微孔NC/TEGN/RDX复合材料的制备及力学性能
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摘要
以硝化纤维素(NC)、太根(TEGN)、黑索今(RDX)为含能基体,热塑性弹性体?甲基丙烯酸甲酯(MMA)为粘结剂,通过溶剂法挤压成型工艺,利用超临界二氧化碳(SC?CO_2)发泡技术制备了微孔NC/TEGN/RDX复合材料,通过扫描电子显微镜和简支梁冲击仪分别研究了该复合材料的泡孔形貌和力学性能。结果表明,提高饱和压力有利于减小泡孔尺寸提高泡孔密度;随着发泡温度的增加,泡孔尺寸逐渐增大,泡孔密度呈现出先增大后减小的趋势;热塑性弹性体的含量由5%提高到15%时,冲击强度可提高37.74%;饱和压力为10～25 MPa时,微孔NC/TEGN/RDX复合材料的冲击强度由3.21 kJ·m~(-2)提高到4.31 kJ·m~(-2),但是随着发泡温度的增加,冲击强度却逐渐下降;泡孔尺寸、泡孔密度皆是影响微孔NC/TEGN/RDX复合材料力学性能的重要因素,致密均匀的泡孔结构可有效改善力学性能。
Micro?porous combustible composites of NC/TEGN/RDX were fabricated by the extrusion molding process of solvent method and supercritical carbon dioxide(SC?CO_2) foaming technique using nitrocellulose(NC),triethylene glycol dinitrate(TEGN) and cyclotrimethylenetrinitramine(RDX) as energetic matrix, and thermoplastic elastomer?methyl methacrylate(MMA)as binder. Scanning electron microscopy and impact test of simple supported beam were used to investigate the cell morphology and mechanical property of the composite,respectively. Results show that increasing the saturation pressure is beneficial to reducing the pore size and increasing the pore density. With increasing the foaming temperature,the cell size of the composites gradually increases,and the cell density shows a trend of increasing first and then decreasing. When the content of ther?moplastic elastomer increases from 5% to 15%,the impact strength can increase by 37.74%. The impact strength of the micro?porous combustible composites of NC/TEGN/RDX increases from 3.21 kJ·m~(-2) to 4.31 kJ·m~(-2) when the saturation pressure is in the range of 10 MPa to 25 MPa. However,the impact strength gradually decreases with the increase of foaming temperature. Cell size and cell density are important factors affecting the mechanical properties of NC?based energetic micro?porous composites,and the dense and uniform cell structure can effectively improve the mechanical properties.
Micro?porous combustible composites of NC/TEGN/RDX were fabricated by the extrusion molding process of solvent method and supercritical carbon dioxide(SC?CO_2) foaming technique using nitrocellulose(NC),triethylene glycol dinitrate(TEGN) and cyclotrimethylenetrinitramine(RDX) as energetic matrix, and thermoplastic elastomer?methyl methacrylate(MMA)as binder. Scanning electron microscopy and impact test of simple supported beam were used to investigate the cell morphology and mechanical property of the composite,respectively. Results show that increasing the saturation pressure is beneficial to reducing the pore size and increasing the pore density. With increasing the foaming temperature,the cell size of the composites gradually increases,and the cell density shows a trend of increasing first and then decreasing. When the content of ther?moplastic elastomer increases from 5% to 15%,the impact strength can increase by 37.74%. The impact strength of the micro?porous combustible composites of NC/TEGN/RDX increases from 3.21 kJ·m~(-2) to 4.31 kJ·m~(-2) when the saturation pressure is in the range of 10 MPa to 25 MPa. However,the impact strength gradually decreases with the increase of foaming temperature. Cell size and cell density are important factors affecting the mechanical properties of NC?based energetic micro?porous composites,and the dense and uniform cell structure can effectively improve the mechanical properties.
引文
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[8]Yang C,Xing Z,Wang M,et al.Merits of the addition of PTFEmicropowder in supercritical carbon dioxide foaming of polypropylene:ultrahigh cell density,high tensile strength,and good sound insulation[J].Industrial&Engineering Chemistry Research,2018,57(5):1498-1505.
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[10]Fan X,Tan H,Lei Z.Influence of thermoplastic polyurethane on mechanical properties of modified double base propellants[J].Journal of Propulsion Technology,2008,29(1):124-128.
[11]Ding Y,Wei R,Ying S.Solubility and diffusivity of supercritical carbon dioxide in cellulose acetate with cosolvents[J].Journal of Elastomers and Plastics,2017,49(1):23-36.
[12]杨伟涛.基于超临界流体发泡技术微孔可燃药筒的制备与性能研究[D].南京:南京理工大学,2015.YANG Wei-tao.Fabrication and performances of microcellular combustible cartridge case using of supercritical CO2[D].Nanjing:Nanjing University of Science and Technology,2015.