Nowadays, when environmental concerns are becoming increasingly important are there great interest in natural materials and recyclability. The possibility of reusing materials with maintained mechanical properties are essential for sustainability. Today produced approximately 90,000 tons of natural fiber reinforced composites in Europe of those are 40,000 tons compression molded of which the automotive industry uses 95%. Natural fiber reinforced composites is recyclable and therefore interesting in many applications. Also, natural fiber reinforced composites is inexpensive, light in weight and shows decent mechanical properties which makes them attractive to manufactures. However, the problem with natural fiber reinforced composites is the poor adhesion between fiber and matrix, the sensitivity of humidity and their low thermal stability. Those problems could be overcome by addition of compatibilizer and reactive filler. This study will examine the technical requirement in order to develop a sustainable and recyclable biocomposite. It investigates the composition of matrix (polypropylene), fiber (flax), compatibilizer (maleic anhydride grafted polypropylene) and reactive filler (CaO) in order to obtain various combinations of stiffness, strength and processability. The two main methods used for preparing samples were compounding and injection molding. Results shows that 20 wt% flax was the optimal fiber content and that maleic anhydride grafted polypropylene is a very good compatibilizer by enhancing the strength significant. Surprisingly was the strength impaired due to the addition of CaO. The composition of 20 wt% flax, 1 wt% maleic anhydride grafted polypropylene and 79 wt% polypropylene is the technically most favorable composition.

自從槓桿型指數基金於各股票市場發行後，各國主管機關皆紛紛發出聲明表示，該商品並不適合長期持有；因此，該類型投資商品的公開說明書皆會註明不宜長期投資。然而，本研究實證結果發現，持有期間長短並非主要風險來源。雖然，如大家所知，槓桿型指數基金多是以「日」為單位追蹤指數，而導致複利效果 (Compounding Effect) 使基金長期報酬與槓桿倍數不同。 根據算出上述的報酬差異(Return Difference)可以發現不論是正向2倍或是反向1倍皆與台灣50報酬率的標準差有統計上顯著關係。反向1倍皆與台灣50報酬率的標準差有顯著負相關；反之，正向2倍與台灣50報酬率的標準差有顯著正向相關。然而，從已實現乘數(Realized Multiple)的分佈中可發現，不合理值並不隨投資期間越長而越多。意即儘管投資期間越長，並不一定會導致複利效果越大，而與目標槓桿倍數脫節。再者，隨著投資期間越長，波動度(volatility)的對於報酬差異的解釋力越強；因此，若想長期投資槓桿型指數資金，預測標的波動度的能力更顯為重要。 / When we browse the reports about the inverse and leveraged ETF, most of them emphasize that the LETF is not appropriate to long-term investors. However, in this research, we attempt to demonstrate the main factor of the performance of the leveraged and inverse ETF is not how long the LETF we hold, but the volatility of the underlying index or ETF. Observing the empirical test, no matter how long the investment horizon is, the coefficient of the variance of the Taiwan 50 is statistically significant both in the Taiwan 50 Bear -1X and the Taiwan 50 Bull. However, its effect on the Bear -1X is opposite to that on the Bull 2X. First, the relationship between the volatility and the return difference of Taiwan 50 and the Bear -1X is negative. In contrast, the relationship between the volatility and the return difference of Taiwan 50 and the Bull 2X is positive. However, in accordance with the distribution of the realized multiples, the frequency of either the Bear -1X or Bull 2X was not more and more when the holding period is longer. As a result, our research show the variance has a significant effect on both, no matter how long investors hold. If the volatility is moderate, the return difference may be close to zero; then the LETFs would be a convenient way to investors who desire to magnify the market return. Moreover, due to the increasing explanatory power of the volatility, we may make a further inference that whether the compounding effect is positive or negative depends on the volatility, especially within longer holding period. Therefore, without the great ability to forecast the variance, the LETFs are not recommended to the long-term investors.

