Correlation of macroscopic properties of segmented polyurethane and polyurethane-urea elastomers and their structure.
III. Discontinuity in changes of properties of linear polyurethane elastomers with non-crystallizable soft segments the function of rigid and soft mers contents
It has been found that the characteristic course and appearance of discontinuity in functions describing the changes in many properties of PUR elastomers versus their molar content of soft and rigid mers does not depend on the regularity and rigidity of soft mers, if soft segments formed by these mers are amorphous. But, independent on the crystallizability of these segments, the change in chemical structure of soft mers reresults in a substantial differentiation both of the absolute values of macroscopic properties and of the relative changes in these values per unit of change of the G/S ratio, it means of the molar ratio of soft mers to rigid mers. The following macroscopic properties have been determined: stress at 100% and 300% elongation, tensile breaking strength, tear strength, hardness, hydro-abrasive wear. Schob elasticity and elongation at break.
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