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EFFECTS OF OMEGA-3 FATTY ACIDS ON MILK PRODUCTION RESPONSES AND MILK AND PLASMA FATTY ACIDS IN DAIRY COWS
Get PDFThesis (M.S.)--Michigan State University. Animal Science - Master of Science, 2024The major bioactive omega-3 (n-3) fatty acids (FA) are eicosapentaenoic acid (EPA; 20:5 n-3) and docosahexaenoic acid (DHA; 22:6 n-3). These 2 FA are derived from desaturation and elongation of the essential FA alpha-linolenic acid (ALA; C18:3 n-3). Low conversion rates of ALA into EPA and DHA indicate that dairy cows may benefit from direct supplementation of these conditionally essential FA, especially during periods of prolonged inflammation such as the transition period (Pawlosky et al., 2001; dos Santos Neto et al., 2024; Bradford et al., 2015). The first experiment in this thesis evaluated the effect of increasing abomasal infusion doses of DHA on milk and plasma FA as well as milk production responses. Correlations between DHA absorption and milk and plasma DHA were calculated to determine potential biomarkers of DHA absorption. Abomasal infusion of DHA linearly reduced milk somatic cell count (SCC) and increased DHA in milk fat as well as total plasma lipids, phospholipids (PL), triacylglycerols (TAG), and cholesterol esters (CE). DHA absorption was positively correlated with DHA in total plasma lipids, PL, TAG, and milk fat. The second experiment in this thesis evaluated the effect of feeding a calcium salt enriched in EPA and DHA to dairy cows during the 3 weeks before and 3 weeks after parturition on milk production, plasma metabolites, and milk FA during the first 3 weeks of lactation. Carryover effects of n-3 FA on milk production were also evaluated for 6 weeks post-supplementation. The diet containing EPA and DHA reduced milk fat yield for the first 5 weeks of lactation and tended to reduce yields of 3.5% fat-corrected milk (FCM) and energy-corrected milk (ECM). Supplementing EPA and DHA also reduced yields of de novo and mixed FA in milk. The results from our two studies will help to inform dairy farmers, nutritionists, and researchers on strategies to feed EPA and DHA and estimate absorption of these bioactive FA in dairy cows.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references
The Gargantuan Gap : A Model of User Reactions Toward and Beliefs About Employee Selection Procedures
Get PDFThesis (Ph.D.)--Michigan State University. Psychology - Doctor of Philosophy, 2024Candidate results from multiple employee selection procedures are most often combined clinically using hiring managers\u2019 judgment, but evidence suggests this approach attenuates predictive validity compared to mechanical data combination approaches due to hiring managers\u2019 misconceptions about selection procedures. The present research proposes and tests a model that explains how and why hiring managers determine the extent to which they will utilize candidate results from various selection procedures or sources of candidate information. Specifically, the model posits that utilization is driven by user beliefs about the predictiveness and fairness of procedures, which are in turn informed by nine dimensions of \u201cuser reactions\u201d or perceptions of properties of predictor methods (procedural autonomy, evaluation autonomy, fidelity, fakability, evaluation consistency, and transparency) and predictor constructs (job relatedness, malleability, and development equity). Study 1 tested the model by asking a sample of hiring managers to view and rate selection procedures manipulated into nine predictor method/construct combinations. Results indicated that users\u2019 predictiveness beliefs are a stronger driver of utilization than fairness beliefs; additionally, most dimensions of user reactions predicted utilization intentions in the hypothesized direction. Study 2 evaluated the efficacy of autonomy-based interventions by having a sample of hiring managers view and rate a structured interview or computerized assessment manipulated into high and low levels of autonomy. Results suggested that slightly increasing hiring manager autonomy within standardized selection procedures led to increases in predictiveness beliefs and utilization intentions. Findings have implications for designing selection procedures and tailoring hiring manager communication and training efforts, both with the goal of encouraging utilization of more valid predictors in employee selection decision-making contexts.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references
HIGH OXYGEN AND MOISTURE BARRIER BIODEGRADABLE MATERIAL
