Thesis (Ph. D.)--West Virginia University, 2002. / Title from document title page. Document formatted into pages; contains xiv, 185 p. : ill. Includes abstract. Includes bibliographical references (p. 158-167).

The mechanical properties of particulate filled polymers are influenced significantly by interfacial interactions. The adhesion between the polymer and the filler depends on the area of the interface and the strength of the interaction. The former is related to specific area of the filler while the strength of the interaction can be modified by surface treatment. This study is focused on comparing the reinforcing ability of muscovite and phlogopite with and without surface treatment. Muscovite and phlogopite are two common forms of mica. Mechanical properties such as Young's modulus, tensile strength, elongation and impact strength were used to compare the reinforcing ability of muscovite and phlogopite in EVA composites. The Young's modulus of the surface treated and non-surface treated composites increased with an increase in filler loading. Composites reinforced with muscovite had similar moduli compared to composites reinforced with phlogopite. The tensile strength of phlogopite reinforced composites increased with an increase in filler content while that of muscovite reinforced composites remained constant. Surface modification by both silane and stearic acid reduced the tensile strength of phlogopite reinforced composites. The tensile strength of stearic acid treated muscovite reinforced composites improved but not to the same extent as the silane treated composites. Both muscovite and phlogopite lead to a lowering of the impact strength at high filler loadings while the tensile impact strength of both muscovite and phlogopite reinforced composites improved when using silane and stearic acid. In non-surface treated systems, muscovite reinforced composites showed an initial increase in elongation while the elongation of phlogopite reinforced composites decreased with an increase in filler loading. Elongation at maximum load values, however, increased at low filler loadings, when using stearic acid. It can be concluded that stearic acid is not an effective coupling agent for mica/EVA composites and that the use of silane for phlogopite reinforced composites does not offer any improvement in mechanical properties. / Dissertation (MSc (Chemical Technology))--University of Pretoria, 2006. / Chemical Engineering / unrestricted

Thermoplastics reinforced with continuous fibers are very promising building materials for the auto industry and consumer electronics to reduce the weight of vehicles and portable devices, and to deliver a high impact tolerance at the same time. Polypropylene is an abundant thermoplastic, and its glass fibers composites make a valuable solution that is suitable for mass production. But the adoption of such composites requires a deep understanding of their mechanical behavior under the relevant loading conditions. In this Ph.D. work, we aim to understand the damage process in continuous glass fiberreinforced polypropylene in detail. We will focus in particular on developing an approach for microscale observation of damage during the out-of-plane loading process and will use these observations for both qualitative and quantitative evaluation of the composite. We will apply our approach to two kinds of polypropylene composites, one of them is specially designed to withstand impact. The comparison between the two types of composites at slow and fast loading cases will shed some light on the effect of the polymer properties on the behavior of composites under out-of-plane loading.

The basic of this work is the construction realization of membrane vacuum press, mark out for shaping thermoplastics by force of membrane. Specially designate for material Twintex. The work deals with the general conception and form this machines. Movement material in machine to the warm up parts and after it to moulding.

No description available.

No description available.

This spraying method for thermoplastic resins is a new manufacturing process for applying thermoplastics to a mold or surface in an efficient way that has the potential of reducing cycle time. Spraying thermoplastic resins is similar to spraying other polymers, such as paint, with the differences being higher pressure and temperature. This method uses an injection molding machine with a modified nozzle to spray the plastic material. In this study, temperature, pressure, and nozzle size were factors that influenced the success of this spraying method. The method of spraying in this study proved spraying without a gas is possible, a statistical analysis of a series of sprayed samples was performed, and a summary of the results is presented. This study is the only known method to use these procedures. The purpose of this thesis is two fold. First, its purpose is to achieve a method of spraying thermoplastic resins without the use of a combustible material. Second, if the spraying method is found to be possible, the thesis investigates what factors, of those selected; have a significant influence on the result? There are other types of spraying plastic methods used currently in industry. One such method, described in the project, is called Flame Spraying. This method, as well as others, has proven to be useful in protecting metals, wood, and other materials from harsh environmental and chemical elements. The results of this study proved that gasless spraying of thermoplastic resin is indeed possible and with further research this method can lead to a new manufacturing process for producing plastic parts or coatings. Future studies can include modifying factors such as temperature, plastic, pressure, tooling, and methods.

The market for nonwoven fabrics has experienced extreme growth in recent years and is expected to double in size from 2010 to 2020. This remarkable growth can be attributed to its numerous applications, ease of manufacturing, and customizable properties such as fabric stiffness, extensibility, and composition. The lifetime of the fabric is extremely important to producers and depends strongly on its micro-mechanical properties. Previously published studies have investigated the bulk fabric properties and the constituent fiber properties. However, nothing has been done to determine the properties of individual thermo-mechanical bonds that connect the constituent fibers of the fabric together. These bonds provide the mechanical integrity of the nonwoven fabrics. This study is the first to examine individual bonds by measuring their mechanical properties via uniaxial tensile tests and by computing the basis weight and orientation of the fibers surrounding the bonds. The results demonstrate that there is a high correlation between the fiber structure around the bond and the bond mechanical properties. The amount and directions of fibers affect how the load is transmitted through the bond and distributed across the fabric. Namely, if there are a few fibers surrounding the bond, or the primary fiber direction is different from the loading direction, then the force sustained by the bond is significantly lower and the bond does not deform. Conversely, if there are many fibers in the loading direction then the bond can sustain a significantly large force and undergoes deformation. The fiber and bond deformation are also observed through microscopic images captured during the uniaxial tensile tests. Ultimately, this research details the results for an effective method to test and analyze the mechanical integrity of thermo-mechanically bond and the lifetime of the nonwoven fabrics. / Master of Science

A cheaper access to space is needed in current times and new technologies need to be developed to reduce the cost of space access to increase productivity. This thesis presents a study on carbon fiber reinforced polymer (CFRP) composites which is an enabling technology for cost reduction in space vehicles. A literature review of the behavior of CFRP composite has been conducted and it was found that the currently used IM7/977 carbon fiber reinforced epoxy composites do not microcrack at a lower number of thermal cycles. Nano-composites and Thermoplastic matrix composites have been found as two promising alternatives for cryogenic applications. With the use of nano sized inclusions in currently used epoxy resins, coefficient of thermal expansion can be reduced while increase in strength and fracture toughness can be achieved. Some thermoplastics were found to have non-linear stress-strain relationships with signs of ductility even at 4.2K. Both of these resin systems show promise in reducing microcracking at cryogenic temperatures.

No description available.