VTechWorks Repository :: Browsing by Author "Kim, Young Teck"

Browsing by Author "Kim, Young Teck"

Now showing 1 - 14 of 14

Catechyl-lignin tissues in Vanilla orchid and Candlenut: structure/property studies
Ristanti, Eky Yenita (Virginia Tech, 2023-05-24)
In 2012, a new type of lignin, catechyl (C)-lignin was found in the seed coat of vanilla orchid (Vanilla planifolia) and Melocactus cacti, and later in the nutshell of Aleurites moluccana (candlenut). This caffeyl alcohol homopolymer is the exclusive lignin in vanilla seed coat but separated in time and/or location with guaiacyl (G)-lignin in candlenut. Unlike conventional guaiacyl/syringyl (G/S-lignins) with alkyl-aryl ether linkages, intermonomer linkages in C-lignin are connected by benzodioxane linkages which are stiffer than alkyl-aryl ether linkages. C-lignin is unusually stable against acid-catalyzed cleavage. Tissues with C-lignin are expected to exhibit high glass transition temperature (Tg) compared to tissues with G/S/H-lignin. C-lignin also probably shows high crystallinity due to its highly linear-homopolymer structure. The ability of some seed coats/nutshells in angiosperms to synthesize a new type of lignin is another level of lignin evolution. However, the role of C-lignin related to the function of the seed coat is unclear while it exhibits different behaviors to the regular G/S/H-lignin. These points motivated us to conduct cell-wall structure/property studies in the context of plant evolution, using microscopy, X-ray diffraction (XRD) and dynamic mechanical analysis (DMA). Light and electron microscopes were used to identify cell's size and type of intact and macerated vanilla seed coat and candlenut shell. Vanilla seeds are tiny, sized approximately 300μm and the surface is covered with dark-colored seed coat. Candlenut is slightly smaller than walnut, with uneven, hard, dark brown shell covering the nut. Microscopy observations indicated that both seed coat and nutshell are dominated by highly lignified cells, known as sclereids. The types of sclereids in vanilla seed coat and candlenut shell are different; vanilla seed coat has ostoesclereid-type cells, while candlenut shell has macrosclereid-type cells. XRD was used to study tissue with C-lignin crystallinity by comparing diffractograms of vanilla seed coat and candlenut shell to Southern Yellow Pine wood diffractograms. The Southern Yellow Pine wood diffractogram corresponds to a typical native cellulose in higher plants, that is cellulose I allomorph. Diffractogram XRD analysis on vanilla seed coat and candlenut shell shows similarities to Southern Yellow Pine native cellulose, suggesting that cellulose is the contributor for crystallinity in seed coat and nutshell, and this also indicated that tissues with C-lignin is not crystalline. Crystallinities of vanilla seed coat and candlenut shell determined using peak deconvolution methods were about half of Southern Yellow Pine crystallinity. DMA was used to measure Tg in vanilla seed coat and candlenut shell. Measurements were conducted in solvent-submersion mode using organic plasticizers to reduce the Tg to non-damaging temperatures. DMA measurement of vanilla seed coat and candlenut shell is challenging due to specimen size and shape. Specimen preparation for DMA measurement included seed coat purification for vanilla and cutting/milling for candlenut shell followed by specimen saturation in plasticizers. Compressive-torsion DMA was used to allow tiny specimens gripping. Vanilla seed coats exhibited higher glass transition temperature compared to wood, while candlenut shells exhibited various Tgs depending on specimen type/size.