Get PDFThesis (Ph.D.)--Michigan State University. Packaging - Doctor of Philosophy, 2024Interest in biodegradable polymers is surging among consumers, businesses, and governments as the accumulation of waste from single-use, petrochemical-based, and non-biodegradable plastics has skyrocketed since the 1960s, with flexible plastics constituting a major part of this surge. However, one major challenge with biodegradable alternatives is their inability to match traditional petrochemical plastics' oxygen and moisture barrier properties, which is critical for maintaining equivalent shelf life. This dissertation addresses several pivotal challenges, presenting innovative solutions within biodegradable polymers. Our research achieved breakthroughs in the extrusion casting of stereocomplex-poly(lactic acid)\u2014SC-PLA films and blends of poly(L-lactic acid)/ poly(D-lactic acid)\u2014PLLA/PDLA in varying ratios, which were not previously documented. We explored the effects of annealing these films from 5 to 30 minutes to enhance crystallization and improve moisture barrier properties. Notably, PDLA served as an effective nucleating agent, significantly accelerating crystallization in blends with as little as 15% PDLA. Further investigations revealed the interplay between density, crystallinity, and barrier properties of PLLA, PDLA, and their blends under varying annealing conditions. Amorphous film samples displayed densities between 1,230 \ub1 6 and 1,243 \ub1 2 kg/m3, while semi-crystalline samples showed higher densities of 1,250 \ub1 8 to 1,257 \ub1 9 kg/m3. Changes in density and crystallinity were analyzed, with findings indicating that homocomplex crystals formed at shorter annealing times exhibit higher densities than stereocomplex crystals forming at longer durations. An innovative lamination technique involving base layers of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) or SC-PLA, coated with a biodegradable polyvinyl alcohol and nanoclay mixture, was developed. This structure was tested for its moisture vapor transmission rate (MVTR) and oxygen transmission rate (OTR), demonstrating promising barrier properties suitable for biodegradable packaging solutions. The MVTR ranged from 20 to 30 g/(m2\ub7d), and the OTR ranged from 54 to 69 cc/(m2\ub7d). We showed that optimizing the structure could obtain either a maximized MVTR of 10 g/(m2 \ub7 d) at 38 \ub0C/90% RH or a maximized OTR of 14.46 cc/(m2\ub7d) at 23 \ub0C/50% RH, both exceptional for a clear biodegradable structure without PVDC or metallization, showcasing low permeability for several biodegradable products. Finally, we assessed the SC-PLA films and the blends\u2019 biodegradability in simulated composting conditions over 120 days. This test was conducted for 120 days of PLLA, PDLA, PLLA/PDLA 50-50, 30-70, and 70-30 films. This study is the first to report on the biodegradation behavior of these materials, particularly highlighting the rapid biodegradation of annealed PLLA/PDLA 50-50 blends compared to slower rates in higher PDLA content films. This is followed by films with higher PDLA content, such as the 30-70 blend with most PDLA. No data on the biodegradation of SC-PLA or PDLA in compost conditions had previously been reported. This comprehensive test provides reassurance and confidence in the biodegradability of our materials. This dissertation contributes significant insights into developing high-performance, biodegradable film structures that offer viable alternatives to traditional plastics and align with global sustainability goals.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references
EXPLORING THE DYNAMICS OF MOTIVATION AND ENGAGEMENT IN MODEL-BASED LEARNING
Get PDFThesis (Ph.D.)--Michigan State University. Plant Biology - Doctor of Philosophy, 2024Attracting and retaining diverse individuals is a core goal for reform efforts within in Science, Technology, Engineering, and Mathematics (STEM) gateway courses. Evidence-based instructional strategies in STEM, including those that incorporate scientific practices, have demonstrated promising findings regarding student learning gains. Inspired by previous findings in an introductory course taught through model-based instruction (MBI), my dissertation aims to gain a better understanding of affective mechanisms involved in the way students across all achievement levels are learning in this context. My dissertation measures student\u2019s motivation, and cognitive and emotional engagement in a model-based, introductory biology context. Using validated survey scales contextualized for a model-based context, I generated student motivational profiles at the beginning and end of a semester to examine how profiles remain stable or change over time, and the relationship between motivational profiles and student achievement level. I also developed and applied tools to measure students\u2019 cognitive and emotional engagement during model-based tasks to study engagement in different model contexts and explore the relationship between engagement and student achievement level. My results found that achievement measures (i.e., grades) did not predict levels of motivation and engagement, which may suggest these as potential mechanisms that explain how and why MBI and other practice-based instructional methods are successful. Continued research into understanding mechanisms that may explain performance differences across student achievement levels can advance pedagogical approaches in STEM and promote persistence and diversity among STEM learners.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references
In Search of Musical Independence : A Critical Realist Exploration of Teacher Decision Making and Learner Processes in High School Choir Classrooms
