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In this project, nanocomposite films and coatings, based on renewable resources, were prepared. A hemicellulose biopolymer, based on xylan, was used as the matrix, and cellulose nanowhiskers (CNWs), as the functional additive. The xylan based matrix is an oxygen, grease and aroma barrier, making it a suitable raw material for packaging applications. Cellulose nanowhiskers were used to improve the mechanical properties and thermal stability of the hemicellulose while improving the barrier properties at high relative humidity. The focus of this thesis was processing and characterization of xylan based nanocomposites’ films and coatings. Two grades of xylans, A and B, and food contact approved plasticizer were used to prepare homogeneous films and coatings of nanocomposites, containing 2.5, 5 and 10 wt% of CNWs. The microscopy study showed no aggregations of CNWs in micro scale. Crosslinking was efficiently performed on A films and coatings, and a crosslinking density of about 70% was obtained. X-ray diffraction studies revealed a semicrystalline structure for A matrices and an amorphous one for B. The addition of CNWs resulted in an increase of crystallinity in both A and B samples. Dynamic mechanical thermal analysis showed that addition of whiskers tended to increase the storage modulus at high temperature (90°C) region. Furthermore, crosslinking as well as small amounts of whiskers (2.5 to 5 wt%) resulted in a shift of tan δ peak of nanocomposites to higher temperatures. Mechanical testing revealed a trend of improved mechanical stability in nanocomposites with small amounts of whiskers, whereas the Young’s modulus, maximum strain and maximum stress increased. However, the mechanical properties decreased at 10 wt% CNW content, probably due to aggregation of whiskers. Moreover, barrier tests, like crisp bag, grease permeability and especially oxygen permeability, indicated improved barrier properties of the materials at moist conditions. In general, improvements in barrier and mechanical performance of the material were observed, resulting from combination of CNW addition and crosslinking. / <p>Validerat; 20111121 (anonymous)</p>

A low-cost, low-temperature packaging concept is proposed for localized sealing and control of the ambient of a device cavity appropriate for Radio-Frequency (RF) Micro- Electro-Mechanical (MEMS) devices, such as resonators and switches. These devices require application specific packaging to facilitate their integration, provide protection from the environment, and control interactions with other circuitry. In order to integrate these devices into standard integrated circuit (IC) process flows and minimize damage due to post-fabrication steps, packaging is performed at the wafer level. In this work Indium and Silver are used to seal a monolithic localized hermetic pack- age. The cavity protecting the device is formed using standard lithography-based processing techniques. Metal walls are built up from the substrate and encapsulated by a glass or silicon lid to create a monolithic micro-hermetic package surrounding a predefined RF microsystem. The bond for the seal is then formed by rapid alloying of Indium and Silver using a temperature greater than that of the melting point of Indium. This ensures that the seal formed can subsequently function at temperatures higher than the melting temperature of pure Indium. This method offers a low-temperature bonding technique with thermal robustness suitable for wafer-level process integration. The ultimate goal is to create a seal in a vacuum environment. In this dissertation, design trade-offs made in wafer-level packaging are explained using thermo-mechanical stress and electrical performance simulations. Prototype passive microwave circuits are packaged using the developed packaging process and the performance of the fabricated circuits before and after packaging is analyzed. The effect of the package on coplanar waveguide structures are characterized by measuring scattering parameters and models are developed as a design tool for wafer-level package integration. The small scale of the localized package is expected to provide greater reliability over conventional full chip packages. / Ph. D.

Energy regulations have shifted commercial retail cases from fluorescent to light emitting-diode lights (LED), however the effect of LED light on milk quality (flavor and nutritional content) has not been thoroughly studied. Packaging efficacy of light protecting additives (LPA) in high-density polyethylene (HDPE) was studied for protection against light-induced oxidation of high-temperature short-time (HTST) 2% milk under fluorescent (1882±993 lux) and LED light (915±150 lux). Milk quality measures included oxidation level, riboflavin (Rb) retention, headspace volatiles, and sensory evaluation were analyzed to determine the interaction between light source, packaging material, and storage time. HDPE packaging included translucent package (0% TiO2) serving as control (light-exposed, light-protected: foil and plastic overwrap) and three LPA packages (low (1.3% TiO2), high (4.9% TiO2), yellow). Rb concentration decreased among all packages (40%-60%) after 72h for both lights. Volatile aldehydes (TBARS), increased in all packages (23%-82%) during storage over 72h at 4C. Sensory evaluation (triangle test) revealed detectable flavor changes at a TBARS value of 0.11 mg/L; LPA packages saw this change starting at 4h and continued through 72h. The high package protected milk flavor effectively at 4h under fluorescent light; yellow package was effective for 4h under LED light. Despite detectable sensory differences, acceptability scores (9-point hedonic scale) were significantly greater for milk exposed to LED light in light-protected and high packages (p<0.05). We conclude that LED light may be less harmful to milk flavor vitamin content, but packaging needs to be improved to maintain milk's ideal flavor past 4h of light exposure. / Master of Science in Life Sciences

This thesis presents the results of research into the performance of advanced polymer dielectrics for the realization of high-power electronic circuits in a miniature form. These polymeric materials must satisfy a number of critical thermal, environmental, and electrical requirements to meet the required performance criteria for microelectronics applications. These desired attributes include thermal stability, low moisture uptake, high breakdown voltage (low leakage current), low dielectric constant, low loss tangent, high glass transition temperature, and low surface roughness. The use of these polymers allows for advanced electronic packaging techniques, resulting in improved system performance and reliability. Research was performed using a commercially available polymer dielectric and evaluated the feasibility of utilizing these materials as interlayer dielectrics in multilayer power electronic circuits. Historically, efforts to develop advanced interlayer dielectric materials have concentrated on promoting their use in high speed digital circuits. However, dielectrics used in power electronics must meet requirements not commonly stressed in designs for digital circuits. Multilayer circuits used in power electronics place a particular emphasis on the material properties of high dielectric strength or breakdown voltage and small values for loss tangent or dissipation factor. The focus of this research has been to characterize these particular properties for a commercially available polymer dielectric. / Master of Science

published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management

Abstract Purpose: The aim of this thesis is to explore the impact of environmental friendly wine packageson wine consumption in Sweden. While there are many different factors influencing this issue,the overall focus of this thesis has been on the perception of the quality of 'Green wine packaging'on behalf of the consumers. Method: A quantitative approach in form of an online survey was followed by an qualitativeapproach in form of semi-structured interviews. While the quantitative approach was the mainapproach, the qualitative approach was used for further interpretation. Conclusions: Despite a great environmental awareness and a great engagement in recyclingactivities in Sweden, the results of this study shows that consumer prefer wine in traditional glassbottles. Quality is considered to be the most important element when purchasing wine and itappears that consumer perceive a low level of quality of wine in Green packages which in turnlowers their aesthetical and hedonic expectations. The quality of the wine appear also to be moreimportant than the environmental issue.

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