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search.filters.applied.f.access: openAccess × End date: 2022 × Type: Article × Version: publishedVersion × Subject: Materials chemistry × WGL Institute: IPF ×

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    Poly(acrylonitrile-co-butadiene) as polymeric crosslinking accelerator for sulphur network formation
    (London [u.a.] : Elsevier, 2020) Hait, Sakrit; Valentín, Juan López; Jiménez, Antonio González; Ortega, Pilar Bernal; Ghosh, Anik Kumar; Stöckelhuber, Klaus Werner; Wießner, Sven; Heinrich, Gert; Das, Amit
    The major controlling factors that determine the various mechanical properties of an elastomer system are type of chemical crosslinking and crosslink density of the polymer network. In this study, a catalytic amount of acrylonitrile butadiene copolymer (NBR) was used as a co-accelerator for the curing of polybutadiene (BR) elastomer. After the addition of this copolymer along with other conventional sulphur ingredients in polybutadiene compounds, a clear and distinct effect on the curing and other physical characteristics was noticed. The crosslinking density of BR was increased, as evidenced by rheometric properties, solid-state NMR and swelling studies. The vulcanization kinetics study revealed a substantial lowering of the activation energy of the sulphur crosslinking process when acrylonitrile butadiene copolymer was used in the formulation. The compounds were also prepared in the presence of carbon black and silica, and it was found that in the carbon black filled system the catalytic effect of the NBR was eminent. The effect was not only reflected in the mechanical performance but also the low-temperature crystallization behavior of BR systems was altered. © 2020 The AuthorsMaterials science; Materials chemistry; Crosslinking accelerator; Sulphur network; Solid state NMR; Curing kinetics; Activation energy; Acrylonitrile butadiene; Polybutadiene; Low-temperature; Crystallization. © 2020 The Authors
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    Mechanochemical route to the synthesis of nanostructured Aluminium nitride
    (London : Nature Publishing Group, 2016) Rounaghi, S.A.; Eshghi, H.; Scudino, S.; Vyalikh, A.; Vanpoucke, D.E.P.; Gruner, W.; Oswald, S.; Rashid, A.R. Kiani; Khoshkhoo, M. Samadi; Scheler, U.; Eckert, J.
    Hexagonal Aluminium nitride (h-AlN) is an important wide-bandgap semiconductor material which is conventionally fabricated by high temperature carbothermal reduction of alumina under toxic ammonia atmosphere. Here we report a simple, low cost and potentially scalable mechanochemical procedure for the green synthesis of nanostructured h-AlN from a powder mixture of Aluminium and melamine precursors. A combination of experimental and theoretical techniques has been employed to provide comprehensive mechanistic insights on the reactivity of melamine, solid state metal-organic interactions and the structural transformation of Al to h-AlN under non-equilibrium ball milling conditions. The results reveal that melamine is adsorbed through the amine groups on the Aluminium surface due to the long-range van der Waals forces. The high energy provided by milling leads to the deammoniation of melamine at the initial stages followed by the polymerization and formation of a carbon nitride network, by the decomposition of the amine groups and, finally, by the subsequent diffusion of nitrogen into the Aluminium structure to form h-AlN.