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The Preparation And Properties Of Boron/Nitrocellulose Composite Fibers

Posted on:2017-01-05Degree:MasterType:Thesis
Country:ChinaCandidate:Y HongFull Text:PDF
GTID:2271330488461117Subject:Applied Chemistry
Abstract/Summary:PDF Full Text Request
The addition of nano-sized boron which has high combustion heat to energetic materials can really achieve a higher energy relesse in certain experiment conditions. However, the high surface energy of nanoparticles and the oxide layer formed easily makes nano-boron aggregation, cause ignition difficulty and low energy release efficiency during the combustion of nano-boron. In this work, the electrospinning was employed to fabricate the boron/nitrocellulose(B/NC) composite nanofibers expecting to create a homogeneous dispersion and improve the combustion property of nano-boron in energetic materials.Firstly, the effect of electrospinning process parameters on the B/NC nanofibers was under study. Resulted of the research, the best electrospinning process parameters for preparing B/NC fibers was that the mass ration of 0.25 to 5 of distilled water and acetone mixture solvent,20kV electrospinning vltage,15cm capillary-collector distance and 4mL·h-1. Under this condition, the B/NC composite nanofibers with smooth surface and uniform size were successfully fabricated. Nano-boron was well dispersed in the B/NC fibers with an average diameter of 172nm under the mass ration of 1 to 20 of B to NC.Then the properties of B/NC fibers with different content of boron were studied. From the testing result of scanning electron microscopy (SEM) and the distribution of diameter, nano-boron was well dispersed in the B/NC fibers with good fiber morphology when the mass ration of B to NC was 1 to 20,1 to 10 and 1 to 5. While, the aggregation of nano-boron caused the morphology of B/NC fibers deterioration when the mass ration of B to NC was 1 to 2 and 1 to 1. Resulted of the thermal analysis (TG-DSC) under the air, the mass increase of boron in B/NC fibers was more than that of the pure boron nanopowder, the exothermic peak temperature of the boron was lower than that of the pure boron nanopowder. The digital high-speed video camera and pressure cell were applied to analysis the constant pressure and constant volume combustion behavior of B/NC fibers and the B/NC physical mixture. When the mass ration of B to NC was 1 to 5, the exothermic peak temperature of the boron of B/NC fibers was 34.5℃ lower than that of the pure boron nanopowder, the mass increase of boron was increased form 89.37%(pure boron nanopowder) to 155.22%(B/NC fiber), the constant pressure combustion rate of B/NC fibers was 79% faster than that of the B/NC physical mixture, the constant volume combustion rate of B/NC fibers was 140.39% faster than that of the B/NC physical mixture.Finally, the 3-aminopropyl triethoxy silane (KH-550) was employed to treat the surface of the boron nanoparticles to further improve the dispersion of nano-boron in B/NC nanofibers. Resulted of the research, nano-boron was better dispersed in the B/NC fibers after treatment. When the mass ration of B to NC was 1 to 5, the exothermic peak temperature of the boron of treated B/NC fibers was 37.4℃ lower than that of the untreated B/NC fibers, the mass increase of boron was increased form 155.22%(untreated B/NC fibers) to 183.28% (treated B/NC fibers), the constant volume combustion rate of treated B/NC fibers was 140.46% faster than that of the untreated B/NC fibers.
Keywords/Search Tags:nanoboron, electrospinning, energetic materials, nitrocellulose, nanofiber, propellant
PDF Full Text Request
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