Get PDFThesis (Ph.D.)--Michigan State University. Music Education - Doctor of Philosophy, 2024Some music education scholars have suggested that large ensemble-based school music instruction is outdated and irrelevant to contemporary society (Kratus, 2007; Williams, 2011), teacher-centric and autocratic (O\u2019Toole, 2005), and complicit in creating teacher-dependent students (Allsup & Benedict, 2008). Recently, Weidner explored musical independence in large instrumental ensembles (2015, 2020), and proposed that student-centered teaching practices may contribute to developing musical independence in band. Although many scholars have examined the concept of musical independence (MI) (Regelski, 1969; Shieh & Allsup, 2016; Stamer, 2002), most have done so from a theoretical viewpoint. There is current empirical work exploring MI in band (Weidner, 2015, 2020), but more research is needed to explore the phenomenon in choirs. New empirical research can help broaden the conceptual understanding of MI, explore how teachers foster MI in choirs, and help uncover what students believe about their opportunities to develop it. In this study, I examined what teachers and learners do in secondary choral settings to develop musical independence. Additionally, I sought to uncover potential structural constraints and affordances which may hinder or support teaching and learning musical independence in choir. The research questions were: 1) What are the skills, dispositions, and agentive characteristics of musically independent students? 2) What instructional decisions do teachers make that facilitate or inhibit musical independence? 3) What are the contextual factors that inhibit or facilitate musical independence in students? To answer these questions, I designed a multiple case study (Yin, 2018) utilizing critical realism (Bhaskar, 2015) as a theoretical and analytical framework. Critical realists seek to explain how a phenomenon happened by considering both potential causal mechanisms and the context within which they may occur (Vincent & O\u2019Mahoney, 2018). Using this lens, I consider the actions of teachers and students as well as potential structural influences upon their actions. I collected data from three research sites. Data sources included (1) field notes of classroom observations, (2) teacher journals, (3) student journals, (4) teacher interviews, and (5) student interviews. I analyzed data through the critical realist process of retroduction (Wynn & Williams, 2012) by first making inferences as to probable causal mechanisms for musical independence. Then, I compared proposed causal mechanisms to data found in multiple streams of evidence (e.g., interviews, field notes, and journal entries), moving from open to axial coding (Strauss & Corbin, 2014). I first looked within each case (Creswell & Poth, 2018) using pattern-matching logic (Yin, 2018) to compare empirical data to patterns I predicted through retroduction. Then I engaged in cross-case analysis to determine if patterns persisted over multiple cases. My cross-case analysis suggested that teachers and students may have different perceptions of MI. Some teachers believed helping students develop skills was most important to MI, whereas many students felt that MI was better defined by an ability to communicate emotional intent and form social connections through music. Participants also considered the role of outside structural influences upon MI such as community expectations, professional pressures, and state festival results. Based on the findings from each case and the cross-case analysis, I offered implications for music teacher education and practicing high school choir teachers, including rethinking the role of notational literacy in choral music, balancing large-group and small group learning experiences, and the importance of creative music making in choral ensembles.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references
PREDICTING Z-STRENGTH IN POLYMER EXTRUSION ADDITIVE MANUFACTURING
No full textThesis (Ph.D.)--Michigan State University. Civil Engineering - Doctor of Philosophy, 2024Material extrusion-based polymer additive manufacturing (AM) processes such as fused deposition modeling (FDM) or fused filament fabrication (FFF) are increasingly being used for large-scale structural applications, necessitating an understanding of the underlying structure-process-property relationships in order to predict performance under load. The strength of material extrusion AM parts along the build direction, and perpendicular to the extruded strands, commonly referred to as \u201cZ-strength\u201d is of particular interest since it is lower than the strength along the extruded strand direction and is a limiting factor in design. Furthermore, the Z-strength is sensitive to the process parameters of the print and could change depending on the geometry of the part, or even at different locations within the same part. This presents a challenge for the qualification and characterization of the part\u2019s structural performance and highlights the need for predictive models for Z-strength. The inter-dependence of process parameters further exacerbates the problem by making it difficult to independently control the parameters and characterize Z-strength using purely an experimental approach.Extensive studies have been performed in the literature to build analytical and computational predictive models for polymer AM. However, they all focus exclusively on polymer chain diffusion to predict interlayer adhesion strength, or coalescence to predict effective bead shape and contact area. While these are important contributors to