Putting on or taking off clothes helps the body to stay within the comfortable temperature range (toavoid shivering or sweating) at different activity levels and ambient conditions. Clothes with built-inthermo-regulating properties would mean maintained comfort without putting on or taking off clothesthat frequently. Integration of phase change materials (PCMs) in clothes is one way of achievingthermo-regulating properties. When the body temperature goes up, the PCM melts and absorbs theheat from the body in the form of latent heat (cooling effect). When the temperature drops, the PCMcrystallizes and the stored heat is released again (warming effect).Research on thermo regulating fibres of the bi-component type containing PCM in the core has beenconducted at Swerea IVF in Mölndal, Sweden, for some time. It has been found that high molecularweight HDPE is a suitable viscosity modifier for hydrocarbon waxes used as PCM. The preparation ofcore materials has so far been done in a batch wise fashion in the way that molten wax has beensoaked into pelletized HDPE at around 180°C during prolonged times followed by melt compoundingin a Brabender batch kneader (0.3 kg per batch). Besides being very impractical for larger productionvolumes the method involves long residence times at high temperatures which may induce thermaldegradation reactions. The objective of the present diploma (master’s thesis) work was to develop acontinuous mixing method to produce PCM/HDPE blends and to test the resulting material in bicomponentfibers with a Nylon (PA6) sheath and to characterize the resulting fiber properties in termsof strength and latent heat.It was proven possible to compound HDPE with large amounts (70%) of octadecane (PCM) on aBrabender twin screw extruder. HDPE was metered to the extruder hoper by means of a screw feederand wax was continuously fed to the hoper in the liquid state by means of a heated membrane pump.To facilitate mixing HDPE in form of powder instead of pellets was used. The extruded threads weresolidified in a water bath followed by granulation. Bi-component fibers were successfully producedfrom such materials. Fibers containing 15 to 42% Octadecane were produced showing heat of fusionsin the range 26 to 86 J/g and tenacities in the range 33 to 16 cN/tex. The heat of fusion of the fiberscompares favorable with existing commercial products showing values in the range 5-15 J/g (acrylicand cellulosic fibres containing microencapsulated hydrocarbon waxes). The peak melting point ofoctadecane measured by DSC was found to be depressed some 4-5°C in the fibers compared to pureoctadecane (28°C). Such a melting point depression is important to consider when choosing type ofhydrocarbon wax. / Program: Magisterutbildning i textilteknologi

Durch das Einbringen von Additiven, Füll- und Verstärkungsstoffen in eine polymere Matrix oder durch das Blenden unterschiedlicher Polymere ist es möglich, die Eigenschaften von Kunststoffen gezielt auf den Anwendungsfall hin zu optimieren. Gerade durch diese „Einstellbarkeit“ der Eigenschaften und infolge ihrer vergleichsweise geringen Dichte verdrängen Kunststoffe zunehmend klassische Werkstoffe und erobern so neue Anwendungsgebiete. Die Entwicklung solcher innovativer Kunststoffrezepturen (Compounds) ist jedoch zeitaufwendig und kostenintensiv. Um die gewünschten Gebrauchseigenschaften des Endproduktes zu erreichen, ist oft eine Vielzahl unterschiedlicher Zusatzstoffe erforderlich; somit werden entsprechende Rezepturen schnell sehr komplex. Bei der klassischen Materialentwicklung wird zumeist nicht erfasst/ermittelt, welche Synergien die einzelnen Bestandteile - positiver oder negativer Art - untereinander haben. Eine gezielte systematische Untersuchung dieser Synergien mit klassischen Methoden ist aus Kosten- und Zeitgründen kaum möglich. Für eine zeitgemäße Materialentwicklung sind daher neue Methoden gefragt, die eine schnelle Rezepturvariation, gepaart mit einem schnellen Eigenschaftsscreening, ermöglichen. Mit der Entwicklung des kombinatorischen Compoundier und High Throughput Screening Systems (CC/HTS-Systems) wurde im Rahmen dieser Arbeit eine, auch industriell einsetzbare, Basisanlage für die schnelle Entwicklung von neuen und innovativen Compoundrezepturen erstellt und hinsichtlich der Übertragbarkeit der Ergebnisse verifiziert. Das CC/HTS-System besteht aus: • einem Doppelschneckenextruder (ZSK 18 MegaLab) Eine entscheidende Besonderheit dieses System resultiert aus der Möglichkeit, die Materialzufuhr und damit die Zusammensetzung über rechnergesteuerte Dosierwaagen kontinuierlich zu verändern. Die im Vergleich zur klassischen