Tesis doctoral de José Gámez Pérez
This thesis analyzes the structure and induced morphology of sheet and thin plaques obtained by different transformation processes. The sheets and plaques were prepared in different thickness using four polypropylene – based materials: an isopolypropylene homopolymer and three ethylene-propylene block copolymers (epbc) with different ethylene content. the transformation processes used to prepare the sheets and plaques were the following: injection moulding (thicknes of 1, 2 and 3 mm), extrusion – calendering (thickness of 0.5 and 1 mm) and compression molding (thickness of 1 and 2 mm). Some injected plaques and extruded sheets were also submitted to and additional annealing step in order to cause morphological changes and a more homogeneus structure. the structural and morpholigical charachteristics were evaluated by polarized light microscopy (mlp), differential scanning calorimetry (dsc) and wide angle x-ray scattering (waxs). The mechanical properties of the sheets and plaques were determined with normalized tensile tests, performed parallel to the melt flow and transverse directions (md and td, respectively). The fracture properties were evaluated using the post-yielding fracture mechanics, which best describes the fracture behaviour of plastic film and thin sheets, with the essential work of fracture (ewf) technique. The fractured surfaces were observed with scanning electron microscopy (sem). the discussion of the experimental results is focused in investigating the structure – properties relationships in both testing directions (md and td), as a function of the following variables: transformation process, material (ethylene content), annealing treatment and thickness. It is concluded that those variables affect to four processing parameters (cooling rate, shear stress, rheological behaviour and crystallization) which are responsible for the processing induced morphologies and, therefore, for the final mechanical and fracture properties. additio
Datos académicos de la tesis doctoral «Relacion estructura-propieddes en placas y laminas de polipropileno y copolimeros en bloque etileno-propileno obtenidas por diferentes procesos de transformacion.«
- Título de la tesis: Relacion estructura-propieddes en placas y laminas de polipropileno y copolimeros en bloque etileno-propileno obtenidas por diferentes procesos de transformacion.
- Autor: José Gámez Pérez
- Universidad: Politécnica de catalunya
- Fecha de lectura de la tesis: 07/07/2006
Dirección y tribunal
- Director de la tesis
- María LLuisa Maspoch RulduÁ
- Tribunal
- Presidente del tribunal: Antonio Martínez benasat
- cristina Rodriguez gonzalez (vocal)
- jozsef Karger-kocsis (vocal)
- c. Viana julio (vocal)