Z-strength, there is a lack of a holistic predictive model that combines these factors together, along with other mechanical factors such as the effect of surface stress concentrations. Surface stress concentrations are especially critical with recent trends towards large format additive manufacturing which uses brittle, filled polymers, and also prints with tall layer heights \u2013 both of which increase the material sensitivity to surface notches. In this work, it was experimentally demonstrated that up to 38% of strength reduction could be attributed solely to the presence of surface beads. The theoretical stress concentration factors (kt) associated with the surface bead shapes were quantified using meso-scale finite element analysis (FEA) with detailed/realistic modeling of the individual beads. Critical parameters influencing kt were identified and parametric FEA studies were performed by varying the geometric parameters. A single empirical equation that can be used for determining kt for any bead shape was generated. In addition, a guideline was proposed for the effective wall thickness to be used when determining nominal stress (FEA or otherwise) such that kt is independent of the direction or type of load applied. Next, a novel framework for predicting Z-strength was proposed by breaking it down into a combination of interlayer adhesion, bead geometry, effective contact area, surface stress concentrations, and notch sensitivity. Interlayer adhesion was determined using a polymer chain diffusion-based model through indirect characterization of weld time, and validated using tensile test data at the coupon level. The evolution of the bead shape and its associated parameters was determined using a coalescence model. The resulting bead shape was used to obtain kt, which was then applied to the interlayer adhesion strength to predict the effective Z-strength. The results were validated with an extensive database of tensile test coupons cut from the walls of AM parts, with over 50 combinations of different process parameters including layer height, extrusion temperature, layer time, and print angle (layer offset). The methodology was successfully integrated into existing commercial software GENOA 3DP along with finite element software ABAQUS and validated to predict part-level structural performance with variable Z-strength. Overall, this work creates a holistic framework for predicting Z-strength in polymer AM as a function of process parameters.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references
TOWARD RESILIENT COMMUNITIES \u2013 VULNERABILITY ASSESSMENTS OF COUPLED HUMAN AND NATURAL SYSTEMS
No full textThesis (Ph.D.)--Michigan State University. Geography - Doctor of Philosophy, 2024Efforts to comprehend and assess social vulnerability amidst environmental hazard events are crucial for fostering adaptive and resilient communities, thereby mitigating risks posed to humans by environmental hazards. However, the intricate interactions between humans and environmental hazards give rise to highly interactive and complex systems, commonly known as coupled human and natural systems (CHANS), necessitating a nuanced approach for accurately assessing environmental and social vulnerability. This dissertation bridges a research gap and provides novel insights into social vulnerability within CHANS, such as understanding the dynamics that the behaviors of one stakeholder group can influence another stakeholder group in the system by affecting the environment, using Lake Erie's harmful algal blooms (HABs) as a case study.This dissertation comprises three main chapters, each offering distinct perspectives. Chapter Two introduces a 5-theme hierarchical spatial framework for assessing social vulnerability to HABs at the county level. This framework not only generates a vulnerability index composed of socioeconomic, resource dependence, and spatial factors affecting vulnerability to HAB events but also provides a practical tool for policymakers and professionals to identify and prioritize communities for intervention. Chapter Three focuses on developing an integrated agent-based and multicriteria evaluation model aimed at simulating the dynamics in the system to pinpoint communities with high vulnerability. The agent-based section of the model simulates the CHANS from a bottom-up perspective to ensure the inclusion of interactions and dynamics, making the model more realistic and applicable. The model outputs are then used in the multicriteria evaluation section, which incorporates criteria representing the three pillars of social vulnerability factors suggested by the Intergovernmental Panel on Climate Change. In Chapter Four, sensitivity and scenario analyses are conducted to scrutinize the model's behavior, introduced in Chapter Three, shedding light on contributing factors to community vulnerability and providing insights for future research and policy development. This dissertation has identified high-vulnerability areas affected by Lake Erie HABs, offering significant insights into environmental and social vulnerability and thereby informing crucial policymaking recommendations. The studies yield three major findings: 1) The social vulnerability indices to harmful algal blooms, generated from both models in Chapters Two and Three, present clear spatial patterns; 2) The