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Direct Writing of a 90 wt% Particle Loading Nanothermite
Author(s) -
Wang Haiyang,
Shen Jinpeng,
Kline Dylan J.,
Eckman Noah,
Agrawal Niti R.,
Wu Tao,
Wang Peng,
Zachariah Michael R.
Publication year - 2019
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.201806575
Subject(s) - materials science , tetrafluoroethylene , composite material , shear thinning , polymer , particle (ecology) , rheology , combustion , shear rate , cellulose , chemical engineering , organic chemistry , oceanography , chemistry , copolymer , geology , engineering
The additive manufacturing of energetic materials has received worldwide attention. Here, an ink formulation is developed with only 10 wt% of polymers, which can bind a 90 wt% nanothermite using a simple direct‐writing approach. The key additive in the ink is a hybrid polymer of poly(vinylidene fluoride) (PVDF) and hydroxy propyl methyl cellulose (HPMC) in which the former serves as an energetic initiator and a binder, and the latter is a thickening agent and the other binder, which can form a gel. The rheological shear‐thinning properties of the ink are critical to making the formulation at such high loadings printable. The Young's modulus of the printed stick is found to compare favorably with that of poly(tetrafluoroethylene) (PTFE), with a particle packing density at the theoretical maximum. The linear burn rate, mass burn rate, flame temperature, and heat flux are found to be easily adjusted by varying the fuel/oxidizer ratio. The average flame temperatures are as high as ≈2800 K with near‐complete combustion being evident upon examination of the postcombustion products.