The Preparation And Performance Research Of Ultra-fine Nitroguanidine

Nitroguanidine (NQ) is a kind of needle like crystalline, which could be directly applied to the explosive. However, the weak fluidity and mechanical performance limit its application. In this paper, granular and superfining NQ was prepared by recrystallization method and mechanical process. What’s more, the mechanical sensitivity and thermal decomposition performance of ultrafine NQ was tested and analyzed, The special content are as follows.Firstly, the preparation process of recrystallization method was studied as follows:water and polyvinyl alcohol (EVA) were used as solvent and growth inhibitor respectively. NQ was solved in a 0.03～0.07% water solution of PVA under high temperature conditions and recrystallized. A low cooling rate was propitious to the crystallizing of granular NQ. When DMF and ethanol were used as solvent and non-solvent, the crystalline of NQ was spherical, and the cooling rate could affect the quality of crystalline.Secondly, NQ was wet-grinded with a HLG-5 nano pulverizer and mechanical process for superfining NQ was investigated as follows:ball mill medium filling rate, material concentration and instrument speed could affect the superfining. These parameters were determined by experiments finding. SEM and particle size measurement revealed that NQ raw material was clubbed crystalline with a size of 20 um. The NQ obtained from the mechanical process above-mentioned was granular crystalline with a size of 200-500nm, which indicated that HLG-5 nano pulverizer had a good grinding result.Thirdly, The drying technology, purity and crystal shape of superfining NQ obtained from the mechanical process were investigated:visual observation and particle size measurement indicated that the product obtained from freeze drying and spray drying had a little water content, good dispersion, and narrow particle size distribution. However, the product obtained from ordinary drying and vacuum drying had serious agglomeration and large particles. IR, EDS, ICP-AES and chemical titration indicated that organic solvent was removed completely and system only introduced a few impurities. XRD and Raman indicated that the product obtained from HLG-5 nano pulverizer had a better crystallinity and crystal form. NQ superfining and drying process above-mentioned could offer reference to the superfining and drying treatment of other materials.