267 research outputs found

    Polyamide capsules via soft templating with oil drops—1. Morphological studies of the capsule wall

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    Poly(terephthalamide) microcapsules can be reproducibly and easily prepared by interfacial polycondensation around emulsion droplets in water. Oil drops of cyclohexane/chloroform mixture stabilized with poly(vinyl alcohol) containing terephthaloylchloride serve as soft template. The interfacial polycondensation starts immediately after addition of an amine mixture (hexamethylenediamine/diethylenetriamine). Light and scanning electron microscopy prove the formation of capsules with size distribution in the range from a few up to 100 µm depending on particular composition of the reaction mixture. The morphology of the capsule wall is characterized by precipitated particles. If instead of pure organic solvents a reactive oil phase is used as template, the capsules can serve in subsequent reactions as templates for the synthesis of composite particles. In this way, styrene can be radically polymerized inside the capsule leading to composite capsules. The capsule morphology is determined by the partition of all components between all phases

    Topological mechanochemistry of graphene

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    In view of a formal topology, two common terms, namely, connectivity and adjacency, determine the quality of C-C bonds of sp2 nanocarbons. The feature is the most sensitive point of the inherent topology of the species so that such external action as mechanical deformation should obviously change it and result in particular topological effects. The current paper describes the effects caused by uniaxial tension of a graphene molecule in due course of a mechanochemical reaction. Basing on the molecular theory of graphene, the effects are attributed to both mechanical loading and chemical modification of edge atoms of the molecule. The mechanical behavior is shown to be not only highly anisotropic with respect to the direction of the load application, but greatly dependent on the chemical modification of the molecule edge atoms thus revealing topological character of the graphene deformation.Comment: 9 pages, 10 figures, 1 table. arXiv admin note: text overlap with arXiv:1301.094

    Solid-State Reactivity of Triacetylenes

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