Polypropylene (PP)/maleic anhydride grafted poly(styrene-b-ethylene-co-butylene-b-styrene) triblock copolymer (SEBS-g-MA)/halloysite nanotube (HNT) ternary nanocomposites were prepared by two methods: onestep simultaneous melt mixing (SM) of all components; and masterbatch-based melt mixing (MB) involving revolution/rotation-type high shear mixing of a concentrated solution of HNT and SEBS-g-MA, followed by melt blending with PP. Organically modified HNTs (Org-HNTs) with cetyltrimethyl ammonium bromide were prepared via a special cryoscopic expansion/modification technique (C-XP/M). The morphological structures and mechanical properties of the composites, as well as the amount of reinforcer/toughener-compatibilizer (HNT/SEBS-g-MA) at a ratio of 1/3, were discussed as a function of SM and MB techniques. Morphological studies showed that the SM technique revealed microcomposite structures with large aggregates of Org-HNTs in the matrix. In contrast, the MB technique, with the help of elastomeric phase encapsulation, resulted in the best HNT dispersion in the PP matrix, leading to improved mechanical properties. In particular, the PP-based ternary nanocomposite with 3 wt % Org-HNT and 9 wt % SEBS-g-MA prepared by the MB method exhibited 200% higher impact strength compared with PP, attributed to well dispersed, encapsulated, and compatibilized HNTs in the matrix, which created a good balance between stiffness and toughness. POLYM. COMPOS., 00:000-000,

Polypropylene (PP)/maleic anhydride grafted polystyrene-b-poly (ethylene/butylene)-b-polystyrene (SEBS-g-MA)/organophilic halloysite nanotube clay ternary nanocomposites were produced by using HNT/SEBS-g-MA masterbatches at different nanotube loadings (1 wt%, 3 wt%, and 5 wt%). The masterbatches with different ratios of HNT/SEBS-g-MA (1/1, 1/2, and 1/3) were prepared via a revolution/rotation type mixing-assisted masterbatch process. All nanocomposites showed higher storage moduli and damping at low temperatures as compared to neat polypropylene. The nanocomposites having HNT/SEBS-g-MA ratio of 1/3 were found to act as effective dampers with their relatively higher damping values. In terms of short-term creep performance, 1 wt% and 3 wt% organophilic halloysite nanotube loaded systems with low amount of SEBS-g-MA (<9 wt%) enhanced dimensional stability of polypropylene with their lower creep strain and permanent deformation values. More specifically, among the nanocomposites, 3 wt% organophilic halloysite nanotube loaded nanocomposite with HNT/SEBS-g-MA ratio of 1/3 and co-continuous like morphology not only exhibited an effective damping over a wide range of temperature (from −70℃ to 50℃) but also showed relatively higher storage moduli at low temperature region together with lower permanent creep deformation as compared to neat polypropylene. As a result, the HNT/SEBS-g-MA masterbatch in 1/3 ratio was found to be the most suitable in polypropylene blend nanocomposites. It may be advantageous for polypropylene nanocomposite based applications where high damping/toughness at low temperature conditions and high dimensional stability under load are desired.

A series of polypropylene (PP)/poly(ethylene- co-vinyl acetate) (EVA) blend nanocomposites was produced by utilizing different amounts of organophilic halloysite nanotube (Org-HNT) and EVA-based compatibilizers/tougheners. They were prepared by using either only EVA elastomer or using EVA with the compatibilizers which are maleic anhydride grafted EVA (EVA-g-MA) and poly(ethylene-vinyl acetate-carbon monoxide) (EVACO) as well as maleic anhydride grafted PP (PP-g-MA). The morphology–mechanical property relationship was investigated as a function of nature of the compatibilizer and the amount of aluminosilicate nanotube/compatibilizer. The composites prepared without using the EVA-based compatibilizers in all nanotube loading degrees (1%, 3%, 5%) exhibited nanotube aggregates as evidenced by scanning electron microscope analyses. On the other hand, EVA-g-MA and EVACO provided a good dispersion of HNTs at both PP–EVA interface and in the PP matrix. The use of compatibilizers together with 3% Org-HNT resulted in PP/EVA blend nanocomposites with higher tensile modulus and toughness when compared to PP/EVA blend. Particularly, EVACO compatibilizer having highly polar carbonyl group at its backbone provided the highest toughness and Young’s modulus as well as impact resistance for the 3% Org-HNT loaded nanocomposite while retaining the yield strength as an indication of a good balance between stiffness/toughness.

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A novel method based on cryoscopic expansion of halloysite nanotubes via frozen water molecules entrapped in their lumens and subsequent lyophilization was described. Detailed analyses confirmed that the inner and outer diameters as well as the surface area of the nanotubes could be efficiently increased without disturbing the inherent tubular structure. The benefits of cryo‐expanded nanotubes for the enhancement of chitosan hydrogel performances were discussed. The composite hydrogels, depending on their compositions and morphologies, exhibited significantly enhanced swelling and mechanical properties compared with neat chitosan hydrogel. This effect was even more pronounced in the hydrogels containing cryo‐expanded halloysite nanotubes. Although neat chitosan is a selectively good adsorbent for anionic dyes, in the presence of a small amount of cryo‐expanded halloysite, the resultant composite hydrogel can establish a relatively high adsorption capacity for anionic and cationic dyes as a broad‐spectrum dye adsorbent. POLYM. COMPOS., 37:2770–2781, 2016. © 2015 Society of Plastics Engineers