Enhancing the integration of bentonite clay with polycaprolactone by intercalation with a cationic surfactant: effects on clay orientation and composite tensile properties

Abstract

Polycaprolactone (PCL)-based nanocomposites reinforced with different clay loadings (1.5, 3 and 5 wt%) of neat and organo-modified bentonites were successfully fabricated using twin-screw melt extrusion followed by melt compression. The whole processing of the materials, including the organic modification of bentonite with benzalkonium chloride (CBK), which is a mixture of cationic surfactants with biocide properties, and the preparation of the nanocomposites by melt extrusion, was fully carried out at pilot scale. The resulting materials were structurally, thermally and mechanically characterized. Our results suggest that while raw natural bentonite acted as a regular inorganic reinforcement, CBK intercalation enhanced the compatibility of the clay with the polymeric matrix, evidenced in an increase in the tensile strength and Young's modulus in a factor of ca. 2 respect to neat PCL values, with only a 3 wt% organoclay loading. The modified clay presented a strong orientation within the matrix due to the material processing and manufacture, registered by small-angle X-ray scattering experiments.