Characterization of Hydrophobically Modified Titanium Dioxide Polylactic Acid Nanocomposite Films for Food Packaging Applications
Baek, Naerin (Virginia Tech, 2016-08-12)
Titanium dioxide (TiO2) polymer nanocomposites improve barrier properties to gas and moisture and mechanical strength as well as providing active packaging functions. However, low compatibility between hydrophilic TiO2 nanoparticles and hydrophobic polymers such as polylactic acid (PLA) causes problems due to the tendency of TiO2 nanoparticles (TiO2) to agglomerate and form large clusters. A surface modification of TiO2 with long chain fatty acid may improve the compatibility between PLA and TiO2. The goal of this study was to enhance barrier properties of oxygen and water vapor, mechanical strength and add light protecting function to PLA composites by incorporation of oleic acid modified TiO2 nanoparticles (OA_TiO2). The objectives of this study were: 1) synthesize TiO2 and modify surface of TiO2 with oleic acid, 2) investigate dispersion stability of TiO2 and OA_TiO2 in hydrophobic media, 3) incorporate TiO2 and OA_TiO2 into a PLA matrix and to characterize properties of TiO2PLA (T-PLA) and OA_TiO2 PLA nanocomposite films (OT-PLA), and 4) to determine stability of green tea infusion in T-PLA and OT-PLA packaging model systems during refrigerated storage at 4 °C under florescent lightening. TiO2 was synthesized by using a sol-gel method and the surface of TiO2 was modified by oleic acid using a one-step method. T-PLA and OT-PLA were prepared by solvent casting. TiO2 and OA_TiO2 were analyzed by X-ray diffraction, Fourier transform infrared spectroscopy, thermal analysis and dynamic light scattering. The barrier properties to oxygen and water vapor, morphology, mechanical properties, thermal stability and light absorption properties of T-PLA and OT-PLA were characterized. Dispersion of TiO2 was improved in PLA matrix by the surface modification method with oleic acid. OT-PLA had more effective improvements in the barrier properties and flexibility than T-PLA and PLA, but toughness of the films based on Young's modules of OT-PLA was lower than the T-PLA and the PLA. The OT-PLA may have a potential to be used as transparent, functional and sustainable packaging films, but limited use for complete visible and UV-light protection for photosensitized foods.
Compositional Characterization of Different Industrial White and Red Grape Pomaces in Virginia and the Potential Valorization of the Major Components
Jin, Qing; O’Hair, Joshua; Stewart, Amanda C.; O'Keefe, Sean F.; Neilson, Andrew P.; Kim, Young Teck; McGuire, Megan N.; Lee, Andrew H.; Wilder, Geoffrey; Huang, Haibo (MDPI, 2019-12-11)
To better evaluate potential uses for grape pomace (GP) waste, a comprehensive chemical composition analysis of GP in Virginia was conducted. Eight commercial white and red pomace samples (cv. Viognier, Vidal Blanc, Niagara, Petit Manseng, Petit Verdot, Merlot, Cabernet Franc, and Chambourcin) obtained from different wineries in Virginia, USA were used. For extractives, GPs contained 2.89%–4.66% titratable acids, 4.32%–6.60% ash, 4.62%–12.5% lipids with linoleic acid being the predominant (59.0%–70.9%) fatty acid, 10.4–64.8 g total phenolic content (gallic acid equivalents)/kg GP, 2.09–53.3 g glucose/kg GP, 3.79–52.9 g fructose/kg GP, and trace sucrose. As for non-extractives, GPs contained 25.2%–44.5% lignin, 8.04%–12.7% glucan, 4.42%–7.05% xylan, and trace amounts of galactan, arabinan, and mannan (less than 3% in total). Potential usages of these components were further examined to provide information on better valorization of GP. Considering the valuable extractives (e.g., polyphenols and oil) and non-extractives (e.g., lignin), designing a biorefinery process aiming at fully recover and/or utilize these components is of future significance.
