Preparation, Purity, and Homogeneity of NBS Standard Samples 705 and 706, Polystyrene
1Institute for Materials Research, National Bureau of Standards, Washington, D.C. 20234.
Summary
This study details the preparation and analysis of polystyrene standard samples for molecular weight measurement. While some heterogeneity was observed in sample 705, conclusive evidence was not found.
Area of Science:
- Polymer Science
- Analytical Chemistry
- Materials Science
Background:
- Accurate molecular weight determination is crucial for polymer characterization.
- Standard samples are essential for calibrating measurement techniques.
- Previous methods for assessing polymer homogeneity have limitations.
Purpose of the Study:
- To describe the preparation of polystyrene standard samples (705 and 706).
- To evaluate the homogeneity of these standard samples.
- To discuss the state-of-the-art in macromolecular weight measurement.
Main Methods:
- Preparation of polystyrene standard samples.
- Carbon-hydrogen microanalysis.
- Ash determination.
- Lithium analysis.
- Volatiles determination.
- Sampling methods for homogeneity assessment.
Main Results:
- Detailed analytical results for carbon-hydrogen content, ash, lithium, and volatiles are provided.
- Sampling methods were employed to assess sample homogeneity.
- Preliminary evidence suggested potential heterogeneity in lot 705.
Conclusions:
- The study provides a comprehensive description of polystyrene standard preparation and analysis.
- Conclusive evidence for material heterogeneity was not established.
- Further investigation may be needed to confirm or refute heterogeneity in the standard samples.
