A New Generation of Highly Branched Polymers:  Hyperbranched, Segmented Poly(urethane urea) Elastomers

A comparative study of the structure–property behavior of highly branched segmented poly(urethane urea) copolymers and their linear analogs

“…These near terminal urea linkages were expected to facilitate inter and intramolecular bidentate hydrogen bonding in these highly branched PUU copolymers. Detailed synthetic procedures are elsewhere [12].…”

“…The hyperbranched polyurethanes, polyureas, or poly-(urethane urea)s discussed above consist only of hard segment (HS) moieties and thus are not segmented, that is, they do not consist of alternating hard and soft segments along the chain backbone. Recently, with the aim of producing branched polymers with a high number of terminal functional groups that also possess useful structural properties, our laboratories reported the synthesis of segmented, highly branched poly(urethane urea)s (PUU) based on the oligomeric A 2 CB 3 approach [12]. In that study, isocyanate end-capped poly(tetramethylene oxide) (PTMO) or poly(propylene oxide) (PPO) was utilized as the oligomeric A 2 , and tris(2-aminoethyl)amine (TRIS) was used as the B 3 monomer.…”

Forced Gelation in an Off‐Stoichiometric Copolymerization of A2 and B3 Monomers

“…Another modification of the polymerization procedure was to dilute the system to halt its gelation. [36,37] Dilution of the system indeed substantially delays gelation due to extensive cyclization.…”

Synthesis and Properties of Hyperbranched Polyurethane with a Long Chain Between the Branching Points

“…Also, the oligomeric A 2 and B 3 methodology offered a facile approach for obtaining products with improved properties and performance. Unal et al [17] and Fornof et al [18] utilized isocyanate end-capped polyether as oligomeric A 2 and triamine or trimethylol as B 3 monomers to get different products. The resulting polymers displayed mechanical properties comparable to their linear analogues [19], but this route needed a lot of solvent to avoid premature gelation.…”