Correlation of the Elastic Properties of Stretch Film on Unit Load Containment
Bisha, James Victor (Virginia Tech, 2012-05-24)
The purpose of this research was to correlate the applied material properties of stretch film with its elastic properties measured in a laboratory setting. There are currently no tools available for a packaging engineer to make a scientific decision on how one stretch film performs against another without applying the film. The system for stretch wrap comparison is mostly based on trial and error which can lead to a significant loss of product when testing a new film or shipping a new product for the first time. If the properties of applied stretch film could be predicted using a tensile test method, many different films could be compared at once without actually applying the film, saving time and money and reducing risk. The current method for evaluating the tensile properties of stretch film advises the user apply a hysteresis test to a standard sample size and calculate several standard engineering values. This test does not represent how the material is actually used. Therefore, a new tensile testing method was developed that considers the film gauge (thickness) and its prestretch. The results of this testing method allowed for the calculation of the material stiffness (Bisha Stiffness) and were used to predict its performance in unit load containment. Applied stretch film is currently compared measuring containment force, which current standards define as the amount of force required to pull out a 15.2cm diameter plate, 10.1cm out, located 25.4cm down from the top and 45.7cm over from the side of a standard 121.9cm width unit load. Given this definition, increasing the amount of force required to pull the plate out can be achieved by manipulating two different stretch film properties, either increasing the stiffness of the film or increasing the tension of the film across the face of the unit load during the application process. Therefore, for this research, the traditional definition of containment force has been broken down into two components. Applied film stiffness was defined as the amount of force required to pull the film a given distance off the unit load. Containment force was defined as the amount of force that an applied film exerts on the corner of the unit load. The applied stretch film was evaluated using two different methods. The first method used the standard 10.1cm pull plate (same plate as ASTM D 4649) to measure the force required to pull the film out at different increments from the center on the face of the unit load. This measurement force was transformed into a material stiffness and film tension (which were subsequently resolved into containment force). The second, newly developed, method involved wrapping a bar under the film, on the corner of the unit load, and pulling out on the bar with a tensile testing machine. This method allowed for the direct measurement of the containment force and material stiffness. The results indicated that while some statistically significant differences were found for certain films, the material stiffness and containment were relatively consistent and comparable using either method.The use of the Bisha Stiffness to predict the applied stiffness and containment force yielded a statistically significant correlation but with a very low coefficient of determination. These results suggest that while film thickness and prestretch are key variables that can predict applied stiffness and containment force, more research should be conducted to study other variables that may allow for a better. High variability of the predictions observed were caused by the differences in film morphology between the different method of elongation (tensile vs application). This study was the first that attempted to define and correlate the tensile properties of stretch film and the applied properties of stretch film. From this research many, terms have been clarified, myths have been dispelled, formulas have been properly derived and applied to the data collected and a clear path forward had been laid out for future researchers to be able to predict applied stiffness and containment force from the elastic properties of stretch film.
Development of Cellulose-Titanium dioxide-Porphyrin Nanocomposite Films with High-barrier, UV-blocking, and Visible Light-Responsive Antimicrobial Features
Lovely, Belladini (Virginia Tech, 2024-06-03)
The packaging does not serve as a mere containment but also can be designed to play a key role in preserving the product from quality-deteriorating factors, including oxygen, light irradiation, and foodborne pathogenic microorganisms (e.g., Escherichia coli). There has been a growing interest in employing ultra-porous metal-organic frameworks (MOF) with visible light-responsive antibacterial mechanisms to generate reactive oxygen species (ROS) that can eliminate bacteria via an oxidative burst. MOF is made of inorganic metal ions/nodes/clusters/secondary building units linked by organic bridge ligands, where titanium dioxide (TiO2) and tetrakis(4-carboxyphenyl)porphyrin) (TCPP) were selected for these components, respectively. TiO2 is an exceptional UV-A/B/C-blocker; meanwhile, TCPP dye performs a remarkable photocatalytic ability even under visible light, on top of its macro-heterocyclic structure that is ideal as a MOF linker. Both have good compatibility but suffer from the notorious tendency to self-quench/aggregate. The incorporation of MOF-based conjugates into a polymeric matrix, like cellulose, is among the proven-successful solutions. Cellulose is the Earth's most abundant and naturally biodegradable, and cellulose nanofibril (CNF) was particularly chosen for its high specific surface area and surface activity. However, a straightforward, cheap, and environmentally friendly approach of multicycle homogenization (0-25 passes) was conducted to solve neat cellulose's challenge of natural hydrophilicity, where low pressure (<10 MPa) was applied to prevent the common over-shearing effect. The antibacterial efficacy of CNF films functionalized with TiO2-TCPP conjugate on inhibiting E. coli growth was analyzed with and without light of different intensities (3000 and 6000 lux). The positive impacts of CNFs' promoted fibrillation and subsequent inter/intra-molecular hydrogen bonding post-homogenization were evidenced in an array of functional properties, i.e., crystallinity, TiO2-TCPP conjugate dispersion, surface smoothness, mechanical properties, thermal stability, hydrophobicity, oxygen barrier (comparable to ethylene-vinyl alcohol (EVOH), a commercial high-barrier polymer), and 100%-antibacterial rate (under 6000 lux after 72 hours). Varying optimum cycles of homogenization demonstrated the prospect of the proposed homogenization approach in preparing CNF with diverse processability and applicability. These findings also exhibited a promising potential for a myriad of high-barrier, UV-blocking, and/or visible light-responsive antibacterial film applications, including food packaging and biomedical.
