Background Presentation

Posted by Marie Dekou on September 26, 2015

Polymers:

Monomers are linked together to form long chains of polymers. It exits a wide diversity of polymers: crystalline, microcrystalline, amorphous.

illustration of an amorphous and semi-crystalline structure

The material we are going to study is the Polyethylene (PE) a semi-crystalline material. It has a lamellar phase (crystalline structure) with amorphous regions between. Polymers films are mainly used the packaging industry

X-rays scattering:

The X-rays scattering method is used to extract information about the structure of a material in dynamic conditions. The beam is diffracted in different directions depending on the atomical plans directions.

X-rays scattering principle

In the case of our material the XRS images show the electrons density information.

Data Extraction:

A tensile test where performed on the blown films, while taking in-situ scattering measurements. From this test the stress-strain curves as well as the time resolved XRS images were extracted.

process conditions and data extraction

Two types of images can be extrated from the X-rays images. SAXS images (Small Angles X-rays Scattering) whitch in case of our material provides informations on a scale of 1 to 100 nm. WAXS images (Wide Angles X-rays Scattering) on a scale of 0.1 to 10 nm.

SAXS vs WAXS

Previous Project:

During the last class project, the previous group studied the SAXS images. The goal was to generate a Process-Structure linkage. They created a toolbox that predicts the evolution of the material structure during the tensile test in the PC space.

previous project prediction model in the PC space

Sources:

Data Science Solutions to XRD

[1]Structure Property Relationship in Polyethylene Blown Films, Abhiram Kannan

[2]Everything SAXS: small angle scattering patterns collection and correction, Brian Richard Pauw