Octol

Both RDX and HMX are substantially desensitized by mixing with TNT to form cyclotols (RDX) and octols (HMX) or by coating with waxes, synthetic polymers, and elastomeric biaders. Most of the RDX made ia the United States is converted to Composition B (60% RDX, 40% TNT, 1 part wax added). Composition A5 (RDX 98.5/stearic acid 1.5) and composition C4 (RDX91/nonexplosive plasticizer) account for the next largest uses. HMX is used as a propellant and ia maximum-performance plastic bonded explosives such as PBX 9401 and PBX N5 and the octols (147—150). 

Property Compositio nE Cyclotol 75/75 Octol 75/25 PentoHte 50/50 Earatol 67/23 Amatol 80/20... 

Figure 9-4. The Octol Oligomerization process for producing Os s and Ci2 s and Cis s olefins from n-butenes (1) multitubular reactor, (2) debutanizer column, (3) fractionation tower.

Comparison of Various FNAA Techniques for Assay of Synthetic Octol Samples Precision of Single-Axis Rotation FNAA for Assay of Octol Plant Samples Fast Neutron Activation Analysis for Nitrogen in Explosives by... 

For this particular product, in addition to a decrease in analysis time, a non-destructive method is especially desirable because of other physical tests that are also required on each sample By FNAA, the total nitrogen content of a sample is first detd and then related to compn of the mixture. Since Octols contain no ingredients other than pure TNT (18.50% N) and pure HMX (37.84%), the following linear relationship is derived from the ealed nitrogen content of each ingredient ... 

In Table 2, results are given comparing the three above FNAA techniques for total nitrogen and corresponding HMX content of three synthetic Octol samples containing 70, 60 and 80% HMX respectively. Chemical analysis by extraction is also included as another basis for comparison. An 80/20 Octol (80% HMX) was used as the reference standard for the activation assays... 

Comparison of various FNAA techniques for assay of synthetic Octol samples... 

It is the preferred method where speed is not essential — but when the number of samples to be analyzed is large, multiple sample irradiation on the lucite wheel. with single-axis rotation is used. The precision of this latter technique for six plant samples of Octol is shown in Table 2a. 

In this series each irradiation consisted of six Octol samples, an 80/20 Octol reference standard and a blank vial mounted on the lucite wheel. 

Precision of single-axis rotation FNAA for assay of Octol Plant samples... 

To achieve the desired cast density for Octol of 1.8g/cc it is necessary that the ratio of HMX TNT be 3 1. However, at this ratio the apparent viscosity, or efflux, is strongly dependent on the polymorphic variety of HMX used and on its particle size distribution. In the initial pilot production of Octol (Ref 3) it was found that for the desired efflux of < 15 sec, 60—70% of the solid HMX must consist of the beta-polymorph having particle diameters in the range of 500—800 microns. Such precise control of particle size was not possible at that time and early Octol casts were made at approximately 50 secs efflux. The economical production of Octol with a satisfactorily short efflux time continues to present a problem in loading shells with this expl (Refs 4, 11 29)... 

The expl performance of Octol was generally an improvement over that of Cyclotol. Based on the physical and chemical properties of HMX and RDX the following improvements were observed (Ref 4) ... 

The higher specific gravity of 75/25 Octol can make the bursting charge of a shell containing it appreciably heavier than that of the same shell... 

The improvement In penetration and damage produced by 105mm shaped charges of Octol over that of Composition B or TNT having the same charge geometry were further documented (Ref 10) ... 

Octol, at least at shorter standoffs, gives about 10% deeper penetrations than Composition B, but the latter is better at long standoffs since it seems to lessen perturbance of the shaped-charge jet... 

In view of the lower impa ct sensitivity of HMX, the trend for Octol is most unexpected and was later (Refs 11, 33 34) shown to be caused by surface effects. The apparently greater sensitivity of Octol can be mitigated or reversed by control of the particle size distribution and by changes in the surface treatment of the HMX used in Octol compns... 

Octol shows a small increase in stability over that of Cyclotol at higher temps which may be sufficient to overcome the marginal stability of Cyclotol in specific cases... 

The 7—15% improvement in expl performance of Octol over that of Cyclotol is achieved at a 250—500% increase in cost (depending on purity), which has to be matched against the overall gain... 

Expls similar to Octol, viz, HMX/TNT/Al/Wax, 47/31/22/3-5, have been prepd and tested for air-blast and underwater effectiveness. The performance improvements that resulted (1—2%) over Cyclotol analogs were not considered worth the additional cost (Ref 4), and other expls are generally exploited for such applications... 

The purification of TNT to remove DNT and other exudation-causing impurities increased the brittleness of TNT-based cast expls. However, since DNT was known to be an effective plasticizer of NC in propint formulations, it was found that Octol + 0.45% plasticized high viscosity NC and Octol +... 

Another variable peculiar to composite, cast expls that must be controlled to achieve precision penetration and predictable destructiveness is the variation in density and compn of the expl within the warhead. In melt-loading operations with Octol, problems occur which do not arise in meltloading with TNT, Composition B, or Cyclotol. Specifically, there is a large amount of settling of HMX crystals while the charge is still molten. 

The superior shaped-charge performance of Octol, as indicated previously, is limited by perturbances of the detonation wave front that af-... 

Thus it can be seen that continuous improvements in defensive armor require ever more sophisticated expl technology for its defeat, which in turn results in the escalation of military budgets for conventional warfare. The increased cost of HMX relative to other expls has caused continuing efforts to reduce manufg costs, to improve and more precisely evaluate its effectiveness. In a recent, very painstaking comparison of Cyclotol and Octol, the effects of changes in the compn, density, and diameter of the expl charge upon detonation velocity were determined. HMX was found more ef-... 

A linear relationship between Chapman-Jouguet pressure and density was confirmed for Cyclotol and Octol (Ref 28). Despite the near-equal performance of RDX and HMX at equal densities there appears to be no economical way of making the density of RDX equal to the cast density of HMX. Dinitrobenzene (DNB) has been evaluated as an economical or emergency substitute for TNT but charges prepared with DNB gave somewhat poorer performance than... 

Table 4 details the physical, chemical and expl properties of Octol Type I and Type II... 

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