Effect of Pallet Deckboard Stiffness and Unit Load Factors on Corrugated Box Compression Strength
Baker, Matthew W. (Virginia Tech, 2016-03-29)
Corrugated paper boxes are the predominant packaging and shipping material and account for the majority of packaging refuse by weight. Wooden pallets are equally predominant in shipping, transportation and warehousing logistics. The interaction between these two components is complex and unexplored leaving industry to compensate with outdated component specific safety factors. Providing a focused exploration of the box and pallet interaction will open the door for holistic design practices that will reduce cost, weight, damage, and safety incidents. This study was separated into four chapters exploring different aspects of the corrugated box to pallet interaction. The first chapter evaluates the support surface provided by a pallet consists of deckboards spaced perpendicular to the length of the pallet. The resulting gaps between deckboards reduce the support to the box. Gaps were limited to 55% of box sidewall length for practical reasons. The effect of gaps was significant and produced a nonlinear reduction in box strength. Small boxes were more susceptible to gaps than larger boxes. Moving the gap closer to the corner increased its effect while increasing the number of gaps did not increase the effect. A modification to the McKee equation was produced that was capable of predicting the loss in strength due to gaps. The equation is novel in that is modifies a widely used equation and is the first such equation capable of handling multiple box sizes. This study also has practical implications for packaging designers who must contend with pallet gap. Chapter 2 explores the relationship between deckboard deflection and box compression strength. Testing found that reducing the stiffness of the deckboard decreases the compression strength of the box by 26.4%. The location of the box relative to the stringer also had varying effects on the box strength. A combination of deckboard stiffness and gaps produced mixed with results with gaps reducing the effect of stiffness. It was observed that lower stiffness deckboards not only deflect but also twist during compression. The torsion is suspected to have a significant influence on compression but further exploration is needed. The third chapter tests the effect of box flap length on box compression strength under various support conditions. Variables included four flap lengths, gaps between deckboards, low stiffness deckboards, column stacking and misaligned stacking. The results show that the box flaps can be reduced by 25% with no significant effect of box strength under any support condition tested. Furthermore, the box flap can be reduced by 50% with less than 10% loss in compression strength under all scenarios. These results have significant sustainability implication as 25% and 50% reduction in box flap reduce material usage by approximately 12% and 24%, respectively. In the fourth and final chapter, the theory of beam-on-elastic foundation is applied to deckboard bending and corrugated boxes. In this model the corrugated box acts and the foundation and the deckboard is the beam. Rotational stiffness, load bridging, and foundation stiffness changes required the development of novel testing solution and model development. The model was capable of predicting the distribution of force along the length sidewall but was not capable of predicting the ultimate strength of the box. The model developed in the study will be applicable in determining potential weakness in the unit load in addition to optimizing those that are over designed. These four chapters represent a considerable contribution of applicable research to a field that relied on outdated safety factors over thirty years. These safety factors often lead to costly over design in an industry where corrugated box and pallets volumes make event the smallest improvements highly beneficial. Furthermore, this research has opened the door for significant additional research that will undoubtedly provided even greater economic and sustainability benefits.
