DEVELOPMENT OF HIGH TEMPERATURE RESISTANT RUBBER COMPOUNDS. Period Covered: July 15, 1956 to November 30, 1957
Elastomers of potential interest for high-temperature aircraft tires --- including butyl, silicone rubber, heatstabie'' polyurethane, and Viton A---were studied to determine tensile, wire-cord adhesion, and air-permeability properties at temperatures ranging up to 400 or 500 deg F, and properties of interest in tire development, such as internal friction and running temperature. Most promising wire adhesions were obtained with solicone rubber, which retained 63% of the 75 deg F adhesive strength at 450 deg F, compared with 9% for Hevea. Silicone rubber is the most highly permeable to air; Thiokoi ST, Vyram and butyl have the lowest air permeabilities. Nitrogen appears to be the most promising of the unreactive gases to use for inflation of high-temperature tires. Type of sulfur crosslink (mono-, di-, or tetrasulfide) had iittle effect on hightemperature propertaes of Hevea. Gamma-irradiation of vulcanized Hevea improved the high-temperature tensile strength. Balata had lower tensile strength than Hevea over the entire range of 73 to 400 deg F, Vyram N-7700 was about equivalent to Vyram N-5400. Polyether-type polyurethane had 400 deg F tensile strength of 60 psi vs. 515 for the --heat-stable'' polyester type. Teflon resin had a tensile strength of 3825 psi at 73 deg F and 980 psi at 600 deg F. Studies on effects of a 4-hour heat-agng at 400 deg F upon burst pressures of a nylon aircraft tire and of a wire tire are described. It is concluded that a 400 deg F tire will require were tirecord an place of organic fabrics used in present tires. A prototype aircraft tire successfully was constructed from silicone rubber and steel wire tirecord. Coating the wire tirecord and the bead wire with a thin layer of partially cured silicone rubber facilitated fabrication of the beads and plies. Experimental butadiene and acrylic polymers containing functional groups were prepared and their hngh-temperature properties were determined. Carboxyl as the functional group gave better results than hydroxyl or epoxy. Best properties at 400 deg F resulted from using a metal oxide--- particularly magnesium oxide or cadmium oxide ---with epoxy resin to cure the carboxy polymers, enabling 400 deg F tensile strengths as high as 1400 psi to be obtained. The advantages of the metal oxide cure ABSTRACTS were obtained with methacrylate rubber (copolymer of butadiene and methyi methacrylate) by curing with barium hydroxide octahydrate, which gave tensile strengths of 4025 psi at 73 deg F and 960 psi at 400 deg F when used in combi-nation with bis( alpha , alpha - dimethylbenzyl) peroxide. In this manner the advantageous high-temperature properties of the metal oxide cure were realized with improved processability compared with the carboxy polymers. It was found that butadiene copolymers can be vulcanized by heat alone at 500 deg F, a GR-S--carbon black mix giving a tensile of 2450 psi: but this crosslinking could only partially be inhibited. Salicylate esters were the most effective inhibi-tors. (auth)
- Research Organization:
- Firestone Tire and Rubber Co., Akron, Ohio
- DOE Contract Number:
- AF33(616)-3953
- NSA Number:
- NSA-12-007783
- OSTI ID:
- 4352432
- Report Number(s):
- WADC-TR-56-331(Pt.II); AD-1510
- Resource Relation:
- Other Information: Project title: RUBBER, PLASTIC AND COMPOSIT MATERIALS. Task title: COMPOUNDING OF ELASTOMERS. Orig. Receipt Date: 31-DEC-58
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ADHESION
AIR
AIRCRAFT
AMIDES
ARYL RADICALS
BARIUM HYDROXIDES
BUTADIENE
BUTYL RADICALS
CADMIUM OXIDES
CARBAMATES
CHEMICAL REACTIONS
COATING
ELASTOMERS
ETHERS
ETHYL RADICALS
FABRICATION
FAILURES
FRICTION
GAMMA RADIATION
HEATING
HIGH TEMPERATURE
IRRADIATION
LAYERS
MACHINE PARTS
MAGNESIUM OXIDES
METALS
METHACRYLIC ACID
METHYL RADICALS
NITROGEN
NYLON
ORGANIC FLUORINE COMPOUNDS
ORGANIC SULFUR COMPOUNDS
OXIDES
POLYESTERS
POLYETHYLENES
POLYMERS
POLYURETHANES
POROSITY
PREPARATION
PRESSURE
RESINS
RUBBER
SALICYLIC ACID
SILICONES
STEELS
SULFIDES
TEFLON
TENSILE PROPERTIES
TEXTILES
WIRES