Thermo-mechanical behavior in Poly(methyl methacrylate) with different molecular weights.

Abstract : During manufacturing processes, thermoplastic polymers can be subjected to extensive stretching above their glass transition temperature but below their flowing temperature. Examples can be found in thermoforming and injection stretch blow molding of bottles. To improve the manufacturing techniques, a good understanding of the material behavior from its flow state to its solid state is determinant. Many thermomechanical approaches have been proposed by different authors to catch the material response for amorphous polymers. However, those models don’t describe the material behavior at temperatures higher than the glass transition temperature. To overcome this limitation, we study the material mechanical response under tensile loading at low strain (linear viscoelastic region) and at high strain in the range of temperatures of interest. The main purpose of this work is to understand and to model the mechanical behavior of amorphous polymers from their glass transition temperature up to their flowing temperature accounting the microstructural evolution in the material.