Nanotest Hungary Kft.

Doped PET polymer quantitative regressions

Being a fast, simple and non-destructive method WDXRF has become a desired quality control technique to check for purity and/or trace process contaminants in the manufacturing of PET. The following Quantitative Regression results, created on a Rigaku ZSX Primus II, originate from empirical calibrations using several PET standard samples which were doped with standard additions of zinc sterate (analyzed by Zn concentration), calcium sterate (analyzed by Ca concentration), talc (analyzed by Mg concentration) and sodium benzoate (analyzed by Na concentration). Other spiked additions of Al, Ti, and P were also added to the PET carrier to illustrate a wide variety of complex polymer matrices.

Extruded polyethylene

The SAXS patterns of extruded polyethylene (left) and stretched polyethylene (right). The samples were taken from a 6-pack ring tab. The SAXS data show that extruded polyethylene has slight orientation, whereas the stretched polyethylene becomes oriented. Data were collected at sample to detector distance of 1.5m with Rigaku S-Max3000 standard 3m 3-pinhole SAXS camera.

Ununiform crystalline state of a PET bottle

Plastic bottles must have strength to resist heat and mechanical shock, and these strengths are said to depend on the degree of crystallinity and stretching orientation. A two-dimensional X-ray diffraction image directly reveals information about preferred orientation and the crystalline state of a sample. If the orientation of the molecules is random, the diffraction image is ring-shaped; however if some preferred orientation is present, the image is in the shape of an arc.

Percent crystallinity of polymers

The crystallinity of a material influences many of its characteristics, including mechanical strength, opacity, and thermal properties. In practice, crystallinity measurements are made both for research and development and for quality control. X-ray scattering occurs from both the crystalline and non-crystalline material illuminated with X-rays. The difference between the two types of scattering is in the ordering of the material. Materials, especially polymers, have some amorphous contributions. The ability to deconvolute the amorphous from the crystalline scattering is the key to obtaining a reliable value that is consistent with other techniques such as NMR and calorimetry.

Comparison of wavelength dispersive X-ray fluorescence and energy dispersive X-ray fluorescence techniques

The wavelength-dispersive fluorescence technique (Primini red lines below) has superior resolution and sensitivity, when compared to the alternative energy-dispersive fluorescence method ("EDX" blue lines below). For example, figure below displays the resolving power of the wavelength technique in the area of the titanium (Ti-KA) and barium (Ba-LA) overlap with two distinct peaks, distinguishing it from the amorphous scatter seen in the energy peak at the same region.