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Thermophysical, Interfacial and Decomposition Analyses of Polyhydroxyalkanoates introduced against Organic and Inorganic Surfaces (open access)

Thermophysical, Interfacial and Decomposition Analyses of Polyhydroxyalkanoates introduced against Organic and Inorganic Surfaces

The development of a "cradle-to-cradle" mindset with both material performance during utilization and end of life disposal is a critical need for both ecological and economic considerations. The main limitation to the use of the biopolymers is their mechanical properties. Reinforcements are therefore a good alternative but disposal concerns then arise. Thus the objective of this dissertation is to investigate a biopolymer nanocomposite where the filler is a synthetically prepared layer double hydroxide (inorganic interface); and a biopolymer paper (organic interface) based coating or laminate. The underlying issues driving performance are the packing density of the biopolymer and the interaction with the reinforcement. Since the polyhydroxyalkanoates or PHAs (the biopolymers used for the manufacture of the nanocomposites and coatings) are semicrystalline materials, the glass transition was investigated using dynamic mechanical analysis (DMA) and dielectric spectroscopy (DES), whereas the melt crystallization, cold crystallization and melting points were investigated using differential scanning calorimetry (DSC). Fourier transform infrared (FTIR) spectroscopy was used to estimate crystallinity in the coated material given the low thermal mass of the PHA in the PHA coating. The significant enhancement of the crystallization rate in the PHA nanocomposite was probed using DSC and polarized optical microscopy (POM) and analyzed …
Date: December 2009
Creator: Dagnon, Koffi Leonard
System: The UNT Digital Library
Wettability of Silicon, Silicon Dioxide, and Organosilicate Glass (open access)

Wettability of Silicon, Silicon Dioxide, and Organosilicate Glass

Wetting of a substance has been widely investigated since it has many applications to many different fields. Wetting principles can be applied to better select cleans for front end of line (FEOL) and back end of line (BEOL) cleaning processes. These principles can also be used to help determine processes that best repel water from a semiconductor device. It is known that the value of the dielectric constant in an insulator increases when water is absorbed. These contact angle experiments will determine which processes can eliminate water absorption. Wetting is measured by the contact angle between a solid and a liquid. It is known that roughness plays a crucial role on the wetting of a substance. Different surface groups also affect the wetting of a surface. In this work, it was investigated how wetting was affected by different solid surfaces with different chemistries and different roughness. Four different materials were used: silicon; thermally grown silicon dioxide on silicon; chemically vapor deposited (CVD) silicon dioxide on silicon made from tetraethyl orthosilicate (TEOS); and organosilicate glass (OSG) on silicon. The contact angle of each of the samples was measured using a goniometer. The roughness of the samples was measured by atomic force …
Date: December 2009
Creator: Martinez, Nelson
System: The UNT Digital Library