Exploring the elongation properties of a linear polystyrene melt

Details

Supervisors

Van Ruymbeke, Evelyne

Faculty

Ecole polytechnique de Louvain

Degree label

Master [120] : ingénieur civil en chimie et science des matériaux, à finalité spécialisée

Abstract

The rheological behavior of polymers melts plays a crucial role in the industrial world, allowing manufacturers to fine-tune and design their products with specific properties. While our understanding of linear rheology is quite well-developed, with models available to predict the linear viscoelastic properties of polymers with different chemistries and molecular architectures, our knowledge of non-linear elongation properties remains limited. In particular, understanding the impact of temperature and strain rate on these properties is essential for optimizing industrial processes that involve high strain (rate) conditions. Therefore, this study aims to investigate the non-linear elongation properties of polymers, focusing on a commercial polystyrene sample, chosen as it is a linear polymer. The rheological analysis is conducted using a rotational ARES system to assess the linear viscoelastic properties, and a filament stretching VADER system to evaluate non-linear elongation properties. Additionally, mechanical tensile tests are performed on an Instron system, at elevated temperatures, to provide a better understanding of the polymer's elongation properties. A direct comparison between the results obtained from the two non-linear characterization methods cannot directly be established, due to variations in experimental conditions, such as in true strain rate. However, each method has offered valuable insights into the elongation properties of the commercial polystyrene. As a perspective, this study also helped designing a new experimental protocol to bridge rheological and mechanical properties.