Exploration of plastic pallets using various fillers on graphite nanoplatelets/polypropylene composites
Lee, Soohyung (Virginia Tech, 2023-01-26)
In this study, composite system was developed to enhance mechanical properties of plastic pallets. The potential of graphite nanoplatelets (GnP)/PP composites for the application in packaging was scrutinized by examining mechanical properties, thermal properties, flow properties, and morphology as a function of GnP loading and by comparison of two mixing methods: physical melt compounding (PMC) and chemical pretreatment compounding (CPC) processes. Incorporation of the GnP into PP resulted in a significant enhancement in the mechanical strength (tensile, impact, and flexural strength) and thermal decomposition temperature compared to the neat PP specimen. The CPC process clearly shows good exfoliation and better distribution on the PP matrix compared to the PMC method based on morphological evaluation measured by SEM. The impact test at low temperature revealed that the composites made by the CPC process showed 64% higher impact strength than neat PP due to higher even-distribution of GnP molecules into the PP matrix. We attempted to discover the degree of dispersion of natural fiber (kenaf) and graphite nanoplatelets (GnP) into the polypropylene (PP) polymer matrix and the effect of filler-adding sequence on physical and mechanical properties. Tensile strength of the composites was increased up to 25%. In the case of Young's modulus, composites showed a 56% enhancement compared to the control. However, the impact strength decreased as a result of the increased brittleness when kenaf fiber was added. Another study investigated the effects of hybrid filler systems (graphite nanoplatelets (GnP)/commercially available modified calcium carbonate (mCaCO3) nanoparticles) on mechanical and physical properties of polypropylene nanocomposites with three variables, filler loading amount, the number of compounding processes, and the compounding order of two different fillers. The impact strength of composite samples, containing 1wt% of GnP and mCaCO3 nanoparticles, increased up to 64% compared to neat PP. Among all tested samples, the highest tensile strength was found at 1wt% of mCaCO3 nanoparticles regardless of the presence or absence of GnP addition. There was no significant difference in flexural strength regardless of any nano-filler addition. However, both the flexural modulus and Young's modulus increased significantly when 10wt% of mCaCO3 nanoparticles were added. The number of compounding processes did not affect any strength, and the single compounding process was found to be more effective than the double compounding process. It may be contributed by thermal degradation of polymeric structure by double heat processing. This study can be able to provide a solution for value-added high-end products in various industries such as application in logistics, aerospace or electric automobile, where carbon-based nanomaterials are more affordable.
Filler effects in resole adhesive formulations
Wang, Xuyang (Virginia Tech, 2016-09-20)
This was a university/industry research cooperation with focus on how organic fillers affect the properties of phenol-formaldehyde resole (PF) resins that are formulated for veneer applications like plywood and laminated veneer lumber. The PF formulations studied in this work used fillers that were derived from walnut shell (Juglans regia), alder bark (Alnus rubra), almond shell (Prunus dulcis), and corn cob (furfural production) residue. The chemical composition of all fillers was measured and compared to published data. The basic rheological behavior of the formulations was determined and used to develop an adhesive tack measurement based upon lubrication theory. In this work, the probe-tack test was adapted to a typical stress-controlled rheometer by using the normal force and displacement system to compress the adhesive between parallel plates. By employing a simple power law to describe the complex rheology of adhesives and a lubrication approximation for the viscous force, squeeze flow of adhesives between two flat, impermeable steels and between steel and porous wood can be successfully modeled. However, deviations from theory were encountered as related to the method of adhesive application. Both meniscus force in consequence of the surface tension of adhesive pull around the edge of plate and viscous force due to the viscosity of adhesive operate inside the meniscus when adhesive was spread on the entire surface by a hard roller. manufacture where viscosity and surface tension effects were both involved. Last but not Such is probably the case when wood veneer is cold-pressed (pre-pressed) in plywood least, rheological behavior and alkali modification of wheat flour was determined by rheological and infrared studies, respectively.
