The Synergistic Effect of Rare-Earth Complex Nucleating Agent and Graphene Oxide on the Non-Isothermal Crystallization Behavior of iPP Originating From the Diverse Self-Assembly Morphology

Rare-earth nucleating agent (WBG-II) is a kind of additive for isotactic polypropylene (iPP), which will dissolve into iPP melt during heating and re-aggregate into diverse morphologies during cooling through self-assembly. However, up to now, little work about the influence of graphene oxide (GO) on the self-assembly of WBG-II can be found. Results in this study suggest that via the hydrogen-bond interaction, GO can provide additional nuclei for WBG-II during self-assembly. Consequently, during non-isothermal crystallization, WBG-II and GO present a synergistic effect rather than a superposition effect on the crystallization onset temperature (Tc-on), the crystallization peak temperature (Tc-peak), the crystallization half time (t(1/2)), and the relative content of beta-iPP (K-beta), especially when the final heating temperature (T-f) is higher than 240 degrees C. Specifically, as T-f is lower than 220 degrees C, Tc-on, Tc-peak, t(1/2), and K-beta are insensitive to the weight concentration of GO-ODA (phi(G)), since that little WBG-II is dissolved into iPP melt and the morphology of WBG-II is changed only very slightly; as T-f is higher than 240 degrees C, Tc-on, Tc-peak, and K-beta first decrease to a minimum value with increasing of phi(G), and then increase when phi(G) exceeded 0.2%.