Elution fractionation of crystalline polypropylene

✍ Scribed by Mendelson, Robert A.

• Publisher: Wiley (John Wiley & Sons)
• Year: 1963
• Tongue: English
• Weight: 487 KB
• Volume: 1
• Category: Article
• ISSN: 0449-2951
• DOI: 10.1002/pol.1963.100010713

✦ Synopsis

Abstract

A number of commercial and experimental samples of crystalline polypropylene were fractionated by sand column solvent gradient elution techniques. Two different solvent—nonsolvent systems were studied under several sets of experimental conditions. Deposition of polymer upon the sand from a thermodynamically poor solvent was found to be necessary to achieve selective fractionation according to molecular weights. Both selective and nonselective fractionation results are illustrated with the latter occurring whenever the polymer is deposited upon the substrate from a thermodynamically good solvent. Molecular weight distributions for ten samples are given as obtained from elution fractionation using o‐dichlorobenzene—diethylene glycol monomethyl ether as solvent—nonsolvent system at 168°C. These molecular weight distributions could be adequately described by the logarithmic‐normal probability distribution function found by Wesslau and others to be applicable for linear polyethylene and by Davis and Tobias for polypropylene. Many of the distributions observed in this work were found to be narrower than those previously reported in the literature.