Details

Autor(en) / Beteiligte

• Lucio, Beatriz
• de la Fuente, José Luis

Titel

Chemorheology and Kinetics of High‐Performance Polyurethane Binders Based on HMDI

Ist Teil von

• Macromolecular materials and engineering, 2021-03, Vol.306 (3), p.n/a

Ort / Verlag

Weinheim: John Wiley & Sons, Inc

Erscheinungsjahr

2021

Quelle

Wiley Online Library

Beschreibungen/Notizen

• Aliphatic diisocyanates, such as 1,6‐hexamethylene diisocyanate (HMDI), are preferred curing agents for the formation of polyurethanes (PUs) in applications where resistance to abrasion or degradation by ultraviolet light takes precedence. Aside from the final properties, the curing agent plays a key role in the bulk manufacturing of such materials, and it mainly affects the polymerization kinetics and their rheology. The copolymerization of HMDI and a metallo‐prepolymer derivative from hydroxyl‐terminated polybutadiene (HTPB) is studied under isothermal conditions (50–80 °C). This study is carried out by means of an indirect method, using both rotational viscometry and dynamic rheometry. At the beginning of the process, the viscosity growth fit well to a first‐order kinetic model. Afterward, the reactive system passes through gelation, from which only rheology is allowed for the investigation of the entire polymerization process. This transition is analyzed in depth together with predictions from percolation theory. The conversion degree is determined from rheological measurements, and then an autocatalytic kinetic model is applied to describe the overall process. Finally, an isoconversional method allows the evolution of activation energy to be studied. This analysis merits attention for the development of high‐performance binders that are of great interest in aerospace propulsion technology. This work describes the chemorheology and the kinetics of high‐performance polyurethane binders based on 1,6‐hexamethylene diisocyanate and a ferrocene‐prepolymer derivative from hydroxyl‐terminated polybutadiene. The Kamal–Sourour model fits well with the overall process, when the four variables are free to be determined. This rheological analysis merits attention for new developments in energetic composite materials of great interest in aerospace propulsion technology.