Phase determination of polymer samples with ARL EQUINOX 100 benchtop X-ray diffractometer

Significance of the Topic

Polymers have become indispensable in industries from packaging to automotive components. Their mechanical, thermal and chemical properties are governed by crystalline structure and morphology. Rapid and accessible phase identification techniques are therefore critical for quality control, research and development of new polymer formulations.

Aims and Study Overview

This application note demonstrates how a compact X-ray diffractometer can be used to quickly identify polymer phases. The study focuses on two common plastics – polyethylene (PE) and polypropylene (PP) – assessing whether a benchtop instrument can deliver data quality comparable to conventional floor-standing systems. The goal is to validate a streamlined workflow for routine polymer screening.

Methodology and Instrumentation

The analysis was performed using the Thermo Scientific ARL EQUINOX 100 benchtop X-ray diffractometer. Key characteristics:

• Micro-focus X-ray tube: Cu anode (50 W) or Co anode (15 W) with mirror optics
• No external water chiller or complex peripheral equipment required
• Curved position sensitive detector (CPS) enabling simultaneous real-time acquisition of all diffraction peaks
• Configuration supports both reflection and transmission geometries

Sample preparation involved thin sheets of high density polyethylene (HD PE) and isotactic polypropylene (α-PP). Transmission measurements under Cu-Kα radiation were recorded for 5 minutes per sample. Phase identification was carried out with MDI JADE 2010 software using the ICDD PDF4+ Organic database.

Main Results and Discussion

The diffractograms exhibited well-defined peaks characteristic of HD PE and α-PP. Peak positions and relative intensities matched reference patterns from the PDF4+ database. Data quality rivaled that of higher power laboratory diffractometers, confirming that the benchtop system can reliably distinguish polymer polymorphs within short measurement times.

Benefits and Practical Applications

This workflow offers several advantages for polymer analysis laboratories:

• Portability: instrument can be relocated between laboratories or to field sites without extensive setup
• Speed: five-minute runs allow high sample throughput for routine screening
• Low maintenance: absence of cooling water circuits reduces downtime and operating costs
• User-friendly software integration: MDI JADE and PDF4+ database streamline qualitative phase identification

This approach is suited for quality assurance in polymer manufacturing, failure analysis and research on novel polymer blends.

Future Trends and Potential Applications

Emerging directions include:

• Integration with automated sample changers to support large-scale screening campaigns
• Development of advanced data analysis algorithms for quantitative phase analysis and texture evaluation
• Coupling with in situ environmental chambers to study crystallization kinetics under temperature or humidity control
• Expansion of reference databases to cover biodegradable and specialty polymer formulations

Such enhancements will extend benchtop XRD capabilities beyond simple phase ID toward comprehensive polymer characterization platforms.

Conclusion

The ARL EQUINOX 100 benchtop diffractometer, combined with MDI JADE 2010 and the ICDD PDF4+ Organic database, provides a rapid, reliable solution for polymer phase determination. Its compact design, simplified operation and high data quality make it an effective tool for both laboratory and on-site polymer analysis.

References

1. Welzmiller S., Weicai J. Phase determination of polymer samples with ARL EQUINOX 100 benchtop X-ray diffractometer. Thermo Fisher Scientific Application Note AN41116, 2018.
2. MDI JADE 2010 Software Suite. Materials Data, Inc.
3. ICDD PDF4+ Organic Database. International Centre for Diffraction Data.