Improved Properties of Poly (Lactic Acid) with Incorporation of Carbon Hybrid Nanostructure
Kim, Junseok (Virginia Tech, 2016-07-01)
Poly(lactic acid) is biodegradable polymer derived from renewable resources and non-toxic, which has become most interested polymer to substitute petroleum-based polymer. However, it has low glass transition temperature and poor gas barrier properties to restrict the application on hot contents packaging and long-term food packaging. The objectives of this research are: (a) to reduce coagulation of graphene oxide/single-walled carbon nanotube (GOCNT) nanocomposite in poly(lactic acid) matrix and (b) to improve mechanical strength and oxygen barrier property, which extend the application of poly(lactic acid). Graphene oxide has been found to have relatively even dispersion in poly(lactic acid) matrix while its own coagulation has become significant draw back for properties of nanocomposite such as gas barrier, mechanical properties and thermo stability as well as crystallinity. Here, single-walled carbon nanotube was hybrid with graphene oxide to reduce irreversible coagulation by preventing van der Waals of graphene oxide. Mass ratio of graphene oxide and carbon nanotube was determined as 3:1 at presenting greatest performance of preventing coagulation. Four different weight percentage of GOCNT nanocomposite, which are 0.05, 0.2, 0.3 and 0.4 weight percent, were composited with poly(lactic acid) by solution blending method. FESEM morphology determined minor coagulation of GOCNT nanocomopsite for different weight percentage composites. Insignificant crystallinity change was observed in DSC and XRD data. At 0.4 weight percent, it prevented most of UV-B light but was least transparent. GOCNT nanocomposite weight percent was linearly related to ultimate tensile strength of nanocomposite film. The greatest ultimate tensile strength was found at 0.4 weight percent which is 175% stronger than neat poly(lactic acid) film. Oxygen barrier property was improved as GOCNT weight percent increased. 66.57% of oxygen transmission rate was reduced at 0.4 weight percent compared to neat poly(lactic acid). The enhanced oxygen barrier property was ascribed to the outstanding impermeability of hybrid structure GOCNT as well as the strong interfacial adhesion of GOCNT and poly(lactic acid) rather than change of crystallinity. Such a small amount of GOCNT nanocomposite improved mechanical strength and oxygen barrier property while there were no significant change of crystallinity and thermal behavior found.
Integrated Process Design and Techno-Economic Analysis of A Grape Pomace Biorefinery
Jin, Qing (Virginia Tech, 2020-09-09)
Grape pomace (GP) is one of the most abundant and underutilized fruit-derived wastes. GP is generated during winemaking, occupying over 60% of the total solid winery wastes. GP may cause serious environmental problems if it is not properly handled. On the other hand, it is rich in valuable compounds that are worthy of recovery. Although research has been working on GP upgrading, the utilizations are limited to producing a single product (e.g., grape seeds oil or polyphenol powders), which leads to large volumes of secondary wastes left. Therefore, the goal of this study is to develop an integrated process for the comprehensive utilization of GP by the production of multiple value-added products and evaluate its economic feasibility at a commercial scale. First, the chemical composition of different industrial GPs was analyzed to lay the foundation for the process design. Based on the analyzed chemical composition, an integrated process was developed to produce grape oil, polyphenols, and biofuels from GP. In this process, GP was extracted by hexane to produce oil, followed by aqueous ethanol solution extraction to obtain polyphenols. The solid residue rich in structural carbohydrates was then pretreated by alkali to partially remove lignin and enzymatically hydrolyzed to produce monomer sugars. The produced sugars were used as feedstock to produce acetone, butanol and ethanol (ABE) through anaerobic fermentation. Under the optimized conditions, the process was able to produce 71.9 g crude oil, 322.8 g crude polyphenols (equivalent to 72.6 g gallic acid), and 20.7 g ABE from 1 kg dry GP. Besides the valuable products, the process co-generated a large amount (50% of input GP biomass) of secondary waste, which is rich in lignin. Therefore, we further converted the secondary waste to biochars and evaluated their potential application in water purification by removing lead (Pb) from contaminated water. Based on the results, the produced biochar showed a high Pb adsorption ability (134 mg/g), with 66.5% of lead removal achieved within the first 30 min. Experimental and modeling results indicated that both physisorption and chemisorption mechanisms were involved in the Pb adsorption of the biochar. Finally, techno-economic analysis was conducted to evaluate the economic feasibility of the integrated processing of GP into oil, polyphenols, and biochar at an industrial scale. The results showed that compared with generating of single product or dual products, the integrated process aiming to produce multiple products had the best economic performance with the net present value (NPV), internal rate of return (IRR), and payback period of $135.0 million, 47.5%, and 1.8 years, respectively. Sensitivity analysis showed that plant capacity and polyphenol selling price had major impacts on process economics. Therefore, a suggestion for implementing this integrated process is to invest more in the polyphenol production and purification process to generate high-quality polyphenols with a high selling price and running the plant with a large capacity. Overall, we explored a novel integrated process that aims to produce multiple value-added products to increase the economic gain for the wine industry, and at the same time, potentially reduce the environmental burdens caused by GP disposal.
