Rheokinetics of Linear Polybutadiene-Based Polyurethanes Affirms Universal Course of Curing

článek v časopise - ostatní, Jost

angličtina

Curing of sixteen dihydroxypolybutadiene-based polyurethane compositions was studied by oscillatory rheometry in a broad time interval. The compositions contained chain extender only, consequently, preferably physical crosslinks were formed. The individual samples differed also in the miscibility and reactivity of their components. Studied linear polyurethanes showed the same general curing behaviour as chemically crosslinked systems investigated in previous work. Regardless of type of the crosslinks, miscibility and reactivity of components development of structures responsible for the viscous response precede development of the elastically effective structures which is faster at the beginning. Formation and evolution of the physical and chemical networks, in systems of different miscibility or reactivity are in general identical at least from the small deformation standpoint. Mechanical properties of final product are, however, affected by both the reactivity and miscibility of reacting components. Good miscibility is not sufficient to obtain materials with good mechanical properties and should be optimally combined with the component reactivity. Further, depending on the actual composition, the same content of hard segments may lead to polyurethanes with different mechanical properties.

Polyurethane, curing, miscibility, deformation, mechanical properties, hard segment

PEKAŘ, M.; KOPECKÝ, P.

2007

1. 6. 2007

0970-0838

Journal of Polymer Materials

24

2

Indická republika

119

128

10