spatial distribution of the resulting indices, along with the social status of spatial units, provides valuable information to prioritize policy implementation, e.g., census tracts around the center of Lucas County, and inform targeted policies, e.g., focusing on alternative drinking water resource accessibility to enhance community resilience for most tracts in Wood County; and 3) Selected best management practices, such as cover crops, play a significant role in mitigating HAB severity in Lake Erie in the long run. The intellectual merit of this dissertation is twofold. Methodologically, through the adaptive agent-based and multicriteria analysis framework, we advocate for increased focus on addressing the inherent multifaceted complexities of the vulnerability within CHANS. This includes understanding how the behaviors of one component in a system indirectly affect another component by influencing the severity of environmental hazard events, thereby enriching the research field of environmental social vulnerability. From the perspective of applied science, these studies yield insights crucial for guiding targeted community adaptation policies to lessen the negative societal impacts of HABs in Lake Erie and enhance community resilience in the study area by informing agricultural regulations to mitigate HAB severity in the lake and other aquatic systems prone to HABs.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references
DISABILITY STUDIES IN SPECIAL EDUCATION : A PERSONAL AND SYSTEMIC EXPLORATION
Get PDFThesis (Ph.D.)--Michigan State University. Special Education - Doctor of Philosophy, 2024This dissertation explores the intersection of disability studies and special education, focusing on the integration of disability-affirming practices within special education teacher preparation programs. The overarching goal is to enhance the preparation of preservice special education teachers by incorporating disability studies content, promoting a more inclusive and affirming approach to disability in education.Chapter 2 presents a critical autoethnography that examines the author's personal journey of discovering their disabilities\u2014Attention Deficit Hyperactivity Disorder and Autism (AuDHD)\u2014while enrolled in a doctoral program in special education. This exploration highlights the dissonance the author discovered between the prevalent deficit-driven perspectives of disability they were taught in their special education program and disability studies\u2019 more holistic, identity-affirming views of disability that they found through their own identity exploration. The autoethnography delves into the challenges faced by disabled students in higher education, the absence of disabled voices in special education curricula, and the impact of ableism within academic settings. The study underscores the importance of incorporating disability studies perspectives to foster a more inclusive and supportive educational environment for disabled students. Chapter 3 critically examines the extent to which disability studies content is included in introductory special education courses across 10 of the top 12 undergraduate programs in the US. Through a transformative analysis of course syllabi, this study reveals a significant gap in the integration of disability studies concepts within preservice special education teacher preparation. The findings indicate that current curricula predominantly adhere to a medical model of disability, emphasizing deficits and interventions rather than a holistic understanding of disability identity and culture. This study advocates for the inclusion of disability studies perspectives to enrich the training of future special educators, promoting a more comprehensive and inclusive approach to teaching disabled students. Building on the findings from Chapter 3, Chapter 4 offers practical recommendations for integrating disability studies content into an introductory special education teacher preparation course. This practitioner-focused guide provides a roadmap for incorporating disability-affirming practices, including a sample syllabus, assignments, and project ideas. The recommendations aim to equip instructors with the tools to provide future special educators with the knowledge and skills necessary to foster an inclusive classroom environment that respects and celebrates disability as a part of human diversity. Additionally, the study addresses potential barriers to implementation and offers strategies for overcoming these challenges. Together, this dissertation contributes to the ongoing discourse on the integration of disability studies in special education. By highlighting the tensions between special education and disability studies, the dissertation calls for a paradigm shift in how special education is taught and practiced. The work advocates for a more inclusive and affirming approach that recognizes and values the voices and experiences of disabled individuals. This dissertation ultimately seeks to bridge the divide between special education and disability studies, fostering a more holistic and equitable educational landscape for all students.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references
UNDERSTANDING THE GENETIC MECHANISMS OF DEVELOPMENT RATE IN PETUNIA AND STEVIA