Investigation of Fundamental Relationships to Improve the Sustainability of Unit Loads
Park, Jonghun (Virginia Tech, 2015-06-12)
Sustainability is one of the most critical issues in today's packaging and supply chain industries. With the increase of environmental concerns, there has been a tremendous effort to improve packaging sustainability. However, most of these works have focused on individual packaging components rather than an integrated unit load. In global supply chains, three levels of packaging components (primary, secondary, and tertiary) are commonly assembled in the unit load form to facilitate efficient and economical storage and transport of goods to customers. Unit loads is important to improved, packaging sustainability. This study developed the fundamental information that facilitates understanding and enhanced sustainability of unit loads from two different perspectives: physical interactions and end-of-life options of unit load components. From the physical interaction perspective, the effects of various characteristics of secondary and tertiary packaging components on load-bridging within unit loads are investigated.. Packaging component characteristics investigated included the flute type and size of corrugated paperboard boxes, stretch wrap containment force, and pallet stiffness. From the end-of-life option perspective, process methods and environmental impacts of wood pallet repair in the United States are analyzed to provide fundamental information for accurate life cycle assessment of pallets. The experimental results of this study demonstrate that the size of corrugated paperboard boxes and stretch wrap containment force significantly affected the bridging of loads on pallets. The results regarding load-bridging, verified in this study, provides essential knowledge regarding factors influencing unit load deflection. Pallet design procedure should include the load-bridging effect. For simulated pallets which was comparable to a stringer class wood pallet spanning the width of a storage rack, average deflection in the unit load decreased by 70% when package size increased to 20 in. x 10 in. x 10 in. from 5 in. x 10 in. x 10 in. In addition, average deflection in the unit load consisting of 5 in. x 10 in. x 10 in. packages decreased by 50% when stretch wrap containment force increased to 30 lbs. from zero pounds. Updated design methods that consider the effect of packaging characteristics on unit load deflection can help to reduce the amount of raw materials required to build pallets using current pallet design methodologies. The life cycle inventory analysis results of this study determined that pallet repair is an environmentally beneficial end-of-life option for 48 by 40- inch stringer class wood pallets in terms of greenhouse gas generation. Most wood pallet repair firms in the United States utilized high levels of manual labor with non-automated machinery support. The life cycle inventory results from this study can be a useful resource for researchers as an input to the life cycle assessment.
Physicochemical Properties and Antioxidant Activity of Enzymatic Modified Soy Protein Isolate Films with Lignin
Mohammad Zadeh, Elham (Virginia Tech, 2016-11-17)
In this study, a sustainable packaging system was developed to provide food safety and security. Soy protein isolate (SPI) was enzymatically modified by transglutaminase under different conditions to ensure desirable and optimized enzyme crosslinking activity before film preparation. Physicochemical properties including viscosity and molecular weight distribution of the modified proteins and films were measured. Results confirmed the enzymatic treatment is an effective way to modify the SPI based biopolymeric film. Modified films with the enzyme had significant increases in tensile strength (TS), percent elongation (%E), initial contact angle, and a reduction in swelling and protein solubility properties compared to the control films. FTIR and XRD spectra revealed that the enzyme treatment modified the structure of SPI film matrix. The optimal film preparation conditions achieved in this part were protein denaturation temperature 80 °C, and enzyme incubation time 2hr. We attempted to enhance antioxidant activity of enzymatically modified SPI film with the addition of two types of lignin, alkali lignin (AL) and lignosulphonate (LSS), at different concentrations. Results indicated that AL carried higher radical scavenging ability than LSS. Films containing AL showed high absorption in the UV region, and this UV-blocking ability increased with increasing lignin concentration. Deconvoluted FTIR spectra and XRD results suggested that the addition of lignin caused some changes in secondary structure of the protein matrix. The addition of lignin improved TS and thermal stability of films, but reduced %E as a function of lignin concentration. Radical scavenging activity and UV-blocking ability alongside improvement in physicochemical properties of enzymatic modified SPI film with lignin motivated us to apply this bioplastic in two types of oil, soy oil and fish oil. Results revealed that applying enzymatically modified SPI film with AL and LSS in the inner layer of a soy oil packaging system, decreased oxidation rate to around 75%, and pentanal production to about 40% of control. UV-blocking ability of AL caused reduction in oxidation rate for more than 75% compared with the normal packaging system. The effectiveness of this active packaging system in soy oil was greater than fish oil. Thus, the developed biopolymeric materials may have application to food packaging.