Vorgehensweise somit vorhandene schnelle Rezepturänderung ermöglicht es in kürzester Zeit, eine große Rezepturvielfalt abzuarbeiten. • einer Flachfolienanlage Durch die direkte Kopplung der Flachfolienanlage mit der Folienextrusion wird der Rezepturgradient in einer Folie, im Sinne einer 1-dimensionalen Library „eingefroren“. • integrierten Prüfeinrichtungen Durch den Einsatz von in das System zu integrierenden unterschiedlichen HTS-Methoden ist eine schnelle und aussagefähige Charakterisierung der so hergestellten Rezepturen direkt online möglich. Erst diese im Rahmen dieser Arbeit entwickelten und validierten mechanischen Online-Prüfungen, als neue HTS-Methoden, ermöglichen durch deren Integration in das Gesamtsystem ein schnelles Materialscreening, indem die im Rahmen des CC hergestellten Folien (Library) online auf ihre mechanische Performance hin geprüft werden. Die mechanische Online-Prüfeinrichtung wurde so konzipiert, dass drei unterschiedliche Tests simultan in einer Vorrichtung durchgeführt werden. Hierbei handelt es sich um: • einen Durchstoßversuch, • einen Weiterreißversuch (wahlweise in oder travers zur Folienabzugsrichtung), • einen modifizierten Zugversuch (wahlweise in oder travers zur Folienabzugsrichtung). Anhand dieser drei zeitgleich online gemessenen Werkstoffkennwerte sind Aussagen über die wichtigsten mechanischen Eigenschaften - Steifigkeit, Zähigkeit und Festigkeit - abhängig von der Werkstoffzusammensetzung möglich. Die Prüfeinrichtungen für den Zug- und den Weiterreißversuch sind so konstruiert, dass sie sich je nach Entwicklungsaufgabe in der Prüfeinrichtung um 90° drehen lassen, um auch mechanische Eigenschaften in und/oder travers zur Folienabzugsrichtung zu ermitteln. Durch das Entfernen der Kerbmesser in der Prüfeinrichtung des Weiterreißversuchs lässt sich dieser zu einem zweiten Online-Zugversuch umrüsten, um z. B. gleichzeitig in und travers zur Folienabzugsrichtung die Zugfestigkeit zu erfassen. Hierdurch ist es möglich, in einem Prozessdurchlauf das anisotrope Werkstoffverhalten rezeptur- und prozessabhängig zu charakterisieren. Die Entwicklung der mechanischen Online-Prüfeinrichtung wurde durch stetige Validierung der Prüfergebnisse abgesichert. Als Ergebnis dieser Validierungsschritte ist festzuhalten, dass die online und offline ermittelten mechanischen Eigenschaften gut miteinander korrelieren. Eine entscheidende Frage beim CC war neben der Korrelierbarkeit der mechanischen Eigenschaften die Zuordnung der Rezepturzusammensetzung - welche sich kontinuierlich infolge der Gradientendosierung verändert - zu den online ermittelten Materialeigenschaften. Hierbei ist das Verweilzeitverhalten des Gesamtsystems, bestehend aus Extruder und Flachfolienanlage, zu berücksichtigen. Zur Beantwortung dieser Fragestellung wurden zunächst verschiedene theoretische Modelle auf ihre Anwendbarkeit hin untersucht. Es konnte gezeigt werden, dass das Double Backflow Cell Model die gewählte Versuchsanordnung am besten beschreibt. Als Ergebnis dieser theoretischen Überlegungen ist festzuhalten, dass für eine gute Korrelation von Rezepturzusammensetzung und online ermittelten Materialeigenschaften nur die System-Totzeit bei hinreichend langer Gradientenzeit zu berücksichtigen ist. Diese Arbeitshypothese konnte durch einen Versuch mittels Gradientenzugabe von Glasfasern von 0 w% auf 30 w% in Polypropylen und anschließender Glührückstandsbestimmung experimentell bestätigt werden. Im Anschluss an die Entwicklung und Validierung des Gesamtsystems (Gradientendosierung und mechanische Online-Prüfung) wurden die Möglichkeiten des CC/HTS-Systems anhand eines praxisrelevanten Zweistoffsystems, bestehend aus Polypropylen und verschiedenen POEs, welche sich im Viskositätsverhältnis zum Polypropylen und dem α-Olefin-Anteil unterscheiden, aufgezeigt. Durch das Blenden von Polypropylen mit einem Polyolefinelastomer (POE) lässt sich Polypropylen schlagzäh modifizieren. Bei einem solchen Blend aus zwei in der Regel nicht mischbaren Polymeren ist die sich einstellende Phasenmorphologie für das mechanische Werkstoffverhalten von entscheidender Bedeutung. Die Phasenmorphologie, also die Form und Größe der POE-Partikel, in der Polypropylenmatrix ist stark von der ausgewählten POE-Type abhängig. Um Aussagen zur Blendmorphologie zu erhalten, wurde im Rahmen dieser Untersuchungen die mechanische Online-Prüfung erstmals mit einer Online-Kleinwinkellichtstreuung als HTS-Methoden gekoppelt. Durch die Online-Kleinwinkellichtstreuung ist es möglich, simultan zu den mechanischen Eigenschaften auch online Rückschlüsse auf die Blendmorphologie zu erhalten. Diese Untersuchungen