Stability hygroscopicity and

Among other things, it became established that the nature of the structure adopted by a given compound on crystallization would then exert a profound effect on the solid-state properties of that system. For a given material, the heat capacity, conductivity, volume, density, viscosity, surface tension, diffusivity, crystal hardness, crystal shape and color, refractive index, electrolytic conductivity, melting or sublimation properties, latent heat of fusion, heat of solution, solubility, dissolution rate, enthalpy of transitions, phase diagrams, stability, hygroscopicity, and rates of reactions were all affected by the nature of the crystal structure. 

Polymorphs differ in solid crystalline phase structure (crystal packing) but are identical in the liquid and vapor states (5). As such, different polymorphs may exhibit very different properties. In effect, two different polymorphs of the same molecule may be as different in their physicochemical properties as the crystals of two different compounds. Properties such as melting point, solubility, dissolution rate, stability, hygroscopicity, and density can all vary with polymorph. In fact, it is a safe bet that multiple polymorphs will exist of a crys-... 

The solvate is poorly stable and the solvent is easily removed leading to either the original polymorphic form but creating a certain degree of disorder in the crystalline structure or to what is called a desolvate solvate form. In this last case, also named isomorphic desolvate , the desolvated solvate retains the structure of its parent solvated form. The X-ray diffraction patterns look similar between the parent and the daughter forms. In this situation we have the creation of a molecular vacuum which could substantially impact on the stability, hygroscopicity and mechanical characteristics of the DS and finally of the DP. 

The rate of hydrolysis of DMAC is very low, but increases somewhat in the presence of acids or bases. DMAC is a stable compound, but is mildly hygroscopic and desiccation and/or dry nitrogen blanketing of storage vessels are sometimes used to reduce water pick-up. In the absence of water, acids, or bases, DMAC is stable at temperatures up to its hoiling point at atmospheric pressure. Its greater stability enables more economical recovery by distillation relative to that of other similar solvents. 

Nylon (Polyamide) PA is a crystalline plastic and the first and largest consumption of the engineering thermoplastic. This family of TPs are tough, slippery, with good electrical properties, but hygroscopic and with dimensional stability lower than most other engineering types. Also offered in reinforced and filled grades as a moderately priced metal replacement. 

Nitromethylhydantoin is an expl comparable to TNT in its sensitivity to impact. Qc =—448-8 kcal/mole Qf = -99.9kcal/mole. It is slightly hygroscopic, and its stability to heat is inadequate... 

It is an expl, more powerful than TNT (about 133% by Ballistic Mortar), and comparable to Tetryl in sensitivity. Its Vel of Deton is 7420 m/sec at d 1.5g/cc, and 5490m/sec at d l.Og/cc. Qc is about 380kcal/mole. It is practically non-hygroscopic and its thermal stability is satisfactory. Has been used by DuPont Co as a base charge for some detonators Refs I) Beil — not found 2) H. Biltz et al, JPraktChem 142, 193-200 (1935) CA 29, 3652 (1935) 3) Anon, Report on Nitro-... 

The formulation for use in the Swedish Army rifle contained Guncotton 96.2, sol cotton 1.8, resin, a stabilizer and other materials 2.0%. These propints were very stable, nearly hygroscopic, and produced much lower temps than corresponding double-base powders such as Cordite, Ballis-tite, etc. As a result, gun barrel life was lengthened... 

It is an expl, having a ballistic strength of 114% (TNT=100) impact sensitivity-less sensitive than TNT friction sensitivity—no detonations ignition temp—270° practically non-hygroscopic and of satisfactory thermal stability Refs 1) Beil—not found 2) L.F. Fieser et... 

Stabilized by bulky organic cations such as EMI+ or BMI+ [BMI+ = butyl(methyl) imidazolium]. Nitrosomethanide-based ionic liquids are very hygroscopic and immediately absorb water when exposed to air. The experimentally determined melting points vary between —4°C and 35 °C (Figure 40, Table 11), with the BMI+ salts always possessing the lower melting point. ... 

Ellern, Pyrotechnics(1968) Particle Size Determination of Pyrotechnic Compositions (pp 259-61) Heats of Combustion of Elements and Compounds Used in Pyrotechnics (pp 276-80) Measurement of Stability and Reactivity of Pyrotechnic Compositions (pp 291-94) Ignition, Initiation and Decomposition of Pyrotechnic Compositions (pp 294-300) Hygroscopicity and Self-Destructive Interaction (pp 300-304) Survival and Surveillance of Finished Pyrotechnic Items (pp 304-307)... 

The product is a very pale yellow to cream-colored solid. It is hygroscopic and is soluble in liquid ammonia, with limited solubility and stability in acetonitrile, dimethyl sulfoxide, and dimethylformamide. Water or moisture from the air leads to disproportionation, and so the product must be stored under anhydrous... 

Dinitro compd is an expl comparable in sensitivity to impact to TNT it is very hygroscopic and hydrolizable by hot w does not possess good thermaL stability (decomposes... 

It was found that the two samples could not be detonated by any of the std test procedures used at Picatinny Arsenal. The lead salts were non-hygroscopic and possessed the same order of stability as TNT in the 120° Vacuum Stability Test. Because of their insensitivity to initiation, these Pb salts were considered to be unsuitable for practical military applications (Ref)... 

HMX is non-hygroscopic and insoluble in water. It behaves like RDX with respect to its chemical reactivity and solubility in organic solvents. However, HMX is more resistant to attack by sodium hydroxide and is more soluble in 55% nitric acid, and 2-nitropropane than RDX. In some instances, HMX needs to be separated from RDX and the reactions described above are employed for the separation. As an explosive, HMX is superior to RDX in that its ignition temperature is higher and its chemical stability is greater however, the explosive power of HMX is somewhat less than RDX. Some of the properties of HMX are presented in Table 2.16. 

The explosibility of AN with approx 7% rosin was investigated by Hopper (Ref 9), who found that rosin increased the sen si tiv- ity to initiation and rendered the mixt less hygroscopic. The mixt was also satisfactory with respect to stability, brisance and impact sensitiviry, being unaffected in the rifle bullet and pendulum friction tests. Marshall (Ref 23) and Banik(Ref 26) studied the explosibility of Amer FGAN contg 1% petrolatum and 5% kaolin in comparison with Brit FGAN contg... 

Pantothenic acid is relatively labile (185,186). In the dry form, it is hygroscopic and unstable in solution its stability is strongly pH dependent, being greatest at pH 4-5. It is subject to hydrolytic cleavage to pantoic acid and /3-alaninc in more acidic or alkaline solutions. Pantothenic acid is very soluble in water, alcohols, and dioxane, less soluble in diethyl ether and acetone, and insoluble in benzene and chloroform. 

Trinitronaphthalene appears to be a genuine stabilizer for nitrocellulose, a true inhibitor of its spontaneous decomposition. Marqueyrol found that a nitrocellulose powder containing 10 per cent of trinitronaphthalene is as stable as one which contains 2 per cent of diphenylamine. The trinitronaphthalene has the further effect of reducing both the hygroscopicity and the temperature of combustion of the powder. 

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