Poly(hexamethylene isophthalamide) (PA6I) is an amorphous polymer characterized by good physical properties, including temperature resistance and significant gas barrier performances that increase at high relative humidity1. New sulfonated PA6I were prepared by melt polycondensation2 of hexamethylene diamine, isophthalic acid and 3-sulfoisophthalic acid, in different ratios. The obtained ionomeric polyamides were characterized in order to investigate the structure-property relationships. Interestingly, a molar amount of sulfoisophthalic acid equal or higher than 10% makes such polyamides water-soluble. Moreover, the presence of ionic groups induces the formation of new interactions among the polymer chains: as a consequence, a more complex macromolecular network causes an increment of Tg and, accordingly, a lowering of the oxygen transmission rate (OTR) at 50% of relative humidity (RH50). On the other hand, at high humidity degree (RH90), good barrier results are achieved only for low amount of ionic groups: in these conditions the water absorption seem to prevail. These characteristics open for sulfonated PA6I a range of new applications, for example in the field of coating.
Synthesis and characterization of novel water-soluble polyamides with enhanced barrier properties
M. Vannini
;P. Marchese;A. Celli;
2017
Abstract
Poly(hexamethylene isophthalamide) (PA6I) is an amorphous polymer characterized by good physical properties, including temperature resistance and significant gas barrier performances that increase at high relative humidity1. New sulfonated PA6I were prepared by melt polycondensation2 of hexamethylene diamine, isophthalic acid and 3-sulfoisophthalic acid, in different ratios. The obtained ionomeric polyamides were characterized in order to investigate the structure-property relationships. Interestingly, a molar amount of sulfoisophthalic acid equal or higher than 10% makes such polyamides water-soluble. Moreover, the presence of ionic groups induces the formation of new interactions among the polymer chains: as a consequence, a more complex macromolecular network causes an increment of Tg and, accordingly, a lowering of the oxygen transmission rate (OTR) at 50% of relative humidity (RH50). On the other hand, at high humidity degree (RH90), good barrier results are achieved only for low amount of ionic groups: in these conditions the water absorption seem to prevail. These characteristics open for sulfonated PA6I a range of new applications, for example in the field of coating.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
