Design and Effects of the Cinnamic Acids Chemical Structures as Organocatalyst on the Polymerization of Benzoxazines.

This study focuses on the catalytic effect of the two geometric isomers of a cinnamic acid derivative,EandZ-forms of 3-methoxycinnamic acid (3OMeCA), analyzing the influence of their chemical structures.EandZ-3OMeCA isomers show very good catalytic effect in the polymerization of benzoxazines, decreasing by 40 and 55 degrees C, respectively, the polymerization temperatures, for catalyst contents of up to 10% w/w. Isothermal polymerizations show that polymerizations are easily realized and analyzed at temperatures as low as 130 degrees C and at much shorter times usingZ-3OMeCA instead ofE-3OMeCA. Thus, both cinnamic acids are good catalysts, withZ-3OMeCA being better. The molecular reasons for this difference and mechanistic implications in benzoxazine polymerizations are also presented.