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We computationally study the chiral transition process of the α-Ala molecule under confined different sizes of armchair SWBNNTs to explore the confinement effect. We find that the influence of a confinement environment (in armchair SWBNNTs) on the α-Ala molecule would lead to different reaction pathways. Meanwhile, the preferred reaction pathway is also different in various sizes of armchair SWBNNTs, and their energy barriers for the rate-limiting step decrease rapidly with the decreasing of the diameters of the nanotubes. It is obvious that significant decrease of the chiral transition energy barrier occurs compared with the isolated α-Ala molecule chirality conversion mechanism, by ∼15.6 kcal mol-1, highlighting the improvement in the activity the enantiomers of α-Ala molecule. We concluded that the confinement environment has a significant impact at the nanoscale on the enantiomer transformation process of the chiral molecule. [ABSTRACT FROM AUTHOR]

To enhance the interfacial interaction between rubber and hybrid nanofiller (HS) consisting of halloysite nanotubes and silica, and simultaneously prevent migration and volatilization of rubber additives, commercial vulcanization accelerator N-cyclohexyl-2-benzothiazole sulfenamide (CZ) was chemically grafted onto HS to obtain a functionalized nanofiller (HS-s-CZ). It was found that the grafted CZ molecules within an inorganic host structure have better efficiency to accelerate cross-linking reaction than free CZ molecules. In addition, HS-s-CZ could be evenly dispersed into styrene butadiene rubber (SBR) with further improved filler-rubber interaction compared with that between HS and SBR. Consequently, SBR/HS-s-CZ composites exhibited greater mechanical strength than SBR/HS composites containing equivalent accelerator component, showing 45% increase in tensile strength when the filler content was 40 phr. Potentially, this work offers a new design strategy for the surface modification of nanofiller and preparation of high-efficiency rubber additives, which may represent a new path for preparing high-performance elastomer composites. [ABSTRACT FROM AUTHOR]