Get PDFThesis (Ph.D.)--Michigan State University. Plant Breeding, Genetics and Biotechnology - Horticulture - Doctor of Philosophy, 2024Development rate, the rate at which plants produce new nodes/leaves, is crucial for determining crop readiness for harvest. Enhancing our genetic understanding and ability to manipulate this rate can lead to faster crop cycles, increased yield, and more efficient production, particularly for plants with short lifecycles or those harvested in the vegetative stage. Despite existing knowledge from other crops like Arabidopsis and rice, significant gaps remain in our understanding of development rate control. This dissertation investigates the genetic mechanisms controlling development rate in Petunia
7 hybrida and Stevia rebaudiana to improve crop timing and yield. Petunia, a popular annual bedding plant, often relies on heated greenhouse production in cooler climates. Identifying genetic factors regulating development rate in petunia is essential for reducing production costs and accelerating development rate at sub-optimal temperatures. The first objective was to evaluate the effect of candidate genes identified in previous studies by using virus-induced gene silencing (VIGS). Despite variable silencing efficiency and phenotypic data variability, the MEI2-like1 RNA binding protein emerged as a promising candidate, warranting further investigation with stable transformation methods. The second study employed an F7 recombinant inbred line (RIL) population developed from P. axillaris and P. exserta (AE population) to identify genes differentially expressed between fast- and slow-developing AE RILs. DEGs included genes related to auxin polar transport, gibberellin signaling, MATE efflux transporters, and the 2OG-Fe(II) dependent oxygenase superfamily, among others. Common DEGs between AE and a previous RIL study involved cell-wall mechanics related genes such as PECTINACETYLESTERASE FAMILY PROTEIN and L-ASCORBATE OXIDASE, providing crucial insights into genetic factors influencing development rate. Stevia, known for its zero-calorie sweetening compounds produced by leaf, benefits from breeding faster-developing varieties to enable multiple harvests per season. Stevia leaf yield depends on morphological traits such as leaf size, leaf production rate, plant canopy width and branch production. An F1 mapping population of 200 individuals was evaluated over two years at two field locations in Michigan for leaf-yield related traits. We generated a novel high-density SNP-based linkage map with eleven linkage groups encompassing eleven chromosomes. QTLs were identified at all four environments for traits such as maximum width, secondary branching, leaf length, and plant vigor, explaining 7-15% of phenotypic variation. Overlapping QTL regions were identified for traits including secondary branching, minimum canopy width, and leaf width explaining 7-15% of phenotypic variation. Differential expression analysis of F1 lines with contrasting development rates highlighted genes related to auxin efflux carrier proteins (PIN-like 2), auxin biosynthesis (YUC2), and cell wall loosening enzymes (EXPANSIN). Notably, CYP78A10, an ortholog of the Arabidopsis KLUH gene known to slow development rate, was upregulated in the slow development rate lines. Results from both species suggest that development rate is a complex process regulated by multiple factors, starting in the shoot apical meristem (SAM) through auxin polar transport, cell wall mechanics, and communication signals from emerging leaf primordia to the SAM. This research lays the foundation for breeding programs aimed at accelerating crop timing and increasing yield, enhancing overall crop production efficiency.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references
Effect of polyglycolic acid and liquid crystal polymer on the performance of polyethylene terephthalate films
No full textThesis (M.S.)--Michigan State University. Packaging - Master of Science, 2024The study aims to develop high-barrier PET films without coatings or laminations using a continuous melt-blending approach. Here, polyethylene terephthalate (PET) is melt-blended with a liquid crystal polymer (Vectra) as well as polyglycolic acid (PGA). In some cases, compatibilizer is also used with PET/PGA and PET/Vectra blends. The scanning electron microscopy analysis reveals improved miscibility within the PET matrix upon incorporating 1 phr Joncryl ADR, enhancing interfacial adhesion and structural integrity. Adding 20 wt% Vectra and 20 wt% PGA to PET reduces oxygen permeability by 41% and 62%, respectively, compared to neat PET. Water vapor barrier properties are also improved by 15% and 41% for 20 wt% Vectra and 20% PGA, respectively. Differential scanning calorimetry studies confirm increased crystallinity of the blends, especially for PET with 20% PGA, where a 71% increase was observed in crystallinity. Moreover, tensile strength is improved by 41% for PET/ PGA blend and 25% for PET/Vectra blend. The tensile modulus is improved by 22% in both blends. Overall, these findings suggest PET blends as potential packaging materials for a longer shelf life for perishable food. This contrasts with multi-layer films, which pose recycling challenges and thus contribute to plastic waste accumulation in the environment.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references