Chain end analysis of bisphenol A polysulfone and its relation to molecular weight

✍ Scribed by J. B. Ibieta; D. S. Kalika; L. S. Penn

• Book ID: 101273012
• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 261 KB
• Volume: 36
• Category: Article
• ISSN: 0887-624X
• DOI: 10.1002/(sici)1099-0518(199806)36:8<1309::aid-pola14>3.0.co;2-a

✦ Synopsis

The preparation of amine-terminated polysulfone by step polymerization of the monomers bisphenol A and dichlorodiphenyl sulfone in the presence of endcapping reagent 4-aminophenol was investigated. A persistent problem with end-capping strategy as applied to step polymerization is the presence of end groups other than those introduced by the end-capping reagent. These unintended end groups, which can persist in the polymer product even when 100% of the end-capping reagent has reacted, are associated with a proportionate decrease in polymer chain length. This situation renders quantitative analysis of a single type of end group invalid as a method for molecular weight determination. The presence of unintended end groups does not appear to correlate with a particular set of reaction conditions; unintended end groups were found to occur in polymerizations conducted under strong base conditions (NaOH), under weak base conditions (K 2 CO 3 ), and with a wide range of monomer feed ratios. A scheme for unambiguous quantification of chain ends and molecular weight for end-capped polysulfone is described.