zeigten, wie die Morphologie und die mechanischen Eigenschaften korrelieren und welche Bedeutung der Auswahl der Blendpartner - des POEs – für das mechanische Werkstoffverhalten zukommt. Interessant war, dass die untersuchten Prozessparameter von untergeordneter Bedeutung für die Performance eines solchen Blends sind. Abschließend wurde die CC/HTS Methode auf eine industrielle Fragestellung - Dreistoffsystem bestehend aus Polypropylen/Glasfasern/Koppler – angewandt. Die Anwendbarkeit des Systems auch auf komplexere Werkstoffzusammensetzungen wurde dabei bestätigt. Es konnte gezeigt werden, dass mit Hilfe dieser Methode / Versuchseinrichtung die Compoundentwicklung deutlich beschleunigt und ressourcenschonender durchgeführt werden kann und die Ergebnisse mit den klassisch erarbeiteten Werten korrelieren.

Blends of poly butylene terephthalate (PBT) and polycarbonate (PC) form a very important class of commercial blends in numerous applications requiring materials with good chemical resistance, impact resistance even at low temperatures, and aesthetic and flow characteristics. PC and PBT are usually blended in a twin screw extruder (TSE). Product melt volume flow rate (MVR) is a property used to monitor product quality while blending the PC/PBT in a twin screw extruder. It is usually measured off line in a quality control laboratory using extrusion plastometer on samples collected discretely during the compounding operation. Typically a target value representing the desired value of the quality characteristics for an in-control process, along with upper and lower control limits are specified. As long as the MVR measurement is within the control limits, the sample is approved and the whole compounded blend is assumed to meet the specification. Otherwise, the blend is rejected. Because of infrequent discrete sampling, corrective actions are usually applied with delay, thus resulting in wasted material. It is important that the produced PC/PBT blend pellets have consistent properties. Variability and fault usually arise from three sources: human errors, feed material variability, and machine operation (i.e. steady state variation). Among these, the latter two are the major ones affecting product quality. The resulting variation in resin properties contributes to increased waste products, larger production cost and dissatisfied customers. Motivated by this, the objective of this project was to study the compounding operation of PC/PBT blend in a twin screw extruder and to develop a feasible methodology that can be applied on-line for monitoring properties of blends on industrial compounding operations employing available extruder input and output variables such as screw speed, material flow rate, die pressure and torque. To achieve this objective, a physics-based model for a twin screw extruder along with a MVR model were developed, examined and adapted for this study, and verified through designed experiments. This dynamic model for a TSE captures the important dynamics, and relates measurable process variables (screw speed, torque, feed rates, pressure etc.) to ones that are not being measured (material holdups and compositions at the partially and filled section along a TSE barrel). This model also provides product quality sensors or inferential estimation techniques for prediction of viscosity and accordingly MVR. The usefulness of the model for inferential MVR sensing and fault diagnosis was demonstrated on experiments performed on a 58 mm co-rotating twin-screw extruder for an industrial compounding operation at a SABIC Innovative Plastics plant involving polycarbonate – poly butylene terephthalate blends. The results showed that the model has the capability of identifying faults (i.e., process deviation from the nominal conditions) in polymer compounding operations with the twin screw extruder. For instance, the die pressure exhibited a change as a function of changes in raw materials and feed composition of PC and PBT. In the presence of deviations from nominal conditions, the die pressure parameters are updated. These die pressure model parameters were identified and updated using the recursive parameter estimation method. The recursive identification of the die pressure parameters was able to capture very well the effects of changes in raw material and/or composition on the die pressure. In addition, the developed MVR model showed a good ability in monitoring product MVR on-line and inferentially from output process variables such as die pressure which enables quick quality control to maintain products within specification limits and to minimize waste production.