TEMPO-oxidized Nanofibrillated Cellulose Film (NFC) incorporating Graphene Oxide (GO) Nanofillers
Kim, Yoojin (Virginia Tech, 2017-12-15)
The development of a new class of alternative plastics has been encouraged in the past few years due to the serious environmental issues, such as toxicity and carbon dioxide emissions. Hence, the introduction of renewable, biodegradable, and biocompatible materials is becoming critical as substituents of conventional synthetic plastics. To design a new system of novel TEMPO-oxidized cellulose nanofibrils (TOCNs)/graphene oxide (GO) composite, the 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-mediated oxidation was utilized to disintegrate never-dried wood nanofibrillated cellulose (NFC). GO was incorporated through high intensity homogenization and ultrasonication with varying degree of oxidation (0.5X, 1X, and 2X) of NFC and GO percent loadings: 0.4, 1.2, and 2.0wt %. As a result, despite the presence of carboxylate groups and graphene oxide (GO), X-ray diffraction (XRD) test showed the crystallinity of the bio-nanocomposite was not altered. Scanning electron microscopy (SEM) was used to characterize their morphologies. In addition, the thermal stability of TOCN/GO composite decreased upon oxidation level, and dynamic mechanical analysis (DMA) signified strong intermolecular interactions with the improvement in Young's storage modulus, and tensile strength. Fourier transform infrared spectroscopy (FTIR) was employed to see the hydrogen bonds between GO and cellulosic polymer matrix. The oxygen transmission rate (OTR) of TOCN/GO composite decreased. The water vapor permeability (WVP) was not significantly affected by the reinforcement with GO, but the moderate oxidation enhanced the barrier properties. Ultimately, the newly fabricated TOCN/GO composite can be utilized in a wide range of life science applications, such as food and medical industries.
Utilization of Lignin in Biopolymeric Packaging Films
Zadeh, Elham Mohammad; O'Keefe, Sean F.; Kim, Young Teck (ACS Publications, 2018-07-06)
Lignin is a byproduct of agricultural industries and only has limited applications. In this study, lignin was investigated for use in sustainable biopolymeric packaging film. Alkali lignin (AL) and lignosulfonate (LSS) were added to enzymatically modified soy protein isolate (SPI) biopolymeric film with different concentrations with the goal of improvement of film physical and functional properties. A radical scavenging activity test revealed that films containing LSS had values 28 and 6% higher than control and AL-based films, respectively; AL itself (not in films) had significantly higher radical scavenging activity than LSS. This indicates the activity of lignin is affected by interaction with SPI. The higher compatibility between LSS and enzymatically modified SPI resulted in a positive effect on surface smoothness, water absorption, and mechanical properties of LSS-based films. Films containing AL showed a high light absorption range in the UV region, and this UV-blocking ability increased with increasing level of lignin. Deconvoluted Fourier transform infrared spectra confirmed that the addition of lignin resulted in some changes in the secondary structure of the protein matrix, which were aligned with X-ray diffraction results. The addition of lignin improved tensile strength (TS) and thermal stability of films compared to the lignin-free control. This improvement in TS and thermal stability was probably a result of new intermolecular interactions between lignin and SPI. Water vapor permeability of the films containing lignin decreased to 50% of the control because lignin played a role as a filler in the matrix. On the basis of our observations, the incorporation of lignin into biopolymeric film is capable of providing additional benefits and solutions to various industries, such as food, packaging, agriculture, and pharmaceuticals.

Browsing by Author "Kim, Young Teck"

Results Per Page

Sort Options