Effect of monofunctional and trifunctional modifiers on a phase mixed polyurethane system

Abstract

AbstractThe dynamic mechanical behavior of a phase mixed polyurethane system modified with trifunctional and monofunctional alcohols was investigated and compared with a typical polyurethane system with a difunctional alcohol. Of interest was verifying that the average functionality of the alcohol would determine the dynamic mechanical properties and not whether that functionality was achieved by an equimolar blend of trifunctional and monofunctional alcohols or by a purely difunctional alcohol. The base system consisted of poly(tetramethylene ether)glycol (PTMG) cured with 4,4′‐diphenylmethane diisocyanate (MDI). The trifunctional alcohol was trimethylol propane (TMP). The monofunctional alcohol was decyl alcohol (DA). Samples with a typical difunctional alcohol, 2,2‐dimethyl‐1,3‐propanediol (DMPD), were prepared and their properties compared with those of the above samples. To a first approximation, the properties of TMP‐DA modified polymers are identical to those of DMPD polymers of the same hard segment concentration. These results confirm our hypothesis that the dynamic properties obtained from a combination of a trifunctional alcohol with a monofunctional alcohol are essentially equivalent to those of a difunctional alcohol.