Degree of Branching of Highly Branched Polyurethanes Synthesized via the Oligomeric A2 Plus B3 Methodology

✍ Scribed by Ann R. Fornof; Thomas E. Glass; Timothy E. Long

• Publisher: John Wiley and Sons
• Year: 2006
• Tongue: English
• Weight: 279 KB
• Volume: 207
• Category: Article
• ISSN: 1022-1352
• DOI: 10.1002/macp.200600096

✦ Synopsis

Abstract

Summary: The oligomeric A~2~ plus monomeric B~3~ synthetic methodology provided highly branched, poly(ether urethane)s based on TMP (B~3~) and isocyanate endcapped polyethers. ^13^C NMR spectroscopic assignments for the branched polyurethanes were verified using model urethane‐containing compounds based on TMP and a monofunctional isocyanate (either cyclohexyl or phenyl isocyanate (PI)). Derivatization of hydroxyl endgroups with trifluoroacetic anhydride enhanced the ^13^C NMR resolution in spectra for branched polyurethanes. The ^13^C NMR resonance for the linear unit exhibited a broad shoulder due to quaternary carbons that were attributed to cyclic species in the highly branched polyurethanes. The classical DB calculation revealed the efficiency of the B~3~ monomer for branching; however, an equation that incorporated the linear contribution of the A~2~ oligomer provided a more accurate DB for highly branched polyurethanes.

SEC chromatograms for increasing addition of A~2~.

magnified imageSEC chromatograms for increasing addition of A~2~.