In this work, the compounding of polycarbonate (PC) / poly-butylene terephthalate (PBT) blends was studied for the purpose of improving quality of products with reduced wastage and finally to satisfaction of end users. The effect of material rheological characteristics and processing conditions on compounding of PC /PBT was investigated through statistical experiments carried out on a 58 mm twin-screw extruder at SABIC Innovative Plastics Limited (formerly GE Plastics Limited) in Cobourg, Ontario. Melt Volume-Flow Rate (MVR) is the most commonly used property to monitor the quality of products of PC/PBT blends. The MVR was studied with different sampling times and correlations between product properties (melt flow) and processing conditions (screw speed, flow rates) were discussed. The rheological behavior of PC/PBT blends was investigated by dynamic and capillary rheometers. The effects of processing conditions (screw speed, feed rate) on viscosity were measured and it was found that the Cox-Merz rule is not valid for PC/PBT blends. The change of morphology of PC/PBT blends was observed under a scanning electron microscope (SEM) by using different types of samples. Those samples were (i) PC/PBT blends pellets, (ii) PC/PBT blend samples, but collected after completing the rheological tests in the parallel plate rheometer, and (iii) PC/PBT blend samples, but collected after completing the rheological tests in the capillary rheometer. There was evidence that the samples collected after completing the tests in the parallel and capillary rheometer might be degraded due to temperature and time.

Blends of poly butylene terephthalate (PBT) and polycarbonate (PC) form a very important class of commercial blends in numerous applications requiring materials with good chemical resistance, impact resistance even at low temperatures, and aesthetic and flow characteristics. PC and PBT are usually blended in a twin screw extruder (TSE). Product melt volume flow rate (MVR) is a property used to monitor product quality while blending the PC/PBT in a twin screw extruder. It is usually measured off line in a quality control laboratory using extrusion plastometer on samples collected discretely during the compounding operation. Typically a target value representing the desired value of the quality characteristics for an in-control process, along with upper and lower control limits are specified. As long as the MVR measurement is within the control limits, the sample is approved and the whole compounded blend is assumed to meet the specification. Otherwise, the blend is rejected. Because of infrequent discrete sampling, corrective actions are usually applied with delay, thus resulting in wasted material. It is important that the produced PC/PBT blend pellets have consistent properties. Variability and fault usually arise from three sources: human errors, feed material variability, and machine operation (i.e. steady state variation). Among these, the latter two are the major ones affecting product quality. The resulting variation in resin properties contributes to increased waste products, larger production cost and dissatisfied customers. Motivated by this, the objective of this project was to study the compounding operation of PC/PBT blend in a twin screw extruder and to develop a feasible methodology that can be applied on-line for monitoring properties of blends on industrial compounding operations employing available extruder input and output variables such as screw speed, material flow rate, die pressure and torque. To achieve this objective, a physics-based model for a twin screw extruder along with a MVR model were developed, examined and adapted for this study, and verified through designed experiments. This dynamic model for a TSE captures the important dynamics, and relates measurable process variables (screw speed, torque, feed rates, pressure etc.) to ones that are not being measured (material holdups and compositions at the partially and filled section along a TSE barrel). This model also provides product quality sensors or inferential estimation techniques for prediction of viscosity and accordingly MVR. The usefulness of the model for inferential MVR sensing and fault diagnosis was demonstrated on experiments performed on a 58 mm co-rotating twin-screw extruder for an industrial compounding operation at a SABIC Innovative Plastics plant involving polycarbonate – poly butylene terephthalate blends. The results showed that the model has the capability of identifying faults (i.e., process deviation from the nominal conditions) in polymer compounding operations with the twin screw extruder. For instance, the die pressure exhibited a change as a function of changes in raw materials and feed composition of PC and PBT. In the presence of deviations from nominal conditions, the die pressure parameters are updated. These die pressure model parameters were identified and updated using the recursive parameter estimation method. The recursive identification of the die pressure parameters was able to capture very well the effects of changes in raw material and/or composition on the die pressure. In addition, the developed MVR model showed a good ability in monitoring product MVR on-line and inferentially from output process variables such as die pressure which enables quick quality control to maintain products within specification limits and to minimize waste production.

