University of PardubiceFaculty of Chemical Technology

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Rheological Properties of the Polyurethane Adhesives

Authors: Palarczyková Zuzana | Šiška Bedřich | Machač Ivan

Year: 2017

Type of publication: ostatní - přednáška nebo poster

Page from-to: nestránkováno

Titles:

Language	Name	Abstract	Keywords
eng	Rheological Properties of the Polyurethane Adhesives	The work is focused on the determination of rheological characteristics of individual components of polymeric adhesives tested and determination of rheological and mechanical properties of the adhesives in the hardening process. For measuring rheological properties of the adhesive components, a rotational Rheometer HAAKE MARS was employed at the temperatures of 23 °C, 37 °C, and 50 °C. To obtain the adhesive gelation times, a rheometer ARES was employed with the plate-plate measuring system at the temperatures of 23 °C and 50°C. The dynamic mechanical analyser DMA DX04T was used for glass transition determination; the adhesive tensile tests in the hardening process were performed on the universal testing machine Zwick Z050 ROELL. All tested components of PUR adhesives were viscoplastic with a certain degree of yield stress. The flow curve courses showed a shear-thinning and thixotropic behaviour. The three-step tests, carried out to obtain information about thixotropy, showed that the structure of majority tested adhesives did not complete regenerate which detected a false thixotropy (partial regeneration). The values of the renewed viscosity were about 70% of the original ones. The results of oscillatory tests demonstrated that elastic behaviour was dominant for all adhesive components. The isocyanate based components showed a significantly higher elasticity than the polyols based components. The elasticity of an adhesive evidently depends on their mixing ratio. It was found out that adhesive gelation points measured in the hardening process were detected much faster at a higher temperature than at a lower one. Glass transition temperatures of the adhesives were determined from the course of the tangent of the loss angle after one day and after seven days from the beginning of the hardening process. From the tensile tests, the values of the tensile strength and the values of a relative elongation were obtained for each adhesive in the hardening process.	polymeric adhesives;rheological properties;gelation time;glass transition;dhesive tensile tests