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

Abstract

Hyperbranched polyurethane (HPU) with a long chain between the branching points was synthesized from isocyanate end-capped polycarbonatediols and diethanolamine via an oligomeric A 2 + CB 2 approach. The effects of the temperature and molar ratio of nPCDL/nNCO on the degree of branching (DB) were studied. The structure of the products was characterized by 13 C-NMR. The results showed that the polymers had a hyperbranched structure and the DB value was 0.75 when the nPCDL/nTDI was 0.5 at 55 • C. The thermal and adhesive properties were investigated by thermogravimetric analysis and tensile test, respectively. The HPUs could be used as hot melt adhesive, and the maximum lap shear strength was up to 6.5 MPa. Moreover, the effects of the length of the chain, reaction temperature and reaction time on the adhesive ability were investigated.