Study Of Surface Deterrent Coating Technology On High Energy Gun Propellant

To solve the problem of surface deterrent of high-energy propellant,a variety of surface deterrent precursors were designed based on the principle that the remaining hydroxyl groups in nitrocellulose and it can participate in chemical reaction.The feasibility of using them to treat propellants was analyzed.TEGDN gun propellant and DB gun propellant were surface treated.The combustion performance and storage stability of propellants were studied,the concentration distribution of the deterrent was tested.The main findings are as follows:Hexamethylene diisocyanate(HDI),4,4'-xylylene diisocyanate(MDI)and isophorone diisocyanate(IPDI)all cross-link with unesterified hydroxyl groups in nitrocellulose and the reactivity catalyst(DBTL)can significantly improve the crosslinking reaction rate;FTIR tracking results show that HDI and nitrocellulose react completely within 6h under the condition that the mass fraction of the DBTL catalyst accounts for 2%of nitrocellulose.The thermal analysis showed that the pyrolysis temperature of MDI and nitrocellulose sample increased by 48? compared with pure nitrocellulose.Alkoxy organotitanium?organoaluminum compounds and nitrocellulose solution react to form a gel;Alkoxysilane and alkoxyboron compounds and nitrocellulose crosslinked no significant gelation observed.The experiments of dissolution and control variables show that reaction between the alkoxylated organic compounds and the unesterified hydroxyl groups on the nitrocellulose.The results of FTIR indicated that the aluminum alkoxide raw materials is moisture sensitive.The thermal analysis results showed that the thermal stability of organic titanium nitrocellulose gels are poor,the thermal stability of organic aluminum nitrocellulose gel are better,boron acid is generated in organoboron nitrocellulose gel.The boiling point of silicone precursors has great influence on the desensitization process,but the effect is not obvious after the boiling point exceeds 300?.ZT12-DG8 samples were prepared by using n-[3-(trimethoxysilyl)propyl]-benzenamin as a precursor and SJ-DG6 samples prepared by using 3-(2,4-dinitrophenylamino)propyltriethoxysilane as a precursor.The precursor of aluminum isopropoxide and chelated aluminum had poor physical compatibility with propellant,and the expected effect is not obtained.55?60d thermal accelerated aging test results show that the samples of SJ-DG6 has great changes in the color,the reasons may be that the precursor of the desensitizer has poor compatibility with the propellant component.Colesd bomb tests showed the changes in the combustion performance after 30 days of accelerated thermal aging.The combustion performance unchanged during the accelerated thermal aging 30d to 60d.The results showed that there was a small arnount of precursor migration in the sample ZT12A-DG8 in long storage.The analysis shows that the main reason is that the process conditions of the anti-repulsion reaction are not reasonable,part of the precursor did not completely react to form macromolecules,leading to its migration to the interior during the aging process,but it did not change after the last reaction was completed.