THESIS - ROC CH ... - FINAL - resubmission.pdf - University of Guelph

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sheets (Marques et al. 2006). Due to the presence of TiO2, cellulose-cellulose interactions were reported to decrease. This alleviates a major obstacle found in the present extrusion of SPI with cellulose fibers; the formation of aggregated cellulose fibers. As described in Section 6.0, aggregation can be promoted during aging and extrusion. By interfering with cellulose-cellulose interactions, fibers could remain separate so that interactions between cellulose and SPI can increase. More importantly, eliminating aggregation would aid in dispersion of the fibers spreading load concentrations upon tension. However this is only speculation and further study is required. Of note is that the maximum tensile strength with using Ti-coupled cellulose fibers still only equated the improvements seen with using 0.25% w/wSPI of either cellulose or TiO2 separately. As such, other forces may be present in influencing the increase in strength observed. 7.4.4 CONCLUSION This experiment showed that the addition of TiO2 nanoparticles alone resulted in mechanical improvements of base SPI film. Comparing different particle sizes, the optimal concentration for maximum tensile strength was found to be greater (0.5% w/w TIO 2/SPI) for the larger (21nm) P25 particle, and fewer (0.25% w/w TiO2/SPI) for the smaller (14nm) P90 particle. When coupled with extracted soy fibers, a synergistic trend was observed. At 0.25% w/w P90/SPI, a positive correlation was found for fiber addition and mechanical strength. However, it must be noted that the maximum strength increase was not more significant than the addition of cellulose fibers alone. Nonetheless, TiO2 coupling highlights the potential for further fiber incorporation to further improve SPI/cellulose blend films. Future investigations may benefit from exploring the optimal ratio between TiO2 and cellulose fibers for use in aiding dispersion which was believed to be the critical factor in the synergistic effects observed. 106
8.0 CONCLUSIONS AND RECOMMENDATIONS Increasing interest into biodegradable alternatives for petroleum plastics has perpetuated current research for environmentally sustainable protein-based plastics. Each part of this study contributed to this ideal by exploring the processing and properties of extruding a protein composite film derived solely from the soy plant. The first part of this study showed that under optimized conditions, SPI can be extruded directly into thin, smooth-surfaced films. The processing window for this is however very limited and highly sensitive to both moisture content and heat applied. The presence of water forms microscopic holes in the thin films and is thought to nucleate the formation of macroscopic bubbles seen during extrusion. The continuous extrusion of puffed films with sustained bubbles was readily achievable through the use of high moisture and high heat. Mechanical properties of the extruded thin films were highly sensitive to relative humidity. But at RH of 58% or lower, SPI films exhibited comparable mechanical properties to synthetic polymers. Barrier characteristics were strong against oxygen but poor against water as expected. Furthermore, FTIR analysis revealed that the extrusion process facilitated the transformation of SPI from mixed β strands to parallel β-sheet structures. The realization of extruding continuous homogenous SPI thin films facilitates industrial integration increasing commercial potential for sustainable bioplastics. The second part affirms that nano to micro cellulose fibers can be extracted from unused stems and pods of the soy plant. The chemi-mechanical process employed yielded two fractions of fibers with differing size distribution, chemical composition, and crystallinity. Confirmed by TEM, a nano-sized fraction was obtained after acid hydrolysis. WAXD showed that crystalline characteristics were present but the presence of pectin and hemicellulose was strong as witnessed by FTIR. The bulk fraction obtained after both chemical and mechanical treatment had a size distribution ranging from nano to micron sizes. FTIR and SEM analysis of each 107
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A Study on the Extrusion of Soy Pro
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ACKNOWLEDGEMENTS My research would
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4.3.9 Statistical Analysis.........
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LIST OF TABLES Table 2.1: Compariso
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Figure 5.2: Light optical microscop
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1.0 INTRODUCTION The production of
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einforcement material. Research int
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via centrifugation into four fracti
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zones are synonymous to feeding, tr
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Ralston (2008) investigated the ext
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onding between hydroxyl groups and
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Table 2.2: Summary of cellulose par
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through the use of enzymes have pro
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matrix such as soy protein (Wang et
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4) Explore the extraction process f
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4.3 METHODS 4.3.1 SAMPLE PREPARATIO
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a Figure 4.2: a) Schematic of extru
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length at break by the initial grip
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4.4 RESULTS AND DISCUSSION 4.4.1 SP
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Further experiments were carried ou
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Figure 4.5: Film with rough texture
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extrusion screw to continuously bre
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stopped which fixes the spherical s
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4.4.3 MECHANICAL PROPERTIES Mechani
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Elongation at break (%) Figure 4.10
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Table 4.5: Water vapor permeability
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4.4.5 FTIR ANALYSIS The main absorb
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4.4.6 CONCLUSION The extrusion of S
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5.3 METHODS 5.3.1 CELLULOSE EXTRACT
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For mechanical treatments, the obta
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initial soy biomass; SNF and SMF. T
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compiled by Moon et al. (2011), thi
Page 65 and 66: RSH: 5min HPH: 20 passes, 4000 - 60
Page 67 and 68: SMF micrographs, the presence of fi
Page 69 and 70: process as described. However, it m
Page 71 and 72: a peak at 22.6° is representative
Page 73 and 74: chemical and mechanical treatment h
Page 75 and 76: 6.3 METHODS 6.3.1 SAMPLE PREPARATIO
Page 77 and 78: 6.3.3 FILM CONDITIONING Similar to
Page 79 and 80: increased in size. At fiber concent
Page 81 and 82: 6.4.2 MORPHOLOGY AND STRUCTURE Due
Page 83 and 84: SEM images of the cryo-fractured su
Page 85 and 86: Table 6.1: Mechanical properties of
Page 87 and 88: cellulose and SPI. This high interf
Page 89 and 90: concentrations at isolated sites. A
Page 91 and 92: Similar to Section 4.4.5, dominatin
Page 93 and 94: Further analysis of the Amide II ba
Page 95 and 96: specimens that have been cryo-crush
Page 97 and 98: crushing. Conversely, this could al
Page 99 and 100: 7.0 EXPLORATORY WORK WITH TIO 2 NAN
Page 101 and 102: 7.3.2 COMPOUNDING AND EXTRUSION Com
Page 103 and 104: smaller size of P90, the ability to
Page 105 and 106: Table 7.1: Mechanical Strength of T
Page 107 and 108: Modulus of Elasticity (MPa) 120 110
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Page 111 and 112: 7.4.3 MECHANICAL PROPERTIES OF TIO2
Page 113 and 114: Tensile Strenght (MPa) 12 11 10 9 8
Page 115: Modulus of Elasticity (MPa) 200 180
Page 119 and 120: The viability of introducing a comp
Page 121 and 122: acting as a coupling agent for furt
Page 123 and 124: Cherian BM, Leao AL, Souza SFD, Tho
Page 125 and 126: Kacurakova M, Capek P, Sasinkova V,
Page 127 and 128: Pääkkö M, Ankerfors M, Kosonen H
Page 129: Wang N, Ding E, Cheng R (2008) Prep
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