3. Control

3.1 Control methods

The structural parameters of high-density polyethylenes are measured using laboratory techniques of varying degrees of sophistication.

3.1.1 Crystallinity/density

The degree of crystallinity can be measured by differential thermal analysis, X-ray diffraction or infrared spectroscopy. Indirectly, density measurement provides an estimate of crystallinity. Routine checks focus on density measurement. This is carried out in accordance with NFEN ISO 1183. In most cases, density...