural and Food Chemistry 42 (1994) 841-845 34 “Cation Exchange Celluloses.” Whatman Ltd., General Electric Healthcare 76 ... Resin and Modified Starch Resin 67 xiv CHAPTER INTRODUCTION This thesis focuses on the production and characterization of “green” composites made with recycled paper products and biodegradable. .. starch -based and soy protein -based resins The production of these composites consists of two parts: first, the production of recycled paper product composites using Soy Protein Isolate -based resin and. .. users of the product and d) the sequestration of carbon dioxide In this thesis, fully biodegradable composites based on a variety of papers and biodegradable resins were prepared and characterized