Hydrophobization of nanodiamond for polypropylene nanocomposites

Purified and de-aggregated nanodiamonds (ND) synthesized by detonation of explosives provide high surface to volume ratio and unique modification opportunities of their surface groups. In general, ND possesses polar groups, therefore, easily forms agglomerates in non-polar polymer matrix. In this study, the effects of hydro-phobization of ND on the structure and the properties of polypropylene (PP) nanocomposites were investigated. Long alkyl chains of octadecyl amine (ODA) were introduced on the surface of ND with the substitution ratio of 68 %. The structural study showed that the dispersibility of ND was remarkably improved by the hydro-phobization so that the PP/ND-ODA nanocomposites showed higher transparency than that of the PP/ND nanocomposites. The increased crystallinity of PP in the nanocomposites indicates that ND and ND-ODA acted as crystallization nuclei in the nanocomposites. As for the mechanical properties, the increased Young's modulus of PP/ND nanocomposites was further increased by the addition of ND-ODA. The Young's modulus of the nano -composites with 0.5 wt% ND-ODA was 64 % higher than that of PP. The strong reinforcement effects also appeared as high heat resistances of the nanocomposites.

Automated summary

Hydro-phobization of nanodiamonds improved dispersibility, transparency, crystallinity, mechanical properties, and heat resistance of polypropylene nanocomposites.