Polyolefin analysis by single-step crystallization fractionation

✍ Scribed by L. J. D. Britto; J. B. P. Soares; A. Penlidis; B. Monrabal

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 415 KB
• Volume: 37
• Category: Article
• ISSN: 0887-6266
• DOI: 10.1002/(sici)1099-0488(19990315)37:6<539::aid-polb6>3.0.co;2-o

✦ Synopsis

Temperature rising elution fractionation (TREF) fractionates polymer chains with respect to their crystallizability, independently of molecular weight effects. In order to achieve a good fractionation, TREF requires a time-consuming polymer deposition step over an inert support before the elution step. A single-step crystallization fractionation method has been developed recently, 1,2 Crystallization Analysis Fractionation (CRYSTAF), in which the chemical composition (or short chain branching) distribution of olefin copolymers can be measured by monitoring on-line polymer concentration in solution at decreasing temperatures. For the present experimental investigation, a CRYSTAF-prototype has been assembled and used to fractionate several linear low-density polyethylene (LLDPE) samples. These results were compared to the ones measured by the commercial CRYSTAF apparatus from Polymer ChAR. Additionally, CRYSTAF results from Polymer ChAR were compared to analytical TREF results.