Highly Branched Poly(arylene ether)s via Oligomeric A2 + B3 Strategies

✍ Scribed by Qin Lin; Serkan Unal; Ann R. Fornof; Iskender Yilgor; Timothy E. Long

• Publisher: John Wiley and Sons
• Year: 2006
• Tongue: English
• Weight: 273 KB
• Volume: 207
• Category: Article
• ISSN: 1022-1352
• DOI: 10.1002/macp.200500503

✦ Synopsis

Abstract

Summary: Branched poly(arylene ether)s were prepared in an oligomeric A~2~ + B~3~ polymerization of phenol endcapped telechelic poly(arylene ether sulfone) oligomers as A~2~ and TFPPO as trifunctional monomer B~3~. The molar mass of the A~2~ oligomer significantly influenced the onset of gelation and the DB. A high level of cyclization during polymerization of low molar mass A~2~ oligomers (U~3~ = 660 and U~6~ = 1 200 g · mol^−1^) led to a high conversion of functional groups in the absence of gelation, and the level of cyclization reactions in the polymerization decreased as the molar mass of the A~2~ oligomer was increased. The pronounced steric effect in the polymerization of higher molar mass A~2~ oligomers (U~8~ = 1 800 and U~16~ = 3 400 g · mol^−1^) resulted in low reactivity of the third aryl fluoride in the B~3~ monomer. As a result, only slightly branched (U~8~ = 1 800 g · mol^−1^) or nearly linear (U~16~ = 3 400 g · mol^−1^) high molar mass products were obtained with higher molar mass A~2~ oligomers. The branched polymers exhibited lower Mark‐Houwink exponents and [η] relative to linear analogs, and differences between the branched polymers and linear analogs were less significant as the molar mass of the A~2~ oligomers was increased due to a decrease in the overall DB.
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