In this work, the compounding of polycarbonate (PC) / poly-butylene terephthalate (PBT) blends was studied for the purpose of improving quality of products with reduced wastage and finally to satisfaction of end users. The effect of material rheological characteristics and processing conditions on compounding of PC /PBT was investigated through statistical experiments carried out on a 58 mm twin-screw extruder at SABIC Innovative Plastics Limited (formerly GE Plastics Limited) in Cobourg, Ontario. Melt Volume-Flow Rate (MVR) is the most commonly used property to monitor the quality of products of PC/PBT blends. The MVR was studied with different sampling times and correlations between product properties (melt flow) and processing conditions (screw speed, flow rates) were discussed. The rheological behavior of PC/PBT blends was investigated by dynamic and capillary rheometers. The effects of processing conditions (screw speed, feed rate) on viscosity were measured and it was found that the Cox-Merz rule is not valid for PC/PBT blends. The change of morphology of PC/PBT blends was observed under a scanning electron microscope (SEM) by using different types of samples. Those samples were (i) PC/PBT blends pellets, (ii) PC/PBT blend samples, but collected after completing the rheological tests in the parallel plate rheometer, and (iii) PC/PBT blend samples, but collected after completing the rheological tests in the capillary rheometer. There was evidence that the samples collected after completing the tests in the parallel and capillary rheometer might be degraded due to temperature and time.

Today, the investigation of fuel economy improvements in internal combustion engines (ICEs) has become the most significant research interest among the automobile manufacturers and researchers. The scarcity of natural resources, progressively increasing oil prices, carbon dioxide taxation and stringent emission regulations all make fuel economy research relevant and compelling. The enhancement of engine performance solely using incylinder techniques is proving increasingly difficult and as a consequence the concept of exhaust energy recovery has emerged as an area of considerable interest. Three main energy recovery systems have been identified that are at various stages of investigation. Vapour power bottoming cycles and turbo-compounding devices have already been applied in commercially available marine engines and automobiles. Although the fuel economy benefits are substantial, system design implications have limited their adaptation due to the additional components and the complexity of the resulting system. In this context, thermo-electric (TE) generation systems, though still in their infancy for vehicle applications have been identified as attractive, promising and solid state candidates of low complexity. The performance of these devices is limited to the relative infancy of materials investigations and module architectures. There is great potential to be explored. The initial modelling work reported in this study shows that with current materials and construction technology, thermo-electric devices could be produced to displace the alternator of the light duty vehicles, providing the fuel economy benefits of 3.9%-4.7% for passenger cars and 7.4% for passenger buses. More efficient thermo-electric materials could increase the fuel economy significantly resulting in a substantially improved business case. The dynamic behaviour of the thermo-electric generator (TEG) applied in both, main exhaust gas stream and exhaust gas recirculation (EGR) path of light duty and heavy duty engines were studied through a series of experimental and modelling programs. The analyses of the thermo-electric generation systems have highlighted the need for advanced heat exchanger design as well as the improved materials to enhance the performance of these systems. These research requirements led to the need for a systems evaluation technique typified by hardware-in-the-loop (HIL) testing method to evaluate heat exchange and materials options. HIL methods have been used during this study to estimate both the output power and the exhaust back pressure created by the device. The work has established the feasibility of a new approach to heat exchange devices for thermo-electric systems. Based on design projections and the predicted performance of new materials, the potential to match the performance of established heat recovery methods has been demonstrated.

Thesis Univ. College London, 2006. / Includes bibliographical references and indexes.