EFFECTS OF RADIATION ON AIRCRAFT LUBRICANTS AND FUELS. Summary Report No. 2 for December 1, 1956 to November 30, 1957
The objectives of the work reported included the development of radiation-resistant lubricants and a survey of the radiation stability of jet fuels. Aromatic base materials were needed in the lubricant work, and most of these had to be synthesized. Exploratory synthesis evolved alkarvl ethers, alkaryl esters, alkylbenzenes, alkyl diphenyl ethers, and diarylalkanes. Chemical structure was correlated with physical properties and also with oxidation, thermal, and radiation stability. Although esters were inferior, each class had members with good radiation stability. Over-all, the alkyl diphenyl ethers offer the most promise for lubrlcant development. Polymers were also synthesized. These were used in an alkyl diphenyl ether to improve viscosity index and to increase viscosity. Compared to conventional thickeners, alkylated poly( alpha -methylstyrenes) (APAMS) and poly(alkylphenoxyethyl methacryiates) (APEMS) show promise for use in future radiation resistant lubricants. The grease research produced CALRESEARCH 159, a material of enhanced radiation stability. It is a selenide-inhibited alkylbiphenyl gelled with an aromatic salt. Promise of improved products was shown in work on new oils, e.g., tris (phenoxyphenyl)dodecylsilanei on new geliing agents, e.g., sodium N-p- tolylterephthalamate or mixtures of aromatic salts; and on new additives, e.g., N, N'-di-2naphthyl-p-phenylenediamine. Many formulations of various hydraulic fluids were evaiuated before and after irradiation. The alkyl diphenyl ethers looked best in radiation stability and in thermal stability at 700 deg F. CALRESEARCH 216 evolved from the formuiation work. It is an alkyl diphenyl ether inhibited with a selenide and thickened with a poiybutene. Chemical inhibitors lmproved oxidatioa stability both before and after gamma irradiation. Aromatic hydrocarbon additives in MLO 8200 fluid reduced viscosity change and gassing caused by irradiation. This fluid was shown to be usable to about 10/sub 10/ ergs/g C of gamma radiation. Criginal and irradiated aromatic base fluids operated satisfactorily in aircraft piston pumps at 275 deg F. lsothermai bulk modulus was found to decrease markedly in a gasliquid system such as would prevail under irradiation. The alkyl aromatics were found best as base materials for gas turbine oils. Esters, mineral oils, and paiygiycois teated were deficient in radiation or thermal stability. CALRESEARCH 230 was developed in the work; it is a selenide-inhibited alkyi diphenyl ether containing a petroleum bright stock and other additives. The alkyl diphenyl ethers showed good oxidation stability before and after irradiation. Their tendency towards high coking and low lubricity was improved by additives. Irradiation lowered coking in these bases and also in aikylbiphenyls. In all base stocks, foaming increased after irradiation, with or without silicone being present. Coking was reduced by blending with high bolling materials, e.g., bright stocks. Certain oil soluble dyes showed synergism with the bene ficial dialkyl selenides in oxidation tests. The thermal stability of nine jet fuels (five JP-4's, three JP-5's, and an RP-1) was studied in the CFR coker. Original stocks and samples irradiated for three different levels were tested. Low level irradiation (0.8 x 10/sup 10/ ergs/g C) impaired thermal atability. Higher level radiation (8 x 10/sup 10/ ergs/g C) improved thermal stability. An equation was developed by which it was possible to predict increase in viscosity with irradiaiion at any dosage once a single dosage point was known. (auth)
- Research Organization:
- California Research Corp., Richmond, Calif.
- NSA Number:
- NSA-12-007731
- OSTI ID:
- 4352795
- Report Number(s):
- WADC-TR-56-646(Pt. II)
- Country of Publication:
- United States
- Language:
- English
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