PMMA-layered silicate intercalated nanocomposites are synthesized using supercritical carbon dioxide (scCO2) to produce ordered materials with significant levels of reinforcement. The scCO2 is used to homogeneously distribute monomer as well as act as a low-viscosity solvent for MMA polymerization. This route allows for synthesis of nanocomposites containing significant levels of organically modified layered silicates (OMLS). Below 40 wt % OMLS, the intercalated nanocomposites exhibit a d spacing commensurate with dimensions of the fully extended surfactant chains. Above 40 wt % OMLS, the composite volume is saturated with inorganic material, and the d spacing decreases to homogeneously distribute the polymer volume. A model for estimating this transition concentration is presented. At concentrations approaching the homogeneously intercalated morphology, the basic mechanical and physical properties of the composite are investigated.

Supercritical carbon dioxide (SC CO2) is used as a reversible plasticizing agent to promote solvent welding in highly oriented LLDPE films. These films are laid up in a quasi‐Isotropic fashion to enhance material properties in all directions. It is shown tht, after processing, the oriented morphology and crystallinity are effectively unchanged. These laminated films are investigated both physically and mechanically. The mechanical strength of laminate interfaces is tested using a T‐Peel test. Tensile properties of the laminated film are evaluated and compared to the single oriented plies. Tear resistance is measured using a single specimen J1C.

Supercritical Carbon Dioxide (SC CO 2 ) is used as a reaction/processing medium in the fabrication of fiber-reinforced composite materials. SC CO 2 allows resin (reactive monomer), to penetrate inside the fibers themselves, partitioning into the amorphous regions of the fiber. The crystal structure then templates polymerization of matrix within the fiber. This process produces a composite that exhibits ultralong-range order from the nanoscale reinforcement of crystals to the macroscale fiber reinforcement of matrix. In addition, SC CO 2 lowers resin viscosity and aids in wetting out Nylon 6,6 fiber reinforcement in a process similar to reaction injection molding (RIM) or resin transfer molding (RTM). This article will discuss the fabrication technique in detail, including process parameters and the structure of resulting composites and morphology of modified fibers.

Recent advancements in SC CO, mediated synthesis and material processing have led to polymer-polymer blends and composite materials with complex morphologies, exhibiting long-range order and orientation on multiple length-scales from the nanometer to the centimeter scale. The material under consideration in this work is a polyamide 6,6 (nylon)/poly (methyl methacrylate) (PMMA) fiber-reinforced composite that was fabricated in a unique SC CO, assisted process. The tensile and flexural properties of these unique composites are studied and the evolution of damage and energy dissipation are monitored through cyclic loading and microscopic analysis of post-stressed composite cross sections. I t is shown that this morphology leads to improved flexural modulus and increased ultimate strength with only a small decrease in tensile modulus. These composites also exhibited significant improvements in stress distribution and load transfer without the use of fiber sizing agents for fiber/matrix compatibilization. 546FYg. I . Schematic diagram of high pressure CO, fabrication facility.

The 3D-IC stacking technology provides improved performance, and reduced form factor for applications such as logic-memory integration, image sensors, MEMS, and LED. We present design and fabrication methods to implement Through Silicon Via (TSV) interposer. Cylindrical copper TSV's of 20 μm diameter and 100 μm depth are fabricated in silicon. We present a method for design and process optimization, by recursive enhancement of parameters. Our approach includes selection of materials, proper thicknesses, tolerances, and geometries to achieve the specifications. A discussion on process module optimization and correlation among the whole will be given. We also present an analysis of the relative contribution to cost of each of the modules and identify areas for improvement.