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

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clumps could not be detected. The observed fragments may be caused by poor dispersion, or conditions promoting cellulose-cellulose interactions. Enhanced dispersion of the fibers may be addressed by utilizing a recirculating compounder at elevated temperatures. By unfolding the protein at higher temperatures, protein chain mobility would be increased which could allow for better flow of cellulose fibers throughout the SPI matrix. With impeded movement through the SPI matrix, cellulose fibers could accumulate against the barrel walls where higher frictional forces can be experienced. Aggregate formation via cellulose-cellulose interactions may be promoted during aging or inside the extruder. When suspended cellulose fibers are mixed into the SPI powder for aging, moisture is driven away from the fibers by the dry SPI powder. This partial drying could possibly encourage fibers in close proximity to interact with each other forming semi- aggregates. Unless these fibers are subject to an environment that would allow them to break apart, these semi-attached fibers could be sustained and further tangled through the extruder. Within the extruder, the self-aggregation of cellulose fibers may be promoted by shear, pressure, or the exposure of embedded hydrophobic groups. As reported in Section 5.4.1, preliminary trials of applying ultrasonic treatment aggregated the extracted soy fiber suspensions. Shear and pressure against two surfaces was also witnessed to yield aggregated clumps from SMF suspensions. As the blended melt flow along screw flights, high shear and pressure could be experienced against the extruder barrel which could induce the aggregation of cellulose fractions into larger fragments. This would explain as to why the majority of these cellulose rich domains were found on the outskirts of the melt against the barrel and screw surfaces. Moreover, during the unfolding process, increased hydrophobic groups from within the protein structures are revealed. This could conceivably promote the self-association of cellulose fibers which are highly hydrophilic. However since both filler and matrix are predominately hydrophilic, the hindrance of hydrophobic groups should be of minimal consequence. 70
6.4.2 MORPHOLOGY AND STRUCTURE Due to the appearance of aggregated fragments, homogeneity of fiber dispersion was a topic of concern. Upon examination of the films under polarized light (Figure 6.3), it was revealed that although mixing was not optimal, the clumping of fibers were independent occurrences unrelated to overall dispersibility. Fibers were seen to be randomly spread throughout the films. SPI NSF0.25 SMF0.25 SMF0.5 SMF1.0 SMF2.5 Figure 6.3: Image of 1 inch wide specimens of SPI/cellulose blend films seen through a cross polarized light filter. Circled are clusters of aggregated cellulose fibers. Further analysis using OM under cross polarized light confirmed that the overall dispersion of fibers within the protein films is even and throughout (Figure 6.4). A large size distribution of fibers was also observed as expected. With increasing concentrations, the overall density of fibers was seen to increase. From 0.25 to 0.5% w/w SMF/SPI, the presence of larger fiber diameters was more prominent for the SMF0.5 specimen. At concentrations beyond 1% w/w SPI, the random presence of aggregates began to appear with more occurrences at 2.5% 71
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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
Page 11 and 12:
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
Page 29 and 30: 4) Explore the extraction process f
Page 31 and 32: 4.3 METHODS 4.3.1 SAMPLE PREPARATIO
Page 33 and 34: a Figure 4.2: a) Schematic of extru
Page 35 and 36: length at break by the initial grip
Page 37 and 38: 4.4 RESULTS AND DISCUSSION 4.4.1 SP
Page 39 and 40: Further experiments were carried ou
Page 41 and 42: Figure 4.5: Film with rough texture
Page 43 and 44: extrusion screw to continuously bre
Page 45 and 46: stopped which fixes the spherical s
Page 47 and 48: 4.4.3 MECHANICAL PROPERTIES Mechani
Page 49 and 50: Elongation at break (%) Figure 4.10
Page 51 and 52: Table 4.5: Water vapor permeability
Page 53 and 54: 4.4.5 FTIR ANALYSIS The main absorb
Page 55 and 56: 4.4.6 CONCLUSION The extrusion of S
Page 57 and 58: 5.3 METHODS 5.3.1 CELLULOSE EXTRACT
Page 59 and 60: For mechanical treatments, the obta
Page 61 and 62: initial soy biomass; SNF and SMF. T
Page 63 and 64: 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: increased in size. At fiber concent
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
Page 109 and 110: (21 nm) particle was seen to have a
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 and 116: Modulus of Elasticity (MPa) 200 180
Page 117 and 118: 8.0 CONCLUSIONS AND RECOMMENDATIONS
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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THESIS - ROC CH ... - FINAL - resubmission.pdf - University of Guelph

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