The use of in-situ X-ray scattering methods have been widely employed to study polymer uniaxial deformation. Despite these previous studies, there still remains a disconnect between the molecular architecture, i.e. branch content, molecular weight between branches, etc, and the macroscopic mechanical properties. The nature of the uniaxial deformation behavior of polyolefins can be explained using continuum models, a surprisingly simple yet effective example of which is the spring and dashpot model of Haward and Thackray. Such models try and interpret the observed behavior in terms of viscous and elastic components associated with the crystalline and amorphous phases within the semi-crystalline polyolefins. However, these continuum models only provide a very indirect correlation between the observed mechanical behavior and the molecular structure. In this paper we discuss our recent studies of polyethylenes possessing controlled architectures where we have exploited in-situ X-ray scattering to develop a more complete molecular interpretation of the deformation processes. In these studies we incorporate results from both small- and wide- angle X-ray scattering to extract information about the role played by the polymer chains in both the crystalline and equally importantly the amorphous phases of the polyethylenes. These results allow us to make direct correlations between the molecular architecture and the mechanical properties.

Elucidating the relationships between polyethylene architecture and mechanical properties

249th National Meeting (2015)

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