Linear thermo-elastic characterization and process -structure -property relationships of thin polymeric films and coatings

• Main Author: Feng, Ru
• Language: ENG
• Published: ScholarWorks@UMass Amherst 2002
• Subjects: Polymers
• Online Access: https://scholarworks.umass.edu/dissertations/AAI3068554

This dissertation presents a procedure to fully characterize the thermal and elastic constants for orthotropic as well as transversely isotropic polymeric films and coatings. Linear elasticity theory was used to describe the response of the studied materials. All of the Young's moduli, shear moduli, Poisson's ratios, and the thermal expansion coefficients (TEC) of the materials were determined. The structure and properties of films or coatings being processed under different conditions were studied, and the relationship of process-structure-property was investigated to instruct the manufacturing of films and coatings with high quality. Sequentially biaxially stretched PET films that were heat set at different temperatures were characterized in the first project. The compliance matrices of the two studied films were determined by special techniques such as vibrational holographic interferometry, pressure-volume-temperature (PVT) apparatus, high-pressure gas dilatometry, and torsion pendulum. The effects of heat treatments, including heat setting and annealing, on the calorimetric properties, the iso-strain force temperature test (IFTT) results, the thermal expansion and shrinkage behavior, and the structure and orientation of the molecules were also studied. In the second project, a new epoxy based negative photoresist, SU8, was investigated. The influence of three important processing parameters: the baking time, baking temperature, and UV exposure dose, on the thermal and mechanical properties of the resultant coatings were studied in detail, SU8 coatings that were processed or post treated under ten different conditions by Hewlett-Packard Company were characterized. The residual stresses generated during processing and post treatments were measured by holography technique, and the moisture absorption of the coatings was also studied. In the last project, the volume-pressure behavior of porous silica gels with different properties was studied using the PVT apparatus. Mercury as well as water was used as the confining liquid for the PVT measurements. The intrusion pressure, extrusion pressure, and the hysteresis between the pressurizing and depressurizing process were all obtained. Some porous polymeric materials, such as porous PS and SAN, were also studied.